WEBVTT - Which of Today's Animals Lived Alongside Dinosaurs?

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<v Speaker 1>Welcome to brainsty a production of iHeartRadio, Hey Brainstuff Laura

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<v Speaker 1>voleban here. According to the prevailing scientific theory, non avian

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<v Speaker 1>dinosaurs met their dramatic end after an enormous asteroid hit

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<v Speaker 1>the Earth near what's now Mexico about sixty six million

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<v Speaker 1>years ago, give or take. This mass extinction, known today

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<v Speaker 1>as the Cretaceous paleagen or the Cretaceous Tertiary extinction, event,

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<v Speaker 1>caused a huge amount of debris like dust and ash

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<v Speaker 1>to fill the atmosphere. This in turn created what's called

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<v Speaker 1>an impact winter, in which life giving light from the

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<v Speaker 1>sun was blocked. A plant life couldn't photosynthesize and thus

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<v Speaker 1>died off. The oceans acidified, the food chain was disrupted,

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<v Speaker 1>and some seventy to eighty percent of all life on

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<v Speaker 1>the planet was wiped out. It was the literal end

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<v Speaker 1>of an era, the Mesozoic to be specific. The mighty

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<v Speaker 1>non avian dinosaurs were perhaps the most famous of the

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<v Speaker 1>life forms that died out post asteroid, but many others

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<v Speaker 1>became extinct as well. These included aquatic reptiles like plesiosaurs,

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<v Speaker 1>the first vertebrate animals to fly by flapping their wings.

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<v Speaker 1>The pterosaurs, the vast numbers of oceanic invertebrates, and some

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<v Speaker 1>ninety percent of algae species. Life was never the same,

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<v Speaker 1>but some types of animals weren't hit nearly as hard.

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<v Speaker 1>At least a few members of about eighty four percent

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<v Speaker 1>of marine families and eighty two percent of land vertebrate

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<v Speaker 1>families made it through. So many life forms survived the

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<v Speaker 1>event that it would take way more than a podcast

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<v Speaker 1>episode to describe them all, and many of the animals

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<v Speaker 1>have descendants that still live today. Some of these species

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<v Speaker 1>look a lot like their Mesozoic counterparts. Others have changed

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<v Speaker 1>quite a bit, including birds, which are the descendants of

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<v Speaker 1>avian dinosaurs that managed to survive the extinction event. So

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<v Speaker 1>aside from birds, which of today's animals walked, crawled, slithered,

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<v Speaker 1>or swam alongside dinosaurs. Dinos lived on Earth during the

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<v Speaker 1>Mesozoic Era, which lasted from two hundred and forty eight

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<v Speaker 1>to sixty six million years ago. Geologists divide the Mesozoic

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<v Speaker 1>Era into three periods, from longest ago to most recent

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<v Speaker 1>the Triassic, Jurassic, and Cretaceous. Dinosaurs became more diverse as

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<v Speaker 1>time went by, and at the same time, other life

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<v Speaker 1>forms developed and became extinct. If the Mesozoic era was

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<v Speaker 1>the age of the dinosaurs, the next era, the Cenozoic era,

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<v Speaker 1>was the age of mammals. The first mammals were monotremes,

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<v Speaker 1>or mammals that reproduce by laying eggs. Mammals in general

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<v Speaker 1>are common today, but only three monotrem species still exist.

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<v Speaker 1>These are the duckbilled platypus and a couple of echidnas,

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<v Speaker 1>and you can see our past episodes on both of those.

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<v Speaker 1>Many types of reptiles species die during the extinction event,

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<v Speaker 1>but some snakes, lizards, and crocodilians persevered. Crocodilians have been

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<v Speaker 1>on the planet for about two hundred and forty million years.

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<v Speaker 1>There are twenty three crocodilian species today, including alligators, crocodiles,

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<v Speaker 1>and caymans. Mesozoic crocodilians were generally larger. Another prehistoric order

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<v Speaker 1>of reptiles is the Saphenodontians. Today there is one living sphenodon,

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<v Speaker 1>the Tuitara, a small, spiky, gray green reptile that lives

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<v Speaker 1>in New Zealand. The most likely evolutionary origin for these

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<v Speaker 1>reptiles is that in the distant past they arose from amphibians.

