Selective breeding
Introduced| English | Meaning |
|---|---|
| selective breeding/sɪˈlektɪv ˈbriːdɪŋ/ | Breeding organisms chosen for desirable inherited characteristics over successive generations. |
| artificial selection/ˌɑːtɪˈfɪʃl sɪˈlekʃn/ | Breeding organisms chosen by humans for desirable inherited characteristics. |
| gene pool/dʒiːn puːl/ | All the alleles present in a population at a particular time. |
Choosing the parents
- For thousands of years, humans have bred animals and plants to get features they want.
- This is selective breeding 选择育种 (artificial selection 人工选择).
Selective breeding means choosing:
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Humans pick the parents with the wanted trait.
Selective breeding is also known as ______ selection.
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Humans, not the environment, do the selecting.
How it works
- Choose parents with the desired feature (e.g. high milk yield, big fruit).
- Breed them together, then choose the best offspring to breed again.
- Repeat over many generations.
In selective breeding, humans choose which organisms breed, over many generations
Selective breeding
Humans choose which organisms breed, to develop a useful feature over many generations.
Which are uses of selective breeding? (Select all that apply.)
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The first three are selective breeding; the last is not.
Examples
- Crops: bred for higher yield, disease resistance, better taste.
- Animals: cows for more milk, dogs for specific traits.
The main difference from natural selection is that selective breeding is driven by:
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Humans choose the parents, not the environment.
Selective breeding can reduce variation in a population.
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Breeding from a narrow set shrinks the gene pool.
Like natural selection, but human-chosen
- In natural selection, the environment decides who reproduces.
- In selective breeding, humans decide — choosing the parents each generation.
Selective breeding reduces variation. Repeatedly breeding from a narrow set of "best" individuals shrinks the gene pool 基因库. This can leave a population vulnerable to disease — the downside of artificial selection.
You've got it
- selective breeding: choose parents with the desired feature, breed, repeat over generations
- used to improve crops (yield, resistance) and animals (milk, traits)
- it's like natural selection but humans choose; it reduces variation
Write from a farmer's choice
- A farmer breeds only the cows that give the most milk.
- The choice is repeated for many generations.
What is this process, and what happens to variation?
The desired parents are picked on purpose.
In selective breeding, who chooses the parents?
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People pick the parents with the feature they want.