# Did different dinosaurs evolve into different birds, or one of them into all birds? **URL:** \ **Category:** Factual Questions\ **Created:** [August 18, 2012, 10:42pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910 "2012-08-18T22:42:35Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [August 19, 2012, 2:39pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/21 "2012-08-19T14:39:13Z")
I would think the common ancestor happened before the reptile, likley that many reptiles evolved into birds over many, many thousands of years. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [August 19, 2012, 2:42pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/22 "2012-08-19T14:42:25Z")
While searching for pictures of feathered dinosaurs, I found a mention that velociraptor was likely a non-flying feathered creature _descending from flying dinosaurs_ (this based on the feather attachment marks on bones). It’s weird to imagine that some flying dinosaurs existed long enough to lose the ability to fly. Also found this quote : [QUOTE=Norell] The feather findings “have rocked the world in terms of how we think of” dinosaurs, he said. “Instead of giant lizards, they were basically weird birds.” [/QUOTE] ---
**Author:** ![Koxinga](https://avatars.discourse-cdn.com/v4/letter/k/4af34b/32.png) [@Koxinga](https://boards.straightdope.com/u/Koxinga)\ **Post date:** [August 19, 2012, 2:57pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/23 "2012-08-19T14:57:25Z")
What I’ve often wondered is whether [“terror birds”](http://en.wikipedia.org/wiki/Phorusrhacidae), which appear to have started at least 62 million years ago and survived to less than 2 million years ago, ought to be dinosaur survivals. If so, we’d have dinosaurs just barely coexisting with early human ancestors. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [August 19, 2012, 3:03pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/24 "2012-08-19T15:03:48Z")
> [@Darwins\_Finch](#): > > Sure it does: Carnosauria. But really, there are more than two ‘main types’ of theropods. There are the Coelophysids and Averostra; Averostra are broken into tetanurans and ceratosauria; tetanurans are broken (primarily) into megalosaurs and Avetheropoda; and Avetheropoda is finally broken into Carnosauria and Coelurosauria. And, you have it backwards: Coelurosauria is actually closer to birds than is Carnosauria. > > To continue the path from Coelurosauria to birds, we go from Coelurosauria to Maniraptora to Eumaniraptora to Avialae to Pygostylia to Ornithothoraces to Euornithes to Ornithurae to Aves. Some of those clade names are more ‘unofficial’ than others (e.g., Pygostalia is pretty much just Confuciusornithidae [_Confuciusornis_ and friends] + Ornithothoraces). I did have it backwards; I blame posting in the middle of the night :P. You’re also right that the two types I was describing are the split between Avetheropoda, as opposed to all theropods. > [@Aspidistra](#): > > Does that mean feathers evolved before flight? (or even, really, gliding - I can’t imagine a Tyrannosaurus gliding very far) > > Does anyone have any idea what they were good for? First, Tyrannosaurus evolved about 15 million years before the end of the Cretaceous. Birds didn’t evolve from T-Rex; they both had a common ancestor, who had feathers. That doesn’t mean that T-Rex could glide. But yes, feathers evolved long before flying (which makes sense, since you can’t fly without feathers). At first, they were probably very short and were basically similar to modern chick feathers: for temperature regulation, most likely. Later on, some species used them for display (Like a peacock!) while others eventually learned to fly. > [@clairobscur](#): > > Thanks, but how do we know that? Many ways! First, and simplest, are shapes. Tyrannosaurs (Not just Rex; this includes Albertosaurus, etc.) have similar body structures to other, smaller, earlier dinosaurs. The group of dinosaurs we believe gave rise to Tyrannosaurus Rex and his kin is the Tyrannosauroidea. They started off small; the early Guanlong was only a few feet long. These dinosaurs are more obviously members of the Coelurosauria. This connection wasn’t always obvious, and for a long time, Carnosauria basically meant “all big dinosaurs”. > [@clairobscur](#): > > While searching for pictures of feathered dinosaurs, I found a mention that velociraptor was likely a non-flying feathered creature _descending from flying dinosaurs_ (this based on the feather attachment marks on bones). It’s weird to imagine that some flying dinosaurs existed long enough to lose the ability to fly. > > Also found this quote : Haven’t heard that one before. Velciraptors are members of Dromaeosauridae, which is generally considered to be the most closely related group to birds. However, I’ve generally heard that the first Avian dinosaurs were probably Dromaeosaurs… I could be wrong, though, and I don’t believe that there is consensus on this point. It’s interesting to note that there are a number of Dromaeosaurs that may have been able to fly and/or glide. If this is true, and Avian dinosaurs had separated from that line before that, then dinosaurs learned to fly not once, but twice! ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 19, 2012, 3:06pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/25 "2012-08-19T15:06:14Z")
> [@badger5149](#): > > I would think the common ancestor happened before the reptile, likley that many reptiles evolved into birds over many, many thousands of years. I’m at a loss as to why you would think that. Do you a some cite that supports that view? ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [August 19, 2012, 3:07pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/26 "2012-08-19T15:07:54Z")
