CH. 3 SEC. 4 REPTILES

ectothermic vertebratehave lungs

scaly skin

lay eggs on land

3 chambered

heart

All reptiles are ectothermic, which is why they warm themselves in the sun.

ways reptiles conserve water

1. eggs • shell & membrane (amniotic sac) protect embryo

• keep it from drying out

2. skin • dry, tough• keeps water in

3. kidneys • concentrate urine

major groups of reptiles • lizards

• snakes

• turtles

• alligators and crocodiles (crocodilians)

lizards

shed their skin as

they grow

most live in

warm areas4 legs

external ears

Reptile defensesReptile defenses• Some kinds of lizards have tails that will break

off when grabbed by an attacker. (They later grow back.)

• The lizard escapes, while the attacker is left with just the tail.

Horned LizardHorned Lizard This is one of the grossest creatures around !

When the Horned Lizard gets really scared, it shoots blood out of its eyes by increasing the blood pressure in its sinuses until they explode.

Ouch! The blood doesn't hurt the lizard's enemy but it really freaks them out, so the Horned Lizard has time to escape.

Horned lizards can squirt a stream of blood as far as 3 feet at an attacker.

snakessnakessnakessnakes

No legsNo legs

No eyelids

No eyelids

No external

ears

No external

ears

most have only

1 lung

most have only

1 lungcarnivorescarnivores

Northern Copperhead

(a venomous snake)

Ouch !

Venomous Eastern Coral Snake

Harmless Scarlet Kingsnake

Bands: YellowYellow--RedRed--YellowYellow-Black--Black-YellowYellow--RedRed

Bands: YellowYellow-Black--Black-RedRed-Black--Black-YellowYellow-Black -Black

Venomous or not?

Can you tell the difference?

Dumeril's Ground BoaDumeril's Ground Boa

Playing DeadAmong North American snakes, the Eastern Hognose has the most impressive defense behavior.

When threatened, it flattens its head and neck like a cobra and hisses loudly. It may strike but rarely bites.

If all this fails, the snake rolls over, writhes as if in pain, opens its mouth, sticks out its tongue, and plays dead.

It is a real actor; you can pick it up and it will remain limp, but when you set it down, it will flop over onto its back again.

Turtles• body covered by protective shell

• made from its spine & ribs

• most turtles & tortoises can pull their heads back into their shells

largest turtles= leatherbacks

Leatherback turtles can weigh over 500 kilograms (about 225 lbs).

Females come ashore in bands and lay their 60 to 100 eggs in holes that have been dug in the sand. Seven weeks later, when the eggs hatch, the babies rush back to the water. 

A painted turtle is about to eat a mayfly - yum!

• largest reptiles (in size) =

alligators & crocodiles

American Alligator American Crocodile

Crocodilians are carnivores that hunt mostly at night.

dinosaursdinosaurs• extinct reptiles- 65 million years ago• paleontologist- scientist who studies

extinct organisms by using fossils-

• occur most often in sedimentary rock• evidence of living thing that

existed a long time ago