1. Reptiles
Section 31.1

2. Animal Classification
Sponges
Cnidarians
Worms
Mollusks
Arthropods
Echinoderms
Invertebrates
Animals
Fishes
Amphibians
Ectotherms
(cold-blooded)
Vertebrates
Reptiles
Birds
Mammals
Endotherms
(warm-blooded)

3. What is a Reptile?
Class Reptilia – snakes, turtles, alligators, and lizards
Evolutionary advantages reptiles have over amphibians
Claws
Dry skin (scales)

4. Scaly Skin
Unlike the moist, thin skin of amphibians, reptiles have a dry, thick skin covered with scales
Scaly skin prevents the loss of body moisture and provides additional protection from predators

5. Scaly Skin
Because of their thick skin, reptiles are dependent on lungs as their primary organ of gas exchange
Desert Horned Lizard

6. Reproduction Most reptiles reproduce by laying eggs on land
Some snakes give live birth to well-developed young
Gartner snake giving birth
Sea turtle eggs

7. Reproduction All reptiles have internal fertilization
Snakes and lizards have hemipenes (plural)
Hemipenis (singular) – structure used to inject sperm into a female
Cloaca – opening where the hemipenes is inserted; waste also exits the cloaca

8. Ectotherms Reptiles do not inhabit extremely cold regions
Many species of reptiles become dormant during cold periods in moderately cold environments (northern United States)

9. Sense Organs
Pit organs – heat-sensitive areas that enable snakes to detect air temperature brought by the presence of warm-blooded animals

10. Sense Organs The tongue is used for smelling
Jacobson’s organ – a pitlike sense organ on the roof of the mouth that picks up and analyzes airborne chemicals

11. Turtles
The dorsal part of the shell is the carapace, and the ventral part is the plastron
The vertebrae and expanded ribs of turtles are fused to the inside of the carapace

12. Turtles Tortoises Aquatic Eat insects and worms (some eat birds)
Have claws
Webbed feet
Can live up to 60 years
Tortoises
Terrestrial
Eat fruits and insects
Do not have claws
Feet are not webbed; they’re round and stumpy
Can live up to 150 years

13. Crocodiles Crocodiles Alligators Long, slender, V-shaped snouts,
Light olive brown coloration
Found in saltwater and estuaries
Estuary – a mixture of freshwater and saltwater
Alligators
Short, broad, U-shaped snouts
Blackish coloration
Found in freshwater

14. Snakes and Lizards Most lizards have four limbs
Snakes have no limbs and lack the bones to support limbs
Exception are pythons and boas which retain bones of the pelvis
The claw is known as a spur

15. Lizards and Snakes Some snakes even swim and climb trees
Have ridges on its belly used for gripping
(like tire treads gripping the road)

16. Lizards and Snakes Snakes usually kill their prey in one of three ways
1. Constriction – snakes wrap themselves around their prey
Examples: boas, pythons, and anacondas
Boa

17. Lizards and Snakes
2. Venom – These snakes use poison to paralyze or kill their prey
Rattlesnakes, cobras, and vipers

18. Lizards and Snakes
3. Non-poisonous and non-constricting snakes get their food by grabbing it with their mouths and swallowing it whole