Reptiles
• Reptiles are ectotherms with a dry,
waterproof skin covered with scales.
Reptiles
– Reptiles breathe with lungs.
• Most reptiles have a 3 -chambered heart.
• The three-chambered heart has a partial wall inside the
main chamber.
• Crocodilians have a 4-chambered heart that completely
separates oxygen-filled and carbon dioxide-filled blood.
Reptiles
• Reptiles use internal fertilization and lay eggs with
shells; the amniotic egg provides a complete
environment for the embryo’s development.
Reptiles
• Reptiles live on every continent except
Antarctica and in all but polar oceans; reptiles
are divided into 3 living groups.
– Lizards and snakes have jaws that unhinge so
they can swallow their prey whole.
Reptiles
• Turtles have a two-part shell made of hard bony
plates that protects against predators.
Reptiles
– Crocodilians are lizard-shaped with large, deep
scales on their backs.
• Crocodiles have a narrow head with a ________shaped snout while alligators have a broad head with a
_________ snout. Gavials have a slender snout with a
large bump on the end.
• Crocodilians are among the few reptiles that care for
their young.
Reptiles
Crocodile vs. alligator
Gavial
Reptiles
• Reptiles are important predators that keep
pests under control; reptiles first appeared in
the fossil record about 345 million years ago.
Dinosaurs are descendants of early reptiles.