What physical proof do we have that birds are direct descendents of dinosaurs?

Answer 1

Their common ancestor, the Archaeopteryx.

From John R Hutchinson, Lecturer
Royal Veterinary College, University of London:

Coelurosaurian dinosaurs are considered the closest relatives of the birds. In some circles birds are referred to as coelurosaurs.

This is based on skeletal morphology of these animals. Bones are used because they are about all that is preserved in the fossils.

The first birds had the following major skeletal characteristics in common with many coelurosaurian dinosaurs (especially those of their own clade, the Maniraptora, which includes Velociraptor):

1. Pubis (one of the three bones making up the vertebrate pelvis) shifted from an anterior to a more posterior orientation ), and bearing a small distal "boot".

2. Elongated arms and forelimbs and clawed manus (hands).

3. Large orbits (eye openings in the skull).

4. Flexible wrist with a semi-lunate carpal (wrist bone).

5. Hollow, thin-walled bones.

6. 3-fingered opposable grasping manus (hand), 4-toed pes (foot); but supported by 3 main toes.

7. Reduced, posteriorly stiffened tail.

8. Elongated metatarsals (bones of the feet between the ankle and toes).

9. S-shaped curved neck.

10. Erect, digitgrade (ankle held well off the ground) stance with feet postitioned directly below the body.

11. Similar eggshell microstructure.

12. Teeth with a constriction between the root and the crown.

13. Functional basis for wing power stroke present in arms and pectoral girdle (during motion, the arms were swung down and forward, then up and backwards, describing a "figure-eight" when viewed laterally).

14. Expanded pneumatic sinuses in the skull.

15. Five or more vertebrae incorporated into the sacrum (hip).

16. Straplike scapula (shoulder blade).

17. Clavicles (collarbone) fused to form a furcula (wishbone).

18. Hingelike ankle joint, with movement mostly restricted to the fore-aft plane.

19. Secondary bony palate (nostrils open posteriorly in throat).

20. Possibly feathers. Small, possibly feathered dinosaurs were recently found in China. Seemingly many coelurosaurs were cloaked in an external fibrous covering which have been referred to as "protofeathers."

Answer 2

We don't have proof, only evidence from comparing dinosaur fossils with modern birds. We also have prehistoric bird fossils with fossilized impressions of feathers which look just like dinosaurs. Dinosaurs had scales and birds have both scales and feathers, and feathers are just another kind of scale.

There were flying reptiles of all sizes too, however they were not related to birds (as I recall).

Answer 3

not being an expert though, i believe there was one once, a fossil that had a dinosaur with feathers, these findings were published as fossil missing link to birds, dont quote me,but the fossil was later found to be two skeletons, so now there is no direct link

Answer 4

There has been plenty of proof ... so why people are posting that don't have a clue is beyond me. Just looking for points?

The bone structure was the first direct connection, but there is more evidence beyond that. Here are links to there reputable sources containing discoveries of evidence:

http://www.sciencedaily.com/releases/2002/02/020214080242.htm
http://news.bbc.co.uk/2/hi/science/nature/2132152.stm
http://www.cnn.com/TECH/science/9806/23/feathered.dinosaur/

Answer 5

I don't think we have any physical proof. It's just a hypothesis based on skeletal and fossil evidence.

Answer 6

they have scales on their feet, they lay eggs, their knees bend backwards

feathered dinasours have been found

Answer 7

gosh, they look prehistoric.

Answer 8

none, it isnt true.