1 00:00:02,040 --> 00:00:07,080 Speaker 1: Welcome to brain Stuff from how Stuff Works. Hey, brain Stuff, 2 00:00:07,120 --> 00:00:10,239 Speaker 1: I'm Lauren vogel Bomb, and here's some information you might 3 00:00:10,360 --> 00:00:14,160 Speaker 1: already know. Not very much can survive the impact of 4 00:00:14,200 --> 00:00:17,960 Speaker 1: a six mile a k a ten kilometer wide asteroid. 5 00:00:18,600 --> 00:00:22,000 Speaker 1: Ask the dinosaurs. With that kind of impact, the world 6 00:00:22,079 --> 00:00:25,919 Speaker 1: catches on fire, and most terrestrial creatures, by the proverbial 7 00:00:25,960 --> 00:00:29,200 Speaker 1: farm within a matter of hours. If the impact and 8 00:00:29,280 --> 00:00:32,400 Speaker 1: fire don't kill them, the resulting impact winter blocks out 9 00:00:32,440 --> 00:00:35,200 Speaker 1: sunlight for a year or more, making it very hard 10 00:00:35,200 --> 00:00:37,680 Speaker 1: for plans to grow and thus for animals to find 11 00:00:37,720 --> 00:00:41,839 Speaker 1: food or indeed muster the will to live. So just 12 00:00:42,000 --> 00:00:45,680 Speaker 1: how many terrestrial species survived the hellscape that resulted from 13 00:00:45,680 --> 00:00:48,800 Speaker 1: an asteroid landing in present day Mexico sixty six million 14 00:00:48,920 --> 00:00:53,199 Speaker 1: years ago. Nobody knows, but the dinosaurs were particularly hard hit. 15 00:00:54,200 --> 00:00:57,160 Speaker 1: But a report published in a issue of the journal 16 00:00:57,200 --> 00:01:01,800 Speaker 1: Current Biology suggests that though the non avian dinos were obliterated, 17 00:01:02,120 --> 00:01:05,880 Speaker 1: a handful of small feathered dinosaurs survived, and that these 18 00:01:05,920 --> 00:01:09,800 Speaker 1: feathered creatures were the ancestors of modern birds. Of course, 19 00:01:09,880 --> 00:01:13,080 Speaker 1: this isn't a new idea that modern birds evolved from 20 00:01:13,080 --> 00:01:16,480 Speaker 1: the dinosaurs that survived the last major asteroid ordeal, but 21 00:01:16,640 --> 00:01:20,560 Speaker 1: the international team of researchers behind the current report hypothesized 22 00:01:20,600 --> 00:01:23,080 Speaker 1: that since forests were burned to the ground all over 23 00:01:23,080 --> 00:01:26,360 Speaker 1: the globe and wouldn't return for hundreds or maybe thousands 24 00:01:26,360 --> 00:01:30,119 Speaker 1: of years, virtually all the birds alive today descended from 25 00:01:30,160 --> 00:01:33,720 Speaker 1: a few small ground dwelling species, probably a bit like 26 00:01:33,760 --> 00:01:38,039 Speaker 1: the modern quail that didn't rely on tree habitats. Lead 27 00:01:38,040 --> 00:01:41,040 Speaker 1: author Daniel Field of the Milner Center for Evolution at 28 00:01:41,040 --> 00:01:44,040 Speaker 1: the University of Bath set in a press release, we 29 00:01:44,120 --> 00:01:47,080 Speaker 1: drew on a variety of approaches to stitch this story together. 30 00:01:47,440 --> 00:01:50,320 Speaker 1: We concluded that the devastation of forests in the aftermath 31 00:01:50,360 --> 00:01:53,640 Speaker 1: of the asteroid impact explains why tree dwelling birds failed 32 00:01:53,640 --> 00:01:57,440 Speaker 1: to survive across this extinction event. The ancestors of modern 33 00:01:57,480 --> 00:02:00,000 Speaker 1: tree dwelling birds did not move into the trees until 34 00:02:00,080 --> 00:02:04,680 Speaker 1: forests had recovered from the extinction causing asteroid The research 35 00:02:04,720 --> 00:02:07,680 Speaker 1: team analyzed pollen grains in the plant fossil record to 36 00:02:07,760 --> 00:02:11,079 Speaker 1: figure out just how many forests survived the asteroids impact, 37 00:02:11,440 --> 00:02:13,840 Speaker 1: and confirmed that the number is pretty close to zero. 38 00:02:14,520 --> 00:02:17,600 Speaker 1: Pooling what's currently known about modern bird evolution, they were 39 00:02:17,639 --> 00:02:20,800 Speaker 1: able to model a basic bird family tree going back 40 00:02:20,840 --> 00:02:23,880 Speaker 1: to the birds that survived this cataclysm. The results of 41 00:02:23,880 --> 00:02:27,760 Speaker 1: that analysis suggest that the common ancestors were probably ground dwellers, 42 00:02:28,040 --> 00:02:30,800 Speaker 1: and that they survived for years on seeds buried in 43 00:02:30,840 --> 00:02:34,080 Speaker 1: the soil. From that small group of birds sprung the 44 00:02:34,080 --> 00:02:37,480 Speaker 1: eleven thousand species of birds that Earth supports today. They're 45 00:02:37,480 --> 00:02:40,200 Speaker 1: the most diverse group of terrestrial vertebrates that our planet 46 00:02:40,240 --> 00:02:43,360 Speaker 1: has going. Now that the researchers have an idea of 47 00:02:43,360 --> 00:02:46,000 Speaker 1: where birds come from, their next move is to study 48 00:02:46,040 --> 00:02:49,000 Speaker 1: how they radiated out across the globe and to pinpoint 49 00:02:49,040 --> 00:02:53,160 Speaker 1: exactly when the forests recovered. Field said, we are working 50 00:02:53,200 --> 00:02:55,680 Speaker 1: hard to shed new light on this murky portion of 51 00:02:55,680 --> 00:02:58,040 Speaker 1: the fossil record, which promises to tell us a lot 52 00:02:58,080 --> 00:03:01,399 Speaker 1: about how birds and other animal groups survived then thrived 53 00:03:01,639 --> 00:03:10,880 Speaker 1: following the extinction of t rex and triceratops. Today's episode 54 00:03:10,919 --> 00:03:13,480 Speaker 1: was written by Jesselyn Shields and produced by Tyler Clang. 55 00:03:13,800 --> 00:03:16,200 Speaker 1: For more on this and lots of other plucky topics, 56 00:03:16,360 --> 00:03:30,320 Speaker 1: visit our home planet, how Stuff Works dot com.