How are birds related to dinosaurs?

Answer 1

Birds are dinosaurs.
According to current cladistics (the paradigm for classification of living beings that is accepted by most biologists worldwide), the taxonomical groupings of animals are included in progressively larger and more abarcative groups by ancestor-descendant relationships. This means that a derived taxon A that is nested within a larger, more inclusive taxon B, is still a part of taxon B, no matter how derived A is with respect to the ancestral B forms.

Birds are archosaurs: like the crocodiles and other dinosaurs, they have skulls with two temporal fenestrae (diapsid), an antorbital fenestra (a "window" in the skull anterior to the eye socket) and a mandibular fenestra (a similar "window" in the lower jaw), among other characteristics.

Within the archosaurs, the dinosaurs differ from the crocodilians (which have their own set of characteristics), and they are defined by synapomorphies (shared derived characters), including (among others):
Three or more sacral vertebrae
Three of fewer phalanges in the fourth digit of the hand
Acetabulum (the place in the hip bone where the femur articulates) completely perforate
Proximal head of femur fully offset, conferring parasagittal gait
Reduced fibula.

As these are dinosaur characters, all birds have them, or else they have character states derived from these. And some theropod dinosaurs (the raptor type) are considered as the closest relatives (or sister-group) to the modern birds.

The fact that birds are dinosaurs does not change the fact that they're still birds (Aves, or Avialae, according to different classification schemes).
Aves also have their synapomorphies (check the last link), including characters of the skull and feet.

Answer 2

Yes. All vertabrates are related to each other, having all descended from the first bony fishes.

But birds and dinosaurs are more closely related than either of them are to mammals, (other than dinsoaur) reptiles, amphibians, or fishes.

The first birds (Archaeopteryx) arose from early therapod dinosaurs (which later became Allosaur, T-rex, etc). Evidence for this is in their hips and skulls.

Answer 3

Because god used the last good piece of bone making eve.
The only bones left was that of some old dinosaurs and he used them to make everything else including birds.

Answer 4

Current theories suggest that birds are descendants of one branch of dinosaurs. Many feathered dinosaurs are being excavated in China, and there is archaeoptryx.

Answer 5

Birds and dinosaurs share a common reptile ancestor.

Answer 6

Dinosaurs evolved into birds. Look at an ostrich and a raptor....its not hard to see the similarities.

Answer 7

Their skeletal structure, when not indentical, is similar. And it is thought that some of their behavior is similar, such as nesting and flocking together. They've dug up fossils showing the evolution of feathers and so on. It gets complicated because there were a great many types of dinosaurs.

Answer 8

convinced, it really is great. surely, many authorities say that birds are dinosaurs, the purely surviving line. Eagles are with regards to T. rex, yet T. rex advanced interior the previous due Cretaceous while the first birds appeared interior the middle Jurassic, some 80 5 million years earlier. that is believed that feathers advanced to regulate temperature and to serve in courtship show. purely later did they grow to be changed for flight.

Answer 9

I am sorry, this will be no answer to your question; the question cannot be answered any better than Calimecita has already done. So, if I were you I'd give her ten points.

Mine will be a response to Hyzakyt answer to your question, which suprises me primarily, because your question was scientific and his answer was not. I think it is necessary to raise a few general issues here.

As a caveat lector, let me quickly say that I am a trained biologist with a PhD and research experience who also taught college for some while. My field of interest was evolution, which I addressed from various angles, using different animal models and always trying to tie things together by focusing on their reproductive biology. I left my scientific career to get a MA in theology and currently am working on my PhD in theology. I am neither atheist nor agnostic, but a believer who has no problem whatsoever with evolutionary biology.

Now to Hyzakyt's long answer to the actual question. I will not refer to any single point, which I am more than happy to do, if Hyzakyt wants to contact me. What I want to say though is that his long expose reflects not only a poor understanding of the actual biology and evolutionary history of life on earth, but also raises questions about how we have to think about science in the first place. If Hyzakyt were to say he simply rejects the results of scientific research, I would have less a problem that I have with his pseudo-scientific approach that has neither to do with science nor with theology, but strictly speaking with very simplistic opinion making.

Perhaps, Hyzakyt can next time restrain himself from answering in a way that has NOTHING to do with sciences, perhaps take a few science courses to know what he is talking about, and stick to the religion section to spread his dubious religious fanatism.

By the way, the question itself was excellent, and as I said before, Calimecita has answered it wonderfully.

Answer 10

Birds are to dinosaurs as model airplanes are to WWI fighter planes.