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Speaker 1: What are the greatest mysteries in science? Surely up near

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Speaker 1: the top of the list have to be questions like

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Speaker 1: how did the universe begin? Or how will it all end?

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Speaker 1: Or how can anyone understand organic chemistry? These are all

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Speaker 1: amazing questions, and I'd love to know the answers to

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Speaker 1: any of them. But in my opinion, the biggest mysteries

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Speaker 1: are the most personal ones, the questions we have about

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Speaker 1: why we are here, how we came to be, who

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Speaker 1: we are. The answers to those questions are the context

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Speaker 1: of our existence, and they can't help but shape the

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Speaker 1: way we live and guide our future. So that's why

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Speaker 1: the history of humanity's evolution has always been so fascinating

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Speaker 1: to me, because it's our story. Where did humanity originate?

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Speaker 1: How did we spread around the globe? What catastrophes did

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Speaker 1: we barely survive? And what marks did that leave in

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Speaker 1: our genetic heritage? Why are we so smart or why

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Speaker 1: aren't we much smarter? What happened to all of our

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Speaker 1: hominid cousins? And what was it like to live on

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Speaker 1: an earth with several closely related, interbreeding, intelligent communities. We

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Speaker 1: don't have the answers to all of those questions, but

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Speaker 1: modern techniques are beginning to flesh out some of the

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Speaker 1: biggest blank spots we have in our history and to

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Speaker 1: help us grapple with the other side of that question,

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Speaker 1: what does the future hold? Is humanity fixed or still changing?

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Speaker 1: Has evolution had it to day or are we still

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Speaker 1: evolving today? On the podcast, we'll chat with doctor Scott

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Speaker 1: Solomon about all of that, and of course about aliens.

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Speaker 1: Welcome to Daniel and Kelly's Extraordinary Evolving Universe.

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Speaker 2: Hi.

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Speaker 1: I'm Daniel. I'm a particle physicist, but I love biology

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Speaker 1: and biologists, well maybe one or two in particular.

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Speaker 3: I'm Kelly Wader Smith, parasitologist. And you are singing a

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Speaker 3: different tune than you did the other day, Daniel, because

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Speaker 3: the other day you told me you weren't a huge

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Speaker 3: fan of biology. So I'm glad to see you're coming around.

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Speaker 1: Well, it may be that my biologist's wife heard that

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Speaker 1: episode and so we had a conversation.

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Speaker 3: Good good. I'm glad. My cartoonist husband the other day

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Speaker 3: when I told him that there was a physics topic

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Speaker 3: I wasn't super excited about. He was like, you are

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Speaker 3: exhibiting a distinct lack of curiosity. I was like, all right, fine,

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Speaker 3: So anyway, our partners are keeping us in line.

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Speaker 1: I love the wealth of topics that anybody can dive

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Speaker 1: into because there's so many things to be curious about

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Speaker 1: in this universe. And that's why we call it the

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Speaker 1: podcast the Extraordinary Universe, right, because it's filled with amazing

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Speaker 1: things to learn about, from our own particular history to

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Speaker 1: whether antelopes do string theory.

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Speaker 3: Yeah, I totally agree. One of the things that stresses

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Speaker 3: me out about having a shortened lifespan is that I

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Speaker 3: will never get to know about all the topics that

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Speaker 3: I want to know about. There's so many cool things

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Speaker 3: I could be learning about, but I don't have time

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Speaker 3: to read about all of them. But on the show

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Speaker 3: get through a lot of them.

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Speaker 1: So that's my question for you. Actually, So in an

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Speaker 1: alternative universe where you got to pick a different kind

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Speaker 1: of science to do instead of being a parasitologist, you

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Speaker 1: would have been.

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Speaker 3: A oh my gosh, that is really hard. I think

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Speaker 3: there's a world where I could have really enjoyed being

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Speaker 3: a historian or being someone who like spent all day

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Speaker 3: digging in the dirt. Although, as we'll hear later in

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Speaker 3: the episode that requires a degree of patience that I

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Speaker 3: might not have realized when I was excited about those

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Speaker 3: ideas when I was younger.

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Speaker 1: But that makes sense to me because you always do

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Speaker 1: a deep dive in the research of asking you a question.

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Speaker 1: You're like, I read three books about this and ten

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Speaker 1: pages of notes, so I'm like, WHOA.

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Speaker 3: Well, I really like to feel confident before I open

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Speaker 3: my mouth, so I'm quiet a lot of times when

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Speaker 3: I don't feel confident. But I don't know, just any

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Speaker 3: job that involves a lot of time reading and trying

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Speaker 3: to understand something deeply. I think there's lots of things

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Speaker 3: I could have done with my life that I really

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Speaker 3: would have enjoyed, but I only have this one lifetime.

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Speaker 3: What about you?

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Speaker 1: Ooh, that's a good question.

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Speaker 3: It's your question, Daniel. You don't get to say that's

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Speaker 3: a great question when it's your question.

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Speaker 1: It's a way for me to delay giving an answer because.

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Speaker 3: I have one, got it.

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Speaker 1: You know, everybody else in my family is a computer

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Speaker 1: scientist of some sort, and I actually have a degree

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Speaker 1: in computer science, and so I couldn't decide between physics

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Speaker 1: and computer science, and I took both paths until basically

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Speaker 1: I applied to grad school in both areas, and then

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Speaker 1: I had to make a decision. So I chose physics

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Speaker 1: because I wanted to be a tool user instead of

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Speaker 1: a tool builder. But I still love building tools for

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Speaker 1: other people to use. And so in some other universe,

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Speaker 1: I'm a programmer, you know, maybe working on scientific tools,

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Speaker 1: maybe something else, who knows. But I love writing programs,

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Speaker 1: and so I could have just done that as a

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Speaker 1: career rather than having it be like the day to

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Speaker 1: day work of my science career.

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Speaker 3: That's pretty cool that, like, if you could rewind and

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Speaker 3: do a completely different career, the other career you would

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Speaker 3: have done is something that you get to do a

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Speaker 3: lot of in your day to day life. That suggests

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Speaker 3: to me that you have really, like made some good

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Speaker 3: choices in your life.

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Speaker 1: Yeah. Except if I did the other career, I've probably

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Speaker 1: making a lot more money.

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Speaker 3: Oh yeah, yeah, Yeah, I also did not pick a

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Speaker 3: lucrative career. Most people don't care about what's happening to

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Speaker 3: brain infecting parasites on little fishies. But what are you

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Speaker 3: gonna do?

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Speaker 1: Yeah, but you're right, and I feel lucky that the

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Speaker 1: day to day work of my job does connect with

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Speaker 1: my other interests, and the people who work for me

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Speaker 1: end up going off to make a lot more money

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Speaker 1: than I do working for Google or Facebook or whatever.

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Speaker 1: So yeah, it worked out pretty well. And I've just

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Speaker 1: love that there's so many things to be excited about,

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Speaker 1: and so many ways life could go, and so many

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Speaker 1: things to be curious about. And I love that our

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Speaker 1: listeners seem to share that that really resonates with them,

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Speaker 1: because they seem to be curious about all sorts of topics,

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Speaker 1: from the details of quantum gravity all the way to

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Speaker 1: how are we here and what is the history and

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Speaker 1: future of humanity?

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Speaker 3: And I have been loving that we've been getting more

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Speaker 3: biology questions lately, and today's episode is essentially the answer

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Speaker 3: to a wonderful biology question that we got from our

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Speaker 3: listener named Seth. So let's go ahead and listen to

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Speaker 3: Seth's awesome question before we introduce the guest we brought

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Speaker 3: on the show to answer the question.

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Speaker 4: Hi, Daniel and Kelly, I have some questions related to

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Speaker 4: human evolution. Are we slowly evolving as a species as

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Speaker 4: we have in the past. If we are, in what

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Speaker 4: ways are we evolving and what is driving that evolution?

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Speaker 4: Are there pockets or groups of people evolving at different

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Speaker 4: rates where natural selection may still play a large role,

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Speaker 4: What changes might arise in humans from future evolution, And finally,

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Speaker 4: what might evolution look like in a future society living

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Speaker 4: on another planet.

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Speaker 1: Thanks love the question. The only complaint I have about

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Speaker 1: it is that you don't need to apologize at the

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Speaker 1: end for asking questions. We love questions. Send us as

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Speaker 1: many as you have, really no limits. Please write to

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Speaker 1: us with your questions to questions at Daniel and Kelly

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Speaker 1: dot org, not Daniel and Kelly dot com. That's the

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Speaker 1: wedding website for a very nice looking couple.

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Speaker 3: That's right. That's right. So it turns out I have

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Speaker 3: a really good friend named Scott Solomon who wrote a

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Speaker 3: book on whether or not humans are still evolving, and

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Speaker 3: he's just wrapped up his second book about what human

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Speaker 3: evolution might look like when humans move out and become interplanetary.

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Speaker 3: So today we're going to have Scott on the show

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Speaker 3: to answer the first set of questions about human evolution

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Speaker 3: here on Earth.

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Speaker 1: Yeah yeah, and.

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Speaker 3: We'll have him back on the show some other time

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Speaker 3: to talk about his next book and the questions about

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Speaker 3: the future of human evolution. When that book becomes available.

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Speaker 1: Future ya Future Yay.

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Speaker 3: So let's go ahead and bring Scott on the show.

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Speaker 3: Scott Solomon is a teaching professor in the Department of

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Speaker 3: Biosciences at Rice University. He's the author of Future Humans

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Speaker 3: Inside the Science of Our Continuing Evolution, and his upcoming book,

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Speaker 3: tentatively entitled Becoming Martian How Living in Space will Change

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Speaker 3: Our Bodies and Minds, is coming out through MIT Press

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Speaker 3: in late twenty twenty five early twenty twenty six. He

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Speaker 3: hosts the podcast Wild World with Scott Solomon, taught What

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Speaker 3: Darwin Didn't know the Modern science of Evolution for the

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Speaker 3: Great Courses, and you can check out his streaming series

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Speaker 3: Becoming Martian on Curiosity stream. And that's like a small

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Speaker 3: subset of many things that my good friend Scott Solomon does.

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Speaker 3: He's incredible. We had to just take a couple so anyway,

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Speaker 3: welcome to the show.

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Speaker 2: Scott, Hey, Kelly, Hey Daniel.

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Speaker 1: Can you also leap buildings in a single bound?

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Speaker 5: I wish, Oh my gosh, maybe I'll evolve to be

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Speaker 5: able to in the future.

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Speaker 3: Right there, we can hit an interesting misconception. Do humans evolve, Scott,

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Speaker 3: or is it populations and species that.

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Speaker 5: Evol Well, humans as a species can evolve, but yeah,

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Speaker 5: individual people, like any individual organism, can maybe change a

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Speaker 5: little bit. We like to think we can improve ourselves

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Speaker 5: over time, but we wouldn't call that evolution.

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Speaker 1: Even if you're bitten by a radioactive spider.

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Speaker 5: Well, that's a change I keep hoping for. But I'm

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Speaker 5: going for radioactive ant ideally, but still not evolution unless

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Speaker 5: your kids also inherit those extraordinary abilities.

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Speaker 3: Yep, all right, I mean you go lots of dangerous places.

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Speaker 3: Is that kind of like the goal that some radioactive

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Speaker 3: animal will get.

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Speaker 5: You searching everywhere for the radioactive ant to bite me?

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Speaker 2: Yeah, I'm still looking.

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Speaker 5: I was just an Antarctica, and contrary to what you

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Speaker 5: might imagine, there are no ants in Antarctica.

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Speaker 2: So well, at least not that we found.

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Speaker 3: Yeah, you know, there are no Kelly Wienersmith's in Antarctica either,

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Speaker 3: because it is way too cold. But you jumped into

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Speaker 3: the water in Antarctica.

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Speaker 2: I did. It was crazy, Yes.

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Speaker 3: I would describe it as crazy.

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Speaker 1: I would describe that as poor judgment.

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Speaker 5: Well, there was a diver in a dry suit perched

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Speaker 5: on the edge of the platform you dive from, prepared

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Speaker 5: to basically drag your lifeless body out of the water.

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Speaker 5: So I felt like they had all the contingencies covered.

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Speaker 3: All right, But you've already had your kids, and so

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Speaker 3: in terms of evolution, you've like checked that box. Good move.

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Speaker 3: So you've mentioned that you are super into ants already.

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Speaker 3: So as a person whose PhD was in ant work

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Speaker 3: and evolutionary questions, what got you interested in studying human

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Speaker 3: evolution in particular?

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Speaker 5: Yeah, so I've been interested in human evolution for a

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Speaker 5: very long time. Actually, I took a class as a

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Speaker 5: college student in anthropology. I first really was introduced to

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Speaker 5: human evolution and what we do and don't know about it,

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Speaker 5: and I was just absolutely fascinated and actually considered going

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Speaker 5: into the field of paleoanthropology, which is the field where

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Speaker 5: people are studying human evolution.

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Speaker 2: But I ended up going a different route.

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Speaker 5: I was actually pre med at the time and thought

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Speaker 5: I was going to be a doctor, mainly because I

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Speaker 5: didn't know that there were a lot of other options

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Speaker 5: for people who like biology and want to have a career,

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Speaker 5: and so I did the pre med thing.

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Speaker 1: You were like, doctor, or I can work at a zoo.

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Speaker 1: Those are the options.

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Speaker 2: Yeah, right, Well, yeah, exactly.

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Speaker 5: Yeah, Yeah, it's just I didn't have role models in

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Speaker 5: my life of people who were doing other kinds of

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Speaker 5: biology careers.

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Speaker 1: I guess were your parents' academics or not.

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Speaker 5: Yeah, so my dad was a professor, but an accounting professor,

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Speaker 5: so quite different. I thought I was going in a

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Speaker 5: very different direction by going into biology, and then it

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Speaker 5: turns out that I ended up having an academic career

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Speaker 5: very much like his in some ways so different.

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Speaker 1: After all, you're both wrangkling spreadsheets and email. But he's

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Speaker 1: probably not jumping into the water in Antarctica.

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Speaker 2: That's true. That's true.

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Speaker 1: Yeah, counting is a little safer as a profession indeed.

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Speaker 2: Indeed, yes, yes, but.

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Speaker 1: What you say really resonates with me thinking about anthropology.

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Speaker 1: I remember hearing about that field and thinking like, wow,

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Speaker 1: this is it. I mean, all of science is some

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Speaker 1: kind of attempt to understand the universe and our context

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Speaker 1: of our lives, but like anthropology is literally like what

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Speaker 1: is the history? How did we get here? Why are

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Speaker 1: we here? In terms of like why are we who

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Speaker 1: we are? So absolutely I think that's it's like, yea

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Speaker 1: one of the most fascinating questions in science.

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Speaker 5: No, exactly, I mean, I've always been fascinated by these

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Speaker 5: big idea questions like who are we, where do we

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Speaker 5: come from?

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Speaker 2: And where are we headed? Right, And that's what the

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Speaker 2: stuff is all about.

