Reproduction, Year 8: animals and flowering plants

Sexual reproduction

提示The offspring are a mix of both parents.

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

Asexual reproduction

提示The offspring are identical copies of the parent.

为什么Bacteria dividing in two, a potato growing from a tuber and a spider plant making plantlets are all examples.

Asexual

提示Count how many parents are involved.

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

Clones

提示News stories have used this word for a famous copied sheep.

为什么With 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

提示Half of the instructions are supplied by each side.

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

The testes

提示They hang outside the body, where it is slightly cooler.

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

Swimming to the egg

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

为什么The 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

提示Ask who the colour and scent are meant to attract.

为什么Colour, 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

提示Its pollen is light, dry and made in huge amounts.

为什么With 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

提示The inventor of Velcro copied it.

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