BIRDS ARE DINOSAURS
The image below is a photo of the exhibit panel. Following it is a transcript of the panel.
Birds are flying dinosaurs. Shared features in hips, feet and arms provide part of the evidence.
Birds are a kind of therapod dinosaur (therapods have stiff tails and three functional fingers on their hands). They evolved from small, fast-running predators that used talon-like hands to seize prey.
Many features that are considered uniquely bird-like (such as long arms, a breastbone, and a wishbone) appear in earlier dinosaurs.
birds:
therapod dinosaurs, including
Archaeopteryx
and all modern birds
New features:
- feathers insulate body and provide lift for flying
- half-moon-shaped bone in wrist for folding hand back against the arm and swinging it forward to seize prey
- long arms support large wings
- large brain coordinates flight activities
When? 152 million years ago to present
Compsognathus
(komp-so-
NAY
-thus)
A long tail balanced this carnivore's body; sharp teeth and claws grabbed prey.
Compsognathus
had three functional fingers on each hand.
Other "avian" features include certain modifications of the tail, hips, and hindlimbs, including a short first toe that is not attached to the ankle.
Archaeopteryx
(ar-kee
OP
-ter-ix)
Only six fossil skeletons of
Archaeopteryx
are known. Its wing feathers had asymmetrical vanes and curved shafts -- exactly like the feathers that power flight in modern birds.
PICTURE CAPTIONS:
- Compsognathus
- Archaeopteryx
- Diagram showing common ancestry and evolution of Tyrannosaurus , Deinonychus , and birds from organisms with a stiff tail and three functional fingers in hand. Evolution of Deinonychus and birds is where a wishbone and "flight stroke" used to seize prey branch off.