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Speaker 5: So yeah, I took a few twists and turns in

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Speaker 5: my career, and as you mentioned, Kelly, I ended up

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Speaker 5: for my PhD research studying ants, which seems like it

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Speaker 5: has nothing to do with human evolution, except that ants

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Speaker 5: in some ways are sort of similar to human right,

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Speaker 5: they have like complex societies. And the answer that I

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Speaker 5: was studying leafcutter ants they grow their own food, they

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Speaker 5: have agriculture, and they manage disease outbreaks, and they do

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Speaker 5: all these sort of complicated things that we normally associate

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Speaker 5: with people. And so, in a sort of strange way,

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Speaker 5: studying ants helped me eventually to get back to thinking

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Speaker 5: about people, because I knew that ants never stopped evolving, right,

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Speaker 5: It's very clear from our studies of ants that they

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Speaker 5: have evolved and are evolving and expect them to continue evolving.

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Speaker 5: So why not people? And that got me to think

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Speaker 5: as a young faculty member. It actually the question came

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Speaker 5: to me as actually a question I asked my students.

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Speaker 5: I was teaching a class, an introductory biology class, and

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Speaker 5: we were learning about evolution, and I just said to

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Speaker 5: the students, well, do you think humans are still evolving?

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Speaker 5: And you know, that was a question that clearly struck

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Speaker 5: a chord with my class. They had a lot of

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Speaker 5: thoughts about that. They had their own questions. It was like,

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Speaker 5: you know, if you're a professor, right, you guys know,

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Speaker 5: like you get your students talking, that's right, that's what

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Speaker 5: you want to do. And so I was like, oh,

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Speaker 5: this is an interesting topic. I wonder what we really

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Speaker 5: know about it. And that led me down this path

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Speaker 5: of eventually researching and writing a whole book on the

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Speaker 5: topic of whether humans are still evolving and if so.

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Speaker 1: How how hard is it to make that kind of

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Speaker 1: transition professionally? I mean, if you were like known in

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Speaker 1: the ant world and you published on ants and you

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Speaker 1: can get ant grants, is it then hard to be

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Speaker 1: taken seriously in another field? I mean, I know, in physics,

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Speaker 1: for example, we're so niche that like, if you do

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Speaker 1: collider physics and then you write a grant proposal on

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Speaker 1: you know, cosmic ray physics, They're like, who is this guy?

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Speaker 1: He knows nothing? Yeah? Right, does it to make that

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Speaker 1: kind of leap.

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Speaker 2: Yeah, I mean I think it's interesting.

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Speaker 5: I guess the challenge for me was that if you

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Speaker 5: look at a lot of popular science, often it's either

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Speaker 5: written by somebody who was writing about their own field, right,

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Speaker 5: and we're used to that, or somebody who isn't necessarily

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Speaker 5: a scientist themselves, but they're writing about a particular topic

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Speaker 5: that they've researched. And I was trying to do something

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Speaker 5: that was sort of in between those two, right, and Kelly,

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Speaker 5: I mean you've done, you know, very similar things in

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Speaker 5: your career as well, right, where you sort of have

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Speaker 5: a certain amount of expertise that you can apply to

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Speaker 5: the thing that you're researching and writing about, but you're still,

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Speaker 5: at the end of the day an outsider in this

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Speaker 5: very particular field that you're researching and writing about. So

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Speaker 5: I found the transition to be, for myself kind of straightforward,

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Speaker 5: because you know, we are used to talking to one

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Speaker 5: another about research that is not exactly what we work on.

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Speaker 5: I mean, we all have conversations with our colleagues and

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Speaker 5: go to meetings and it's just sort of like that.

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Speaker 5: But you have to kind of encourage people to answer

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Speaker 5: questions in a way that is a little different from

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Speaker 5: how you would speak to you know, your peers, which

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Speaker 5: of course you guys know very well because it's what

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Speaker 5: you do here on the podcast. It's a lot of fun,

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Speaker 5: it is, it is.

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Speaker 1: It's one of my favorite side benefits of doing the

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Speaker 1: podcast is we'll be working on an episode about, you know,

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Speaker 1: how galaxies formed, and I'm like, well, I never took

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Speaker 1: a class on that. Let me go learn about it. It's

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Speaker 1: like an excuse to learn something about it and go

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Speaker 1: talk to the experts and digest it. Yeah, it's a

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Speaker 1: lot of fun.

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Speaker 2: Yeah.

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Speaker 3: The other day, I was embarrassed to realize that I

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Speaker 3: didn't know why the Y chromosome is smaller than the

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Speaker 3: X chromosome, and I was like, oh, I need to

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Speaker 3: explain that on a show. So I guess I'm spending

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Speaker 3: four hours reading about that and it ended up being great.

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Speaker 3: And also my insecurities are slowly going away something. Oh

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Speaker 3: I didn't know that, but now I know that anyway.

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Speaker 5: Well, and I think partly like I'm sure you've both experiences.

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Speaker 5: In teaching, university classes were often asked to teach something

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Speaker 5: that is a little outside or a lot outside of

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Speaker 5: our own research areas, and so, yeah, we have to

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Speaker 5: learn as much as we can about it so that

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Speaker 5: we can explain it to students and keep.

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Speaker 2: Ahead of them. Yeah, so we do that, right.

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Speaker 5: I think it's just a slightly different way. I mean, Daniel,

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Speaker 5: you've done this too, right, So, like, I find it

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Speaker 5: to be kind of a natural thing to do. I

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Speaker 5: think maybe it looks weird from the outside to certain people.

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Speaker 2: I don't know.

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Speaker 5: I don't know if it does, but I really enjoy it.

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Speaker 5: Like you said, it's fun to explore topics that are

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Speaker 5: not the things that we know are always reading about

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Speaker 5: and doing and talking about on a daily basis.

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Speaker 3: Yeah, so let's back up and let's get into the

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Speaker 3: meat of the content of the book. So let's just

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Speaker 3: start with like a simple definition of like what is

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Speaker 3: evolution and how do you go about measuring evolution and

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Speaker 3: like showing that it's happening.

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Speaker 5: Yeah, So biologists define evolution as change over generations, and

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Speaker 5: I guess specifically we these days define evolution and measure

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Speaker 5: it by talking about evolution as change in allele frequencies

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Speaker 5: over generation. So an allele is just a version of

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Speaker 5: a gene. So to give a like overly simplistic. Example,

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Speaker 5: you can have a gene for hair color, and the

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Speaker 5: different alleles would be like an allele for brown hair,

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Speaker 5: an allele for black hair, and allele for blonde hair,

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Speaker 5: for red hair, et cetera. So how common each of

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Speaker 5: those alleles is in a population. If that changes over time,

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Speaker 5: if they either become more common or less common, then

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Speaker 5: we say evolution has happened. And so that's something that

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Speaker 5: is very quantifiable. It's something we can go out and

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Speaker 5: look for in a population and say, look, this allele

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Speaker 5: has become more common, it's become less common. The next question,

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Speaker 5: of course is why. But just whether or not evolution

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Speaker 5: has taken place is really just as simple as is

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Speaker 5: this allele or the trait that it codes for changing

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Speaker 5: in how common it is?

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Speaker 1: Isn't there always change happening just due to randomness? I mean,

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Speaker 1: if you measured like the fraction of the population that

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Speaker 1: had brown hair, even if there wasn't large scale change happening,

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Speaker 1: it'd be going up and down. This noise in that measurement, right,

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Speaker 1: is there like a threshold beyond But you say, okay,

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Speaker 1: this is meaningful change and this is statistical noise.

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Speaker 5: Yeah, so we actually have an equation that we can

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Speaker 5: use to measure whether there has been significant change from

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Speaker 5: one generation to the next. It's called the Hardy Weinberg

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Speaker 5: equilibrium equation, and we can measure it. The key thing

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Speaker 5: here is that it has certain assumptions, and the assumptions

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Speaker 5: actually are sort of the thing that man makes it

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Speaker 5: most interesting, I would say, because as you point out,

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Speaker 5: we actually almost never find that a population is not evolving,

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Speaker 5: is not changing in allele frequencies. So the only ways

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Speaker 5: that it would not be changing where if a set

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Speaker 5: of five very strict assumptions are in fact taking place.

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Speaker 5: And those assumptions are that everybody has equal chances of survival,

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Speaker 5: not just chances, equal actual outcomes of survival. There's completely

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Speaker 5: random mating, So who's mating with whom? It's all completely random.

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Speaker 1: That sounds like an interesting society.

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Speaker 5: Yes, exactly right, right, Well, it gets even more implausible

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Speaker 5: an infinite population size or a near infinite population size.

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Speaker 5: Good luck with that, no movement. Nobody's allowed to move around.

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Speaker 5: Everybody has to stay in the same geographical location.

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Speaker 1: Then how a You're going to mate with a random

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Speaker 1: person in this infinite society If you can't exactly exactly right,

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Speaker 1: exactly even assign a mate in China. Oops, well I

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Speaker 1: can't go there.

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Speaker 2: So.

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Speaker 5: You've got it exactly right. And then the last one

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Speaker 5: is no mutation, so no genetic changes can pop up spontaneously.

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Speaker 5: And of course the point here is that we know

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Speaker 5: that all of those are constantly taking place in any

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Speaker 5: real population, whether it's humans or any other species. So

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Speaker 5: because of that, we expect that there's always going to

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Speaker 5: be evolution taking place, and that is in fact what

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Speaker 5: we see.

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Speaker 1: I think there's also a sometimes disconnect between the public

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Speaker 1: conception of a topic and the scientific use of the words.

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Speaker 1: So when you say evolution, you just defined it very crisply,

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Speaker 1: But when the public here is evolution, I think they

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Speaker 1: mean big changes over a long time, Like, you know,

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Speaker 1: we used to have common ancestors with apes and chimpanzees

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Speaker 1: and everything on earth, And so can you help us

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Speaker 1: disentangle like the difference between macro evolution and micro evolution?

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Speaker 1: And you know, I often see on social media creationists

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Speaker 1: are admitting like, Okay, micro evolution happens, but macro evolution

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Speaker 1: is nonsense. Yeah, is there an important scientific distinction there?

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Speaker 5: Yeah, exactly, So we have this kind of historical distinction

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Speaker 5: that we've made between micro and macro evolution, And basically

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Speaker 5: the difference between them is that microevolution is any change

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Speaker 5: that is happening within a species, and it's all the

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Speaker 5: things that we were just talking about, mutations, violation of

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Speaker 5: random mating, or individuals moving around that we can get

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Speaker 5: into all of those types of things. Macro evolution is

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Speaker 5: evolutionary changes at the species level or above. And so

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Speaker 5: the question then becomes, can we explain macro evolution through

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Speaker 5: the processes that we understand very well of micro evolution,

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Speaker 5: And I think there's still ongoing work in doing that,

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Speaker 5: but I think the short answer is yes, we can. Right,

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Speaker 5: we can look at how new species come into existence,

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Speaker 5: and we can point to the microevolutionary processes that are

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Speaker 5: giving rise to the evolution of a new species. And

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Speaker 5: then once you've got different species, then of course there

440
00:20:56,400 --> 00:20:58,760
Speaker 5: are sort of other processes that can take place over

441
00:20:58,880 --> 00:21:01,240
Speaker 5: long periods of time that can lead to those sort

442
00:21:01,240 --> 00:21:03,639
Speaker 5: of large scale patterns that we see, like you know,

443
00:21:03,760 --> 00:21:06,919
Speaker 5: increases in body size and like dinosaurs and things like that.

444
00:21:06,960 --> 00:21:11,000
Speaker 5: Those are macroevolutionary trends. But at the end of the day,

445
00:21:11,040 --> 00:21:15,119
Speaker 5: we can boil everything down to those microevolutionary processes that

446
00:21:15,119 --> 00:21:17,560
Speaker 5: are operating within a particular species.

447
00:21:17,880 --> 00:21:21,960
Speaker 3: On the topic of popular misconceptions about evolution, I think

448
00:21:21,960 --> 00:21:24,760
Speaker 3: that when people in the general public talk about evolution,

449
00:21:24,840 --> 00:21:27,640
Speaker 3: they also sort of imply a value judgment, like, when

450
00:21:27,680 --> 00:21:32,520
Speaker 3: evolution is happening that always results in improvement? Is that true?

451
00:21:32,880 --> 00:21:34,880
Speaker 5: It is not true, And I agree with you, Kelly,

452
00:21:34,960 --> 00:21:37,800
Speaker 5: I think that is a common misconception. Yeah, I mean

453
00:21:37,800 --> 00:21:40,040
Speaker 5: we have this notion of progress, right, that like, every

454
00:21:40,119 --> 00:21:43,880
Speaker 5: time evolution is happening, it's making a species better. And

455
00:21:44,200 --> 00:21:47,240
Speaker 5: basically the way that we would typically talk about this

456
00:21:47,320 --> 00:21:50,720
Speaker 5: in you know, evolutionary biology is natural selection.

457
00:21:51,040 --> 00:21:53,560
Speaker 2: Is one of the mechanisms of microevolution.

458
00:21:54,000 --> 00:21:56,920
Speaker 5: Natural selection, of course, this is what Darwin figured out, right,

459
00:21:57,280 --> 00:22:00,480
Speaker 5: and that is the process that makes a specie better

460
00:22:00,560 --> 00:22:04,160
Speaker 5: adapted to its environment. So in that sense you can

461
00:22:04,200 --> 00:22:07,280
Speaker 5: see it as a kind of progress perhaps, But the

462
00:22:07,440 --> 00:22:11,680
Speaker 5: other mechanisms of evolution that can change allele frequencies, they

463
00:22:11,680 --> 00:22:14,280
Speaker 5: do not necessarily. In fact, they do not we would

464
00:22:14,280 --> 00:22:17,080
Speaker 5: not expect them to make a species better adapted to

465
00:22:17,160 --> 00:22:19,920
Speaker 5: its environment. So just getting like, you know, Daniel, you're

466
00:22:20,040 --> 00:22:22,399
Speaker 5: saying about like what about just random changes and an

467
00:22:22,400 --> 00:22:25,800
Speaker 5: allele becoming more or less common. Absolutely, that can happen,

468
00:22:25,840 --> 00:22:28,160
Speaker 5: And of course you wouldn't expect that randomness to make

469
00:22:28,160 --> 00:22:32,040
Speaker 5: a species better at living in its environment. So those

470
00:22:32,119 --> 00:22:34,520
Speaker 5: changes do not lead to what we sort of might

471
00:22:34,600 --> 00:22:37,000
Speaker 5: look at and call progress or improvement.

472
00:22:37,560 --> 00:22:39,560
Speaker 1: And it's not hard to think of an example of

473
00:22:39,600 --> 00:22:43,520
Speaker 1: a random natural selection. Say, for example, there's a supernova

474
00:22:43,640 --> 00:22:46,960
Speaker 1: that sends in incredible amount of radiation towards our solar

475
00:22:46,960 --> 00:22:50,080
Speaker 1: system and kills everybody on one half of the planet

476
00:22:50,240 --> 00:22:52,800
Speaker 1: instantly and the other half are protected by the Earth.

477
00:22:53,240 --> 00:22:56,840
Speaker 1: Doesn't make the people who survived better or even better

478
00:22:56,880 --> 00:22:59,520
Speaker 1: adapted at living, right, They're just like flip a coin.

479
00:22:59,560 --> 00:23:02,280
Speaker 2: They have to survive, yeah exactly.

