1. Reptiles!!!

2. Classification Kingdom: Animalia Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Orders:
Crocodilia
Sphenodontia
Squamata
Testudines

3. Characteristics Ectothermic(Cold-blooded)
Regulate body temperature by seeking or avoiding sun.
Air Breathing
Tetrapods
Scales instead of feathers or hair
Three and a half chambered hearts
Most lay eggs
Amniotes!

4. Evolutionary Milestone
The Amniote Egg
Adapted for land.
Allows for full development inside safety of egg.

5. Reptile History
First reptiles appeared around 380 million years ago, during the Pennsylvanian time period, when the climate was warm and humid, and amphibians dominated.
Many different reptile species appeared during the Triassic, which had a drier, cooler climate.
Today, 6,500 species of reptile walk and slither on the Earth, and reside on every continent, except Antarctica.

6. The Four Reptilian Orders
Testudines
Crocodilia
Squamata
Sphenodontia

7. Sphenodontia
2 species of Tuatara living in New Zealand; all others went extinct 60 mya.
Has not changed in 225 million years
Living fossil!
They have a 3rd “eye”, have no external ear openings, and males lack a penis.

8. Crocodilia Appeared 85 mya Large reptiles with elongated head
Alligators, Crocodiles, Caimans, and Gharials
4 Chambered Heart
Teeth in bony socket
Closest living relative to birds.

9. Testudines Turtles and Tortoises Bodies with two-piece bony shell
Carapace: dorsal; arose from ribs
Plastron: ventral
Appeared in fossil record 220 mya

10. Squamata Lizards and snakes 5640 species!
Tough epidermal scales made of keratin
Possess moveable quadrate bone.
Most variable order in size