1 00:00:01,920 --> 00:00:06,960 Speaker 1: Welcome to brain Stuff production of iHeart Radio, Hey brain Stuff, 2 00:00:07,000 --> 00:00:10,720 Speaker 1: Lauren vocal bomb here. Convergent evolution is the idea that 3 00:00:10,760 --> 00:00:14,640 Speaker 1: two organisms that aren't very closely related can independently evolve 4 00:00:14,680 --> 00:00:18,360 Speaker 1: a very similar trait. For instance, the last ancestor that 5 00:00:18,400 --> 00:00:21,279 Speaker 1: we shared in common with an octopus probably looked a 6 00:00:21,320 --> 00:00:24,439 Speaker 1: lot like a worm, even though that animal might have 7 00:00:24,480 --> 00:00:27,240 Speaker 1: been able to detect light and dark. It took something 8 00:00:27,280 --> 00:00:30,160 Speaker 1: like seven dred and fifty million years of both human 9 00:00:30,240 --> 00:00:33,720 Speaker 1: and octopus ancestors working on being able to see properly 10 00:00:34,000 --> 00:00:37,159 Speaker 1: to evolve the incredibly similar eye structures that humans and 11 00:00:37,280 --> 00:00:43,680 Speaker 1: octopuses now share nifty. But this isn't how it always happens. Take, 12 00:00:43,800 --> 00:00:46,400 Speaker 1: for instance, the voice box of a bird. It's called 13 00:00:46,479 --> 00:00:49,880 Speaker 1: a syrinx, and no other organism on Earth has one. 14 00:00:50,560 --> 00:00:54,360 Speaker 1: It's something of an evolutionary mystery. Why not? Actually, After all, 15 00:00:54,520 --> 00:00:57,040 Speaker 1: other animals need to be able to communicate, just like 16 00:00:57,200 --> 00:00:59,520 Speaker 1: both cephalopods and mammals need to be able to see 17 00:00:59,560 --> 00:01:03,000 Speaker 1: what they're doing. In fact, the SEARINGX is arguably much 18 00:01:03,080 --> 00:01:06,240 Speaker 1: weirder than the high acuity camera style I we share 19 00:01:06,280 --> 00:01:09,120 Speaker 1: with the octopus because the SEARINGX came out of nowhere. 20 00:01:09,240 --> 00:01:13,320 Speaker 1: Evolutionarily speaking, it could be argued that the synx is 21 00:01:13,360 --> 00:01:16,760 Speaker 1: a bit redundant in bird anatomy, as they also possess larynxes, 22 00:01:17,120 --> 00:01:19,640 Speaker 1: the voice box structure that they share with we mammals 23 00:01:19,680 --> 00:01:23,000 Speaker 1: and some amphibians and reptiles, though it only functions very 24 00:01:23,040 --> 00:01:26,399 Speaker 1: well in mammals and a few lizards. The larynx is 25 00:01:26,400 --> 00:01:29,319 Speaker 1: what enables cows to move, dogs to bark, and babies 26 00:01:29,360 --> 00:01:33,600 Speaker 1: to cry, and it's situated at the top of the throat. However, 27 00:01:33,920 --> 00:01:37,880 Speaker 1: birds use their synx to make their fluty vocalizations. It's 28 00:01:38,000 --> 00:01:40,400 Speaker 1: similar to the larynx and that it's made of folds 29 00:01:40,400 --> 00:01:44,240 Speaker 1: of vocal membranes supported by cartilage. However, the synx is 30 00:01:44,280 --> 00:01:46,920 Speaker 1: buried deep in a bird's chest, right above where their 31 00:01:46,920 --> 00:01:52,120 Speaker 1: tracheo bronchial tube splits off into their lungs. In twenty sixteen, 32 00:01:52,320 --> 00:01:55,720 Speaker 1: paleontologists from the University of Texas in Austin reported that, 33 00:01:55,840 --> 00:01:58,480 Speaker 1: based on fossil evidence, the structure we know as the 34 00:01:58,480 --> 00:02:02,560 Speaker 1: syrinx is around sixties million years old. Since then, the 35 00:02:02,600 --> 00:02:05,880 Speaker 1: research team has been comparing the larynx and syrinx anatomy, 36 00:02:06,080 --> 00:02:09,680 Speaker 1: genetics and development of birds to those of modern reptiles 37 00:02:09,720 --> 00:02:12,480 Speaker 1: and have discovered the evolution of the syrinx is even 38 00:02:12,520 --> 00:02:17,040 Speaker 1: stranger than previously thought. In a paper published in eighteen 39 00:02:17,120 --> 00:02:19,560 Speaker 1: issue of the Proceedings of the National Academy of Sciences, 40 00:02:19,840 --> 00:02:22,840 Speaker 1: the research team reported the function, form, and development of 41 00:02:22,840 --> 00:02:26,919 Speaker 1: the syrinx and the larynx are actually quite different. For starters, 42 00:02:27,080 --> 00:02:29,640 Speaker 1: the vocal cords of the larynx are manipulated by muscles 43 00:02:29,680 --> 00:02:32,880 Speaker 1: attached to the cartilage that supports them. The seynx, on 44 00:02:32,919 --> 00:02:35,720 Speaker 1: the other hand, partially attaches to muscles that in other 45 00:02:35,760 --> 00:02:38,960 Speaker 1: animals fastened the tongue to the bones connecting the arms 46 00:02:39,000 --> 00:02:42,840 Speaker 1: to the rest of the body. Secondly, while baby birds 47 00:02:42,840 --> 00:02:46,120 Speaker 1: and baby lizards are developing different types of cells form 48 00:02:46,200 --> 00:02:50,079 Speaker 1: their respective voice boxes, larynxes are made of a mixture 49 00:02:50,160 --> 00:02:53,359 Speaker 1: of mesoderm and neural crest cells, which are a temporary 50 00:02:53,360 --> 00:02:56,080 Speaker 1: group of cells that arise from the ectoderm, while the 51 00:02:56,160 --> 00:03:01,680 Speaker 1: syrinx is created exclusively using mesoderm cells. So at some point, 52 00:03:01,960 --> 00:03:04,840 Speaker 1: the ancestors of modern birds just started making a new 53 00:03:04,919 --> 00:03:08,359 Speaker 1: voice box, which eventually took over the job of the larynx. 54 00:03:08,919 --> 00:03:15,440 Speaker 1: As a result, now birds can sound like this. This 55 00:03:15,560 --> 00:03:19,040 Speaker 1: research is exciting because although convergent evolution is a really 56 00:03:19,080 --> 00:03:22,280 Speaker 1: cool thing for scientists to wander over, a true evolutionary 57 00:03:22,320 --> 00:03:31,000 Speaker 1: outlier is arguably cooler. Today's episode was written by Jesselyn 58 00:03:31,040 --> 00:03:33,600 Speaker 1: Shields and produced by Tyler Clang. Brain Stuff is a 59 00:03:33,600 --> 00:03:35,960 Speaker 1: production of I Heart Radio's How Stuff Works. For more 60 00:03:36,000 --> 00:03:38,120 Speaker 1: on this and lots of other convergent topics, visit our 61 00:03:38,200 --> 00:03:40,760 Speaker 1: home planet, how stuff works dot com. And for more 62 00:03:40,840 --> 00:03:43,240 Speaker 1: podcasts from my heart Radio, visit the iHeart Radio app, 63 00:03:43,400 --> 00:03:45,960 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.