480
00:23:02,440 --> 00:23:05,040
Speaker 1: It sort of puzzles me sometimes that people think that

481
00:23:05,200 --> 00:23:07,320
Speaker 1: things that survive are always better, or the things that

482
00:23:07,359 --> 00:23:09,840
Speaker 1: propagate into the future always better. Like every time I

483
00:23:09,880 --> 00:23:12,320
Speaker 1: get an upgrade on my iPhone, I'm like, man, this sucks,

484
00:23:12,960 --> 00:23:17,480
Speaker 1: you know, it's a pretty common experience. Or I'd be like, man,

485
00:23:17,600 --> 00:23:19,520
Speaker 1: the good old days were better.

486
00:23:19,640 --> 00:23:21,800
Speaker 2: Yeah. Change is not always good.

487
00:23:21,720 --> 00:23:25,200
Speaker 5: Exactly right, It can just be changed, yeah, yeah exactly.

488
00:23:25,560 --> 00:23:25,960
Speaker 2: Yeah.

489
00:23:26,160 --> 00:23:28,480
Speaker 5: Yeah, we have a name for this process, right, So

490
00:23:28,960 --> 00:23:32,880
Speaker 5: in biology, the process of this kind of random fluctuation

491
00:23:33,560 --> 00:23:36,760
Speaker 5: in allele frequencies we call genetic drift. So the idea

492
00:23:36,800 --> 00:23:39,440
Speaker 5: is that the frequency of an allele is just drifting

493
00:23:39,560 --> 00:23:42,080
Speaker 5: up or drifting down over time, and it's hard to

494
00:23:42,119 --> 00:23:44,840
Speaker 5: predict because it's random. Right, If something is getting more common,

495
00:23:44,880 --> 00:23:47,560
Speaker 5: it's not because it's better in some way, it's just

496
00:23:47,640 --> 00:23:51,600
Speaker 5: because of random change. And we actually see that operating

497
00:23:51,960 --> 00:23:55,800
Speaker 5: all the time in species, especially in small populations, where

498
00:23:55,800 --> 00:23:58,040
Speaker 5: it can be a pretty powerful agent of change.

499
00:23:58,160 --> 00:23:59,960
Speaker 3: All right, so I think we should dig into that

500
00:24:00,160 --> 00:24:01,920
Speaker 3: topic a little bit more, and when we get back,

501
00:24:02,080 --> 00:24:04,000
Speaker 3: Scott Solomon is going to tell us about whether or

502
00:24:04,040 --> 00:24:23,120
Speaker 3: not we can see genetic drift happening in humans. And

503
00:24:23,200 --> 00:24:26,320
Speaker 3: we're back. So Scott Solomon was telling us about genetic drift,

504
00:24:26,320 --> 00:24:28,600
Speaker 3: which is sort of random changes in a little frequencies

505
00:24:28,640 --> 00:24:31,320
Speaker 3: over time. And so, Scott, is this our first example

506
00:24:31,320 --> 00:24:33,840
Speaker 3: of evolution happening in humans? Do we see this happening

507
00:24:33,960 --> 00:24:34,680
Speaker 3: in our species?

508
00:24:35,119 --> 00:24:35,359
Speaker 2: Yeah?

509
00:24:35,400 --> 00:24:38,160
Speaker 5: So, actually, there are some interesting examples of genetic drift

510
00:24:38,240 --> 00:24:41,800
Speaker 5: operating in humans. And one of the I think really

511
00:24:42,000 --> 00:24:46,040
Speaker 5: interesting examples is from an island in the Pacific, the

512
00:24:46,160 --> 00:24:50,879
Speaker 5: island of pingalap It's called pingalap Atoll, and this is

513
00:24:50,960 --> 00:24:54,879
Speaker 5: out in the western Pacific, and in seventeen seventy five

514
00:24:55,040 --> 00:24:58,800
Speaker 5: there was a major typhoon that struck this island and

515
00:24:58,840 --> 00:25:02,960
Speaker 5: it was very catastrophic. Out of about one thousand people

516
00:25:03,000 --> 00:25:06,080
Speaker 5: that were living on this island, there were only twenty survivors,

517
00:25:07,200 --> 00:25:10,000
Speaker 5: so it was a devastating disaster for the people living there.

518
00:25:10,480 --> 00:25:14,000
Speaker 5: And it turned out that one of the twenty survivors

519
00:25:14,359 --> 00:25:18,760
Speaker 5: was the ruler. And this ruler happened to be a

520
00:25:19,000 --> 00:25:24,280
Speaker 5: carrier for a genetic condition known as a chromatopsia better

521
00:25:24,320 --> 00:25:29,240
Speaker 5: known as complete color blindness wow, and he himself was

522
00:25:29,600 --> 00:25:32,840
Speaker 5: not colorblind. He was a carrier, meaning that this is

523
00:25:32,880 --> 00:25:35,440
Speaker 5: a recessive allele, and you have to have two copies

524
00:25:35,480 --> 00:25:38,399
Speaker 5: of the recessive allele to actually have the condition of

525
00:25:38,480 --> 00:25:42,680
Speaker 5: complete color blindness. But because there were only twenty survivors,

526
00:25:43,200 --> 00:25:46,640
Speaker 5: what that meant is that after a few generations, that

527
00:25:47,160 --> 00:25:51,399
Speaker 5: rare recessive allele had actually become much more common in

528
00:25:51,440 --> 00:25:54,920
Speaker 5: the population. And after about four generations you started seeing

529
00:25:54,960 --> 00:25:59,280
Speaker 5: the first individuals that had two copies of that rare allele,

530
00:25:59,320 --> 00:26:03,119
Speaker 5: and they in fact were colorblind, completely COLORBLINDO and So

531
00:26:03,359 --> 00:26:07,119
Speaker 5: if you go to that population today, it's something like

532
00:26:07,359 --> 00:26:12,440
Speaker 5: one in every ten people are color blind. And if

533
00:26:12,480 --> 00:26:15,160
Speaker 5: you compare that with the sort of frequency of that

534
00:26:15,200 --> 00:26:18,440
Speaker 5: condition in humans in general, it's normally more like one

535
00:26:18,480 --> 00:26:22,840
Speaker 5: in thirty thousand people. So you have this rare condition

536
00:26:23,000 --> 00:26:26,320
Speaker 5: that just happened to become more common due to chance,

537
00:26:26,520 --> 00:26:31,159
Speaker 5: due to genetic drift operating once that population became very small,

538
00:26:31,200 --> 00:26:33,520
Speaker 5: and as it recovered, it just happened to get more

539
00:26:33,520 --> 00:26:38,000
Speaker 5: common over time, and now it's surprisingly common.

540
00:26:38,280 --> 00:26:41,040
Speaker 1: And just to close off a potential avenue of criticism there,

541
00:26:41,240 --> 00:26:44,040
Speaker 1: It's not like the reason this guy survived is said

542
00:26:44,040 --> 00:26:46,000
Speaker 1: he had this gene. It's not like it made him

543
00:26:46,240 --> 00:26:50,000
Speaker 1: exactly that right. Well, those twenty people survived out of

544
00:26:50,040 --> 00:26:51,760
Speaker 1: the thousand, was it just totally random?

545
00:26:52,320 --> 00:26:55,080
Speaker 5: I don't think we do know, although I would hazard

546
00:26:55,080 --> 00:26:57,960
Speaker 5: a guess that it probably wasn't random that the ruler survived.

547
00:26:58,000 --> 00:26:59,240
Speaker 2: I'm guessing the ruler.

548
00:26:58,920 --> 00:27:02,680
Speaker 5: May have had access to things that not everybody else

549
00:27:02,680 --> 00:27:04,560
Speaker 5: had access to that might have made it more likely

550
00:27:04,600 --> 00:27:07,320
Speaker 5: for him to survive. But in terms of the other nineteen,

551
00:27:07,359 --> 00:27:09,160
Speaker 5: I don't know if there was any particular reason why

552
00:27:09,160 --> 00:27:10,160
Speaker 5: they have them to survive.

553
00:27:10,840 --> 00:27:13,480
Speaker 1: So I'm really fascinated to here about current human evolution,

554
00:27:13,600 --> 00:27:16,480
Speaker 1: but I'm also really curious about the history of human evolution.

555
00:27:16,880 --> 00:27:19,960
Speaker 1: How well we know that story. I keep reading articles

556
00:27:19,960 --> 00:27:22,720
Speaker 1: about how we've discovered a new fossil which completely upends

557
00:27:22,760 --> 00:27:26,320
Speaker 1: our story of human evolution. Is that just clickbait? Are

558
00:27:26,359 --> 00:27:29,040
Speaker 1: we constantly learning new things about the story of human evolution?

559
00:27:29,440 --> 00:27:32,280
Speaker 1: Do we have a complete picture? Is the concept of

560
00:27:32,280 --> 00:27:36,320
Speaker 1: a missing link a popular misunderstanding and out of date concept,

561
00:27:36,640 --> 00:27:38,600
Speaker 1: or are there really gaps in the story?

562
00:27:38,840 --> 00:27:39,080
Speaker 2: Yeah?

563
00:27:39,119 --> 00:27:41,359
Speaker 5: So you know this idea of a missing link, which

564
00:27:41,680 --> 00:27:43,480
Speaker 5: I think we hear about all the time, not only

565
00:27:43,520 --> 00:27:46,320
Speaker 5: in the context of human evolution, but an evolution in general.

566
00:27:46,560 --> 00:27:50,280
Speaker 5: That concept goes back to the eighteen hundreds, when the

567
00:27:50,400 --> 00:27:54,720
Speaker 5: idea of evolution was still new, and in fact, there

568
00:27:54,800 --> 00:28:00,560
Speaker 5: were no fossils of early humans. So Darwin speculates that

569
00:28:00,680 --> 00:28:05,879
Speaker 5: eventually somebody would find fossils of an early human or

570
00:28:06,040 --> 00:28:09,679
Speaker 5: some human like species that can kind of make the

571
00:28:09,720 --> 00:28:13,560
Speaker 5: connection between us and what he assumed were our closest

572
00:28:13,600 --> 00:28:17,720
Speaker 5: living relatives, the great apes. And we now know first

573
00:28:17,720 --> 00:28:21,000
Speaker 5: of all that in fact, the great apes, the chimpanzees, gorillas,

574
00:28:21,040 --> 00:28:24,000
Speaker 5: and orangutans are in fact our closest living relatives. We

575
00:28:24,040 --> 00:28:27,399
Speaker 5: can tell from looking at genetic and genomic data. It's

576
00:28:27,480 --> 00:28:31,119
Speaker 5: quite clear. That's not disputed at all anymore. And we

577
00:28:31,200 --> 00:28:34,720
Speaker 5: know in fact, specifically that chimpanzees are our closest living relatives.

578
00:28:34,920 --> 00:28:37,880
Speaker 1: And that doesn't mean that we are descended from chimpanzees,

579
00:28:37,880 --> 00:28:39,960
Speaker 1: but that we and chimpanzees have a common ancestor.

580
00:28:40,160 --> 00:28:42,720
Speaker 5: Yes, that's exactly right. So what it means is that

581
00:28:43,240 --> 00:28:45,560
Speaker 5: about six to seven million years ago, there was a

582
00:28:45,600 --> 00:28:48,719
Speaker 5: species that was not a chimpanzee and was not a human,

583
00:28:49,320 --> 00:28:54,360
Speaker 5: and there was a split, and one lineage eventually gave

584
00:28:54,440 --> 00:28:57,760
Speaker 5: rise to the chimpanzees, and the other lineage eventually gave

585
00:28:57,880 --> 00:29:00,920
Speaker 5: rise to humans. So this concept of a link was

586
00:29:01,160 --> 00:29:03,440
Speaker 5: you know, it made sense back in the mid eighteen

587
00:29:03,520 --> 00:29:06,920
Speaker 5: hundreds when there weren't any fossils that kind of span

588
00:29:07,120 --> 00:29:10,800
Speaker 5: that time period, but that is definitely not the case today.

589
00:29:10,840 --> 00:29:14,440
Speaker 5: So we have had an incredible last you know, one

590
00:29:14,520 --> 00:29:18,200
Speaker 5: hundred hundred and fifty years in the fields of paleo anthropology,

591
00:29:18,520 --> 00:29:24,000
Speaker 5: archaeology and paleontology, and the number of specimens that has

592
00:29:24,240 --> 00:29:30,960
Speaker 5: come into our collections or scientific understanding is just remarkable. So, yes,

593
00:29:31,000 --> 00:29:33,840
Speaker 5: there are still questions, there are still gaps, there are

594
00:29:33,880 --> 00:29:36,800
Speaker 5: still a lot of things that we don't fully understand,

595
00:29:37,320 --> 00:29:40,080
Speaker 5: but the picture of human evolution in the past is

596
00:29:40,240 --> 00:29:42,800
Speaker 5: much clearer than it used to be. And so one

597
00:29:42,840 --> 00:29:44,520
Speaker 5: of the things I think that's really clear, Like, one

598
00:29:44,520 --> 00:29:47,160
Speaker 5: of the big take home messages from the study of

599
00:29:47,200 --> 00:29:49,720
Speaker 5: human evolution in the past is that this old idea

600
00:29:49,880 --> 00:29:53,240
Speaker 5: of what's called the march of progress. If you like

601
00:29:53,320 --> 00:29:56,440
Speaker 5: just close your eyes and picture human evolution, right, you

602
00:29:57,000 --> 00:29:59,160
Speaker 5: very likely have this image in your mind of like

603
00:29:59,160 --> 00:30:02,479
Speaker 5: a hunch to over ape looking thing that kind of

604
00:30:02,840 --> 00:30:05,400
Speaker 5: is moving from left to right and standing up a

605
00:30:05,440 --> 00:30:09,080
Speaker 5: little bit straighter and eventually upright. And then you know,

606
00:30:09,200 --> 00:30:11,040
Speaker 5: if this is like a funny meme, then it might

607
00:30:11,160 --> 00:30:13,480
Speaker 5: kind of go from there to like being hunched over

608
00:30:13,520 --> 00:30:14,360
Speaker 5: a computer.

609
00:30:14,120 --> 00:30:14,960
Speaker 2: Or something like that.

610
00:30:15,840 --> 00:30:19,680
Speaker 5: But the idea of this march of progress is that

611
00:30:19,760 --> 00:30:22,440
Speaker 5: you know, there was a linear progression from something that

612
00:30:22,600 --> 00:30:26,400
Speaker 5: was more like an ape to us, and we now

613
00:30:26,440 --> 00:30:30,959
Speaker 5: know that that notion is really not correct. In fact,

614
00:30:31,080 --> 00:30:34,640
Speaker 5: there was not a linear progression one you know, A

615
00:30:34,800 --> 00:30:37,240
Speaker 5: leading to B leading to C leading to D, but

616
00:30:37,400 --> 00:30:41,520
Speaker 5: instead there was really this incredible explosion of diversity that

617
00:30:41,640 --> 00:30:44,480
Speaker 5: took place, meaning that at any one point in time,

618
00:30:44,560 --> 00:30:49,000
Speaker 5: there were multiple species of humans or human like species

619
00:30:49,000 --> 00:30:52,440
Speaker 5: we call these hominids alive at any one point in time,

620
00:30:52,640 --> 00:30:55,440
Speaker 5: and that always blows my mind. It's actually only very

621
00:30:55,560 --> 00:30:57,600
Speaker 5: very recently that we live in a world where there's

622
00:30:57,600 --> 00:30:58,720
Speaker 5: only one type of human.

