Science notes, unit 4

Animals

Textbook Science Year 2 (DLP), pages 35–48

What this chapter covers

You can name animals that lay eggs and animals that give birth (4.1.1, 4.1.2)
You can say which animals lay a few eggs and which lay many eggs (4.1.3)
You can say which animals have a few young and which have many young (4.1.4)
You can put the life cycle of a frog, a cow and a butterfly in order (4.1.5, 4.1.7)
You can tell which young look like their parents and which do not (4.1.6)

Animals make more animals of their own kind. This is called reproduction. In this unit you will learn how animals have their young, how many young they have, and how the young grow.

4.1Animal reproduction

Lay eggs or give birth

Animals reproduce in two ways: they lay eggs or they give birth.

Nisa and her father see a stork's eggs hatching in a nest. Storks lay eggs.

A frog, a crocodile and a mosquito, three animals that lay eggs — A frog, a crocodile and a mosquito all lay eggs.

Figure: Science Year 2 (DLP), p.36.

Animals that lay eggs	Animals that give birth
bird, chicken, frog, crocodile, fish, ant, butterfly, mosquito	cat, rabbit, elephant, dolphin, kangaroo, panda, monkey

A cat gives birth to kittens. Kittens are alive when they are born. They do not come from eggs.

Does a duck lay eggs or give birth? What about a rabbit?

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A duck lays eggs. A rabbit gives birth.

A few eggs or many eggs

Some animals lay only a few eggs. Other animals lay many eggs.

Bird, fish, swan, frog, penguin and ant — Bird, swan and penguin lay a few eggs. Fish, frog and ant lay many eggs.

Figure: Science Year 2 (DLP), p.39.

A few eggs	Many eggs
bird, swan, penguin, ostrich, chicken	fish, frog, ant, butterfly, crocodile

Other animals sometimes eat eggs. So animals that lay eggs look after them. A bird builds a nest in a tree to keep its eggs safe from animals on the ground. (Extra fact: a turtle buries its eggs in the sand.)

A few young or many young

Animals that give birth also have different numbers of young.

Pangolin, dolphin, rabbit and cat — Pangolin and dolphin have a few young. Rabbit and cat have many young.

Figure: Science Year 2 (DLP), p.41.

A few young	Many young
pangolin, dolphin, elephant, panda	rabbit, cat, porcupine, wolf

A mother animal that gives birth looks after her young and feeds them with milk. A cat hides her kittens in a safe place.

Do not mix up the two. "Lay eggs" goes with eggs. "Give birth" goes with young. A fish lays many eggs. It does not give birth.

Young that look like their parents

The mother and father are called parents. The babies are the young.

Bear, hippopotamus, tiger and grasshopper, each with its young — These young look like their parents.

Figure: Science Year 2 (DLP), p.43.

Bear cubs, young hippopotamuses, tiger cubs and young grasshoppers look like their parents.

Young that do not look like their parents

A ladybird and a moth with their larvae, which look different — The young of a ladybird and a moth do not look like their parents.

Figure: Science Year 2 (DLP), p.44.

The young of a ladybird are called larvae. The young of a moth is a caterpillar. Frogs and mosquitoes also have young that do not look like their parents.

Name one animal whose young look like its parents and one whose young do not.

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Look like parents: bear, tiger, cow or grasshopper. Do not look like parents: ladybird, moth, frog or mosquito.

4.2Life cycle of animals

A life cycle is the changes an animal goes through as it grows.

Frog

Figure: Science Year 2 (DLP), p.45.

egg
tadpole
froglet
adult frog

Cow

Life cycle of a cow: calf, yearling, cow — Calf, yearling, cow.

Figure: Science Year 2 (DLP), p.46.

A cow gives birth, so there is no egg. The young is a calf. It grows into a yearling and then an adult cow.

Butterfly

Figure: Science Year 2 (DLP), p.46.

A butterfly goes from egg to larva (caterpillar) to pupa to butterfly.

Remember the order. For animals that lay eggs, the egg comes first. The adult comes last.

Write the four stages of a frog in order.

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egg, tadpole, froglet, adult frog.