AMPHIBIANS & REPTILES ARE ADAPTED FOR LIFE ON

LAND• VERTEBRATES ADAPTED TO LIVE ON

LAND.• AMPHIBIANS HAVE MOIST SKIN & LAY

EGGS WITHOUT SHELLS.• REPTILES HAVE DRY, SCALY SKIN & LAY

EGGS WITH SHELLS.• BODY TEMPERATURES OF AMPHIBIANS &

REPTILES CHANGE WITH THE ENVIRONMENT.

Vertebrates Adapted to Live on Land

• Amphibians (frog/toad/salamanders) & Reptiles (turtle/snake/lizards/crocodiles) have adapted to live on land.

• Some fish can breathe air and walk short distances on land.

• Some amphibians have adapted to life only in water.

Amphibians: moist skin & eggs without shells

• Most adult amphibians have: 2 pairs legs (4 limbs), lay eggs in water, get oxygen thru smooth, moist skin, have lungs, sense organs adapted for land.

• Most live in moist or damp environments• Reproduce sexually (female lays eggs in water &

male fertilizes them in water with sperm); offspring develop & hatch on own- yolk inside eggs gives nutrients; soft shells so water (with dissolved oxygen) can pass through.

Amphibian Life Cycle

• Young amphibian hatches as a larva (tadpoles for frogs & toads; look & act like small fish- breathe via gills, swim with tail)

• After few weeks, tadpole’s body changes (lungs develop, tail shrinks, legs form)

• Young frog’s body changes: gills stop working so breathes with lungs, uses tongue to capture & eat small animals, uses legs to move around on land.

• Some amphibians stay near water (sirens, bullfrogs), while some just go to moist areas (wood frogs, toads, salamanders)

Reptiles have dry, scaly skin & lay eggs with shells

• Most have 2 pairs legs (total 4 limbs); have tough, dry skin covered by scales; get oxygen from air with lungs; sensory organs adapted for land; lay eggs (with shells) on land.

• Lungs: born with lungs, filled with tiny blood vessels where oxygen is exchanged with carbon dioxide waste.

• Dry, scaly, skin: covered with scales made of keratin (like fingernails). Thick, waterproof skin protects from environment & predators (but can’t exchange oxygen through skin).

Reptile Eggs with Shells• Reptile egg lets

vertebrate animals survive in hot, dry environment.

• Eggs have everything embryo needs (water, nutrients, gas exchange).

• Reptiles reproduce sexually (sperm fertilizes egg, then shell forms around it-while still within female).

• Female finds place to lay eggs (usually nest or buries them).

Amphibians & Reptiles areEctotherms

• Are Ectotherms: body temperature changes with environmental conditions; can move more quickly when warm. Usually warm themselves in sunlight.

• Most of food is changed right into energy. Some (alligator & tortoise) may survive long time without eating food.

• If too hot or too cold, body stops working well. (usually live where temp. doesn’t change too much- or may hibernate & slow down body processes in cold)

• Many live near water to cool off.