> [@Koxinga](#): > > What I’ve often wondered is whether [“terror birds”](http://en.wikipedia.org/wiki/Phorusrhacidae), which appear to have started at least 62 million years ago and survived to less than 2 million years ago, ought to be dinosaur survivals. If so, we’d have dinosaurs just barely coexisting with early human ancestors. I don’t think you could really say that terror birds were dinosaurs in any meaningful sense. They (almost) definitely evolved from creatures that were already Avian. Keep in mind that birds split off from “true” dinosaurs in the Jurassic, long before the dinosaurs went extinct. On the other hand, all birds are technically dinosaurs. Which is why they should all be destroyed before they learn to open doors and kill us all. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 19, 2012, 3:09pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/27 "2012-08-19T15:09:32Z")
> [@Koxinga](#): > > What I’ve often wondered is whether [“terror birds”](http://en.wikipedia.org/wiki/Phorusrhacidae), which appear to have started at least 62 million years ago and survived to less than 2 million years ago, ought to be dinosaur survivals. If so, we’d have dinosaurs just barely coexisting with early human ancestors. Well, they were no more or less “dinosaurs” than a hummingbird is. They do not represent some different line of descent, but share a common ancestor. All birds can be considered dinosaurs, and you often see the term non-avian dinosaurs to distinguish between birds and what most people think of as dinos. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [August 19, 2012, 3:09pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/28 "2012-08-19T15:09:45Z")
> [@John\_Mace](#): > > I’m at a loss as to why you would think that. Do you a some cite that supports that view? There is a camp that holds that birds evolved from more primitive Archosaurs rather than dinosaurs. It’s lost popularity over the years, especially now that we have strong evidence that many dinosaurs had feathers. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 19, 2012, 3:13pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/29 "2012-08-19T15:13:54Z")
The whole bird/dinosaur dichotomy thing is just one of the many examples of [Polyphyletic groupings](http://en.wikipedia.org/wiki/Polyphyletic) out there. As we’ve noted many times in this forum, one might say that humans are fish since there are some fish (lobe finned) that are more closely related to us than they are to other fish (ray finned). Apes and Old World monkeys are more closely related to each other than either is to New World monkeys, so are apes monkeys? Depends on what your purpose is in slicing and dicing. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 19, 2012, 3:15pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/30 "2012-08-19T15:15:53Z")
> [@Babale](#): > > There is a camp that holds that birds evolved from more primitive Archosaurs rather than dinosaurs. It’s lost popularity over the years, especially now that we have strong evidence that many dinosaurs had feathers. But Archosaurs are still reptiles. The poster was postulating a pre-repitlian ancestor for birds, representing a separate line of descent from other reptiles. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [August 19, 2012, 3:21pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/31 "2012-08-19T15:21:33Z")
> [@John\_Mace](#): > > But Archosaurs are still reptiles. The poster was postulating a pre-repitlian ancestor for birds, representing a separate line of descent from other reptiles. So basically from early Reptilomorphs? As in, reptile-like amphibians? That’s a little ridiculous. Doesn’t that mean that things as basic as, say, terrestrial eggs would have to evolve twice? ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 19, 2012, 3:22pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/32 "2012-08-19T15:22:59Z")
> [@Babale](#): > > So basically from early Reptilomorphs? As in, reptile-like amphibians? That’s a little ridiculous. Doesn’t that mean that things as basic as, say, terrestrial eggs would have to evolve twice? Yes, it would. That view reflects a misunderstanding of the similarities between birds and reptiles as well as a misunderstanding of how evolution works. Which is why I asked for a cite, since it is counter-factual. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [August 19, 2012, 3:25pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/33 "2012-08-19T15:25:14Z")
Then no, that makes no sense at all. It’s like saying that placental mammals and Marsupials both evolved separately from a common reptile ancestor. There are differences, but they have a lot more in common with each other than with the supposed ancestor. ---
**Author:** ![fumster](https://avatars.discourse-cdn.com/v4/letter/f/e9c0ed/32.png) [@fumster](https://boards.straightdope.com/u/fumster)\ **Post date:** [August 19, 2012, 3:41pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/34 "2012-08-19T15:41:42Z")
> [@clairobscur](#): > > T-rex had feathers? :eek: Only on stage. ---
**Author:** ![fumster](https://avatars.discourse-cdn.com/v4/letter/f/e9c0ed/32.png) [@fumster](https://boards.straightdope.com/u/fumster)\ **Post date:** [August 19, 2012, 3:43pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/35 "2012-08-19T15:43:19Z")
> [@Babale](#): > > So basically from early Reptilomorphs? As in, reptile-like amphibians? That’s a little ridiculous. Doesn’t that mean that things as basic as, say, terrestrial eggs would have to evolve twice? Eyes evolved multiple times. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [August 19, 2012, 3:54pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/36 "2012-08-19T15:54:32Z")