623
00:30:59,120 --> 00:31:01,800
Speaker 1: How disappointing. Wouldn't it be awesome to have like six

624
00:31:01,920 --> 00:31:04,560
Speaker 1: or seven different kinds of humans that the politics have

625
00:31:04,640 --> 00:31:07,120
Speaker 1: probably be insane.

626
00:31:07,200 --> 00:31:10,120
Speaker 5: For sure, for sure, yeah, exactly, but intriguing, right like

627
00:31:10,160 --> 00:31:12,040
Speaker 5: how do they interact and they view one another?

628
00:31:12,440 --> 00:31:13,720
Speaker 2: And this is what a lot of people are trying

629
00:31:13,720 --> 00:31:14,480
Speaker 2: to work on today.

630
00:31:14,520 --> 00:31:19,200
Speaker 5: But yeah, we definitely have way more information about the

631
00:31:19,280 --> 00:31:22,480
Speaker 5: history of human evolution, how we became human, than we've

632
00:31:22,520 --> 00:31:24,160
Speaker 5: ever had in the past. But as you point out,

633
00:31:24,160 --> 00:31:26,960
Speaker 5: there are new discoveries still being made that kind of

634
00:31:27,000 --> 00:31:30,320
Speaker 5: shake up that understanding, and part of that involves discovery

635
00:31:30,360 --> 00:31:33,680
Speaker 5: of new species. So these keep happening. People are out

636
00:31:33,680 --> 00:31:38,040
Speaker 5: there finding these incredible things. So in South Africa, and

637
00:31:38,120 --> 00:31:40,560
Speaker 5: I think it was in twenty thirteen, there was the

638
00:31:40,600 --> 00:31:44,040
Speaker 5: discovery in a cave of a species called Homo nouletti.

639
00:31:44,320 --> 00:31:46,800
Speaker 5: And this is just remarkable, a lot of unanswered questions

640
00:31:46,800 --> 00:31:49,760
Speaker 5: about it, but you know that species hadn't been seen previously.

641
00:31:50,120 --> 00:31:54,240
Speaker 5: And then in twenty nineteen, Homo lousenensis was discovered in

642
00:31:54,280 --> 00:31:58,520
Speaker 5: the Philippines. So you know, we keep finding new species

643
00:31:58,600 --> 00:32:02,520
Speaker 5: that contribute to a sort of a clearer picture of

644
00:32:02,520 --> 00:32:06,040
Speaker 5: our evolution. They still kind of, you know, give us

645
00:32:06,440 --> 00:32:08,960
Speaker 5: some new mysteries to solve, but they also help to

646
00:32:09,000 --> 00:32:10,320
Speaker 5: kind of fill in some of those gaps.

647
00:32:10,520 --> 00:32:13,680
Speaker 1: It's so amazing, but also to me so frustrating to

648
00:32:13,680 --> 00:32:17,160
Speaker 1: think that there are fossils out there waiting to be undearthed.

649
00:32:17,160 --> 00:32:19,440
Speaker 1: They're just lying in a cave that could reveal so

650
00:32:19,560 --> 00:32:21,560
Speaker 1: much about our story, and like we just don't know

651
00:32:21,600 --> 00:32:23,600
Speaker 1: where they are. If somebody could just like say over

652
00:32:23,640 --> 00:32:25,720
Speaker 1: here and over there, and these fossils by the way,

653
00:32:25,840 --> 00:32:28,400
Speaker 1: because they're just sitting there waiting. It's like in physics

654
00:32:28,440 --> 00:32:30,880
Speaker 1: if somebody had done a bunch of experiments that revealed

655
00:32:31,040 --> 00:32:33,600
Speaker 1: the nature of the universe and then just like hidden

656
00:32:33,640 --> 00:32:37,560
Speaker 1: them around the Globe's.

657
00:32:36,200 --> 00:32:38,800
Speaker 5: Yes, it's absolutely true, and the people that are doing

658
00:32:38,800 --> 00:32:41,120
Speaker 5: this work are incredibly patient people. I have to say,

659
00:32:41,120 --> 00:32:44,680
Speaker 5: so I co teach a class at Rice University in

660
00:32:44,720 --> 00:32:47,640
Speaker 5: the summer where I co teach this with my colleague

661
00:32:47,920 --> 00:32:51,400
Speaker 5: Manuel Dominguez Rodrigo, who is himself a paleo anthropologist and

662
00:32:51,440 --> 00:32:53,880
Speaker 5: an archaeologist, and he works at old and VII Gorge

663
00:32:53,880 --> 00:32:56,840
Speaker 5: and Tanzania, and we brought students out there and one

664
00:32:56,880 --> 00:32:58,320
Speaker 5: of the things that the students got to do is

665
00:32:58,360 --> 00:33:01,400
Speaker 5: help with the excavations that his team is doing at

666
00:33:01,440 --> 00:33:03,240
Speaker 5: these sites that are, you know, like one and a

667
00:33:03,240 --> 00:33:04,560
Speaker 5: half million years old.

668
00:33:05,160 --> 00:33:06,520
Speaker 2: And one of the.

669
00:33:06,440 --> 00:33:08,480
Speaker 5: Things that I took away from that is, you know,

670
00:33:08,520 --> 00:33:11,120
Speaker 5: you can see the excavations that they're doing, and you

671
00:33:11,120 --> 00:33:13,680
Speaker 5: can understand what they're unearthing, but you look at the

672
00:33:13,800 --> 00:33:16,200
Speaker 5: hill that they're kind of digging into, and as you

673
00:33:16,200 --> 00:33:19,360
Speaker 5: point out, Daniel, there's so much more in there. They

674
00:33:19,400 --> 00:33:21,200
Speaker 5: know there's more in there. They don't know exactly what,

675
00:33:21,320 --> 00:33:23,600
Speaker 5: but they know there's more in there. But it takes

676
00:33:23,640 --> 00:33:27,680
Speaker 5: them years and sometimes more than years, like decades, to

677
00:33:28,200 --> 00:33:32,400
Speaker 5: very slowly and very carefully chip away at that hillside,

678
00:33:32,400 --> 00:33:36,200
Speaker 5: at that slope, because they want to very very meticulously

679
00:33:36,800 --> 00:33:40,680
Speaker 5: not only unearth it, but be able to describe the

680
00:33:40,760 --> 00:33:44,360
Speaker 5: exact spatial relationships between each of the things that they're finding.

681
00:33:44,360 --> 00:33:46,440
Speaker 5: Because they get so much information from that, so they're

682
00:33:46,560 --> 00:33:50,040
Speaker 5: very very careful people and you know, very patient people.

683
00:33:51,200 --> 00:33:52,160
Speaker 5: I would struggle with that.

684
00:33:52,200 --> 00:33:54,920
Speaker 1: It's incredible who we found anything, you know, it takes

685
00:33:54,960 --> 00:33:57,520
Speaker 1: so much time, so much luck. I have these fantasies

686
00:33:57,560 --> 00:33:59,960
Speaker 1: about like developing scanning technology that you could just like

687
00:34:00,280 --> 00:34:03,160
Speaker 1: see everything inside the earth and automatically just like identify

688
00:34:03,200 --> 00:34:06,360
Speaker 1: this stuff. Man, maybe someday there'll be a transformational leap

689
00:34:06,400 --> 00:34:07,200
Speaker 1: in our technology.

690
00:34:07,480 --> 00:34:08,120
Speaker 2: Oh, that'd be great.

691
00:34:08,239 --> 00:34:08,919
Speaker 3: In Jurassic Park.

692
00:34:08,960 --> 00:34:11,280
Speaker 2: There you go, exactly if only.

693
00:34:11,080 --> 00:34:13,720
Speaker 3: We could recreate all the stuff in Jurassic part that would.

694
00:34:13,560 --> 00:34:16,480
Speaker 2: Be what could possibly Yeah.

695
00:34:15,920 --> 00:34:17,480
Speaker 3: That's right, that's right, no doubt.

696
00:34:17,520 --> 00:34:20,320
Speaker 1: But that's definitely not a cautionary tale. No, no, no,

697
00:34:20,320 --> 00:34:20,759
Speaker 1: no no.

698
00:34:21,080 --> 00:34:24,440
Speaker 3: I think when most people read the title of today's episode,

699
00:34:24,680 --> 00:34:27,719
Speaker 3: are humans still evolving? They were expecting that they would

700
00:34:27,760 --> 00:34:30,040
Speaker 3: hear a story about how we're getting better at dealing

701
00:34:30,080 --> 00:34:34,200
Speaker 3: with some stressor are there examples like that as well,

702
00:34:34,239 --> 00:34:36,680
Speaker 3: where we can show that humans are evolving in response

703
00:34:36,760 --> 00:34:39,279
Speaker 3: to something that's bad and we're doing better now because

704
00:34:39,280 --> 00:34:39,520
Speaker 3: of that.

705
00:34:39,600 --> 00:34:40,640
Speaker 1: Yeah, tell us some good news.

706
00:34:40,640 --> 00:34:45,759
Speaker 5: Scott Well, I think one of the clear examples of

707
00:34:45,840 --> 00:34:48,759
Speaker 5: ways in which evolution is still happening for humans today

708
00:34:48,800 --> 00:34:51,080
Speaker 5: has to do with disease, right, So we know that

709
00:34:51,080 --> 00:34:54,400
Speaker 5: disease has been a major player in our species history.

710
00:34:54,520 --> 00:34:56,880
Speaker 5: We can look at malaria as an example of a

711
00:34:56,920 --> 00:34:59,680
Speaker 5: disease that we know has a very long history in humans,

712
00:35:00,239 --> 00:35:04,600
Speaker 5: and unfortunately, because it has a tendency to not only

713
00:35:04,680 --> 00:35:07,000
Speaker 5: kill people, but to kill people when they're very young,

714
00:35:07,480 --> 00:35:12,240
Speaker 5: it has had a major effect on human evolution because

715
00:35:12,880 --> 00:35:16,840
Speaker 5: any individual that happens to have a slight ability to

716
00:35:17,040 --> 00:35:20,120
Speaker 5: kind of tolerate malaria, or might be able to survive

717
00:35:20,120 --> 00:35:22,799
Speaker 5: a little bit longer with malaria, or even to really

718
00:35:22,880 --> 00:35:27,320
Speaker 5: kind of fight it off completely, those individuals are likely

719
00:35:27,400 --> 00:35:30,480
Speaker 5: to survive longer and are more likely to pass on

720
00:35:30,520 --> 00:35:34,279
Speaker 5: their genes to children who are going to inherit those abilities.

721
00:35:34,920 --> 00:35:39,200
Speaker 5: And so we see examples of traits that are related

722
00:35:39,239 --> 00:35:43,880
Speaker 5: to resistance to malaria popping up in different human populations

723
00:35:43,920 --> 00:35:46,719
Speaker 5: in areas where malaria was common. So examples of this

724
00:35:46,840 --> 00:35:50,279
Speaker 5: include sickle cell disease. So sickle cell disease we think

725
00:35:50,320 --> 00:35:52,480
Speaker 5: of it as a disease, and it very much is

726
00:35:52,640 --> 00:35:56,480
Speaker 5: for people living today, especially in areas where there isn't malaria,

727
00:35:56,600 --> 00:35:59,200
Speaker 5: But it just so happens that if you have one

728
00:35:59,320 --> 00:36:03,319
Speaker 5: copy of the allele for sickle cell disease, you have

729
00:36:03,440 --> 00:36:07,280
Speaker 5: a certain amount of resistance to severe malaria. And because

730
00:36:07,320 --> 00:36:11,799
Speaker 5: of that, that allele was favored by natural selection for many,

731
00:36:11,840 --> 00:36:14,040
Speaker 5: many years in parts of the world that have a

732
00:36:14,080 --> 00:36:18,680
Speaker 5: lot of malaria. Thalacemia is another example of that, particularly

733
00:36:18,719 --> 00:36:22,200
Speaker 5: in the Mediterranean region. Different types of thalocemia like betas

734
00:36:22,239 --> 00:36:27,400
Speaker 5: thalacemia is a condition that can help you to survive

735
00:36:27,440 --> 00:36:31,400
Speaker 5: a malarial infection. So that was the case in the past.

736
00:36:31,560 --> 00:36:34,279
Speaker 5: It's much less the case today because of course, we

737
00:36:34,400 --> 00:36:40,160
Speaker 5: have access to other types of prevention and treatment for malaria. Actually,

738
00:36:40,200 --> 00:36:42,600
Speaker 5: there are still some places in the world where there

739
00:36:42,719 --> 00:36:46,480
Speaker 5: isn't sufficient access to modern medicine, and there's some indication

740
00:36:46,680 --> 00:36:51,400
Speaker 5: that natural selection actually still does favor those conditions in

741
00:36:51,400 --> 00:36:53,040
Speaker 5: those parts of the world. That have been some studies

742
00:36:53,040 --> 00:36:56,200
Speaker 5: that have documented that. But we can also point to

743
00:36:56,440 --> 00:37:02,640
Speaker 5: more recent disease outbreaks, right, and so for example, COVID nineteen. Actually,

744
00:37:02,680 --> 00:37:08,200
Speaker 5: there's some studies that suggest that there are genetic traits

745
00:37:08,400 --> 00:37:12,320
Speaker 5: that are correlated with people having a more severe reaction

746
00:37:12,480 --> 00:37:15,759
Speaker 5: to COVID nineteen, and that suggests that that is a

747
00:37:15,800 --> 00:37:19,920
Speaker 5: trait that is at least capable of evolving, meaning that

748
00:37:20,360 --> 00:37:24,120
Speaker 5: the genetic condition that would make somebody sort of better

749
00:37:24,280 --> 00:37:27,760
Speaker 5: able to handle COVID nineteen without having a severe reaction

750
00:37:27,920 --> 00:37:31,480
Speaker 5: to it could become more common over time. And you know,

751
00:37:31,600 --> 00:37:35,680
Speaker 5: while nobody wishes for there to be more pandemics, it

752
00:37:35,760 --> 00:37:39,520
Speaker 5: is unfortunately likely that new diseases will continue to pop

753
00:37:39,640 --> 00:37:42,640
Speaker 5: up in the future, and you know, we should expect

754
00:37:42,880 --> 00:37:45,680
Speaker 5: that any individuals that have a little bit of an

755
00:37:45,719 --> 00:37:49,080
Speaker 5: advantage when it comes to tolerating those diseases are going

756
00:37:49,160 --> 00:37:51,400
Speaker 5: to be more likely to pass those traits on to

757
00:37:51,480 --> 00:37:52,040
Speaker 5: their children.

758
00:37:52,200 --> 00:37:53,799
Speaker 3: Yeah, this is, of course. The thing that sucks about

759
00:37:53,840 --> 00:37:56,160
Speaker 3: natural selection is it requires people to die for it to.

760
00:37:56,080 --> 00:37:59,160
Speaker 5: Happen, exactly right. Yeah, it is not a pleasant process.

761
00:37:59,160 --> 00:38:01,080
Speaker 5: It's not a good process in the sense, but it

762
00:38:01,120 --> 00:38:01,720
Speaker 5: does work.

763
00:38:02,080 --> 00:38:05,880
Speaker 3: When I talk to people about are human still evolving?

