Chapter 41ReptilesSection 3

Modern Reptiles

Characteristics• Amniotic egg, internal fertilization

of eggs, dry scaly skin, respiration through lungs, ectothermic metabolism

Order Chelonia• 250 species of turtles & tortoises

• Tortoise- terrestrial (cannot swim)

• Turtle- aquatic (can swim)

• Shell- evolutionary successful

• Carapace- top (dorsal) shell

• Plastron- bottom (ventral) shell

Order Chelonia• No teeth- sharp beaks

• Ribs are fused to shell (carapace)

• Some are permanently aquatic, terrestrial, or both

• Depends on shell & limbs

• Marine turtles- flippers, land tortoises- elephant like feet, aquatic turtles- web feet

Marine turtle- green sea turtle

Land tortoise- Galapagos

Aquatic turtle- Map turtle

Semi-terrestrial- eastern box

Reproduction- turtles• Lay eggs• All females lay eggs on land• Marine turtles travel long distances

and lay eggs on beach where they hatched

• How do you think they find their way back?

Arribada

Order Crocodilia• Crocodiles & alligators

• Carnivorous- fish, turtles, land animals

• Ambush predators

• Difference between alligators & crocodiles?

Crocodile

Alligator

Order Squamata• Lizards & snakes

Lizards• Common: iguanas, chameleons,

geckos

• Diet: insects, small animals

• Komodo dragon eats goats & deer

• Venomous lizards: Gila monster & beaded lizard

Lizards• Escape predators- agility, speed,

& camouflage

• Autotomy- ability to detach tail

• The dropped tail still moves to attract predators to the tail and the lizard will escape

Komodo Dragon

Iguana

Leopard Gecko

Anole

Snakes• Lack of legs, shed to grow• What was the selective pressure that

caused snakes to evolve legless?• **Snakes lived in thick vegetation and

needed to move faster• Made of bones and over 400 ribs &

many muscles

Black Racer

Common Garter

Water Moccasin

Capturing & Consuming Prey

• Two killing methods: constriction or injection of venom

• Constrictors- wrap their bodies around prey

• Boas, pythons, anacondas

Anaconda

Capturing & Consuming Prey

• Toxic venom- snake will fangs in back of mouth

• Cobras, kraits, coral snakes

• Elapid- snakes inject poisons through two small, fixed fangs in the front of the mouth

King Cobra

Capturing & Consuming Prey

• Vipers- inject venom through large, mobile fangs in the front of the mouth

• Examples: rattlesnakes, copperheads, & water moccasins

• Swallow prey whole, lower jaw

Timber rattlesnake

Order Rhynchocephalia• New Zealand

• “spiny crest”

• 2 feet

• Hide in burrow during day, feed on insects

• Humans introduced predators and tuataras are disappearing

REVIEW!!!• Compare the characteristics of

aquatic turtles to the characteristics of land tortoises.

• Describe two methods snakes use for killing prey.