> [@fumster](#): > > Eyes evolved multiple times. So did fins and wings, but you still don’t have a point. First of all, there are clear “missing links” between dinosaurs and birds. Second, birds and crocodiles are more closely related than crocodiles and other reptiles, or amphibians. Unless you’re saying amphibians split off into a “crocodile/bird” line and a “other reptile” line, you’re not making much sense. Genetic research backs up the theory that amphibians led to reptiles, which eventually split into archosaurs and other reptiles. Archosaurs eventually split into crocodiles and their kin and dinosaurs and their kin. And birds developed from dinosaurs. Besides, eyes are generally accepted to be of common origin. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [August 19, 2012, 4:25pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/37 "2012-08-19T16:25:54Z")
> [@Babale](#): > > IHaven’t heard that one before. Velciraptors are members of Dromaeosauridae, which is generally considered to be the most closely related group to birds. However, I’ve generally heard that the first Avian dinosaurs were probably Dromaeosaurs… I could be wrong, though, and I don’t believe that there is consensus on this point. [Here’s a link](http://www.sciencedaily.com/releases/2007/09/070920145402.htm)to the article. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [August 19, 2012, 6:27pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/38 "2012-08-19T18:27:22Z")
Gregory S. Paul was among the first to speculate that dromaeosaurs were secondarily flightless – see, for example, [this note](http://gspauldino.com/JVP99.pdf) (.pdf) from 1999 (I believe he also mentioned the possibility in his book _Predatory Dinosaurs of the World_ (1988)). Also, it’s worth noting that the feathers that were found for tyrannosauroids (but not specifically _Tyrannosaurus_) weren’t flight feathers or even downy feathers, but more like a feather pre-cursor. True downy feathers don’t show up until Maniraptoriformes (a clade containing Maniraptora), countour feathers show up in Eumainiraptora, and “flight feathers” show up in Avialae. [QUOTE=clairobscur] It’s weird to imagine that some flying dinosaurs existed long enough to lose the ability to fly. [/quote] Keep in mind that _Archaeopteryx_ is from the Late Jurassic - around 150 million years ago. The first dinosaurs show up around 230 million years ago, and non-avian dinosaurs went extinct 65 million years ago. So we have a full 80 million years worth of evolution leading from the first dinos to the likes of _Archaeopteryx_, and another 85 million years of dinosaur evolution **after** _Archaeopteryx_ until the K-Pg\* (aka the K-T\*\*) extinction. There was plenty of time for flight to be gained and lost in that time! - Cretaceous- Paleogene \*\* Cretaceous - Tertiary ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [August 19, 2012, 6:31pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/39 "2012-08-19T18:31:16Z")
> [@Babale](#): > > Besides, eyes are generally accepted to be of common origin. Depends on where you’re drawing the boundary lines. [Evolution of the Eye](http://en.wikipedia.org/wiki/Evolution_of_the_eye) > [@](#): > > Certain components of the eye, such as the visual pigments, appear to have a common ancestry – that is, they evolved once, before the animals radiated. However, complex, image-forming eyes evolved some 50 to 100 times – using many of the same proteins and genetic toolkits in their construction. … > > Whether one considers the eye to have evolved once or multiple times depends somewhat on the definition of an eye. Much of the genetic machinery employed in eye development is common to all eyed organisms, which may suggest that their ancestor utilized some form of light-sensitive machinery – even if it lacked a dedicated optical organ. However, even photoreceptor cells may have evolved more than once from molecularly similar chemoreceptors, and photosensitive cells probably existed long before the Cambrian explosion. Higher-level similarities – such as the use of the protein crystallin in the independently derived cephalopod and vertebrate lenses – reflect the co-option of a protein from a more fundamental role to a new function within the eye. > > Shared traits common to all light-sensitive organs include the family of photo-receptive proteins called opsins. All seven sub-families of opsin were already present in the last common ancestor of animals. In addition, the genetic toolkit for positioning eyes is common to all animals: the PAX6 gene controls where the eye develops in organisms ranging from mice to humans to fruit flies. These high-level genes are, by implication, much older than many of the structures that they are today seen to control; they must originally have served a different purpose, before being co-opted for a new role in eye development. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [August 20, 2012, 1:43pm UTC](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910/40 "2012-08-20T13:43:00Z")
> [@Aspidistra](#): > > Does that mean feathers evolved before flight? (or even, really, gliding - I can’t imagine a Tyrannosaurus gliding very far) > > Does anyone have any idea what they were good for? I have read that (caveat: going from memory here, and my understanding is not current enough to assess whether this is mainstream thought) feathers seem to have developed on the early theropods, which were notably smaller than the general run of dinosaurs. Small animals have more trouble maintaining thermal homeostasis (constant internal body temperature) because their surface area is relatively larger for their mass. Crudely put, massive animals retain heat better. The thinking is, feathers developed (from scales), and proved useful enough to insulate these smaller dinos from cooling off that they were selected for by evolution. Possibly supporting this interpretation, early feathers do appear to be “hairy” or stringy instead of airfoil-like. [Previous page](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910.md?page=1) [Next page](https://boards.straightdope.com/t/did-different-dinosaurs-evolve-into-different-birds-or-one-of-them-into-all-birds/631910.md?page=3)