Reproduction, Year 8: animals and flowering plants：全部卡片
整套按顺序列出——孩子看到之前，您可以先通读一遍。
- Reproduction that needs two parents and the joining of two gametes
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.
- Reproduction from a single parent, with no gametes involved
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.
- A strawberry plant sends out runners that take root and grow into new plants. Is this sexual or asexual reproduction?
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.
- Offspring from asexual reproduction are genetically identical to their parent. What are such offspring called?
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.
- Why do offspring from sexual reproduction differ from both of their parents?
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 pair of human organs where sperm cells are made
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.
- A sperm cell has a long tail. What is the tail for?
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.
- A flower has large, bright, scented petals and makes nectar. Is it pollinated by wind or by insects?
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.
- A grass flower has no petals, and its anthers dangle outside in the open air. How is it pollinated?
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.
- A burdock seed head is covered in tiny hooks. How are its seeds dispersed?
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.
1★ KS3-BIOL-REP-0037
2★ KS3-BIOL-REP-0038
3★ KS3-BIOL-REP-0039
4★ KS3-BIOL-REP-0040
5★ KS3-BIOL-REP-0041
6★ KS3-BIOL-REP-0042
7★ KS3-BIOL-REP-0043
8★ KS3-BIOL-REP-0044
9★ KS3-BIOL-REP-0045
10★ KS3-BIOL-REP-0046