Process diagram: Life cycle of a frog

The diagram shows the stages in the life cycle of a frog, from the laying of spawn to the adult frog.

Overall, the cycle has eight stages. The frog begins life in water and develops legs and lungs, and the adult returns to the water to breed, so that the cycle continues.

The cycle begins when the female lays eggs, known as spawn, in a pond. Inside its jelly coating, each embryo develops, and a tadpole with a tail then hatches and swims out. The tadpole breathes underwater using gills and eats algae.

After several weeks, the hind legs appear. Later, lungs develop and the front legs emerge, so that the tadpole starts to look like a small frog.

In the next stage, the animal becomes a froglet, and its tail shortens as the body changes. Finally, it is an adult frog. The adult leaves the water, but it later returns to the pond in order to breed, and the cycle starts again. This means that the adult spends part of its life on land.