764
00:38:05,960 --> 00:38:08,080
Speaker 3: The question that I usually get asked is like, well,

765
00:38:08,080 --> 00:38:10,600
Speaker 3: we've got all of these antibiotics, we've got all of

766
00:38:10,600 --> 00:38:14,640
Speaker 3: these ways of keeping people alive, So evolution is probably

767
00:38:14,640 --> 00:38:17,480
Speaker 3: not happening anymore because all of these things that used

768
00:38:17,520 --> 00:38:20,680
Speaker 3: to kill us we can protect ourselves from now. And

769
00:38:20,719 --> 00:38:22,360
Speaker 3: I feel like, what you're saying is to some extent

770
00:38:22,400 --> 00:38:25,040
Speaker 3: that's true, but we don't have that great stuff everywhere,

771
00:38:25,080 --> 00:38:26,719
Speaker 3: and there's still some new stuff that pops up from

772
00:38:26,760 --> 00:38:28,480
Speaker 3: time to time to kill us. So, yeah, how do

773
00:38:28,520 --> 00:38:29,799
Speaker 3: you respond to that critique?

774
00:38:30,040 --> 00:38:33,239
Speaker 5: Yeah, so you're absolutely right that natural selection is not

775
00:38:33,360 --> 00:38:36,880
Speaker 5: operating in the same way as it has in the past,

776
00:38:36,960 --> 00:38:40,960
Speaker 5: because we have all sorts of things, not only modern medicine,

777
00:38:41,000 --> 00:38:44,120
Speaker 5: but other types of technologies that can help us to

778
00:38:44,160 --> 00:38:45,920
Speaker 5: deal with all of these things. And that means that

779
00:38:45,960 --> 00:38:48,400
Speaker 5: we're not just stuck with whatever sort of the genetic

780
00:38:48,440 --> 00:38:50,839
Speaker 5: cards that you were dealt at birth, right, Like, it's

781
00:38:50,880 --> 00:38:54,360
Speaker 5: not only about those traits that we inherit from our parents.

782
00:38:54,640 --> 00:38:57,440
Speaker 5: They do play a role, and so there is still

783
00:38:57,719 --> 00:39:01,279
Speaker 5: the possibility for natural selection to operate, and the data

784
00:39:01,320 --> 00:39:04,960
Speaker 5: suggests that natural selection is operating, but I think increasingly

785
00:39:05,120 --> 00:39:09,040
Speaker 5: we have this kind of separation where other factors our culture,

786
00:39:09,160 --> 00:39:13,640
Speaker 5: our society, our behaviors, our collective intelligence can play some

787
00:39:13,760 --> 00:39:15,600
Speaker 5: of the role that natural selection used to play.

788
00:39:15,960 --> 00:39:18,600
Speaker 1: The way I think about it is natural selection still happens,

789
00:39:18,600 --> 00:39:21,600
Speaker 1: of course, It's just that the environment we're adapted to

790
00:39:22,120 --> 00:39:26,840
Speaker 1: is being changed and manipulated. We're modifying what's required to survive,

791
00:39:27,360 --> 00:39:30,600
Speaker 1: which means natural selection selects for different things. Right in

792
00:39:30,600 --> 00:39:33,239
Speaker 1: this case, you know, the wealth of your parents is

793
00:39:33,280 --> 00:39:36,080
Speaker 1: probably a factor because of the healthcare they can provide

794
00:39:36,120 --> 00:39:37,040
Speaker 1: in all sorts of stuff.

795
00:39:37,400 --> 00:39:38,000
Speaker 2: Yeah, for sure.

796
00:39:38,080 --> 00:39:41,080
Speaker 5: No, that's definitely operating today in a way that probably

797
00:39:41,200 --> 00:39:43,359
Speaker 5: was the case in the past. But of course those

798
00:39:43,360 --> 00:39:46,839
Speaker 5: differences in wealth are so exaggerated today in a way

799
00:39:46,920 --> 00:39:49,080
Speaker 5: that they wouldn't have been if you look back at

800
00:39:49,200 --> 00:39:49,920
Speaker 5: early humans.

801
00:39:50,880 --> 00:39:52,920
Speaker 3: And this is why biologists don't get invited to a

802
00:39:52,960 --> 00:39:55,520
Speaker 3: lot of parties. We're going to take a break and

803
00:39:55,600 --> 00:39:58,800
Speaker 3: when we get back, we're going to ask Scott about

804
00:39:58,800 --> 00:40:15,839
Speaker 3: whether or not our MicroB iome is evolving with us.

805
00:40:17,880 --> 00:40:20,719
Speaker 1: All Right, we're back, and Kelly's joking about how biologists

806
00:40:20,760 --> 00:40:23,440
Speaker 1: don't get invited to parties. But as a physicist, I

807
00:40:23,560 --> 00:40:25,360
Speaker 1: knew that the best thing to do to make a

808
00:40:25,400 --> 00:40:28,240
Speaker 1: physics party fund was to invite a bunch of biologists.

809
00:40:28,719 --> 00:40:28,919
Speaker 2: Yeah.

810
00:40:31,600 --> 00:40:35,160
Speaker 3: Well, that's because every party's better with and that's what

811
00:40:35,160 --> 00:40:36,320
Speaker 3: we bring to the table.

812
00:40:36,160 --> 00:40:37,840
Speaker 1: And it also improved the gender balance.

813
00:40:39,400 --> 00:40:42,799
Speaker 3: All right, Scott, So microbiomes, right, We've got a lot

814
00:40:42,840 --> 00:40:46,800
Speaker 3: of interest in microbiomes these days. Do they play averle

815
00:40:46,880 --> 00:40:49,800
Speaker 3: in our evolution or do we impact how they evolve?

816
00:40:49,960 --> 00:40:52,480
Speaker 3: Is their cross play there? What's going on with our microbiomes.

817
00:40:52,560 --> 00:40:54,480
Speaker 5: I'm fascinated by the microbiome. I mean, I feel like

818
00:40:54,520 --> 00:40:56,960
Speaker 5: this is one of the areas in biology in the

819
00:40:57,000 --> 00:40:59,640
Speaker 5: last just couple of decades that's totally changed the way

820
00:40:59,640 --> 00:41:03,360
Speaker 5: that we think about the world, nature, ourselves. So I

821
00:41:03,360 --> 00:41:05,799
Speaker 5: think part of the answer is it's still such a

822
00:41:05,840 --> 00:41:08,279
Speaker 5: new field that we're still trying to sort of, you know,

823
00:41:08,320 --> 00:41:10,480
Speaker 5: wrap our heads around it and fully understand it. But

824
00:41:10,560 --> 00:41:12,160
Speaker 5: we do know a few things. So one of the

825
00:41:12,200 --> 00:41:15,839
Speaker 5: things that is known is that, first of all, many

826
00:41:15,840 --> 00:41:18,320
Speaker 5: of the microbes that live in and on our bodies,

827
00:41:18,360 --> 00:41:21,480
Speaker 5: what we call the microbiome, they do things that are helpful,

828
00:41:21,560 --> 00:41:24,640
Speaker 5: are useful, right, And we also know that there are

829
00:41:24,680 --> 00:41:29,200
Speaker 5: certain types of microbes that only live in our bodies,

830
00:41:29,400 --> 00:41:32,239
Speaker 5: like you don't find that same species of microbe in

831
00:41:32,320 --> 00:41:36,120
Speaker 5: other species, even in our closest relatives. And in fact,

832
00:41:36,160 --> 00:41:39,239
Speaker 5: if you look at the evolutionary history of some of

833
00:41:39,280 --> 00:41:44,160
Speaker 5: those species and trace it not only in our own lineage,

834
00:41:44,160 --> 00:41:46,960
Speaker 5: but also in our closest living relatives like chimps and

835
00:41:46,960 --> 00:41:53,200
Speaker 5: gorillas and orangutans. The relationships among the microbes mirror the

836
00:41:53,280 --> 00:41:57,080
Speaker 5: relationships among the apes, and what that tells us is

837
00:41:57,120 --> 00:42:00,960
Speaker 5: that as we evolved, they evolved to they've been co

838
00:42:01,040 --> 00:42:05,080
Speaker 5: evolving together with us. And so combining that with the

839
00:42:05,120 --> 00:42:08,919
Speaker 5: knowledge that many of these microbes are helpful does sort

840
00:42:08,960 --> 00:42:11,640
Speaker 5: of lead us to think that, yeah, you know, these

841
00:42:11,680 --> 00:42:16,400
Speaker 5: species may have influenced our evolution, we may have influenced

842
00:42:16,440 --> 00:42:17,080
Speaker 5: their evolution.

843
00:42:17,239 --> 00:42:18,880
Speaker 2: It's probably a little of both.

844
00:42:19,120 --> 00:42:21,480
Speaker 1: How do you learn about the history of evolution of microbes?

845
00:42:21,840 --> 00:42:23,719
Speaker 1: Is it just looking at the genetic codes and how

846
00:42:23,800 --> 00:42:25,000
Speaker 1: much variation there is.

847
00:42:25,440 --> 00:42:27,799
Speaker 5: Yeah, it is looking at the genetics. So basically we

848
00:42:27,880 --> 00:42:31,319
Speaker 5: need to get samples of the microbes, and this is

849
00:42:31,400 --> 00:42:35,600
Speaker 5: often done looking at gut microbes. We've got microbes all

850
00:42:35,680 --> 00:42:39,680
Speaker 5: over us, but the greatest number in diversity is in

851
00:42:39,840 --> 00:42:43,520
Speaker 5: our digestive tract, in our stomach and our especially our intestines.

852
00:42:43,880 --> 00:42:46,600
Speaker 2: So you need to get access to like.

853
00:42:46,560 --> 00:42:50,399
Speaker 5: A gorilla's gut microbiome, and that is not something that

854
00:42:50,600 --> 00:42:53,759
Speaker 5: you know people are normally siting up to know volunteer

855
00:42:53,840 --> 00:42:54,040
Speaker 5: to do.

856
00:42:54,600 --> 00:42:57,359
Speaker 1: Aren't chimpanzees constantly throwing their poop at people? It seems

857
00:42:57,400 --> 00:42:58,160
Speaker 1: like could be pretty easier.

858
00:42:59,320 --> 00:43:03,560
Speaker 5: Yeah, just a butterfly net. Wait, make it angry and

859
00:43:03,600 --> 00:43:06,719
Speaker 5: then catch what comes at you. That's yeah, let's write

860
00:43:06,760 --> 00:43:15,080
Speaker 5: a proposal. Luckily, it turns out that yeah, actually poop

861
00:43:15,200 --> 00:43:17,759
Speaker 5: is the answer. So yes, see, it all comes back

862
00:43:17,760 --> 00:43:19,600
Speaker 5: to the poop, right, Kelly, I knew.

863
00:43:19,400 --> 00:43:20,359
Speaker 3: We'd get there. I knew it.

864
00:43:20,440 --> 00:43:20,640
Speaker 2: Yeah.

865
00:43:20,800 --> 00:43:23,440
Speaker 5: Yeah, So it turns out the microbes that are in

866
00:43:23,600 --> 00:43:26,840
Speaker 5: poop are a pretty good representation of the microbes that

867
00:43:26,880 --> 00:43:30,160
Speaker 5: are in the intestines more generally. And so what you

868
00:43:30,200 --> 00:43:32,840
Speaker 5: need to do is go out and like find gorilla poop.

869
00:43:33,440 --> 00:43:36,800
Speaker 5: And so, you know, researchers will do things like, for example,

870
00:43:36,880 --> 00:43:40,239
Speaker 5: to train dogs to sniff out gorilla poop, and then

871
00:43:40,680 --> 00:43:42,560
Speaker 5: you know, you can go around the forest and look

872
00:43:42,560 --> 00:43:45,520
Speaker 5: for gorilla poop, take some samples and sequence.

873
00:43:45,600 --> 00:43:48,239
Speaker 1: The DNA science is always glamorous, isn't it. It's just

874
00:43:48,320 --> 00:43:51,000
Speaker 1: always glamorous. It's like James Bond every day.

875
00:43:53,520 --> 00:43:55,520
Speaker 3: Imagine being trained for that job.

876
00:43:56,480 --> 00:43:57,439
Speaker 2: The poop sniffing dog.

877
00:43:57,560 --> 00:43:59,719
Speaker 5: Yeah, this is like the dogs that didn't make it

878
00:43:59,719 --> 00:44:01,640
Speaker 5: to the like drug sniffing school.

879
00:44:01,400 --> 00:44:02,120
Speaker 2: Or something like that.

880
00:44:02,480 --> 00:44:04,279
Speaker 3: But you know, I bet the real challenge there is

881
00:44:04,320 --> 00:44:06,480
Speaker 3: getting the poop away from the dog before it rolls

882
00:44:06,520 --> 00:44:06,719
Speaker 3: in it.

883
00:44:07,600 --> 00:44:09,560
Speaker 2: Yeah, that's true. My dogs would not be good at that.

884
00:44:09,600 --> 00:44:12,000
Speaker 1: I bet that dog is very proud of the roles

885
00:44:12,040 --> 00:44:15,600
Speaker 1: playing in our scientific understanding, as he should.

886
00:44:15,600 --> 00:44:16,759
Speaker 2: They should be they should be.

887
00:44:16,920 --> 00:44:20,000
Speaker 1: Yes, yeah, exactly, this boy of science. Yes, good job.

888
00:44:22,920 --> 00:44:25,920
Speaker 3: Our listener also had a question about are humans affecting

889
00:44:25,960 --> 00:44:28,480
Speaker 3: the evolution of other species on the planet more than

890
00:44:28,520 --> 00:44:30,560
Speaker 3: we have in the past. What do you think about that?

891
00:44:30,840 --> 00:44:31,799
Speaker 2: We definitely are.

892
00:44:31,920 --> 00:44:33,920
Speaker 5: I mean, look, first of all, there's just more of

893
00:44:34,000 --> 00:44:36,440
Speaker 5: us than there ever have been by you know, orders

894
00:44:36,440 --> 00:44:39,319
Speaker 5: of magnitude, so of course you would expect us to

895
00:44:39,360 --> 00:44:41,400
Speaker 5: have a bigger impact. And of course we also have

896
00:44:41,480 --> 00:44:44,080
Speaker 5: much more technology than we've ever had in the past,

897
00:44:44,120 --> 00:44:46,960
Speaker 5: and that means that our ability to affect the rest.

898
00:44:46,719 --> 00:44:48,280
Speaker 2: Of the world is enhanced.

899
00:44:48,840 --> 00:44:51,160
Speaker 5: So yeah, I mean there's tons of examples, right, Some

900
00:44:51,280 --> 00:44:54,440
Speaker 5: of them, actually, I would say, are reminiscent of the

901
00:44:54,480 --> 00:44:57,600
Speaker 5: impacts that we've had in the past, like, for example,

902
00:44:57,640 --> 00:45:01,600
Speaker 5: through hunting. So there's actually an interesting study of elephants

903
00:45:01,760 --> 00:45:07,759
Speaker 5: in Mozambique that showed that they are evolving to become tuskless.

