Biology notes on Amphibians.

Notes Frogs, toads, salamanders, and newts are direct descendants from fish. Amphibians evolved from a type of lobe-finned fish. The name amphibian is from the Greek amphi, which means "double," and bios, which means "life." The name is appropriate because of the fact that they can live in water, as well as on land. Fossil evidence indicates that amphibians evolved from lobe-finned fishes about 370 million years ago. Recent analysis of the DNA of coelacanths and …

…the Tertiary period, all modern amphibians have certain key characteristics in common. Legs, lungs, cutaneous respiration, pulmonary veins, and a partially divided heart have helped them to adapt, and is what they all have in common. There are 3,680 species of frogs and toads in 22 families. They live in environments ranging from deserts to mountains, and ponds to puddles. Frogs and toads do not have tails. Salamanders lay their eggs in water or in moist places.