演化

浏览

一个生物学理论,现代生物学的基本原则之一,认为各种类型的动物和植物都来自先於它们存在的其他类型,这些明显的差异是在连续的世代中不断发生改变的结果。1858年达尔文华莱士(Alfred Russel Wallace)发表有关演化的论文,对日後生物学研究具有革命性的影响。达尔文演化论的核心就是自然选择(natural selection)机制。存活下来的个体可能具有一些能使它们活得更久并能生殖後代的微小变化(参阅variation),它们会将这些优点传递给以後的世代。1937年多布赞斯基(Theodosius Dobzhansky)将孟德尔遗传学(Mendelian genetics,参阅Mendel, Gregor (Johann))应用於达尔文学说,指出自然选择不断作用於生物整个种群中的微小遗传变异,这些作用的累积就是演化。化石纪录给演化提供了部分证据,证明生物的形态在不断地变化,直至今日。现存类型之间结构上的相似以及不同物种胚胎发育的相似也表明它们有共同的祖先。分子生物学(molecular biology,尤其是对基因和蛋白质的研究)为演化改变提供了更详细的证据。虽然演化论已被科学界绝大部份人所接受,但从达尔文的时代至今,演化论一直引起相当的争论。大部分反对来自神学家和思想家(参阅creation science)。亦请参阅Vries, Hugo de、Haeckel, Ernst、human evolution、Mayr, Ernst、parallel evolution、phylogeny、sociocultural evolution、speciation。

evolution

Biological theory that animals and plants have their origin in other types and that the distinguishable differences are due to modifications in successive generations. It is one of the keystones of modern biological theory. In 1858 Charles Darwin and Alfred Russel Wallace published a paper on evolution that revolutionized all later biological study. The heart of Darwinian evolution is the mechanism of natural selection. Surviving individuals, who vary (see variation) in some way that enables them to live longer and reproduce, pass on their advantage to succeeding generations. In 1937 Theodosius Dobzhansky applied Mendelian genetics (see Gregor Mendel) to Darwinian theory, contributing to the new understanding of evolution as the cumulative action of natural selection on small genetic variations in whole populations. Part of the proof of evolution is in the fossil record, which shows a succession of gradually changing forms leading up to those known today. Structural similarities and similarities in embryonic development among living forms also point to common ancestry. Molecular biology (especially the study of genes and proteins) provides the most detailed evidence of evolutionary change. Though the theory of evolution is accepted by nearly the entire scientific community, it has sparked much controversy from Darwin's time to the present; most objections have come from religious leaders and thinkers (see creation science). See also Hugo de Vries, Ernst Haeckel, human evolution, Ernst Mayr, parallel evolution, phylogeny, sociocultural evolution, speciation.

参考文章