1. Zoology
Phylum Chordata
Class Reptilia

2. General Characteristics
7000 species
Repto means to creep
Many extinct species
Lizards, snakes, turtles and crocodilians
First to escape dependence on water

3. 4 main adaptations to land without water
1. tough, dry, scaly, skin that restricts water loss
2. Internal fertilization
3. Kidneys are good at conserving water
4. Amniotic egg
Embryos develop to an advanced stage before being hatched or born
Egg have membranes that conserve water and protect it

4. Respiration by lungs – can’t breath through moist skin
Jaws are well-muscled with formidable teeth for crushing or gripping prey
Limbs more efficient at supporting body
Most lay shelled eggs on land
Called cold blooded
Don’t have metabolism to control body temperature
Do regulate temperature in other ways
Ectotherm – absorb external heat instead of absorbing their own

5. Extinct Reptiles
Dinosaurs
Lived on land
Different sizes
Up to 45m long
Many were very fast
Social
Parental care

6. Pterosaurs
Flying reptiles
Wings were a membrane of skin stretched from the body wall to the tip of an elongated finger

7. Order Crocodilia
Crocodiles and alligators
Closest relative of birds and dinosaurs
Live in or near water
Spend most time in water breathing through upturned nostrils
Live in warmer areas
Complex social behaviors
Largest living reptile

8. Order Chelonia
Turtles
Have not changed much since the Mesozoic era (triassic times)
Shell is attached to skeleton
Instead of teeth, have tough, horny plates

9. Order Squamata
Lizards and snakes
95% of living reptiles
Lizards
Most numerous and diverse
Eat insects
Grab prey with small peglike teeth
Many give up tail when a predator grabs them. The detached tail wriggles for a bit and might distract predator so they can get away
Ex. Geckos, iguanas, chameleons

10. Snakes
Descendants of lizards that adapted a burrowing lifestyle
Today – most live above ground
Have vestigial pelvic and limb bones in boa’s
Carnivores
Flexible skull bones to swallow prey
Acute chemical sensors on tongue
No eardrum – feel vibrations on the ground
Heat detecting organs between eyes and nostrils
Inject poison through hollow teeth

11. Tuataras
2 existing species
Haven’t changed for last 140 million years
Have a “third” eye with retina, lens and nerves to the brain. Covered with skin, it can only register changes in day length and light intensity
Mate after 20 years old