1. General Characteristics
Reptiles
General Characteristics

2. Classification Phylum Chordata Subphylum Vertebrata - Class Reptilia
Order Squamata- Lizards & Snakes
Order Testudine- Turtles & Tortoises
Order Crocodilia- Crocodiles & Alligators

3. Order Squamata

4. Order Testudine

5. Order Crocodilia

6. Herpetology
The field of science that studies reptiles and amphibians.

7. Skin
Dry thick skin covered with scales; Scales are part of the skin- all connected
Scales provide protection from water loss and protection from predators.
Scales are made of keratin
Keratin is protein in the epidermis, often modified into nails, horns, and hair

8. Skin cont… Skin consists of 2 layers
Epidermis- thin layer, and shed periodically
Dermis- Thicker layer, contains chromatophores which give reptiles their color

10. Appendages Paired limbs Usually 5 toes with claws
Limbs located under body provides more support for walking and running on land.
Limbs absent in snakes and some lizards.

12. Respiration
All reptiles breathe through Lungs.

13. Circulation Most reptiles have 3 chambered hearts.
Crocodiles have a 4 chambered heart that enables more oxygen to reach body tissues.

14. Ectothermic All reptiles are ectothermic.
Do not inhabit extremely cold regions.
Live in temperate, tropical and desert climates.

15. Reproduction Reptiles do not need water to reproduce. Separate Sexes
Internal Fertilization
Most lay leathery or calcareous eggs, with the embryo developing after the egg is laid
Young look like small adults
Most do not provide parental care.

16. The Amniotic Egg
The evolution of the amniotic egg was the adaptation that freed reptiles from dependence on water for reproduction.
Amniotic Egg is a shelled egg that contains food and protective membranes for supporting embryonic development.

17. Parts of the Amniotic Egg
1. amnion- cushions; prevents dehydration
2. outer shell- protection
3. allantois- waste sac
4. yolk- food supply
5. albumin- additional food
6. chorion- gas exchange