Life cycles: insects, amphibians, birds and mammals

In a nutshell

The life cycle shows the beginning of an animals life to the end of its life, or to the point where the animal has its own babies and new life is created. Having babies ensures these animals are replaced when they die, this allows the cycle to continue. All life cycles feature four key stages: birth, growth, reproduction and death. Insects, amphibians, birds and mammals all have different life cycles.

Insect life cycle

Science; Living things and their habitats; KS2 Year 5; Life cycles: insects, amphibians, birds and mammals

1.	Eggs are laid by an insect such as a butterfly.
2.	Larva such as a caterpillar then hatches from the eggs.
3.	The larva then becomes a pupa, in butterflies this is called chrysalis.
4.	The adult then emerges from the pupa.
5.	The cycle starts again when the adult insect lays eggs.

Amphibian life cycle

Science; Living things and their habitats; KS2 Year 5; Life cycles: insects, amphibians, birds and mammals

1.	Eggs are laid in water.
2.	Tadpoles begin to develop in the eggs.
3.	Tadpoles hatch and begin to develop in water.
4.	The tadpole with legs becomes a froglet.
5.	The tadpoles have now developed into adults and the cycle starts again.

Bird life cycle

Science; Living things and their habitats; KS2 Year 5; Life cycles: insects, amphibians, birds and mammals

1.	Eggs are laid, normally in a nest.
2.	The embryo develops inside the egg.
3.	The egg hatches.
4.	The chick continues to grow into an adult.
5.	The cycle starts again when the adult female bird lays an egg.

Mammal life cycle

Science; Living things and their habitats; KS2 Year 5; Life cycles: insects, amphibians, birds and mammals

1.	A fertilised egg develops into an embryo.
2.	The embryo becomes a foetus inside the body of the female.
3.	A baby is born.
4.	The baby becomes a child.
5.	The child grows into an adolescent (teenager), this is when puberty occurs.
6.	The adolescent becomes an adult.
7.	The adult grows into old age.

The cycle continues when adult mammals have their own babies.

Puberty

At around the ages of $9-18$ , which is during adolescence, the bodies of males and females change.

Males	Changes include hair growing on their bodies and faces. Their testicles will now start to produce sperm.
Females	Changes include the development of breasts, widening of hips and hair growing on their bodies. Ovaries will begin to release an egg every month and this is known as a period or menstruation.