Reproduction, Year 8: animals and flowering plants

Sexual reproduction

HintThe offspring are a mix of both parents.

The whyA male gamete and a female gamete fuse at fertilisation, so each offspring gets half of its genetic information from each parent.

Asexual reproduction

HintThe offspring are identical copies of the parent.

The whyBacteria dividing in two, a potato growing from a tuber and a spider plant making plantlets are all examples.

Asexual

HintCount how many parents are involved.

The whyThere is one parent, no flowers are involved and nothing is fertilised. The new plants are genetically the same as the parent.

Clones

HintNews stories have used this word for a famous copied sheep.

The whyWith only one parent and no mixing, every offspring carries exactly the same genetic information as the parent.

They inherit a mix of genes from two parents

HintHalf of the instructions are supplied by each side.

The whyEach gamete carries half of one parent's genetic information. Fertilisation combines two halves into a set that neither parent had.

The testes

HintThey hang outside the body, where it is slightly cooler.

The whySperm are made continuously from puberty onwards. The slightly lower temperature outside the body cavity suits their production.

Swimming to the egg

HintFor its size, this cell has a very long way to travel.

The whyThe tail lashes from side to side to drive the sperm forward. It is one of the features that make the sperm a specialised cell.

Insects

HintAsk who the colour and scent are meant to attract.

The whyColour, scent and nectar are advertisements and rewards. An insect visiting for the nectar picks up pollen and carries it to the next flower.

By the wind

HintIts pollen is light, dry and made in huge amounts.

The whyWith nothing to attract animals, the plant releases clouds of light pollen and relies on some of it landing on another flower's feathery stigma.

By catching on animal fur

HintThe inventor of Velcro copied it.

The whyThe hooks cling to a passing animal and the seeds are carried away, dropping off far from the parent plant where there is less competition.