WEBVTT - What Kind of Dinos Did Today's Birds Evolve From?

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<v Speaker 1>Welcome to brain Stuff from how Stuff Works. Hey, brain Stuff,

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<v Speaker 1>I'm Lauren vogel Bomb, and here's some information you might

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<v Speaker 1>already know. Not very much can survive the impact of

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<v Speaker 1>a six mile a k a ten kilometer wide asteroid.

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<v Speaker 1>Ask the dinosaurs. With that kind of impact, the world

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<v Speaker 1>catches on fire, and most terrestrial creatures, by the proverbial

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<v Speaker 1>farm within a matter of hours. If the impact and

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<v Speaker 1>fire don't kill them, the resulting impact winter blocks out

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<v Speaker 1>sunlight for a year or more, making it very hard

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<v Speaker 1>for plans to grow and thus for animals to find

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<v Speaker 1>food or indeed muster the will to live. So just

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<v Speaker 1>how many terrestrial species survived the hellscape that resulted from

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<v Speaker 1>an asteroid landing in present day Mexico sixty six million

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<v Speaker 1>years ago. Nobody knows, but the dinosaurs were particularly hard hit.

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<v Speaker 1>But a report published in a issue of the journal

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<v Speaker 1>Current Biology suggests that though the non avian dinos were obliterated,

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<v Speaker 1>a handful of small feathered dinosaurs survived, and that these

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<v Speaker 1>feathered creatures were the ancestors of modern birds. Of course,

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<v Speaker 1>this isn't a new idea that modern birds evolved from

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<v Speaker 1>the dinosaurs that survived the last major asteroid ordeal, but

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<v Speaker 1>the international team of researchers behind the current report hypothesized

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<v Speaker 1>that since forests were burned to the ground all over

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<v Speaker 1>the globe and wouldn't return for hundreds or maybe thousands

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<v Speaker 1>of years, virtually all the birds alive today descended from

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<v Speaker 1>a few small ground dwelling species, probably a bit like

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<v Speaker 1>the modern quail that didn't rely on tree habitats. Lead

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<v Speaker 1>author Daniel Field of the Milner Center for Evolution at

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<v Speaker 1>the University of Bath set in a press release, we

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<v Speaker 1>drew on a variety of approaches to stitch this story together.

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<v Speaker 1>We concluded that the devastation of forests in the aftermath

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<v Speaker 1>of the asteroid impact explains why tree dwelling birds failed

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<v Speaker 1>to survive across this extinction event. The ancestors of modern

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<v Speaker 1>tree dwelling birds did not move into the trees until

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<v Speaker 1>forests had recovered from the extinction causing asteroid The research

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<v Speaker 1>team analyzed pollen grains in the plant fossil record to

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<v Speaker 1>figure out just how many forests survived the asteroids impact,

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<v Speaker 1>and confirmed that the number is pretty close to zero.

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<v Speaker 1>Pooling what's currently known about modern bird evolution, they were

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<v Speaker 1>able to model a basic bird family tree going back

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<v Speaker 1>to the birds that survived this cataclysm. The results of

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<v Speaker 1>that analysis suggest that the common ancestors were probably ground dwellers,

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<v Speaker 1>and that they survived for years on seeds buried in

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<v Speaker 1>the soil. From that small group of birds sprung the

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<v Speaker 1>eleven thousand species of birds that Earth supports today. They're

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<v Speaker 1>the most diverse group of terrestrial vertebrates that our planet

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<v Speaker 1>has going. Now that the researchers have an idea of

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<v Speaker 1>where birds come from, their next move is to study

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<v Speaker 1>how they radiated out across the globe and to pinpoint

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<v Speaker 1>exactly when the forests recovered. Field said, we are working

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<v Speaker 1>hard to shed new light on this murky portion of

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<v Speaker 1>the fossil record, which promises to tell us a lot

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<v Speaker 1>about how birds and other animal groups survived then thrived

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<v Speaker 1>following the extinction of t rex and triceratops. Today's episode

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<v Speaker 1>was written by Jesselyn Shields and produced by Tyler Clang.

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<v Speaker 1>For more on this and lots of other plucky topics,

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<v Speaker 1>visit our home planet, how Stuff Works dot com.