What Is So Special About Amphibians?

The name amphibian comes from the Greek words amphi and bios meaning two kinds of life and this describes an amphibian perfectly. It lives two kinds of life – one in the water and one on dry land and has different life stages that are well adapted to each environment.

The life cycle of an amphibian begins when eggs hatch into larvae. These live totally submerged in water and the use gills to extract oxygen from the water in order to 'breathe'. When the larvae have grown, they undergo a radical metamorphosis; unlike insects which pupate, the amphibians just transform gradually. They reabsorb their gills and use the lungs that have developed in the later larval stages to breathe in oxygen from the air. They also develop legs for walking on land.

The most successful amphibians are those still around today – the frogs, the toads, the salamanders and the newts. Amphibians are one of the smallest groups of verterbrates – there are only 4000 species in existence, all belonging to the four groups just mentioned.