Extinct Reptiles and Dinosaurs Flashcards
What species was the earliest reptile to arise after the first amniote?
- parareptiles
what are some characteristics on parareptiles? how did they go extinct?
they are a group anapsid (no hole) reptiles were large herbivores, and 95% of their lives went extinct and they died at the end of the triassic period
- one idea was that dinosaurs out competed parareptiles
What are archosaurs?
they are extinct members that include pterosaurs and non avian dinosaurs
What are some characteristics of pterosaurs?
- they were the first tetrapod capable of flight
- not homologous with wings of bats and birds (their wings were a result of convergent evolution and they were analogous characters)… skeletal structure underneath the skin though is homologous
- it had wings that stretched from its hind leg to foreleg which birds don’t have
What are some characteristics of dinosaurs?
- they were the largest animals to inhabit land
- they were divided into two groups: ornithischians and saurischians
what were the characteristics of ornithischians?
herbivores, and used elaborate defences on their bodies against predators
What are characteristics of saurischians?
- included carnivorous and herbivorous species and evidence that these dinosaurs were endotherms (they relied on metabolic activity to maintain their temperature in their bodies)
What are Theropods?
- they are a subgroup of the saurischians
- they include the T-rex
and small fast hunters like the velociprator and some were ancestors of birds and were definitely endothermic
What are some similarities between theropods and birds?
- many theropods had feathers
- scales on the theropods were homologous with feathers on a bird, they were both made of keratin
- Hollow thin walled bones
- similar respiratory system
- musculature, brain, heart and other organs were highly similar
- built nests and incubated eggs
