hey smart people Joe here this holiday season I bet many of you are gonna sit down with family and friends to celebrate and I bet a lot of you are gonna be sitting down to eat some nice delicious dinosaur birds are dinosaurs but why is that that's what we're gonna talk about today today I'm here with my friends Anna Rothschild who makes science magic show hooray at the Washington Post and fun fact she's 25% mashed potatoes it's true I am and doctor shame on tonari who is not only a pumpkin beer aficionado but is a dinosaur expert extraordinaire really happy to be here Joe we have all heard that birds are dinosaurs but what exactly does that really mean that's a great question Anna so the way that we can even tell that anything is related to something else is through looking at their Anatomy and what kind of characteristics that they share these are called synapomorphies traits shared by two or more groups of organisms and derived from a common ancestor like how humans and chimps both have opposable thumbs so there's different kinds of dinosaurs and we can look at the characteristics of birds to figure out exactly what kind of dinosaurs they are there's actually lots of clues preserved in their bones that show that they are very closely related in that birds are actually dinosaurs and we're gonna find those today with this so we couldn't get a turkey it's not quite Thanksgiving yet but everything we show you we promise that you can do at your holiday table with the people that you're celebrating with and explain to them the science of why they're eating a dinosaur in the 1860s scientists unearthed the most famous feathered dinosaur fossil Archaeopteryx early defenders of evolution like thomas henry huxley began to suggest that these extinct reptiles were so similar to birds they must be related but the idea didn't really catch on until the 1970s when new fossils filled in more empty branches on the dinosaur family tree about 250 million years ago a group called ARCA soars in two crocodilian reptiles and dinosaurs and a lot of evolution has happened since that split okay so there are two groups of dinosaurs and it's the ornithiscians and sirisha in dinosaurs and that split happened about 240 million years ago and the way that we know that birds belong to the certian group is mainly because of their hands waiting hands right first I really do have hands they just don't really look like hands anymore so if you've eaten a chicken wing or at least you know held on door chicken you've been shaking hands with a chicken can we dig into this chicken and check it back it's time to check it out let's go find that chicken hand so these are like the original chicken fingers now I usually dissect these with my teeth you're doing it completely differently yeah so that little skinny part of the wing at the end that you don't typically eat this little measurement on it that little nubbin is the finger of the chicken that's gotten super reduced I accidentally bring on the very tip of the bird finger but here is like the second digit the very very tip of the finger it's a tiny bird finger I'm gonna let you hold that as well at the first digit the second digit and the third digit the length of the three bird fingers inside a wing narrows down which group of dinosaurs birds descended from the second finger is longest in birds and in sireesha and dinosaurs that's a big way that we know that birds belong to the certian group as opposed to the ornithischian group so birds are sushi and dinosaurs but are all sirisha and dinosaurs birds no they're not that's a great question so even within searching dinosaurs as we're walking up this dinosaur family tree there is another group that branches off and we can tell which one birds are part of and it's the theropod dinosaurs and the one bone that is the biggest clue of theropod dinosaurs is something that you've probably a little game with after your Thanksgiving dinner the wishbone right here cool I think it's time to dissect a wishbone what is the wishbone do does it serve a purpose for a flight or for something else what help it helps birds get their get their wishes all their dreams come true their curricula is actually support for the flight muscles a wishbone or circular is actually a bird's collarbones but instead of two separate collarbones like we have theirs is fused into one wish bones have only been found in birds and theropod dinosaurs like Allosaurus and they draw a clear line from those extinct creatures to our modern feathered friends let's get this wishbone out here in one piece oh this is nerve-racking I got it so all birds will have a form of this and all of the dinosaurs in this part of the tree also had something like this right we found a fur Fila in most theropod dinosaurs fossils that we found around the world so we'll save this for later fossil wishbones are one of the most important pieces of evidence we have that birds descended from theropod dinosaurs so actually one of the similarities between birds and theropods and how we know Birds or theropod dinosaurs is inside their bones this is another one of those tibia Tarsus bones from a thick brown stick bones and I have channels all of my rage and broken this one in half you can see that the walls of the bone is very thin and basically hollows when people say oh birds have hollow bones that's what they need there's a very little spongy bone on the inside and it's just a very thin wall this makes it easier for them to fly theropod dinosaurs have these hollow bones - so did that help them be like more agile you know going for more Jurassic Park type kills right that's a great question because theropods had a lot of the characteristics that modern birds do but they didn't fly so these characteristics must have been helpful for them to do other things and hunting is definitely one of them that's a cool thing about evolution is that something that could have helped theropods that didn't fly in one way like birds could have taken advantage of that in a completely different way as lightweight for flight right exactly so even within theropods as we're going down the family tree there's more branches and the way that we can tell which one birds fall in is how many fingers they have so our chicken we've got 1 2 3 fingers around 200 million years ago theropods split one branch kept 4 or even 5 fingers but a branch called Teton array all descended from an ancestor with just three fingers our bird three fingers later some Teton urns like t-rex even lost an additional finger going from 3 to 2 poor t-rex so to get to the next identifying characteristic of this bird really gonna have to dig in here I'm just ripping just parts out here this is kind of fun it's like the brain scoop crossed with a cooking show right now yeah I mean honestly this entire scene is so McCobb it's so bad darkest Thanksgiving yeah you can do any of this with a turkey that's just gonna be a lot Messier which in my book is makes it more fun okay so we know that birds are teton neurons but is that the last branch or can we get like even more specific we can get even more specific there's a few more branches to go before we get to what we call crown Birds or living birds and birds are a specific type of theropod called manner actor in theropods so manner Raptor one of the characteristics of this group is that the hips point backwards specifically the rearward tilted bone is a part of the pelvis called the pubis look at our backward facing pelvis for the manner after ins is there another branch beyond this yes so there's a me alley so ABS is part of a viale a veces modern birds and a big difference between the kinds of theropod dinosaurs that you're probably envisioning in your head like Velociraptor and Birds is a tail so birds actually do not have tails this little bit at the end and represents what's left there's a dinosaur tail called a piyo style so the PI go style is the last remnants of a long fluffy feathered theropod tail and narrows down the bird dinosaur family tree even further so birds are avian and a raptor in dead nuran theropod dinosaurs and these anatomical features are just a few of the similarities that scientists have used to place birds in the dinosaur family tree there's even more from the shape of their necks to their weird feet - yes even feathers okay my holiday dinner is never gonna be the same it's gonna be way awesomer and a little grosser but that's okay so if you want to do this at home you definitely can and if you want to learn more there's links in the description you know we've taken a deep dive inside of a dinosaur to see what makes them what they are but what were they like on the outside what did they act like that is an excellent question and if you want to learn a little bit more about what color's dinosaurs were and maybe even what sounds they made head over to my channel where Joe and I explore those questions can we all try to do our best dinosaur sound impression okay like every holiday dinner this one has to end with traditional breaking of the wishbone grab a side guys three two one what I wish for everyone to stay curious and all that because it's natural and