Animal Growth and Life Cycle

Animal Life Cycles

What is a life cycle?

A life cycle is all of the changes that happen to an animal or plant during its life.

The young organism grows and changes into an adult.

Some young organisms are small versions of the adult.

In other plants and animals, the young organism is very different from the adult.

Describe the life cycle of a person.

A baby grows up to become a child and then an adult. An adult may have a baby, beginning the cycle again.

Open Ended

Describe the life cycle of a person.

What is a tadpole?

A tadpole is a young frog that hatches from an egg. It has a tail and no legs and breathes through gills.

Multiple Choice

What is a tadpole?

• A series of changes that some animals go through.

• A young frog that comes out of an egg and has gills to take in oxygen from the water.

• The stage of complete metamorphosis in which an insect changes from a larva to an adult.

• The stage between egg and pupa in complete metamorphosis in insects.

What does “metamorphosis” mean?

Metamorphosis takes place when an animal’s body changes form during its life cycle after birth. For example, a frog changes from a tadpole that uses gills to get oxygen to an adult frog that breathes with lungs.

Complete metamorphosis

A butterfly goes through complete metamorphosis. The body of a newly hatched caterpillar is completely different from the body of an adult butterfly.

Multiple Choice

What is metamorphosis?

• A series of changes that some animals go through.

• A young frog that comes out of an egg and has gills to take in oxygen from the water.

• The stage of complete metamorphosis in which an insect changes from a larva to an adult.

• The stage between egg and pupa in complete metamorphosis in insects.

Multiple Choice

What is a pupa?

• A series of changes that some animals go through.

• A young frog that comes out of an egg and has gills to take in oxygen from the water.

• The stage of complete metamorphosis in which an insect changes from a larva to an adult.

• The stage between egg and pupa in complete metamorphosis in insects.

Multiple Choice

What is a larva?

• A series of changes that some animals go through.

• A young frog that comes out of an egg and has gills to take in oxygen from the water.

• The stage of complete metamorphosis in which an insect changes from a larva to an adult.

• The stage between egg and pupa in complete metamorphosis in insects.

Multiple Select

Does a butterfly go through complete metamorphosis or incomplete metamorphosis?

• complete metamorphosis

• incomplete metamorphosis

In complete metamorphosis, the adult form is very different from the larva stage. For example, the butterfly is very different from the caterpillar. In incomplete metamorphosis, the larva stage looks much more like the adult stage. For example, a newly hatched cockroach is similar to an adult cockroach.

Typical animal life cycle.

The life cycle begins with birth. At first, an animal depends on its parent for food. As the young animal grows, it begins to eat on its own and learns skills to help it survive. Eventually, the adult animal reproduces, or has young. 

How do animals learn skills they need to survive as adults?

Animals learn many skills by watching their parents. They also practice as they play with other young animals.

Some insects, such as cockroaches, go through a process called incomplete metamorphosis. How is incomplete metamorphosis different from the complete metamorphosis of a butterfly?

​Insects that go through 3 stages of change in their life cycle have an incomplete metamorphosis while complete metamorphosis has 4 stages.

3 Stages of Incomplete Metamorphosis

1. The first stage of incomplete metamorphosis is the egg. During this time, the insect will hatch into a form called a nymph.

2. The nymph is basically a small version of the adult insect. This is very similar to how a child looks like his or her parents. Nymphs usually have a thin exoskeleton and no wings. They eat the same food as their parents and live in the same place. As insect nymphs grow larger, their exoskeleton becomes too tight and they must replace it.

3. Once a nymph outgrows its exoskeleton it will go through a process called molting, in which it leaves the old “skin” or exoskeleton behind. The new “skin” will harden and become the new exoskeleton. This will happen many times until the insect finally becomes the size of an adult.

Some text here about the topic of discussion

Multiple Select

Do frogs go through complete or incomplete metamorphosis?

• Complete metamorphosis

• incomplete metamorphosis

Do frogs go through complete or incomplete metamorphosis?

A frog goes through several stages—egg, tadpole, tadpole with legs, and adult—during its life cycle. A newly hatched tadpole is completely different from an adult frog. Therefore, a frog goes through complete metamorphosis.

Open Ended

Why are young animals different from their parents?

Why are young animals different from their parents?

A young animal gets some of its looks from each of its parents. Because of this, it will not look or act exactly like either parent.

Open Ended

How is the life cycle of a frog different from the life cycle of a person or other animals?

How is the life cycle of a frog different from the life cycle of a person or other animals?

Some animals, including people, do not go through metamorphosis. The young animal looks like a smaller version of the adult, and they have no larva stage.

Multiple Choice

Name one kind of insect that goes through incomplete metamorphosis.

• butterfly

• cockroach

• frog

Multiple Select

Name two kinds of animals that go through complete metamorphosis.

• butterfly

• cockroach

• frog