自然选择

“物竞天择”重定向至此。关于电子游戏模组，请见“物竞天择 (游戏)”。

自然选择（英语：natural selection，传统上也译为天择）指生物的遗传特征在生存竞争中，由于具有某种优势或某种劣势，因而在生存能力上产生差异，并进而导致繁殖能力的差异，使得这些特征被保存或是淘汰。自然选择则是演化的主要机制，经过自然选择而能够成功生存，称为“适应”。自然选择是唯一可以解释生物适应环境的机制。

加拉巴哥群岛（Galápagos Islands）拥有13个雀鸟物种（Darwin's finches），他们相当亲近，主要的特征差异在于鸟喙的形状。不同种类的鸟喙皆与合适于它们的食性。达尔文认为，这是自然选择造成的演化后果。

1858年，英国生物学家查尔斯·达尔文和阿尔弗雷德·罗素·华莱士发表了《On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection》，首次提出天择的概念。

查尔斯·达尔文在1859年出版的《物种起源》中提出，其于早年在加拉巴哥群岛观察了数种动物后发现，岛上很少有与邻近大陆相似的物种，并且还演化出许多独有物种，如巨型的加拉巴哥象龟，达尔文一开始以为，岛上的鸴鸟应与南美洲发现的为同种，经研究，十三种燕雀中只有一种是与其大陆近亲类似的，其馀皆或多或少发生了演化现象，他们为了适应岛上的生存环境，改变了鸟喙的大小。

自然选择的因素

因为生物族群呈指数成长，但资源有限，因此不是每个个体都能存活。影响存活率的因素包括无机环境，如温度、湿度、日照、空气；以及生物因子，如掠食者、共生、种内竞争、食物、疾病等等。个体之间存在的个体差异（变异）使每个个体的存活率不同，如果个体可以耐干旱、在空中飞、在海里呼吸、用爪子掠食、抵抗病原、制造工具、或是合作猎食等等，就会有不同的适应力，因此个体间的存活率不同。这些个体差异如果可以遗传，则会造成演化。

由于进化主要关注的是有机体是否能存活到繁衍下一代的年龄，在有机体繁衍年龄之后才会影响存活率的因素几乎会被自然选择机制忽略。例如遗传性疾病亨廷顿舞蹈症通常在40岁左右发病，这个年龄超过了大多数人生育孩子的年龄，因而几乎不会由于进化机制而被自然淘汰。当中性或有害的基因靠近基因组中一个对人高度有益的基因旁边，中性或有害的基因会同这个有益基因一起遗传给后代，从而达到比其原有更高的遗传概率。^[1]

类别

定向选择、平衡选择和破坏选择。横轴是性状，纵轴是个体数量。红线代表原本的性状分布，蓝色是选择后的结果。

• 定向选择（Directional selection）：往某一方向偏离平均的个体存活率最高，例如较白的北极熊毛。
• 稳定化选择（stabilizing selection）：性状位于中间的个体存活率最高，两侧的个体低。
• 破坏选择（Disruptive selection）：性状位在中间的个体存活率最低，例如环境中有黑色和白色石头时，灰色的蛾无保护色。可能导致种化。

性择和生殖选择和人择有时被视为广义的自然选择的次分类。狭义的自然选择（又称生态选择）指个体在自然环境中存活率的差异，性择是取得交配对象的能力差异，而生殖选择则是交配后生育后代的数目差异。人工选择则将自然选择概念应用在受人类圈养的生物上，例如家畜、宠物与农作物的育种。

单位

最容易观察到的自然选择是作用在个体上，依据个体之间性状的不同。

因为是基因带有个体的大多数资讯但不能自我复制，George C. Williams和理察·道金斯主张以基因为单位的演化观点。个体只是基因为了自我复制所制造的“机器”。这种观点在解释转座子和亲缘选择上较为方便。

在癌症的例子中，基因突变造成细胞的性状差异，引发在细胞层次的自然选择。

自然选择作用在族群上时，称为族群选择（group selection）。族群选择在自然界中的普遍程度仍有争议。

自然选择也可能运作在物种的层次。当一个物种中的不同族群因为自然选择而产生生物分类学上的差异时，则称为“物种形成”；若是族群因为不受自然选择青睐而导致族群规模缩小进而消失，则称为“灭绝”，物种形成和灭绝的速率决定一个支系的适应力。

参考文献

1. 基因编辑出错可能改变人类物种. BBC News 中文. [2023-03-10]. （原始内容存档于2023-03-15） （中文（简体））.

