The maintenance of a relatively constant internal Homeostasis environment by an organism in a variable external environment is called homeostasis, All organisms adopt a degree of homeostatic control, but, as t rule, large organisms are more decoupled from their external environment than small ones Most biological homeostatic mechanisms act in a Negative feedback broadly similar way: if the current internal level of a factor(e.g. temperature or osmolarity) is too high, the mechanism will reduce it: if the level is too low the mechanism will increase it. This process, by which the response is opposite to the signal, is known as negative feedback
The maintenance of a relatively constant internal environment by an organism in a variable external environment is called homeostasis, All organisms adopt a degree of homeostatic control, but, as t rule, large organisms are more decoupled from their external environment than small ones. Most biological homeostatic mechanisms act in a broadly similar way: if the current internal level of a factor(e.g.temperature or osmolarity) is too high, the mechanism will reduce it; if the level is too low the mechanism will increase it. This process, by which the response is opposite to the signal, is known as negative feedback. Homeostasis Negative feedback
耐受性 有机体能够应付其外部环境的变化(虽然不同物质表 现很不相同)。种的成员能够生存的环境条件上限和 下限是种的耐受限度。在此极端条件下通常不出现生 长,但在条件更狭窄的范围内能生长,而适合度最大 只能出现在更窄的最适范围内 相关主题 植物与水(见D2) 对温度的响应(见E2) 动物与水(见D3) 太阳辐射与植物(见F1)
耐 受 性 有机体能够应付其外部环境的变化（虽然不同物质表 现很不相同）。种的成员能够生存的环境条件上限和 下限是种的耐受限度。在此极端条件下通常不出现生 长，但在条件更狭窄的范围内能生长，而适合度最大 只能出现在更窄的最适范围内。 相关主题 植物与水（见D2） 对温度的响应（见E2） 动物与水（见D3） 太阳辐射与植物（见F1）
tolerance Organisms can cope with variation in their external environment(though different species may differ markedly) The upper and lower extremes of species limits of tolerance Usually, growth will not occur at these extremes but in a narrower range of conditions, and fitness will be greatest only for a yet narrower optimal range responses to Related topics Plants and water(D2) temperature(E2) Animals and water(D3) solar radiation and plants (F1)
Organisms can cope with variation in their external environment (though different species may differ markedly). The upper and lower extremes of species limits of tolerance. Usually, growth will not occur at these extremes but in a narrower range of conditions, and fitness will be greatest only for a yet narrower optimal range. Plants and water (D2) responses to temperature (E2) Animals and water (D3) solar radiation and plants (F1) Related topics tolerance
B3生态位 要点 生态位 有机体的生态位( niche)是它在它的环境中所处的位 置,包括它发现的各种条件、所利用的资源和在那里 的时间 有机体的栖息地( habitat,或译生境)是它所处的物理 栖息地 环境,例如,温带阔叶林。每一个栖息地提供许多生 态位 定义有机体生态位的每一个条件和资源,对于有机体 多维生态位空间 能出现的空间提供一个维度。一起考虑所有维度,全 面确定的有机体的生态位,是多维生态位空间,或“n 维超体积
B3 生 态 位 要 点 有机体的生态位（niche）是它在它的环境中所处的位 置，包括它发现的各种条件、所利用的资源和在那里 的时间。 有机体的栖息地（habitat，或译生境）是它所处的物理 环境，例如，温带阔叶林。每一个栖息地提供许多生 态位。 定义有机体生态位的每一个条件和资源，对于有机体 能出现的空间提供一个维度。一起考虑所有维度，全 面确定的有机体的生态位，是多维生态位空间，或“n- 维超体积”。 生 态 位 栖 息 地 多维生态位空间
B3 THE NICHE Key Notes Niche The ecological niche of an organism is the position it fills in its environment, comprising the conditions under which it is found the resources it utilizes and the time it occurs there Habitat The habitat of an organism is the physical environment it is found in, for example, a temperate broad-leaved woodland. Each habitat provides Each condition or resource which defines the niche Multidimensional of an organism contributes one dimension to the niche space space in which the organisms niche, and is the multidimensional niche space, or'n-dimensional hypervolume
The ecological niche of an organism is the position it fills in its environment, comprising the conditions under which it is found, the resources it utilizes and the time it occurs there. Key Notes The habitat of an organism is the physical environment it is found in, for example, a temperate broad-leaved woodland. Each habitat provides. Each condition or resource which defines the niche of an organism contributes one dimension to the space in which the organism’s niche, and is the multidimensional niche space, or’n-dimensional hypervolume’. B3 THE NICHE Niche Habitat Multidimensional niche space