In this topic you will learn about the changes animals go through as they live and grow.

Organisms change as they grow through their life cycle. A life cycle is all the changes in an organism's life. Organisms go through stages. At birth, the organism's life begins. As an organism lives, it grows and changes. It may take on a new form. During reproduction, an organism creates new organisms like itself. At death, the organism's life ends.

Like people, some organisms get larger as they grow older. Unlike people, some organisms go through a life cycle change called metamorphosis. Metamorphosis means a change in the body form of an organism. Big changes take place in insects like the butterfly. Other animals, such as frogs and toads, also go through metamorphosis. Young frogs live only in water. Adult frogs live both in and out of water. Their bodies must change to live in both places. Other animals like birds, turtles, cats, and bears do not go through metamorphosis.

What makes you you? You have inherited traits. Inherited traits are characteristics that come from your parents. How do you inherit traits? People start out life as an egg. The egg contains special material from both parents. This material determines your traits.

Not all traits are inherited. Some are learned traits. A learned trait is something that you are taught or learn from experience. You learn to ride a bicycle or speak a language.