904
00:45:08,280 --> 00:45:10,960
Speaker 5: And the reason is very sad. It's because, of course,

905
00:45:11,000 --> 00:45:14,839
Speaker 5: the elephants are being killed for the ivory that their

906
00:45:14,840 --> 00:45:17,160
Speaker 5: tusks are made out of. But what it means is

907
00:45:17,200 --> 00:45:20,760
Speaker 5: that any elephant that happens to be born without tusks

908
00:45:21,320 --> 00:45:25,880
Speaker 5: has a real survival advantage. And there is a genetic

909
00:45:26,480 --> 00:45:28,920
Speaker 5: trait in some of these elephants in which some of

910
00:45:28,920 --> 00:45:32,319
Speaker 5: the females it's only females. Unfortunately for the males, they

911
00:45:32,400 --> 00:45:35,279
Speaker 5: can be born without tusks. And so there was a

912
00:45:35,280 --> 00:45:38,960
Speaker 5: study that showed that because of how much poaching was

913
00:45:39,000 --> 00:45:43,400
Speaker 5: taking place in Mozambique, particularly during the civil war that

914
00:45:43,440 --> 00:45:48,440
Speaker 5: took place there, that actually the rise in tusklessness was

915
00:45:48,560 --> 00:45:51,279
Speaker 5: like threefold. So in other words, it used to be

916
00:45:51,280 --> 00:45:53,960
Speaker 5: pretty rare for an elephant to be born tuskless, and

917
00:45:54,040 --> 00:45:57,239
Speaker 5: now it's something like about half of the females are

918
00:45:57,280 --> 00:46:00,200
Speaker 5: born without tusks. So that is clearly humans have having

919
00:46:00,200 --> 00:46:05,359
Speaker 5: a major impact on this particular population. And I say

920
00:46:05,360 --> 00:46:07,160
Speaker 5: that's like the things that you know. I mean, humans

921
00:46:07,200 --> 00:46:10,440
Speaker 5: have been hunting elephants since before we were Homo sapiens, right,

922
00:46:10,480 --> 00:46:13,359
Speaker 5: So in that sense, it's not new. It's just that

923
00:46:13,400 --> 00:46:16,000
Speaker 5: we're so good at it now that the elephants don't

924
00:46:16,000 --> 00:46:19,600
Speaker 5: stand a chance. Unfortunately, but yeah, we're having other impacts, right,

925
00:46:19,640 --> 00:46:22,359
Speaker 5: I mean, climate change of course is a huge one,

926
00:46:22,560 --> 00:46:26,959
Speaker 5: and we see examples of coral evolving to be able

927
00:46:27,000 --> 00:46:31,440
Speaker 5: to tolerate warmer sea temperatures. Right, The question is can

928
00:46:31,480 --> 00:46:34,719
Speaker 5: they evolve fast enough? And can all of them evolve

929
00:46:34,880 --> 00:46:36,839
Speaker 5: that ability or only some of them?

930
00:46:37,080 --> 00:46:40,200
Speaker 1: Right, Because evolution is not omnipotent, Right, It's possible to

931
00:46:40,320 --> 00:46:43,680
Speaker 1: just wipe out a species if there isn't enough diversity

932
00:46:44,320 --> 00:46:46,759
Speaker 1: and just zero it out, and then it just can't recover.

933
00:46:46,600 --> 00:46:47,719
Speaker 2: Right exactly.

934
00:46:47,880 --> 00:46:51,040
Speaker 5: And you know, evolution only is dealing with whatever is

935
00:46:51,080 --> 00:46:53,840
Speaker 5: the immediate challenge to it. It can't sort of predict

936
00:46:53,840 --> 00:46:56,760
Speaker 5: what's coming down the line. So that stuff is concerning.

937
00:46:56,760 --> 00:46:59,080
Speaker 5: But we do see a lot of examples of humans

938
00:46:59,120 --> 00:47:01,080
Speaker 5: having this impact. I mean, one of the other clear

939
00:47:01,120 --> 00:47:06,239
Speaker 5: examples through our agricultural practices and use of pesticide, so

940
00:47:06,280 --> 00:47:10,040
Speaker 5: we can see the evolution of pesticide resistant insects, or

941
00:47:10,040 --> 00:47:15,320
Speaker 5: in medicine, the evolution of antibiotic resistant bacteria another microorganism.

942
00:47:15,400 --> 00:47:18,520
Speaker 5: So this is clearly an impact that humans are having

943
00:47:18,600 --> 00:47:22,160
Speaker 5: on the natural world that is a much bigger impact

944
00:47:22,280 --> 00:47:24,160
Speaker 5: than what we've ever been able to have before, and

945
00:47:24,200 --> 00:47:26,320
Speaker 5: it is very clearly an evolutionary impact.

946
00:47:26,680 --> 00:47:28,439
Speaker 1: The comment you just made reminds me of a question

947
00:47:28,480 --> 00:47:33,280
Speaker 1: I've long had, which is, basically, why are humans so smart?

948
00:47:33,560 --> 00:47:36,280
Speaker 1: I mean, we evolved in a situation where we needed

949
00:47:36,320 --> 00:47:40,520
Speaker 1: to learn to stay dry and feed ourselves and make friends,

950
00:47:41,000 --> 00:47:44,200
Speaker 1: but not necessarily to play chess and think about eleven

951
00:47:44,239 --> 00:47:49,279
Speaker 1: dimensional spatial manifolds and do super complicated mathematics. Why are

952
00:47:49,360 --> 00:47:51,800
Speaker 1: humans so smart? Do we understand that from an evolutionary

953
00:47:51,840 --> 00:47:54,400
Speaker 1: point of view? What happened in our ancient past to

954
00:47:54,480 --> 00:47:57,960
Speaker 1: create this brain which, as far as I understands, equivalent

955
00:47:57,960 --> 00:48:00,759
Speaker 1: to the brain people had fifty thousand years ago. Why

956
00:48:00,800 --> 00:48:02,680
Speaker 1: did we end up so intelligent?

957
00:48:03,040 --> 00:48:03,279
Speaker 2: Yeah?

958
00:48:03,320 --> 00:48:05,560
Speaker 5: So, I mean, this is actually a really interesting question,

959
00:48:05,640 --> 00:48:08,040
Speaker 5: and it's one of the things that paleo anthropologists are

960
00:48:08,040 --> 00:48:11,120
Speaker 5: trying to study in terms of looking at what we

961
00:48:11,160 --> 00:48:13,520
Speaker 5: can see from the fossil evidence. And one thing that

962
00:48:13,680 --> 00:48:17,440
Speaker 5: is clear is that there was a big expansion in

963
00:48:17,680 --> 00:48:20,080
Speaker 5: the size of the cranium, the part of the skull

964
00:48:20,120 --> 00:48:24,160
Speaker 5: that holds the brain, that happens during the Pleistocene era.

965
00:48:24,320 --> 00:48:27,160
Speaker 5: So this is a period that going back about million

966
00:48:27,200 --> 00:48:28,920
Speaker 5: and a half to you know, two or three million

967
00:48:29,000 --> 00:48:33,400
Speaker 5: years ago, in which there were dramatic climatic changes, dramatic

968
00:48:33,440 --> 00:48:37,760
Speaker 5: climate changes that were happening around the world, and specifically

969
00:48:38,000 --> 00:48:42,200
Speaker 5: changes that were happening in Africa, where our ancestors were

970
00:48:42,200 --> 00:48:44,879
Speaker 5: living at the time. And actually the reason there were

971
00:48:44,920 --> 00:48:48,399
Speaker 5: such dramatic climatic changes has to do with changes in

972
00:48:48,520 --> 00:48:51,440
Speaker 5: the tilt of the Earth. Right, So we are on

973
00:48:51,480 --> 00:48:53,239
Speaker 5: a planet that has a tilt of about twenty three

974
00:48:53,239 --> 00:48:55,640
Speaker 5: and a half degrees at the moment, but that tilt

975
00:48:55,760 --> 00:48:59,520
Speaker 5: changes over time and there's sort of fluctuations. And also

976
00:48:59,800 --> 00:49:02,640
Speaker 5: in the shape of our planet's orbit around the Sun,

977
00:49:02,680 --> 00:49:04,960
Speaker 5: it can be sort of more round or more stretched out.

978
00:49:05,280 --> 00:49:08,760
Speaker 5: And as you sort of put those two changes together,

979
00:49:09,320 --> 00:49:14,400
Speaker 5: you get time periods in which the climate is especially volatile,

980
00:49:14,640 --> 00:49:18,399
Speaker 5: in which you can have relatively rapid swings from really

981
00:49:18,440 --> 00:49:21,759
Speaker 5: wet to really dry, really cold to really warm. And

982
00:49:22,040 --> 00:49:26,120
Speaker 5: that type of change was happening worldwide, but especially in

983
00:49:26,200 --> 00:49:29,600
Speaker 5: Africa during this time period. And that is the time

984
00:49:29,680 --> 00:49:33,000
Speaker 5: in which we see this really dramatic rise in the

985
00:49:33,040 --> 00:49:37,120
Speaker 5: size of the cranium in different species of humans. So

986
00:49:37,960 --> 00:49:45,200
Speaker 5: we think that this was basically natural selection favoring greater intelligence. Now,

987
00:49:45,239 --> 00:49:49,040
Speaker 5: the correlation between brain size and intelligence isn't perfect, right,

988
00:49:49,200 --> 00:49:52,719
Speaker 5: Just because the grain grows larger doesn't necessarily mean that

989
00:49:52,760 --> 00:49:55,560
Speaker 5: they get smarter. I mean, the largest brain of any

990
00:49:55,960 --> 00:49:59,239
Speaker 5: animal species in the world is that of you know,

991
00:49:59,280 --> 00:50:02,319
Speaker 5: certain species of whales, which are they intelligent? Yeah, they're

992
00:50:02,320 --> 00:50:05,239
Speaker 5: pretty intelligent. Are they more intelligent than us? Probably not?

993
00:50:05,840 --> 00:50:08,239
Speaker 5: But in general, we do think that that increase in

994
00:50:08,280 --> 00:50:11,680
Speaker 5: brain size probably had to do with an increase in

995
00:50:11,680 --> 00:50:14,440
Speaker 5: intelligence to a certain extent. So it probably did have

996
00:50:14,480 --> 00:50:19,239
Speaker 5: to do with the ability to handle and cope with

997
00:50:19,320 --> 00:50:22,160
Speaker 5: those dramatic changes. I mean, if you're sort of living

998
00:50:22,160 --> 00:50:25,919
Speaker 5: out on the African savannah and just trying to feed

999
00:50:25,960 --> 00:50:28,960
Speaker 5: your children and not get eaten by lions, you know,

1000
00:50:29,360 --> 00:50:31,640
Speaker 5: and you've sort of figured that out to a certain extent,

1001
00:50:31,640 --> 00:50:36,000
Speaker 5: and then all of a sudden the climate completely changes, Right,

1002
00:50:36,080 --> 00:50:37,719
Speaker 5: you have to figure out a new way to do

1003
00:50:37,800 --> 00:50:41,640
Speaker 5: those things. That is really going to be a tall order.

1004
00:50:41,760 --> 00:50:45,040
Speaker 5: So we think natural selection was really operating at that

1005
00:50:45,160 --> 00:50:49,680
Speaker 5: time to help people to deal with those dramatic changes.

1006
00:50:49,680 --> 00:50:52,200
Speaker 5: They had to work together, right, So part of what

1007
00:50:52,239 --> 00:50:56,200
Speaker 5: we think is driving some of this change in intelligence

1008
00:50:56,280 --> 00:50:59,640
Speaker 5: is the ability to communicate with one another, the ability

1009
00:50:59,680 --> 00:51:03,240
Speaker 5: to work together to understand what another person is thinking

1010
00:51:03,280 --> 00:51:05,960
Speaker 5: and maybe predict what the other person is going to do,

1011
00:51:06,560 --> 00:51:08,200
Speaker 5: and as we all know, that's a hard thing to do.

1012
00:51:08,320 --> 00:51:13,040
Speaker 5: So that intelligence would have been favored by natural selection

1013
00:51:13,400 --> 00:51:16,200
Speaker 5: as our species was just having to cope with these

1014
00:51:16,239 --> 00:51:17,680
Speaker 5: new challenges to our survival.

1015
00:51:17,800 --> 00:51:19,719
Speaker 1: There has to be something more than that, right, I mean,

1016
00:51:19,760 --> 00:51:21,399
Speaker 1: I know that we don't have the whole picture, of course,

1017
00:51:21,400 --> 00:51:23,400
Speaker 1: and I don't expect you to have the whole picture.

1018
00:51:23,800 --> 00:51:26,680
Speaker 1: But like other species existed at the same times in

1019
00:51:26,719 --> 00:51:29,920
Speaker 1: the same environment, and antelopes can't do string theory right

1020
00:51:29,920 --> 00:51:31,799
Speaker 1: as far as I know. Maybe they are and they're

1021
00:51:31,800 --> 00:51:33,359
Speaker 1: just not sharing the answers with us.

1022
00:51:33,640 --> 00:51:35,319
Speaker 3: Maybe string theory is maladaptive.

1023
00:51:36,719 --> 00:51:38,880
Speaker 1: Maybe having physicists is bad for humans. Is that what

1024
00:51:38,920 --> 00:51:41,680
Speaker 1: you're saying. But my point is, beyond the only ones

1025
00:51:41,719 --> 00:51:43,600
Speaker 1: to face that environment, we seem to be the only

1026
00:51:43,600 --> 00:51:46,640
Speaker 1: ones to develop this capacity, not just to solve the

1027
00:51:46,680 --> 00:51:48,560
Speaker 1: problems of that era, because you didn't have to be

1028
00:51:48,600 --> 00:51:52,120
Speaker 1: able to do string theory to survive in those volatile circumstances,

1029
00:51:52,320 --> 00:51:56,200
Speaker 1: but to do this crazy intellectual wrestling matches that we

1030
00:51:56,280 --> 00:51:58,160
Speaker 1: do today. So it seems like there's got to be

1031
00:51:58,200 --> 00:51:59,200
Speaker 1: more of the story, don't you.

1032
00:51:59,200 --> 00:52:01,920
Speaker 5: Think, Yeah, well, it is definitely true that, you know,

1033
00:52:02,080 --> 00:52:05,839
Speaker 5: not all species became more intelligent during that time, So

1034
00:52:05,920 --> 00:52:07,080
Speaker 5: what was it about us?

1035
00:52:07,200 --> 00:52:07,439
Speaker 2: Right?

1036
00:52:07,880 --> 00:52:10,080
Speaker 5: And I think one of the answers to that seems

1037
00:52:10,080 --> 00:52:11,600
Speaker 5: to be that we already had a bit of a

1038
00:52:11,600 --> 00:52:13,799
Speaker 5: head start. So if you look at the change in

1039
00:52:13,880 --> 00:52:17,239
Speaker 5: brain size over the last like six million years, like

1040
00:52:17,280 --> 00:52:19,480
Speaker 5: going back to the time in which we shared a

1041
00:52:19,480 --> 00:52:23,719
Speaker 5: common ancestor with chimpanzees, there was already a trend towards

1042
00:52:24,000 --> 00:52:28,120
Speaker 5: bigger brain size in some of the early human ancestors,

1043
00:52:28,520 --> 00:52:31,799
Speaker 5: but then it really just sort of rapidly increased in

1044
00:52:31,920 --> 00:52:34,520
Speaker 5: size during this period from around one to two million

1045
00:52:34,600 --> 00:52:37,560
Speaker 5: years ago. So what was happening then, Well, that's when

1046
00:52:37,600 --> 00:52:41,040
Speaker 5: you get these climate changes, So it's probably something to

1047
00:52:41,080 --> 00:52:43,240
Speaker 5: do with that. Of course, we need a time machine

1048
00:52:43,239 --> 00:52:45,160
Speaker 5: to go back and be able to tell for sure.