• Agutter, Paul S.; Wheatley, Denys N. Thinking about Life: The History and Philosophy of Biology and Other Sciences. Dordrecht, the Netherlands; London: Springer Science+Business Media. 2008. ISBN 978-1-4020-8865-0. LCCN 2008933269. OCLC 304561132.
• Andersson, Malte. Sexual Selection. Monographs in Behavior and Ecology. Princeton, NJ: Princeton University Press. 1994. ISBN 978-0-691-00057-2. LCCN 93033276. OCLC 28891551.
• Ariew, André. Platonic and Aristotelian Roots of Teleological Arguments (PDF). Ariew, André; Cummins, Robert; Perlman, Mark (编). Functions: New Essays in the Philosophy of Psychology and Biology. Oxford; New York: Oxford University Press. 2002. ISBN 978-0-19-824103-4. LCCN 2002020184. OCLC 48965141. （原始内容 (PDF)存档于19 February 2009）.
• Aristotle. Physics. Translated by R.P. Hardie and R.K. Gaye. The Internet Classics Archive. OCLC 54350394.
• Begon, Michael; Townsend, Colin R.; Harper, John L. Ecology: Individuals, Populations and Communities 3rd. Oxford; Cambridge, MA: Blackwell Science. 1996. ISBN 978-0-632-03801-5. LCCN 95024627. OCLC 32893848.
• Christiansen, Freddy B. The Definition and Measurement of Fitness. Shorrocks, Bryan (编). Evolutionary Ecology: The 23rd Symposium of the British Ecological Society, Leeds, 1982. Symposium of the British Ecological Society 23. Oxford; Boston: Blackwell Scientific Publications. 1984. ISBN 978-0-632-01189-6. LCCN 85106855. OCLC 12586581.Modified from Christiansen by adding survival selection in the reproductive phase.
• Darwin, Charles. On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life 1st. London: John Murray. 1859. LCCN 06017473. OCLC 741260650.The book is available from The Complete Work of Charles Darwin Online （页面存档备份，存于互联网档案馆）. Retrieved 2015-07-23.
• Darwin, Charles. On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life 3rd. London: John Murray. 1861 [2022-01-19]. LCCN 04001284. OCLC 550913. （原始内容存档于2021-06-08）.
• Darwin, Charles. The Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life 6th. London: John Murray. 1872 [2022-01-19]. OCLC 1185571. （原始内容存档于2014-10-18）.
• Darwin, Charles. Barlow, Nora , 编. The Autobiography of Charles Darwin, 1809–1882: With original omissions restored; Edited and with Appendix and Notes by his grand-daughter, Nora Barlow. London: Collins. 1958 [2022-01-19]. LCCN 93017940. OCLC 869541868. （原始内容存档于2021-06-10）.
• Dawkins, Richard. The Selfish Gene. New York: Oxford University Press. 1976. ISBN 978-0-19-857519-1. LCCN 76029168. OCLC 2681149.
• Dennett, Daniel C. Consciousness Explained 1st. Boston, MA: Little, Brown and Company. 1991. ISBN 978-0-316-18065-8. LCCN 91015614. OCLC 23648691.
• Dennett, Daniel C. Darwin's Dangerous Idea: Evolution and the Meanings of Life. New York: Simon & Schuster. 1995. ISBN 978-0-684-80290-9. LCCN 94049158. OCLC 31867409.
• Dobzhansky, Theodosius. Genetics and the Origin of Species. Columbia University Biological Series. New York: Columbia University Press. 1937. LCCN 37033383. OCLC 766405.
  • ——. Genetics and the Origin of Species. Columbia University Biological Series 3rd revised. New York: Columbia University Press. 1951. LCCN 51014816. OCLC 295774.
• Eisley, Loren. Darwin's Century: Evolution and the Men Who Discovered It 1st. Garden City, NY: Doubleday. 1958. LCCN 58006638. OCLC 168989.
• Empedocles. Empedokles. Fairbanks, Arthur (编). The First Philosophers of Greece. Translation by Arthur Fairbanks. London: Kegan Paul, Trench, Trübner & Co. Ltd. 1898. LCCN 03031810. OCLC 1376248.互联网档案馆收藏的《The First Philosophers of Greece》

