1. Reptiles
EQ: What are reptiles?

2. What is a reptile?
A vertebrate that has dry, scaly skin, lungs, and terrestrial eggs, with several membranes
While reptiles have a dry waterproof skin, it doesn’t grow with the reptile, therefore they must shed periodically
Reptiles live everywhere except in very cold areas

3. Evolution of Reptiles Reptiles evolved from amphibian-like ancestors
Early reptile fossils date back to the Carboniferous period (350 million years ago)
End of the Permian Period (245 million years ago) there was a great variety of reptiles due to the drier climate (negative impact on amphibians)
During this time, mammalian reptiles started to appear (link between reptiles & mammals)
Mesozoic Era (late Triassic & Jurassic periods) = Age of Reptiles

4. Dinosaurs
Triassic Period (215 million years ago)- dinosaurs became dominant
Great variety of species, eating habits, and behaviors
End of the Cretaceous Period (about 65 million years ago)- mass extinction occurred worldwide
The extinction of dinosaurs gave way for other organisms to evolve

5. Body Temperature Controls
Ectotherms- behavior to control body temperature
Bask in the sun for heat

6. Feeding
Wide range
Herbivores (Iguana, turtles)- tear plants to shreds and long digestive tract enables the breakdown of the plant material
Carnivores (snakes, chameleons, crocodiles, alligators, etc)- prey on small animals, bird eggs, fish, insects

7. Respiration
Lungs (more spongy than amphibians) with muscles surrounding to help expand/collapse the chest cavity
Most have 2 lungs (some snakes have 1)

8. Circulation Double-loop system (like amphibians)
Most have 3-chambered heart
Crocodiles and alligators have 4-chambered hearts (also found in birds and mammals)

9. Excretion
Reptiles that live primarily in water excrete waste as ammonia since they are able to drink large amounts of water
Reptiles that live primarily on land instead convert the ammonia into uric acid and will form a white pasty solid to conserve water

10. Response Reptile’s brain is similar to amphibian’s
Diurnal reptiles tend to have complex eyes and can see color
Many snakes have good sense of smell
Most reptiles have a sensory organ in the roof of their mouth that can detect chemicals when they flick their tongues
Snakes can detect body heat and vibrations

11. Movement
Reptiles with legs have larger and stronger limbs than amphibians
Many aquatic turtles developed their legs into flippers

12. Reproduction
All reptiles internal fertilization (male deposits sperm into female)
Most are oviparous (lays eggs)
Some (ex. Box turtles) will make a nest and abandon the eggs while others (ex. Alligators) will defend their nests/eggs
Amniotic egg- an egg that developed a shell to protect the egg without needing to be in water
One of the most important adaptions to living on land
Others are Ovoviviparous (live birth)
Ex. Some snakes and lizards

13. Groups of Reptiles: Lizards & Snakes
Order: Squamata (scaly reptiles)
Some lizards developed highly specialized forms, such as the Gila monsters who have glands in the lower jaw that produces venom
Snakes are legless, but they are highly efficient predators
Some are as small as earthworms, while others can grow more than 8 meters (24 feet)

14. Groups of Reptiles: Crocodillians
Order- Crocodilia
Includes: Crocodiles, caimans, alligators, and gavials
Fierce carnivores that prey on deer, fish, and even humans
Very protective of their young
Lives in tropics and subtropics where it is warm year-round
Alligators and caimans live only in fresh water are exclusively in North and South America
Crocodiles can live in fresh and salt waters and are native to Africa, India, and Southeast Asia

15. Groups of Reptiles: Turtles and Tortoises
Order- Testudines
Turtles refer to members that live in water while tortoises refer to members that live on land
Both have shells on the back, though not all are hard; the shell consists of 2 parts the carapace (top part) and the plastron (bottom part)
They lack teeth, have horny ridges that covers powerful jaws

16. Groups of Reptiles: Tuatara
Order- Sphenodonta
Found only on a few small islands off the coast of New Zealand
Resembles lizards but lack external ears and retain primitive scales
Has a ‘third eye’ that can detect levels of sunlight