[abefortas]

This is interesting, and would be epsecially so if he could actually get to a making a dinosaur stage.

Larsson says chickens are direct descendents of dinosaurs. He is a paleontologist. My brother says they are dinosaurs. He is merely an aspiring paleontologist. Perhaps both are the case? Can anyone clear this up?

[run4yourlives]

Chickens are dinosaurs in the same way that you are a prehistoric Lemur.

You, and all other primates are descendent from the first proto-primates that appeared millions of years ago. A lot changes in 65 million years, so to say they are exactly the same is not any more accurate than calling you a lemur.

That said, it is likely that you do have a hell of a lot in common with ancient lemurs, at least DNA wise.

[abefortas]

But "lemur" is rather more specific than "dinosaur." Dinosaur is just a broad category defined by scientists. If they want "Dinosaur" to include modern animals, that's up to them.

From the tone of your answer, you sound pretty confident that chickens are not dinosaurs-- perhaps you have some authoritative information on this? If so, can you direct me to it? My google-fu deserts me.

[run4yourlives]

prehistoric Lemur not lemur.

If you are hung up on the fact that lemurs still exist, use the word prosimians instead.

you sound pretty confident that chickens are not dinosaurs

That's because I'm pretty confident that this:

http://scienceblogs.com/gregladen/chicken.jpg

is not this:

http://domz60.files.wordpress.com/2009/05/dinosaur.jpg

If you really need something to prove that, I think we are dealing with bigger problems than can ever be resolved within this discussion.

They are certainly related however, and even a layman can see this even without looking at the evolutionary hip structure. That said they are far enough apart that calling a bird a dinosaur is the same as calling you a lemur.

[asdlfj2sd33]

Humans and lemurs are both primates. And some people theorize that both chicken and dinosaurs are aves.

If you ask me, all dinosaurs were birds and some survive until today, makes more sense then some dinosaurs were birds and it's just those that survive.

But I'm not a paleontologists.

And what bugs me is that we have all manner of lizards, even huge turtles and crocodiles and warm blooded birds, but not a single small dino.

There being no huge dinos makes sense, but if we have Nile crocodiles and ostriches, why not one chicken sized dino?

[run4yourlives]

all dinosaurs were birds and some survive until today, makes more sense then some dinosaurs were birds and it's just those that survive

Um, no. Birds are members of the larger dinosaur family the same way you are a member of the primate family. They are dinosaurs in the way that you are a primate, but they aren't dinosaurs in the way that you aren't a lemur.

There was a time when a whole host of other animals were a part of this family, but they have died off. The entire group of animals is collectively known as dinosaurs, but since birds evolved and were proven distinct prior to the extinction, it is correct to say that birds are a subset of dinosaurs, not that all dinosaurs were birds.

People who speculate that such a split is incorrectly classified, and that birds are simply evolved dinosaurs have a pretty big uphill climb in my opinion. The presence of fossils that show that what we would classify as birds living before the extinction is a pretty major hurdle.

[abefortas]

Either birds are dinosaurs, or they aren't. My brother says there ain't no two ways about it-- as you say, they are dinosaurs the same way I'm a primate. Obviously they aren't Composognathus* the way I'm not a lemur, but that's not what I was wondering.

*a small theropod, most probably an ancestor of birds

[a-priori]

It's just a sign that this is still such new knowledge that a consensus hasn't been reached yet on the terminology. Some people think birds are distinct from dinosaurs. Others think they still are dinosaurs. It just depends where people draw the line. So yes, they're both right, depending on your definitions of "bird" and "dinosaur".

[hughprime]

In evolutionary terms, dinosaurs are best described as a region of the family tree which lies somewhere between:

a) the last common ancestor of all birds, and b) the last common ancestor of all birds and reptiles

As such, whether they're classified as reptiles, birds, or in their own category is really just a matter of taste.