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Metamorphosis is the way an animal's body changes as it grows up. The word comes from a Greek word meaning "change in form." You can see metamorphosis happen in insects like butterflies, grasshoppers, and beetles.

Not all animals go through metamorphosis. Dogs, cats, and birds just grow bigger and look like smaller versions of their parents. But insects go through amazing body changes! You can learn more about how different animals grow in Growth Patterns: How Different Organisms Grow and Change.

There are two types of metamorphosis you will learn about: complete metamorphosis and incomplete metamorphosis.

Complete metamorphosis has four stages: egg, larva, pupa, and adult. The animal looks very different at each stage. Scientists call it "complete" because it includes all four stages, especially the pupa stage.

Here is how a butterfly goes through complete metamorphosis:

• Egg: The adult female butterfly lays a tiny egg on a leaf.
• Larva (caterpillar): The egg hatches into a caterpillar. The caterpillar eats lots of leaves and grows bigger.
• Pupa (chrysalis): The caterpillar wraps itself in a chrysalis and rests. Inside, its body completely changes.
• Adult: A beautiful butterfly with colorful wings comes out. The adult butterfly lays eggs to start the cycle again.

Other insects that go through complete metamorphosis include moths, beetles, and ladybugs.

Incomplete metamorphosis has only three stages: egg, nymph, and adult. It is called "incomplete" because it is missing the pupa stage. The young insect, called a nymph, already looks like a small adult.

Here is how a grasshopper goes through incomplete metamorphosis:

• Egg: The adult female lays eggs in the ground.
• Nymph: The egg hatches into a nymph. A nymph looks like a tiny grasshopper but does not have fully grown wings yet.
• Adult: The nymph slowly grows bigger and develops full wings to become an adult grasshopper.

Other insects with incomplete metamorphosis include crickets and cockroaches. You can explore more about how different animals grow in Animal Life Cycles: Various Animal Growth Patterns.

Frogs also go through big body changes as they grow. A frog egg hatches into a tadpole, which swims in water using a tail. As the tadpole grows, it develops four legs and its tail slowly disappears. The tadpole becomes an adult frog that can live on land and in water.

Frogs do not have a nymph or pupa stage like insects do. Their life cycle is different but still involves dramatic body changes.

Metamorphosis: Metamorphosis is the big change an animal's body goes through as it grows from a young animal into an adult. The word means "change in form."

Complete Metamorphosis: Complete metamorphosis is a life cycle with four stages: egg, larva, pupa, and adult. The animal looks very different at each stage. Butterflies, moths, and beetles go through complete metamorphosis.

Incomplete Metamorphosis: Incomplete metamorphosis is a life cycle with three stages: egg, nymph, and adult. It is missing the pupa stage. Grasshoppers and crickets go through incomplete metamorphosis.

Egg: The egg is the first stage in both complete and incomplete metamorphosis. The adult female insect lays the egg, and a young insect hatches from it.

Larva: The larva is the stage right after the egg in complete metamorphosis. The larva hatches from the egg and spends most of its time eating and growing. A caterpillar is the larva of a butterfly. The larva looks very different from the adult it will become.

Pupa: The pupa is the resting and changing stage in complete metamorphosis. During the pupa stage, the insect's body completely transforms inside a protective covering. The pupa stage does NOT happen in incomplete metamorphosis.

Adult: The adult is the final stage in both complete and incomplete metamorphosis. The adult insect can fly, find a mate, and lay eggs to start the life cycle again.

Nymph: A nymph is the young insect in incomplete metamorphosis. A nymph looks like a small adult insect but does not have fully grown wings yet. Grasshopper nymphs are a good example.

Chrysalis: A chrysalis is the hard protective covering that a butterfly caterpillar forms around itself during the pupa stage. The butterfly transforms completely inside the chrysalis.

Cocoon: A cocoon is the silky covering that a moth caterpillar spins around itself during the pupa stage. A cocoon is similar to a chrysalis but is made by moths, not butterflies.

Tadpole: A tadpole is the young form of a frog. It hatches from a frog egg and swims in water using a tail. As it grows, it develops legs and loses its tail to become an adult frog.

You can practice identifying the stages of complete and incomplete metamorphosis by looking at pictures of insects. Try to name each stage and decide if the insect goes through complete or incomplete metamorphosis.

You can also compare a butterfly life cycle and a grasshopper life cycle side by side. Look for the pupa stage if it is there, you know it is complete metamorphosis! Learn more about how animals are grouped in Animal Groups: Major Animal Classifications.

Before learning about metamorphosis, you already explored some important ideas. You learned about Living vs Non-living: Characteristics That Define Life, which helps you understand that living things grow and change.

You also learned about Animal Classification: Major Animal Groups and Characteristics and External Features: Body Coverings, Limbs, and Sensory Organs, which help you notice how animals look different at each stage of metamorphosis.

You explored Growth Patterns: How Different Organisms Grow and Change and Parent-Offspring Relations: Similarities Between Parents and Offspring, which show you how young animals compare to their parents.

This topic connects to many other exciting science ideas you will explore. You can compare metamorphic life cycles with Non-metamorphic Life Cycles: Direct Development Patterns, where animals grow without dramatic body changes.

You can also explore Plant Life Cycles: Seed Production and Dispersal to see how plants grow and change in their own way, just like insects do.

Learning about metamorphosis will help you understand Animal Adaptations: Physical and Behavioral Features and Plant Adaptations: Structural Adaptations, because the body changes in metamorphosis are a kind of adaptation.

After this topic, you will be ready to learn about Structural Adaptations: Physical Features for Survival and Behavioral Adaptations: Actions That Aid Survival, which build on what you know about how animals change and grow.