1049
00:52:45,680 --> 00:52:48,719
Speaker 5: But the reason that other species didn't also become more

1050
00:52:48,760 --> 00:52:51,480
Speaker 5: intelligent during that time probably has something to do with

1051
00:52:51,520 --> 00:52:55,319
Speaker 5: the fact that they didn't have much genetic variation for

1052
00:52:55,480 --> 00:52:58,359
Speaker 5: brain size or intelligence. So that's like a really key

1053
00:52:58,400 --> 00:53:02,319
Speaker 5: thing to recognize is that natural selection by itself is

1054
00:53:02,719 --> 00:53:07,719
Speaker 5: powerless unless there's some kind of variation that already exists,

1055
00:53:08,040 --> 00:53:11,040
Speaker 5: that selection can sort of sift through and say, Okay,

1056
00:53:11,160 --> 00:53:14,839
Speaker 5: this version is going to do a better job than

1057
00:53:14,880 --> 00:53:17,439
Speaker 5: this other version. And do a better job just means

1058
00:53:17,520 --> 00:53:20,640
Speaker 5: basically make more babies. At the end of the day, right,

1059
00:53:21,280 --> 00:53:25,120
Speaker 5: evolution it's just all about babies and who's making more babies.

1060
00:53:25,640 --> 00:53:28,239
Speaker 5: So if there were some individuals that happened to have

1061
00:53:28,280 --> 00:53:31,640
Speaker 5: a slightly bigger brain, happened to be more intelligent, and

1062
00:53:31,760 --> 00:53:34,920
Speaker 5: if that led to them making more babies, then you

1063
00:53:35,000 --> 00:53:36,760
Speaker 5: know that was what became more common.

1064
00:53:36,880 --> 00:53:40,120
Speaker 1: I mean some ultimate universe where a population of humans

1065
00:53:40,120 --> 00:53:42,800
Speaker 1: found a different strategy for surviving those vault of times

1066
00:53:42,800 --> 00:53:45,680
Speaker 1: by being like really good climbers or super fast, then

1067
00:53:45,680 --> 00:53:48,040
Speaker 1: we might all be Usain Bolt today for example.

1068
00:53:48,280 --> 00:53:51,680
Speaker 5: Yeah, exactly. Yeah, That's it's pretty stochastic at the end

1069
00:53:51,719 --> 00:53:53,839
Speaker 5: of the day. And there's a lot of things that

1070
00:53:53,880 --> 00:53:56,320
Speaker 5: could have gone differently that would have turned us into

1071
00:53:56,440 --> 00:53:58,960
Speaker 5: a very different species or caused us to not exist

1072
00:53:59,000 --> 00:53:59,279
Speaker 5: at all.

1073
00:54:00,160 --> 00:54:03,040
Speaker 3: I talked a lot today about different misconceptions people have

1074
00:54:03,080 --> 00:54:06,480
Speaker 3: about evolution and human evolution. Are there any others that

1075
00:54:06,520 --> 00:54:08,880
Speaker 3: you encounter when you talk to people about evolution that

1076
00:54:08,920 --> 00:54:11,200
Speaker 3: are worth debunking while you're on the show.

1077
00:54:11,600 --> 00:54:13,480
Speaker 5: Yeah, I guess to me, the one that comes up

1078
00:54:13,520 --> 00:54:16,440
Speaker 5: most often is this idea that just because a trait

1079
00:54:16,480 --> 00:54:18,800
Speaker 5: seems like it would be useful, that we should expect

1080
00:54:18,800 --> 00:54:22,239
Speaker 5: it to evolve, like where are my wings? Scott, Yeah,

1081
00:54:22,280 --> 00:54:24,840
Speaker 5: exactly right. Or the one that I hear so often

1082
00:54:25,120 --> 00:54:28,520
Speaker 5: is like, you know, hey, everybody's playing video games these days.

1083
00:54:28,600 --> 00:54:30,480
Speaker 5: Does that mean our thumbs are going to be bigger

1084
00:54:30,520 --> 00:54:33,480
Speaker 5: and stronger in the future, because you know'd be better

1085
00:54:33,560 --> 00:54:36,960
Speaker 5: at playing video games? And my answer to that is, well,

1086
00:54:37,440 --> 00:54:41,160
Speaker 5: do people, first of all, have variation in thumb size

1087
00:54:41,200 --> 00:54:41,680
Speaker 5: and strength.

1088
00:54:41,760 --> 00:54:42,160
Speaker 2: I don't know.

1089
00:54:42,280 --> 00:54:44,600
Speaker 5: Maybe they do, but that would be one thing that

1090
00:54:44,640 --> 00:54:46,440
Speaker 5: would have to be true. The other thing is that

1091
00:54:46,480 --> 00:54:48,719
Speaker 5: the people with the big, strong thumbs would have to

1092
00:54:48,760 --> 00:54:49,560
Speaker 5: have more babies.

1093
00:54:49,719 --> 00:54:50,960
Speaker 2: And that's where I have my doubts.

1094
00:54:55,000 --> 00:54:58,279
Speaker 3: So I've read both of your books and yeah, that's right.

1095
00:54:58,320 --> 00:55:00,239
Speaker 3: I got to read his second book early. And I

1096
00:55:00,239 --> 00:55:02,720
Speaker 3: get the sense from reading your books that you really

1097
00:55:02,840 --> 00:55:06,160
Speaker 3: enjoy the travel that goes into researching the book. What

1098
00:55:06,280 --> 00:55:09,200
Speaker 3: was your favorite research trip that you've taken for a

1099
00:55:09,239 --> 00:55:09,919
Speaker 3: book so far?

1100
00:55:10,239 --> 00:55:13,080
Speaker 5: Well, first of all, Kelly, I love that you have

1101
00:55:13,160 --> 00:55:16,000
Speaker 5: been willing to read my books, including in advance, and

1102
00:55:16,040 --> 00:55:19,400
Speaker 5: you've given me some really great feedback and suggestions, So

1103
00:55:19,840 --> 00:55:20,440
Speaker 5: thank you for that.

1104
00:55:20,640 --> 00:55:22,200
Speaker 1: Kelly is so good at that she is.

1105
00:55:22,440 --> 00:55:24,440
Speaker 3: Ah, thanks guys, It's my pleasure. I love getting to

1106
00:55:24,440 --> 00:55:25,600
Speaker 3: read early copies of books.

1107
00:55:25,640 --> 00:55:28,120
Speaker 5: But you're right, I do like to travel, and so,

1108
00:55:28,440 --> 00:55:30,400
Speaker 5: you know, one of the things that I've enjoyed in

1109
00:55:30,480 --> 00:55:33,520
Speaker 5: researching that these books that I've written is traveling around

1110
00:55:33,600 --> 00:55:36,160
Speaker 5: and you know, meeting people who are doing interesting work.

1111
00:55:36,200 --> 00:55:39,480
Speaker 5: And I really enjoy being able to kind of describe

1112
00:55:39,520 --> 00:55:42,399
Speaker 5: the work that someone's doing by kind of you know,

1113
00:55:42,719 --> 00:55:45,360
Speaker 5: showing people how they do it, and you know, getting

1114
00:55:45,400 --> 00:55:47,800
Speaker 5: to know them in their natural environment, so to speak.

1115
00:55:47,840 --> 00:55:50,400
Speaker 5: So yeah, I mean I've done some interesting trips for

1116
00:55:50,440 --> 00:55:53,360
Speaker 5: this book, Future Humans. I think the trip that was

1117
00:55:53,440 --> 00:55:55,880
Speaker 5: maybe the most fun that I got to do was

1118
00:55:56,160 --> 00:55:59,360
Speaker 5: to go to Quebec. And there's an island in the

1119
00:55:59,400 --> 00:56:02,640
Speaker 5: Saint Laurence River with a French name that I will

1120
00:56:02,640 --> 00:56:06,200
Speaker 5: not attempt to pronounce apologies to my high school French teacher,

1121
00:56:06,800 --> 00:56:11,400
Speaker 5: but the reason is that this island is a place

1122
00:56:11,520 --> 00:56:15,080
Speaker 5: where there has been a very interesting series of research

1123
00:56:15,160 --> 00:56:19,680
Speaker 5: studies by a biologist named Emmanuel Milo, and I got

1124
00:56:19,680 --> 00:56:22,400
Speaker 5: to go actually to this island with Emmanuel Milo. We

1125
00:56:22,480 --> 00:56:25,520
Speaker 5: traveled there together, and what was interesting about it is

1126
00:56:25,560 --> 00:56:30,680
Speaker 5: that this island was first settled by French Canadians in

1127
00:56:30,800 --> 00:56:35,160
Speaker 5: the seventeen hundreds, and he and some of his colleagues,

1128
00:56:35,200 --> 00:56:38,160
Speaker 5: Emmanuel and some of his colleagues were able to basically

1129
00:56:38,239 --> 00:56:41,920
Speaker 5: trace the history of the human population on this island

1130
00:56:42,560 --> 00:56:47,080
Speaker 5: and show that there has actually been evolutionary change among

1131
00:56:47,120 --> 00:56:50,080
Speaker 5: the people living on that island between about eighteen hundred

1132
00:56:50,400 --> 00:56:53,680
Speaker 5: and the nineteen sixties. So this is like, you know,

1133
00:56:53,960 --> 00:56:57,719
Speaker 5: roughly sort of seven or eight generations of people that

1134
00:56:57,840 --> 00:57:00,000
Speaker 5: lived on this island. And because it was an island,

1135
00:57:00,160 --> 00:57:02,359
Speaker 5: because it's kind of hard to get to, it was

1136
00:57:02,480 --> 00:57:05,759
Speaker 5: relatively isolated from the surrounding communities. And so what they

1137
00:57:05,800 --> 00:57:09,239
Speaker 5: showed is that actually the age at which women had

1138
00:57:09,239 --> 00:57:14,640
Speaker 5: their first child changed on that island from averaging about

1139
00:57:14,680 --> 00:57:19,560
Speaker 5: twenty six years old to about age twenty two over

1140
00:57:19,640 --> 00:57:23,560
Speaker 5: that time span, So women started having their first child

1141
00:57:23,720 --> 00:57:27,920
Speaker 5: at a younger age during that time period. And what

1142
00:57:28,000 --> 00:57:31,680
Speaker 5: was especially interesting about this population is that they had

1143
00:57:31,680 --> 00:57:37,440
Speaker 5: a complete genealogical record of the entire population because of

1144
00:57:37,800 --> 00:57:41,440
Speaker 5: church records, so everybody pretty much went to the same church,

1145
00:57:41,560 --> 00:57:45,080
Speaker 5: and the church keeps track of births, deaths, and marriages,

1146
00:57:45,320 --> 00:57:48,200
Speaker 5: and so because of that, they had this whole genealogy

1147
00:57:48,720 --> 00:57:51,760
Speaker 5: of this population and they were able to basically rule

1148
00:57:51,800 --> 00:57:55,240
Speaker 5: out that this change in the age of first birth

1149
00:57:56,040 --> 00:57:57,840
Speaker 5: it could have been due to other factors. You might

1150
00:57:57,880 --> 00:58:00,320
Speaker 5: imagine that it was like, well, some people might have been,

1151
00:58:00,440 --> 00:58:03,320
Speaker 5: you know, richer or poorer, or had access to more

1152
00:58:03,400 --> 00:58:08,080
Speaker 5: food or different culture, whatever it is, right, And basically

1153
00:58:08,080 --> 00:58:09,800
Speaker 5: they were able to rule out all of those other

1154
00:58:09,880 --> 00:58:13,120
Speaker 5: possibilities and show that in fact, it was a response

1155
00:58:13,160 --> 00:58:17,440
Speaker 5: to natural selection. So basically natural selection was favoring women

1156
00:58:17,760 --> 00:58:21,560
Speaker 5: starting their families at a younger age because women that do,

1157
00:58:21,680 --> 00:58:25,040
Speaker 5: on average tend to have more children, and that is

1158
00:58:25,080 --> 00:58:28,200
Speaker 5: actually something that is predicted from evolutionary theory, but it

1159
00:58:28,240 --> 00:58:31,400
Speaker 5: had never been shown before in humans, particularly not in

1160
00:58:31,480 --> 00:58:34,760
Speaker 5: a modern human population. So it was really interesting. It's

1161
00:58:34,800 --> 00:58:37,280
Speaker 5: a beautiful place. They are lovely people. We got to

1162
00:58:37,320 --> 00:58:39,960
Speaker 5: go and spend several days on this island and we

1163
00:58:40,040 --> 00:58:42,160
Speaker 5: met a lot of great folks there, got to learn

1164
00:58:42,200 --> 00:58:43,160
Speaker 5: a little bit more.

1165
00:58:43,000 --> 00:58:44,480
Speaker 2: About the history of the island.

1166
00:58:45,040 --> 00:58:48,600
Speaker 5: It was really interesting to go with Emmanuel Milo and

1167
00:58:48,680 --> 00:58:51,920
Speaker 5: actually see this place that had been you know, this

1168
00:58:52,440 --> 00:58:54,439
Speaker 5: subject of this really interesting study he had done.

1169
00:58:54,480 --> 00:58:56,800
Speaker 1: It's amazing how important islands are to the history of

1170
00:58:56,840 --> 00:58:59,360
Speaker 1: evolution and our study and understanding of it. Right, We're

1171
00:58:59,440 --> 00:59:00,520
Speaker 1: lucky we have islands.

1172
00:59:00,680 --> 00:59:01,280
Speaker 2: Yeah, it's true.

1173
00:59:01,280 --> 00:59:03,360
Speaker 5: I mean partly because they're sort of like these little

1174
00:59:03,400 --> 00:59:07,600
Speaker 5: miniature versions of what are normally much more complex systems. So,

1175
00:59:08,080 --> 00:59:10,040
Speaker 5: you know, going back to Darwin, right, you know, in

1176
00:59:10,080 --> 00:59:13,520
Speaker 5: the Galapagos. I mean, biologists still go to islands because

1177
00:59:13,560 --> 00:59:17,280
Speaker 5: they often helped to kind of reveal more complicated phenomena

1178
00:59:17,840 --> 00:59:19,120
Speaker 5: in a somewhat simpler way.

1179
00:59:19,360 --> 00:59:21,120
Speaker 3: I also feel like if I could go back and

1180
00:59:21,360 --> 00:59:24,360
Speaker 3: have a different career being a historian would be really

1181
00:59:24,360 --> 00:59:26,880
Speaker 3: cool to just be able to like handle old documents

1182
00:59:26,920 --> 00:59:29,240
Speaker 3: and see like old writings I don't know something about

1183
00:59:29,280 --> 00:59:31,640
Speaker 3: like really old stuff. Oh yeah, it is really exciting.

1184
00:59:31,880 --> 00:59:32,280
Speaker 2: Absolutely.

