Amphibians Class Amphibia

Amphibians are tetrapod vertebrates (four footed) Include all tetrapod vertebrates that are not amniotes (lay eggs on land) Frogs, toads, salamanders, and newts

Characteristics Integumentary Skeletal/Muscular Moist skin with mucus glands Found near moist habitats to keep skin damp Skeletal/Muscular Endoskeleton Adult: legs for walking or jumping; no legs Larva: swim

Characteristics Circulatory Reproductive Adult: 3 chambered heart, closed-double loop Larva: 2 chambered heart Reproductive External fertilization; eggs must stay moist (no shell)

Characteristics Nervous Respiratory Brain; eyes w/ nictitating membrane; tympanic membrane (like a drum) for hearing; lateral lines Respiratory Adult: through lungs, skin, & lining of the mouth Larva: through skin and gills

Characteristics Digestive Excretory Complete digestive system (mouth --> anus) Adult: carnivore Larva: herbivore or filter feeder Excretory Kidneys filter wastes from blood, urine travels through ureters to urinary bladder and out through cloaca

Characteristics Body Temperature Habitat Ectothermic (cold blooded, find heat from an outside source like the sun) Habitat Adult: live on land near water Larva: live in water

Lifecycle of a Frog Adult Frog Young Frog Fertilized Eggs Tadpoles Adults are typically ready to breed in about one to two years. Frog eggs are laid in water and undergo external fertilization. The eggs hatch into tadpoles a few days to several weeks later. Tadpoles gradually grow limbs, lose their tails and gills, and become meat-eaters as they develop into terrestrial adults.

Evolution The first amphibians looked similar to lobe-finned fish

Groups of Amphibians Salamanders – have long bodies & tails, most have 4 legs, usually live in moist woods

Groups of Amphibians Frogs & toads – both jump & lack tails; frogs more closely tied to water

Groups of Amphibians Caecilians – legless animals; live in water or burrow in moist soil; many have fishlike scales,resemble earthworms or snakes