Introduction to Natural Selection · 自然选择导论
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| natural selection/ˈnætʃərəl sɪˈlekʃn/ | 自然选择 | zì rán xuǎn zé |
| variation/ˌveərɪˈeɪʃn/ | 变异 | biàn yì |
| adaptation/ˌædæpˈteɪʃn/ | 适应 | shì yìng |
How life fits its world
- Every living thing seems remarkably suited to its way of life.
- A cactus stores water; a cheetah runs fast; a moth blends into bark.
- No designer arranged this — it arose on its own.
- The process behind it is natural selection.
生命如何契合它的世界
- 每个生物似乎都非凡地适合它的生活方式。
- 仙人掌储水;猎豹跑得快;蛾融入树皮。
- 没有设计者安排这一切——它是自己产生的。
- 背后的过程就是自然选择。
Variation and competition
- Within any population, individuals show variation 变异 — they differ.
- Populations produce more offspring than can possibly survive.
- So individuals compete for limited food, space, and mates.
- Not all of them will live long enough to reproduce.
变异与竞争
- 在任何种群里,个体表现出变异(variation)——它们彼此不同。
- 种群产生的后代多于可能存活的数量。
- 所以个体为有限的食物、空间和配偶竞争。
- 不是所有个体都能活到繁殖。
Natural selection needs variation in a population, which means… · 自然选择需要种群中的变异,这意味着……
Variation · 变异 means individuals differ; selection can only act if there are differences to choose between. · 变异意味着个体不同;只有存在可供选择的差异,选择才能起作用。
Survival of the fittest
- Individuals best suited to the environment are most likely to survive.
- They live longer and leave the most offspring.
- This is often called "survival of the fittest".
- The helpful trait must be heritable, so it can pass to those offspring.
适者生存
- 最适应环境的个体最可能存活。
- 它们活得更久,留下最多的后代。
- 这常常被称为"适者生存"。
- 有帮助的性状必须能遗传,这样它才能传给那些后代。
Selection in action · 选择在起作用
On a dark, sooty tree the better-camouflaged moths survive and breed, so over generations the population shifts. · 在黑暗、布满煤灰的树上,伪装更好的蛾存活并繁殖,于是经过许多代,种群发生改变。
Which individuals leave the most offspring under natural selection? · 在自然选择下,哪些个体留下最多的后代?
The best-suited individuals survive and reproduce most — "survival of the fittest". · 最适应的个体存活并繁殖得最多——"适者生存"。
Populations change over time
- Because survivors pass on their helpful traits, those traits become more common.
- Over many generations, the whole population shifts.
- A useful feature that spreads this way is an adaptation 适应.
- This gradual change is natural selection 自然选择 at work.
种群随时间改变
- 因为幸存者把它们有帮助的性状传下去,那些性状变得更常见。
- 经过许多代,整个种群发生改变。
- 一个这样传播开来的有用特征就是一个适应(adaptation)。
- 这种渐进的改变就是自然选择(natural selection)在起作用。
A feature that helps an organism survive in its environment is an . · 一个帮助生物在它环境中生存的特征是一个。
An adaptation is a helpful feature that natural selection has favoured over generations. · 适应是一个有帮助的特征,自然选择在许多代里青睐它。
For natural selection to change a population, the helpful trait must be inherited. · 要让自然选择改变一个种群,那个有帮助的性状必须能被遗传。
Only heritable traits pass to offspring, so only they let a population change over generations. · 只有可遗传的性状才传给后代,所以只有它们才让种群经许多代改变。
Select all · 所有 conditions natural selection needs. · 选出自然选择需要的所有条件。
Selection needs variation, so identical individuals would make it impossible. The other three are correct. · 选择需要变异,所以相同的个体会让它不可能。其余三条正确。
An individual does not adapt during its life to fit the environment. Populations change over generations, as some individuals reproduce more than others. Natural selection acts on the whole population, not on a single organism trying to change.
一个个体在它一生中并不为了契合环境而适应。种群经许多代改变,因为一些个体比其他个体繁殖得更多。自然选择作用于整个种群,而不是作用于一个试图改变的单个生物。
The peppered moth:
- Peppered moths came in pale and dark forms.
- When soot blackened the tree trunks, dark moths were better camouflaged and survived more.
- Over generations the population became mostly dark — natural selection in action.
桦尺蛾(胡椒蛾):
- 桦尺蛾有浅色和深色的形态。
- 当煤灰把树干熏黑时,深色的蛾伪装得更好,存活得更多。
- 经过许多代,种群变得大多是深色的——自然选择在起作用。
Natural selection needs variation within a population, more offspring than can survive, and heritable traits. Individuals best suited to their environment survive and reproduce most, so their traits spread. Over generations the population changes, building up adaptations — features that fit the environment.
自然选择需要种群内的变异、多于能存活的后代,以及可遗传的性状。最适应它们环境的个体存活并繁殖得最多,所以它们的性状传播开来。经过许多代,种群改变,积累起适应——契合环境的特征。