• Endler, John A. Natural Selection in the Wild. Princeton,NJ: Princeton University Press. 1986. ISBN 978-0-691-08386-5. LCCN 85042683. OCLC 12262762.
• Engels, Friedrich. Dialectics of Nature. 1939 preface by J.B.S. Haldane 3rd rev. Moscow, USSR: Progress Publishers. 1964 [1883]. LCCN 66044448. OCLC 807047245.The book is available from the Marxist Internet Archive （页面存档备份，存于互联网档案馆）.
• Falconer, Douglas S.; Mackay, Trudy F.C. Introduction to Quantitative Genetics 4th. Harlow, England: Longman. 1996. ISBN 978-0-582-24302-6. OCLC 824656731.
• Fisher, Ronald Aylmer. The Genetical Theory of Natural Selection. Oxford: The Clarendon Press. 1930. LCCN 30029177. OCLC 493745635.
• Futuyma, Douglas J. Evolution. Sunderland, MA: Sinauer Associates. 2005. ISBN 978-0-87893-187-3. LCCN 2004029808. OCLC 57311264.
• Goldberg, David E. Genetic Algorithms in Search, Optimization and Machine Learning. Reading, MA: Addison-Wesley Publishing Company. 1989. ISBN 978-0-201-15767-3. LCCN 88006276. OCLC 17674450.
• Haldane, J B.S. The Causes of Evolution. London; New York: Longmans, Green & Co. 1932. LCCN 32033284. OCLC 5006266."This book is based on a series of lectures delivered in January 1931 at the Prifysgol Cymru, Aberystwyth, and entitled 'A re-examination of Darwinism'."
• Haldane, J.B.S. The Measurement of Natural Selection. Montalenti, Giuseppe; Chiarugi, A. (编). Atti del IX Congresso Internazionale di Genetica, Bellagio (Como) 24–31 agosto 1953 [Proceedings of the 9th International Congress of Genetics]. Caryologia. 6 (1953/54) Suppl. Florence, Italy: University of Florence. 1954: 480–487 [2022-01-19]. OCLC 9069245. （原始内容存档于2016-03-04）.
• Kauffman, Stuart. The Origins of Order: Self-Organisation and Selection in Evolution. New York: Oxford University Press. 1993. ISBN 978-0-19-507951-7. LCCN 91011148. OCLC 23253930.
• Lamarck, Jean-Baptiste. Philosophie Zoologique. Paris: Dentu et L'Auteur. 1809. OCLC 2210044. 互联网档案馆收藏的《Philosophie zoologique (1809)》

• Lear, Jonathan. Aristotle: The Desire to Understand. Cambridge, UK; New York: Cambridge University Press. 1988. ISBN 978-0-521-34762-4. LCCN 87020284. OCLC 16352317. 含有内容需登入查看的页面 (link)
• Kuhn, Thomas S. The Structure of Scientific Revolutions 3rd. Chicago, IL: University of Chicago Press. 1996. ISBN 978-0-226-45808-3. LCCN 96013195. OCLC 34548541.
• Lemey, Philippe; Salemi, Marco; Vandamme, Anne-Mieke (编). The Phylogenetic Handbook: A Practical Approach to Phylogenetic Analysis and Hypothesis Testing 2nd. Cambridge, UK; New York: Cambridge University Press. 2009. ISBN 978-0-521-73071-6. LCCN 2009464132. OCLC 295002266.
• Lucretius. Book V. Leonard, William Ellery (编). De rerum natura. Translated by William Ellery Leonard. Medford/Somerville, MA: Tufts University. 1916. OCLC 33233743.
• MacArthur, Robert H.; Wilson, Edward O. The Theory of Island Biogeography. Princeton Landmarks in Biology. New preface by Edward O. Wilson. Princeton, NJ: Princeton University Press. 2001 [Originally published 1967]. ISBN 978-0-691-08836-5. LCCN 00051495. OCLC 45202069.
• Malthus, Thomas Robert. An Essay on the Principle of Population, As It Affects the Future Improvement of Society: with Remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers 1st. London: J. Johnson. 1798. LCCN 46038215. OCLC 65344349.The book is available here （页面存档备份，存于互联网档案馆） from Frank Elwell, Rogers State University.
• Mayr, Ernst. Systematics and the Origin of Species from the Viewpoint of a Zoologist. Columbia Biological Series 13. New York: Columbia University Press. 1942. LCCN 43001098. OCLC 766053.
• Mayr, Ernst. Sexual Selection and Natural Selection. Campbell, Bernard G. (编). Sexual Selection and the Descent of Man: The Darwinian Pivot. New Brunswick, NJ: AldineTransaction. 2006 [Originally published 1972; Chicago, IL: Aldine Publishing Co.] ISBN 978-0-202-30845-6. LCCN 2005046652. OCLC 62857839.
• Michod, Richard A. Darwinian Dynamics: Evolutionary Transitions in Fitness and Individuality. Princeton, NJ: Princeton University Press. 1999. ISBN 978-0-691-02699-2. LCCN 98004166. OCLC 38948118.
• Miller, Geoffrey. The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature 1st. New York: Doubleday. 2000. ISBN 978-0-385-49516-5. LCCN 00022673. OCLC 43648482.
• Mitchell, Melanie. An Introduction to Genetic Algorithms. Complex Adaptive Systems. Cambridge, MA: MIT Press. 1996. ISBN 978-0-262-13316-6. LCCN 95024489. OCLC 42854439.
• Pinker, Steven. The Language Instinct: How the Mind Creates Language 1st Harper Perennial. New York: Harper Perennial. 1995 [Originally published 1994; New York: William Morrow and Company]. ISBN 978-0-06-097651-4. LCCN 94039138. OCLC 670524593.
• Rice, Sean H. Evolutionary Theory: Mathematical and Conceptual Foundations. Sunderland, MA: Sinauer Associates. 2004. ISBN 978-0-87893-702-8. LCCN 2004008054. OCLC 54988554.
• Roux, Wilhelm. Der Kampf der Theile im Organismus. Leipzig: Wilhelm Engelmann. 1881. OCLC 8200805.Retrieved 2015-08-11互联网档案馆收藏的《Der Kampf der Theile im Organismus》