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<v Speaker 1>Very large amphibian species lived before and during the Mesozoic.

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<v Speaker 1>These are gone today, but in their place three primary

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<v Speaker 1>types of amphibians survived, frogs and toads, nuts and salamanders,

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<v Speaker 1>and celions, which are animals that mostly look like worms

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<v Speaker 1>but have skeletons. But not. Every family that lived during

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<v Speaker 1>the Mesozoic has only a few descendants left today. All

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<v Speaker 1>modern insect groups existed before or arose during the Mesozoic era,

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<v Speaker 1>and perhaps most notable of these is the usocial bee

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<v Speaker 1>of bees that live in colonies. Most likely these evolved

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<v Speaker 1>along with flowering plants, which started to develop in the

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<v Speaker 1>Cretaceous period. Without this code development, we humans wouldn't have

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<v Speaker 1>honey or a whole host of bee pollinated fruits, vegetables, nuts,

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<v Speaker 1>and grains today. Ferns and conifers were also widespread during

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<v Speaker 1>the Mesozoic era, and ferns actually experienced a huge population

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<v Speaker 1>spike after the extinction event. Then there's Gingo biloba. If

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<v Speaker 1>you see one of these trees but which has fan

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<v Speaker 1>shaped green leaves that turn golden yellow in the fall,

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<v Speaker 1>you're looking at a plant that's almost identical in appearance

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<v Speaker 1>to its Mesozoic ancestors, but the oceans were particularly devastated

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<v Speaker 1>by the event. Dinosaurs were not particularly aquatic, but there

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<v Speaker 1>were lots of sea dwelling animals during the Mesozoic. The

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<v Speaker 1>aforementioned pleasyosaurs were long necked, finned reptiles. Think of the

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<v Speaker 1>Lochness monster and you've got a pretty good idea of

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<v Speaker 1>what one looked like, though as far as science knows,

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<v Speaker 1>they did not survive. Other marine life forms experienced heavy

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<v Speaker 1>losses but eventually recovered and went on to thrive and diversify.

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<v Speaker 1>Those include the echinoderms like sea stars, sea urchins, and

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<v Speaker 1>sea cucumbers, plus mollusks with their soft bodies and hard shells.

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<v Speaker 1>The clams, snails, lobsters, crabs, and shrimp that make their

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<v Speaker 1>way to the mouths of oceanic carnivores, and the plates

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<v Speaker 1>of hungry humans come from predecessors that, one way or another,

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<v Speaker 1>lived through the extinction event. Sharks also inhabited the world's

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<v Speaker 1>oceans long before the first dino made its way across land,

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<v Speaker 1>and they're among the most well known oceanic predators today,

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<v Speaker 1>but a few of today's species are the only remaining

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<v Speaker 1>examples of long extinct marine families. The most famous may

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<v Speaker 1>be the Sila camp, the last known marines sarcopterrigian, which

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<v Speaker 1>were lobe finned bony fish. There are plenty of other

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<v Speaker 1>Sarcopterygians in the world, though. All of the four limbed

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<v Speaker 1>vertebrates on the planet, from turtles to tucans to humans,

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<v Speaker 1>arose from common ancestors that diverged from the sarcoptigians long

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<v Speaker 1>before the Mesozoic era. Scientists thought selacanths were extinct until

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<v Speaker 1>the nineteen thirties, so hey, it's possible that researchers may

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<v Speaker 1>one day find other remnants of Mesoic life out there.

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<v Speaker 1>Today's episode is based on the article which of today's

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<v Speaker 1>animals lived alongside dinosaurs on how stuffworks dot Com, written

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<v Speaker 1>by Tracy V. Wilson. Brain Stuff is production of by

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<v Speaker 1>Heart Radio in partnership with how Stuffworks dot Com, produced

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<v Speaker 1>by Tyler Klang. For more podcasts from my Heart Radio,

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<v Speaker 1>visit the iHeartRadio app, Apple Podcasts, or wherever you listen

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<v Speaker 1>to your favorite shows.