Chapter 3 Section 4

Drying Out Reptile: Types of Reptiles: Ectothermic vertebrate that has lungs and scaly skin Types of Reptiles: Snakes, lizards, turtles, and alligators

Reptiles Background Can spend their entire life on dry land 1st vertebrates that are well adapted to life on land Dominant land species for 160 million years 7,000 kinds of reptiles are alive today

Reptiles Adaptations to life on land Eggs Skin Kidneys Adaptations help them conserve water

Egg with a Shell What type of fertilization do reptiles use? Internal fertilization Fertilized eggs are covered with a membrane and a shell The membrane and shell protect the embryo and prevent it from drying out

Egg with a Shell Amniotic Egg Information Soft and leathery Tiny holes let oxygen in and carbon dioxide out Eggs can be laid on land 1 membrane holds the liquid that surrounds the embryo – keeps it from being crushed and keeps it moist 2nd membrane holds the yolk or food 3rd membrane holds the wastes

Egg with a Shell

Skin and Kidneys What type of skin did amphibians have? Thin and moist How is a reptiles skin different? It is dry, tough, and covered with scales What is the function of scales? Protection Conserve water in their body

Skin and Kidneys What is the other organ that helps conserve water? Kidneys filter out the waste from the blood The waste from the blood is excreted in the urine Concentrate their urine so much that they barely lose any water

Obtaining Oxygen Have a heart with 2 atria and 1 ventricle Breathe entirely with lungs 2 loops for their blood to circulate 1st blood travels from the heart to the lungs back to the heart Becomes oxygenated 2nd loop travels from the heart to the tissues Oxygen moves out of the blood and into the tissues Then the blood returns to the heart

Lizards Live in warm areas Have skin with overlapping scales Shed their skin replacing worn scales with a new coat

Lizards Eating Habits A Lizard’s Body A few lizards are herbivores Most are carnivores Eat frogs, ground-dwelling birds, and insects A Lizard’s Body 4 legs and claws with toes Long tails Slender bodies Moveable eyelids External ears

Snakes Snake bodies: Similar to lizards but streamlined No legs No eyelids No external ears Most have only 1 lung

Snakes Movement: Contract bands of muscles that are connected to their ribs and backbones Alternating contractions creates a slithering side-to-side motion

Snakes Eating: All snakes are carnivores They can spread their jawbones wide apart A snake’s skull can move to let the snake swallow an animal much larger in diameter than itself

Snakes

Snakes Eating Cont’d: Sharp-tailed snakes of W. North America Hook their slippery prey West Indian Boas Snatch their prey out of the air Rattlesnakes and copperheads Venom glands

Turtles Reptile covered by a protective shell Made from its ribs and backbone Shell sizes and strengths vary Examples on 108 in the reading There are turtles that are carnivores while some are herbivores

Alligators and Crocodiles Largest living reptiles Spend most of their day resting in the sun or lying in the water How do you tell an alligator from a crocodile? Alligators have a broad, rounded snout with only a few visible teeth Crocodiles have a pointed snout and you can see most of their teeth

Alligators and Crocodiles

Alligators and Crocodiles Carnivores that hunt at night Strong, muscular tails to swim rapidly Large, sharp teeth Extremely strong jaw muscles Usually do not attack humans

Alligators and Crocodiles Care for their eggs and newly hatched young After birth the mother scoops them into her mouth and carries them to a safer location Typically females stay with the young for up to a year

Dinosaurs 225-65 million years ago reptiles were the major form of vertebrate May have been endothermic Have been extinct for 65 million years Due to climate Huge meteorite