Speaker 1: Welcome to brain Stuff from how Stuff Works. Hey, brain Stuff,
Speaker 1: I'm Lauren vogel Bomb, and here's some information you might
Speaker 1: already know. Not very much can survive the impact of
Speaker 1: a six mile a k a ten kilometer wide asteroid.
Speaker 1: Ask the dinosaurs. With that kind of impact, the world
Speaker 1: catches on fire, and most terrestrial creatures, by the proverbial
Speaker 1: farm within a matter of hours. If the impact and
Speaker 1: fire don't kill them, the resulting impact winter blocks out
Speaker 1: sunlight for a year or more, making it very hard
Speaker 1: for plans to grow and thus for animals to find
Speaker 1: food or indeed muster the will to live. So just
Speaker 1: how many terrestrial species survived the hellscape that resulted from
Speaker 1: an asteroid landing in present day Mexico sixty six million
Speaker 1: years ago. Nobody knows, but the dinosaurs were particularly hard hit.
Speaker 1: But a report published in a issue of the journal
Speaker 1: Current Biology suggests that though the non avian dinos were obliterated,
Speaker 1: a handful of small feathered dinosaurs survived, and that these
Speaker 1: feathered creatures were the ancestors of modern birds. Of course,
Speaker 1: this isn't a new idea that modern birds evolved from
Speaker 1: the dinosaurs that survived the last major asteroid ordeal, but
Speaker 1: the international team of researchers behind the current report hypothesized
Speaker 1: that since forests were burned to the ground all over
Speaker 1: the globe and wouldn't return for hundreds or maybe thousands
Speaker 1: of years, virtually all the birds alive today descended from
Speaker 1: a few small ground dwelling species, probably a bit like
Speaker 1: the modern quail that didn't rely on tree habitats. Lead
Speaker 1: author Daniel Field of the Milner Center for Evolution at
Speaker 1: the University of Bath set in a press release, we
Speaker 1: drew on a variety of approaches to stitch this story together.
Speaker 1: We concluded that the devastation of forests in the aftermath
Speaker 1: of the asteroid impact explains why tree dwelling birds failed
Speaker 1: to survive across this extinction event. The ancestors of modern
Speaker 1: tree dwelling birds did not move into the trees until
Speaker 1: forests had recovered from the extinction causing asteroid The research
Speaker 1: team analyzed pollen grains in the plant fossil record to
Speaker 1: figure out just how many forests survived the asteroids impact,
Speaker 1: and confirmed that the number is pretty close to zero.
Speaker 1: Pooling what's currently known about modern bird evolution, they were
Speaker 1: able to model a basic bird family tree going back
Speaker 1: to the birds that survived this cataclysm. The results of
Speaker 1: that analysis suggest that the common ancestors were probably ground dwellers,
Speaker 1: and that they survived for years on seeds buried in
Speaker 1: the soil. From that small group of birds sprung the
Speaker 1: eleven thousand species of birds that Earth supports today. They're
Speaker 1: the most diverse group of terrestrial vertebrates that our planet
Speaker 1: has going. Now that the researchers have an idea of
Speaker 1: where birds come from, their next move is to study
Speaker 1: how they radiated out across the globe and to pinpoint
Speaker 1: exactly when the forests recovered. Field said, we are working
Speaker 1: hard to shed new light on this murky portion of
Speaker 1: the fossil record, which promises to tell us a lot
Speaker 1: about how birds and other animal groups survived then thrived
Speaker 1: following the extinction of t rex and triceratops. Today's episode
Speaker 1: was written by Jesselyn Shields and produced by Tyler Clang.
Speaker 1: For more on this and lots of other plucky topics,
Speaker 1: visit our home planet, how Stuff Works dot com.