Amazing Life Cycles

Every living thing goes through a life cycle — the journey of stages it passes through as it is born, grows, changes, and eventually has young of its own. When those young grow up and have babies too, the cycle begins all over again. That is why we call it a cycle: it goes round and round, never truly ending.

Some animals change their bodies dramatically as they grow. A butterfly does not start out with wings at all. It begins as a tiny egg, hatches into a hungry caterpillar, then wraps itself inside a hard case called a chrysalis. Inside, its whole body is rebuilt — and out comes a winged adult that looks nothing like the caterpillar it once was.

Frogs have a famous life cycle too. They start as jelly-covered eggs called frogspawn, floating in a pond. These hatch into tadpoles with long tails and gills for breathing underwater, just like fish. As a tadpole grows it sprouts back legs, then front legs, its tail shrinks away, and it develops lungs — becoming a froglet and finally an adult frog that can hop onto land.