• Sober, Elliott. The Nature of Selection: Evolutionary Theory in Philosophical Focus. Chicago, IL: University of Chicago Press. 1993 [Originally published 1984; Cambridge, MA: MIT Press]. ISBN 978-0-226-76748-2. LCCN 93010367. OCLC 896826726.
• Wallace, Alfred Russel. Contributions to the Theory of Natural Selection. A Series of Essays 2nd, with corrections and additions. New York: Macmillan & Co. 1871 [Originally published 1870] [2022-01-19]. LCCN agr04000394. OCLC 809350209. （原始内容存档于2021-07-18）.
• Williams, George C. Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought. Princeton Science Library. Princeton, NJ: Princeton University Press. 1966. ISBN 978-0-691-02615-2. LCCN 65017164. OCLC 35230452.
• Wilson, David Sloan. Darwin's Cathedral: Evolution, Religion, and the Nature of Society. Chicago, IL: University of Chicago Press. 2002. ISBN 978-0-691-02615-2. LCCN 2002017375. OCLC 48777441.
• Zimmer, Carl; Emlen, Douglas J. Evolution: Making Sense of Life 1st. Greenwood Village, CO: Roberts and Company Publishers. 2013. ISBN 978-1-936221-17-2. LCCN 2012025118. OCLC 767565909.

延伸阅读

For technical audiences

• Gould, Stephen Jay. The Structure of Evolutionary Theory. Harvard University Press. 2002. ISBN 0-674-00613-5.
• Maynard Smith, John. The Theory of Evolution: Canto Edition. Cambridge University Press. 1993. ISBN 0-521-45128-0.
• Popper, Karl (1978) Natural selection and the emergence of mind. Dialectica 32:339-55. See [1] （页面存档备份，存于互联网档案馆）
• Sober, Elliott (1984) The Nature of Selection: Evolutionary Theory in Philosophical Focus. University of Chicago Press.
• Williams, George C. (1966) Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought. Oxford University Press.
• Williams, George C. (1992) Natural Selection: Domains, Levels and Challenges. Oxford University Press.

For general audiences

• Dawkins, Richard (1996) Climbing Mount Improbable. Penguin Books, ISBN 978-0-670-85018-1.
• Dennett, Daniel (1995) Darwin's Dangerous Idea: Evolution and the Meanings of Life. Simon & Schuster ISBN 978-0-684-82471-0.
• Gould, Stephen Jay (1997) Ever Since Darwin: Reflections in Natural History. Norton, ISBN 978-0-393-06425-4.
• Jones, Steve (2001) Darwin's Ghost: The Origin of Species Updated. Ballantine Books ISBN 978-0-345-42277-4. Also published in Britain under the title Almost Like a Whale: The Origin of Species Updated. Doubleday. ISBN 978-1-86230-025-5.
• Lewontin, Richard (1978) Adaptation. Scientific American 239:212-30
• Mayr, Ernst (2001) What Evolution Is. Weidenfeld & Nicolson, London. ISBN 978-0-297-60741-0
• Weiner, Jonathan (1994) The Beak of the Finch: A Story of Evolution in Our Time. Vintage Books, ISBN 978-0-679-73337-9.

Historical

• Zirkle, C. Natural Selection before the "Origin of Species. Proceedings of the American Philosophical Society. 1941, 84 (1): 71–123.
• Kohm M (2004) A Reason for Everything: Natural Selection and the English Imagination. London: Faber and Faber. ISBN 978-0-571-22392-3. For review, see [2] （页面存档备份，存于互联网档案馆） van Wyhe J (2005) Human Nature Review 5:1-4

参见

• 性选择
• 族群选择

外部链接

• On the Origin of Species by Charles Darwin （页面存档备份，存于互联网档案馆） – Chapter 4, Natural Selection
• Natural Selection- Modeling for Understanding in Science Education, University of Wisconsin
• Natural Selection （页面存档备份，存于互联网档案馆） from University of Berkeley education website
• T. Ryan Gregory: Understanding Natural Selection: Essential Concepts and Common Misconceptions^{[永久失效链接]} Evolution: Education and Outreach
• ENCODE threads explorer （页面存档备份，存于互联网档案馆） