An amphibian is a “vertebrate that is ectothermic and spends it early life in water.”

The three main characteristics of amphibians are it having a circulatory system, obtaining oxygen through the use of lungs, and having a respiratory system.

The metamorphosis of a salamander is different to that of a frog’s in that the metamorphosis of a salamander means they lose their gills.  A frog’s metamorphosis is “not as dramatic” in that the frog doesn’t “look” like an adult.  In addition, eggs are fertilized internally in salamanders while externally in frogs.

Four adaptations of adult amphibians of adult amphibians for living on land are having sticky pads on their toes for climbing, developing camouflage for obtaining food, having a circulatory system, and obtaining oxygen through developing lungs.

Three adaptations frogs and toads have for moving are webbed feet, sticky pads, and strong skeletons and muscular limbs.  Each adaptation helps the amphibian survive by helping it grasp onto its desired environment, swim, or leap from place to place; this can help the frog or toad by avoiding predators, finding a new place to live, or even hunting for food.

The two upper chambers of the heart, called atria, receive blood.  One atrium receives “oxygen-rich blood” from the lungs, and the other receives “oxygen-poor blood” from the rest of the body.  From the atria, blood moves in to the lower chamber, the ventricle.  It then leaves the ventricle and proceeds to the lungs and body.