Natural Selection · 自然选择
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| directional selection/daɪˈrekʃənl sɪˈlekʃn/ | 定向选择 | dìng xiàng xuǎn zé |
| disruptive selection/dɪsˈrʌptɪv sɪˈlekʃn/ | 分裂选择 | fēn liè xuǎn zé |
| stabilizing selection/ˈsteɪbɪlaɪzɪŋ sɪˈlekʃn/ | 稳定选择 | wěn dìng xuǎn zé |
| fitness/ˈfɪtnəs/ | 适合度 | shì hé dù |
Selection can push in different ways
- Natural selection does not always push a population the same direction.
- Sometimes it favours one extreme; sometimes the average; sometimes both ends.
- The pattern depends on which individuals leave the most offspring.
- Three named patterns describe how selection reshapes a trait.
选择能朝不同方向推
- 自然选择并不总是把种群推向同一个方向。
- 有时它青睐一个极端;有时青睐平均;有时青睐两端。
- 模式取决于哪些个体留下最多的后代。
- 三个有名字的模式描述了选择如何重塑一个性状。
Directional selection
- Directional selection 定向选择 favours one extreme of a trait.
- The whole population gradually shifts that way.
- The dark peppered moths spreading in a sooty city is a classic example.
- One end of the range is favoured; the population follows.
定向选择
- 定向选择(directional selection)青睐一个性状的一个极端。
- 整个种群逐渐朝那个方向移动。
- 深色桦尺蛾在布满煤灰的城市里扩散,是一个经典的例子。
- 范围的一端被青睐;种群随之而去。
In biology, an organism's fitness measures its… · 在生物学中,一个生物的适合度衡量它的……
Fitness is reproductive success — leaving more surviving offspring — not just physical strength. · 适合度是繁殖成功——留下更多存活的后代——而不只是体力。
Stabilizing selection
- Stabilizing selection 稳定选择 favours the average, middle form.
- Both extremes are selected against.
- Human birth weight is a good example — very small and very large babies fare worse.
- The population becomes more uniform around the middle.
稳定选择
- 稳定选择(stabilizing selection)青睐平均的、中间的形态。
- 两个极端都被选择淘汰。
- 人类的出生体重是一个好例子——非常小和非常大的婴儿处境更差。
- 种群在中间附近变得更加一致。
Selection shifts a population · 选择使种群移动
Watch the population change as the environment favours one form over another. · 观察种群随着环境偏好一种形态胜过另一种而改变。
Directional selection shifts a population… · 定向选择使种群……
Directional selection favours one extreme, shifting the whole population that way (like the dark moths). · 定向选择青睐一个极端,使整个种群朝那个方向移动(像深色的蛾)。
Stabilizing selection favours… · 稳定选择青睐……
Stabilizing selection favours the middle and removes both extremes — like human birth weight. · 稳定选择青睐中间,去掉两个极端——像人类的出生体重。
Disruptive selection favours both extremes and works against the average. · 分裂选择青睐两个极端,并不利于平均值。
Disruptive selection favours both extremes at once, which can split a population into two forms. · 分裂选择同时青睐两个极端,这能把一个种群分裂成两种形态。
Disruptive selection and fitness
- Disruptive selection 分裂选择 favours both extremes and works against the average.
- It can split one population into two distinct forms.
- Which individuals win is measured by fitness 适合度 — reproductive success.
- Fitness is about leaving offspring, not simply being strong.
分裂选择与适合度
- 分裂选择(disruptive selection)青睐两个极端,并不利于平均值。
- 它能把一个种群分裂成两种不同的形态。
- 哪些个体获胜,由适合度(fitness)衡量——繁殖成功。
- 适合度关乎留下后代,而不只是强壮。
Select all · 所有 true statements about selection patterns. · 选出关于选择模式的所有正确说法。
Fitness is reproductive success, not just strength. The other three are correct. · 适合度是繁殖成功,不只是体力。其余三条正确。
Biological fitness does not mean being the strongest or fastest. It means leaving the most surviving offspring. A small, dull animal that reproduces successfully has higher fitness than a magnificent one that never breeds.
生物学的适合度不意味着最强或最快。它意味着留下最多存活的后代。一只小而不起眼、但成功繁殖的动物,比一只从不繁殖的华丽动物有更高的适合度。
Birth weight and stabilizing selection:
- Very small babies historically had lower survival.
- Very large babies were harder to deliver safely.
- So selection favoured the middle weight — a clear case of stabilizing selection.
出生体重与稳定选择:
- 历史上非常小的婴儿存活率较低。
- 非常大的婴儿更难安全分娩。
- 所以选择青睐中间的体重——一个稳定选择的清楚案例。
Natural selection can act in three patterns: directional (shifts toward one extreme), stabilizing (favours the average), and disruptive (favours both extremes). Which individuals succeed is measured by fitness — reproductive success, not just strength.
自然选择能以三种模式起作用:定向(朝一个极端移动)、稳定(青睐平均)和分裂(青睐两个极端)。哪些个体成功,由适合度衡量——繁殖成功,而不只是强壮。