Effect of Density on Populations · 密度对种群的影响
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| population density/ˌpɒpjʊˈleɪʃn ˈdensɪti/ | 种群密度 | zhǒng qún mì dù |
| density-dependent/ˈdensɪti dɪˈpendənt/ | 密度制约 | mì dù zhì yuē |
| density-independent/ˈdensɪti ˌɪndɪˈpendənt/ | 非密度制约 | fēi mì dù zhì yuē |
When crowding matters
- A population near its carrying capacity is crowded.
- Crowding changes how strongly some things limit the population.
- Other limits ignore crowding entirely.
- Sorting the two kinds explains how populations are kept in check.
当拥挤起作用时
- 一个接近承载力的种群是拥挤的。
- 拥挤改变某些东西限制种群的强度。
- 另一些限制则完全不顾拥挤。
- 把这两类分开,能解释种群是如何被约束的。
Population density
- Population density 种群密度 is how many individuals live in a given area.
- A dense population is crowded; a sparse one is spread out.
- Density changes as a population grows toward carrying capacity.
- Some limiting factors respond to density; some do not.
种群密度
- 种群密度(population density)是给定区域里生活着多少个体。
- 密集的种群是拥挤的;稀疏的则分散开。
- 密度随着种群朝承载力增长而改变。
- 有些限制因素对密度有反应;有些没有。
Population density measures… · 种群密度衡量……
Population density is the number of individuals per unit area or volume. · 种群密度是每单位面积或体积里的个体数量。
Density-dependent factors
- A density-dependent 密度制约 factor gets stronger as crowding increases.
- Disease spreads faster when individuals are packed together.
- Competition for food and space grows fiercer in a dense population.
- Predators, too, find crowded prey more easily.
密度制约因素
- 一个密度制约(density-dependent)因素随着拥挤增加而增强。
- 当个体挤在一起时,疾病传播得更快。
- 在密集的种群里,对食物和空间的竞争变得更激烈。
- 捕食者也更容易找到拥挤的猎物。
A density-dependent factor is one whose effect… · 一个密度依赖因素是它的作用……
A density-dependent factor (disease, competition, predation) hits harder in a crowded population. · 一个密度依赖因素(疾病、竞争、捕食)在拥挤的种群里打击更重。
A factor like a harsh winter, whose effect does not change with crowding, is density-____. · 一个像严冬这样、作用不随拥挤而改变的因素,是密度____的。
A density-independent factor (weather, disaster) affects a population the same at any density. · 一个密度非依赖因素(天气、灾难)在任何密度下对种群的影响都一样。
Density-independent factors
- A density-independent 非密度制约 factor has the same effect at any density.
- A harsh winter, a flood, or a fire strikes crowded and sparse populations alike.
- These factors do not care how many individuals there are.
- They can cut a population no matter its size.
非密度制约因素
- 一个非密度制约(density-independent)因素在任何密度下有相同的作用。
- 一个严冬、一场洪水或一场火灾,对拥挤和稀疏的种群一视同仁地打击。
- 这些因素不在乎有多少个体。
- 它们无论种群大小都能削减它。
Density-dependent or not? · 依赖密度还是不依赖?
Sort each limiting factor by whether its effect gets stronger as the population becomes more crowded. · 按照每个限制因素的作用是否随着种群变拥挤而增强,给它们分类。
Density-dependent factors help hold a population near its carrying capacity. · 密度依赖因素帮助把种群保持在它的承载力附近。
As a population grows, density-dependent factors strengthen and push it back toward carrying capacity. · 随着种群增长,密度依赖因素增强,把它推回承载力。
Select all · 所有 true statements about density. · 选出关于密度的所有正确说法。
Density-independent factors do not get stronger with crowding. The other three are correct. · 密度非依赖因素不随拥挤而增强。其余三条正确。
The difference is whether crowding changes the effect. A density-dependent factor hits harder as the population grows — that is what pulls it back toward carrying capacity. A density-independent factor (like weather) hits the same regardless. Match each factor to the right type.
区别在于拥挤是否改变作用。一个密度制约因素随着种群增长打击更重——这正是把它拉回承载力的东西。一个非密度制约因素(比如天气)无论如何打击都一样。把每个因素对应到正确的类型。
Disease in a crowded population:
- When a population is sparse, a disease spreads slowly — individuals rarely meet.
- As the population grows dense, contact becomes frequent and the disease spreads fast.
- The disease is density-dependent: it grows stronger exactly when the population is largest, checking its growth.
拥挤种群里的疾病:
- 当种群稀疏时,疾病传播缓慢——个体很少相遇。
- 随着种群变密集,接触变得频繁,疾病传播得快。
- 这种疾病是密度制约的:它恰好在种群最大时增强,抑制它的增长。
Population density is individuals per area. A density-dependent factor (disease, competition, predation) gets stronger as crowding increases, helping hold the population near carrying capacity. A density-independent factor (weather, disaster) affects the population the same at any density.
种群密度是每单位面积的个体数。一个密度制约因素(疾病、竞争、捕食)随着拥挤增加而增强,帮助把种群保持在承载力附近。一个非密度制约因素(天气、灾难)在任何密度下对种群的影响都一样。