Section 4

Reptile: ◦ Ectothermic vertebrate that has lungs and scaly

skin

Types of Reptiles:◦ Snakes, lizards, turtles, and alligators

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

Adaptations to life on land ◦ Eggs

◦ Skin

◦ Kidneys

Adaptations help them conserve water

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

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

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

What is the other organ that helps conserve water?◦ Kidneys

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

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

Live in warm areas

Have skin with overlapping scales

Shed their skin replacing worn scales with a new coat

Eating Habits◦ 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

Snake bodies:◦ Similar to lizards but streamlined

◦ No legs

◦ No eyelids

◦ No external ears

◦ Most have only 1 lung

Movement:◦ Contract bands of

muscles that are connected to their ribs and backbones

◦ Alternating contractions creates a slithering side-to-side motion

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

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

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

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

Carnivores that hunt at night

Strong, muscular tails to swim rapidly

Large, sharp teeth

Extremely strong jaw muscles

Usually do not attack humans

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

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