1185
00:59:32,320 --> 00:59:33,560
Speaker 5: I mean one of the things that we did was

1186
00:59:33,600 --> 00:59:36,880
Speaker 5: we actually visited the Archdiocese of Quebec and got to

1187
00:59:36,960 --> 00:59:40,720
Speaker 5: see the archives where they actually had these original records

1188
00:59:40,720 --> 00:59:42,480
Speaker 5: of birth, deaths, and marriages. We had to open up

1189
00:59:42,520 --> 00:59:45,040
Speaker 5: those books and see for ourselves, and I get goosebumps

1190
00:59:45,040 --> 00:59:46,480
Speaker 5: when I see that kind of thing, right, I mean,

1191
00:59:46,480 --> 00:59:49,840
Speaker 5: it's just getting to have that immediate connection with history.

1192
00:59:50,320 --> 00:59:51,200
Speaker 2: I think it's super cool.

1193
00:59:51,480 --> 00:59:53,480
Speaker 1: That reminds me of the exhibit in the British Museum

1194
00:59:53,520 --> 00:59:56,360
Speaker 1: where they have original manuscripts from famous people, so you

1195
00:59:56,400 --> 00:59:59,800
Speaker 1: can see like Mozart's scribbles and Beethoven like crossing stuff

1196
00:59:59,800 --> 01:00:03,240
Speaker 1: out and really fascinating to think, like that guy actually

1197
01:00:03,280 --> 01:00:05,000
Speaker 1: wrote on this piece of paper. I don't know why,

1198
01:00:05,040 --> 01:00:06,720
Speaker 1: but it is really powerful, right.

1199
01:00:06,640 --> 01:00:08,200
Speaker 2: It is. We actually at Rice.

1200
01:00:08,280 --> 01:00:11,640
Speaker 5: In our library collection, we have the collection of work

1201
01:00:11,680 --> 01:00:14,160
Speaker 5: from a biologist named Julian Huxley, who is a famous

1202
01:00:14,160 --> 01:00:19,280
Speaker 5: biologist in the early twentieth century. His grandfather, Thomas Henry Huxley,

1203
01:00:19,360 --> 01:00:21,920
Speaker 5: was one of Darwin's closest friends, and there is a

1204
01:00:21,960 --> 01:00:25,160
Speaker 5: copy of the Origin of Species in the library that

1205
01:00:25,360 --> 01:00:29,160
Speaker 5: was given by Charles Darwin to Thomas Henry Huxley, and

1206
01:00:29,240 --> 01:00:33,000
Speaker 5: it has both Thomas Henry Huxley and Julian Huxley's notes

1207
01:00:33,080 --> 01:00:33,840
Speaker 5: in the margin.

1208
01:00:34,400 --> 01:00:35,360
Speaker 2: It's just the.

1209
01:00:35,120 --> 01:00:37,720
Speaker 5: Coolest thing to see. No, I still get chills thinking

1210
01:00:37,760 --> 01:00:39,200
Speaker 5: about it. Yeah, it's so cool.

1211
01:00:39,360 --> 01:00:42,480
Speaker 1: Speaking of chills and connecting back to Antarctica. One of

1212
01:00:42,520 --> 01:00:44,880
Speaker 1: the things they have in the British Museum is like

1213
01:00:45,000 --> 01:00:47,800
Speaker 1: the logbook of one of these journeys to the South Pole,

1214
01:00:48,160 --> 01:00:49,920
Speaker 1: and you can see like the last page where the

1215
01:00:49,920 --> 01:00:52,760
Speaker 1: guy rights it is very cold, and then that's it.

1216
01:00:53,160 --> 01:00:55,520
Speaker 1: That's the end of the law. Oh yeah, oh they

1217
01:00:55,560 --> 01:00:56,360
Speaker 1: found him with it.

1218
01:00:56,600 --> 01:00:57,320
Speaker 2: Oh that's ominous.

1219
01:00:57,440 --> 01:00:58,560
Speaker 3: Is that the Scott expedition?

1220
01:00:58,840 --> 01:01:02,240
Speaker 1: Yeah it might have been yea, yeah exactly, but you

1221
01:01:02,240 --> 01:01:04,640
Speaker 1: know he was taking data to the end a real scientist,

1222
01:01:04,840 --> 01:01:07,560
Speaker 1: you know, keeping records. But now I want to get

1223
01:01:07,600 --> 01:01:10,560
Speaker 1: to the inevitable place we always get to on this podcast,

1224
01:01:10,560 --> 01:01:16,040
Speaker 1: because everything leads to aliens and wealism, and I want

1225
01:01:16,040 --> 01:01:18,520
Speaker 1: to ask you about aliens because I want to know

1226
01:01:18,760 --> 01:01:21,960
Speaker 1: if what we've learned here on Earth is particular to

1227
01:01:22,480 --> 01:01:24,640
Speaker 1: our experience here where we tend to have islands and

1228
01:01:24,640 --> 01:01:27,040
Speaker 1: we have this particular history, or if this is something

1229
01:01:27,120 --> 01:01:30,240
Speaker 1: general and universal we've learned about life in the universe.

1230
01:01:30,760 --> 01:01:33,560
Speaker 1: So we're landing on an alien planet and we brought

1231
01:01:33,560 --> 01:01:36,080
Speaker 1: you along, Scott. Are you expecting to learn that on

1232
01:01:36,120 --> 01:01:39,640
Speaker 1: this planet there's natural selection and this evolution or do

1233
01:01:39,680 --> 01:01:41,600
Speaker 1: you think that that those are things that just happen

1234
01:01:41,680 --> 01:01:44,080
Speaker 1: here on Earth because of our particular set of circumstances.

1235
01:01:44,280 --> 01:01:47,320
Speaker 5: Yeah, I love this question because it forces us to ask, like,

1236
01:01:47,520 --> 01:01:50,080
Speaker 5: what is life? And do the things that we know

1237
01:01:50,200 --> 01:01:54,000
Speaker 5: about life actually apply, you know, universally or only to

1238
01:01:54,080 --> 01:01:57,440
Speaker 5: this particular version of life that we know. We actually

1239
01:01:57,520 --> 01:02:01,680
Speaker 5: in biology struggle to even to find what life is.

1240
01:02:01,760 --> 01:02:04,080
Speaker 5: And there's a lot of things that are sort of

1241
01:02:04,200 --> 01:02:07,920
Speaker 5: like gray areas, like, for example, viruses. Right, I don't know, Kelly,

1242
01:02:08,080 --> 01:02:10,520
Speaker 5: if you have opinions on our viruses alive, that's like

1243
01:02:10,560 --> 01:02:13,400
Speaker 5: a way to start a fight at a biology conference, right.

1244
01:02:15,120 --> 01:02:17,880
Speaker 5: But one of the definitions that people have proposed for

1245
01:02:18,440 --> 01:02:21,480
Speaker 5: what is life is that life is capable of evolving,

1246
01:02:22,280 --> 01:02:25,520
Speaker 5: and so like by definition, then if we see life,

1247
01:02:25,840 --> 01:02:29,160
Speaker 5: then yes, it should be capable of evolving. But that's

1248
01:02:29,320 --> 01:02:31,880
Speaker 5: like a circular definition, so it's not very satisfying. So

1249
01:02:32,200 --> 01:02:35,840
Speaker 5: I think another way of thinking about it is unless

1250
01:02:36,960 --> 01:02:42,240
Speaker 5: another form of life is immortal, if it has immortality

1251
01:02:42,240 --> 01:02:45,760
Speaker 5: and one individual can just live forever, then no, they

1252
01:02:45,760 --> 01:02:48,080
Speaker 5: wouldn't evolve the way that we think about it. But

1253
01:02:48,120 --> 01:02:50,560
Speaker 5: as long as there is mortality, as long as there

1254
01:02:50,600 --> 01:02:53,040
Speaker 5: is death, and as long as there is reproduction, and

1255
01:02:53,080 --> 01:02:55,240
Speaker 5: as long as there is some way for individuals to

1256
01:02:55,360 --> 01:03:00,160
Speaker 5: pass something of themselves to their offspring to the next generation.

1257
01:03:00,800 --> 01:03:05,000
Speaker 5: In that basic setup, you will always expect natural selection

1258
01:03:05,120 --> 01:03:07,880
Speaker 5: to work. You would always expect the basic principles that

1259
01:03:07,880 --> 01:03:09,760
Speaker 5: we've been talking about of evolution to work, and that,

1260
01:03:09,840 --> 01:03:12,320
Speaker 5: to me is one of the most powerful things about

1261
01:03:12,320 --> 01:03:15,080
Speaker 5: it that I think people don't often realize. We're not

1262
01:03:15,120 --> 01:03:18,320
Speaker 5: just saying evolution can happen, or you know, under some

1263
01:03:18,360 --> 01:03:22,000
Speaker 5: circumstances you might get changed. No, it's actually inevitable. It's

1264
01:03:22,000 --> 01:03:25,120
Speaker 5: sort of built into the system that anytime you have

1265
01:03:25,760 --> 01:03:29,520
Speaker 5: a thing that lives for some amount of time, reproduces,

1266
01:03:29,760 --> 01:03:34,000
Speaker 5: passes something on somehow to the next generation, right, that

1267
01:03:34,040 --> 01:03:37,680
Speaker 5: there will be changes that are heritable that are happening

1268
01:03:37,680 --> 01:03:41,400
Speaker 5: from one generation to the next. Now, the specific things

1269
01:03:41,440 --> 01:03:44,480
Speaker 5: that are evolving, the traits, the rules that maybe govern

1270
01:03:44,840 --> 01:03:47,600
Speaker 5: who survives and how they reproduce, that's all up for graps.

1271
01:03:47,640 --> 01:03:49,920
Speaker 1: The biochemical mechanism, whether it's DNA or.

1272
01:03:49,880 --> 01:03:52,560
Speaker 5: Not, yeah, exactly, doesn't have to be DNA, doesn't have

1273
01:03:52,600 --> 01:03:56,280
Speaker 5: to be anything like the way genetics works for Earth life.

1274
01:03:56,280 --> 01:04:00,000
Speaker 5: But as long as there is some mechanism of inheritance

1275
01:04:00,680 --> 01:04:04,800
Speaker 5: and as long as there is reproduction and multiple generations,

1276
01:04:05,160 --> 01:04:05,960
Speaker 5: there will be evolution.

1277
01:04:06,360 --> 01:04:08,640
Speaker 1: I like that you're very clear about the assumptions that

1278
01:04:08,680 --> 01:04:11,480
Speaker 1: go into that conclusion, because that immediately opens doors for

1279
01:04:11,520 --> 01:04:14,200
Speaker 1: like potential science fiction stories like I imagine now a

1280
01:04:14,320 --> 01:04:18,400
Speaker 1: planet where abiogenesis is very common. It didn't just happen once,

1281
01:04:18,440 --> 01:04:20,800
Speaker 1: but it's like constantly happening, and you're always getting like

1282
01:04:20,880 --> 01:04:23,440
Speaker 1: new forms of life propping up and they don't reproduce,

1283
01:04:23,480 --> 01:04:25,320
Speaker 1: they just die out. I guess in that scenario, you

1284
01:04:25,320 --> 01:04:28,080
Speaker 1: wouldn't have evolution, right, you just have like a constant,

1285
01:04:28,160 --> 01:04:30,160
Speaker 1: random genesis of weird kinds of life.

1286
01:04:30,280 --> 01:04:32,160
Speaker 5: Yeah, And that is an interesting thing that I often

1287
01:04:32,160 --> 01:04:35,240
Speaker 5: think about, is how come we only see the evolution

1288
01:04:35,880 --> 01:04:39,200
Speaker 5: of the origin of life one single time right here

1289
01:04:39,240 --> 01:04:41,920
Speaker 5: on Earth that we know of, or at least only

1290
01:04:42,000 --> 01:04:44,840
Speaker 5: one lineage of life has left descendants that we can

1291
01:04:44,960 --> 01:04:47,919
Speaker 5: find today. Why doesn't it keep happening? And I think

1292
01:04:47,920 --> 01:04:50,480
Speaker 5: there's reasons for that that we think we understand, But yeah,

1293
01:04:50,520 --> 01:04:54,400
Speaker 5: it could be that in some other world that it

1294
01:04:54,520 --> 01:04:57,600
Speaker 5: is much more common for life to just pop up spontaneously.

1295
01:04:57,640 --> 01:05:01,760
Speaker 5: And yeah, and that circumstance each individual origin of life

1296
01:05:02,280 --> 01:05:06,320
Speaker 5: could give rise to separate sort of evolutionary trajectories. But

1297
01:05:06,920 --> 01:05:10,160
Speaker 5: we would still expect them to evolve if they could reproduce.

1298
01:05:10,120 --> 01:05:12,680
Speaker 1: Eventually they would end up with podcasts, right.

1299
01:05:14,160 --> 01:05:18,680
Speaker 3: Everyone podca can hope that's right. Everyone on the show

1300
01:05:18,680 --> 01:05:19,280
Speaker 3: today has.

1301
01:05:19,120 --> 01:05:24,280
Speaker 1: Their own podcast, therefore dot that's.

1302
01:05:24,200 --> 01:05:27,280
Speaker 3: Right, all right, Well, Scott, this has been amazing and

1303
01:05:27,360 --> 01:05:29,600
Speaker 3: informative and a ton of fun. And thank you so

1304
01:05:29,680 --> 01:05:31,000
Speaker 3: much for being on the show. And we plan on

1305
01:05:31,040 --> 01:05:34,040
Speaker 3: having you back to talk about the future of human evolution,

1306
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Speaker 3: which is the second half of the question that we

1307
01:05:35,680 --> 01:05:38,120
Speaker 3: got from the listener, what would happen when our species

1308
01:05:38,120 --> 01:05:40,400
Speaker 3: moves out into space? So we look forward to having

1309
01:05:40,400 --> 01:05:42,560
Speaker 3: you back when you are ready to talk about your

1310
01:05:42,600 --> 01:05:43,080
Speaker 3: next book.

1311
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Speaker 5: Well, thanks so much, Kelly and Daniel. This has been

1312
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Speaker 5: fun and I can't wait to come back.

1313
01:05:47,040 --> 01:05:49,400
Speaker 1: Thanks for evolving our understanding of biology.

1314
01:05:49,640 --> 01:05:51,240
Speaker 2: Oh anytime.

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01:05:58,640 --> 01:06:02,480
Speaker 3: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We

1316
01:06:02,520 --> 01:06:04,920
Speaker 3: would love to hear from you, We really would.

1317
01:06:05,080 --> 01:06:07,720
Speaker 1: We want to know what questions do you have about

1318
01:06:07,720 --> 01:06:09,720
Speaker 1: this Extraordinary Universe.

1319
01:06:09,840 --> 01:06:12,800
Speaker 3: We want to know your thoughts on recent shows, suggestions

1320
01:06:12,800 --> 01:06:15,800
Speaker 3: for future shows. If you contact us, we will get

1321
01:06:15,840 --> 01:06:16,240
Speaker 3: back to you.

1322
01:06:16,480 --> 01:06:19,920
Speaker 1: We really mean it. We answer every message. Email us

1323
01:06:20,040 --> 01:06:22,880
Speaker 1: at Questions at Danielankelly dot org.

1324
01:06:23,080 --> 01:06:25,280
Speaker 3: You can find us on social media. We have accounts

1325
01:06:25,280 --> 01:06:29,280
Speaker 3: on x, Instagram, Blue Sky and on all of those platforms.

1326
01:06:29,280 --> 01:06:32,200
Speaker 3: You can find us at D and K Universe.

1327
01:06:32,360 --> 01:06:33,880
Speaker 1: Don't be shy right to us.