Artificial Selection
Introduced| English |
|---|
| artificial selection/ˌɑːtɪˈfɪʃl sɪˈlekʃn/ |
| selective breeding/sɪˈlektɪv ˈbriːdɪŋ/ |
Humans as the selector
- Long before we understood genetics, humans were shaping other species.
- We chose which plants and animals to breed, again and again.
- Over generations, this produced crops and animals unlike their wild ancestors.
- This human-guided version of selection is artificial selection.
Selective breeding
- Artificial selection 人工选择 is choosing which individuals reproduce.
- It is also called selective breeding 选择育种.
- A farmer breeds only the cows that give the most milk.
- Their offspring inherit that trait, and the herd slowly improves.
In artificial selection, who decides which individuals reproduce?
In artificial selection, humans choose which individuals breed — also called selective breeding.
The same mechanism
- Artificial selection works just like natural selection.
- In both, some individuals leave more offspring than others.
- The only difference is who chooses: humans, not the environment.
- So a wolf, bred by people over thousands of years, becomes a chihuahua.
Artificial and natural selection use the same basic mechanism — differences in who reproduces.
Both work by some individuals reproducing more than others; only the selector differs.
Which is an example of artificial selection?
Breeding wheat for bigger grains is humans choosing the trait — artificial selection.
A hidden cost
- Breeding from only a few "best" individuals narrows the gene pool.
- This reduces the population's genetic diversity.
- A uniform breed can be more vulnerable to a new disease.
- So artificial selection is powerful but must be used with care.
Who is doing the selecting?
Sort each example by whether nature or humans decide which individuals reproduce.
Breeding only a few "best" individuals can reduce a population's genetic ____.
Selecting only a few types lowers genetic diversity, which can make a breed more vulnerable.
Select all true statements about artificial selection.
In artificial selection humans, not the environment, do the selecting. The other three are correct.
Do not confuse the two selectors. In natural selection, the environment decides who survives and breeds. In artificial selection, humans decide. The mechanism is identical — only the hand doing the choosing is different.
From wolf to hundreds of dog breeds:
- Every dog breed descends from wolves.
- People bred the tamest, most useful animals, over and over.
- Choosing different traits gave us everything from huskies to poodles — all by artificial selection.
Artificial selection (selective breeding) is humans choosing which individuals reproduce, using the same mechanism as natural selection — only the selector differs. It has reshaped crops and animals from their wild ancestors, but breeding from few individuals can reduce genetic diversity.