The life cycle of an amphibian

A life cycle is the series of changes a living thing goes through during its life. Amphibians have a very interesting life cycle. Amphibians usually lay their eggs in water. After several days, larvae emerge from the eggs. The larvae live in water and breathe using gills. As the larvae grow their lungs develop and they start to look more like adults. Their gills disappear and they start to breathe air. Then they are able to leave the water and live on land. Let us look at the life cycle of one type of amphibian.

 

The life cycle of a frog

Female frogs usually lay their eggs in water. Can you see the frog eggs in the picture below?

 

Larvae emerge from these eggs. The larva of a frog is called a tadpole. A tadpole has a round body and a tail which it uses to swim. Look at the tadpoles in the picture below.

 

At first tadpoles have no legs, but as they grow their legs start to develop. First their two hind legs grow. Later, their two front legs grow (see picture below).

 

As the tadpoles continue to develop, their legs grow bigger and their tails get shorter. Their lungs develop so they can breathe air. They lose their gills and their tails disappear. At this point they can leave the water and live on land as adult frogs.

 

Adult frogs mate and the females lay their eggs in water, starting the cycle over.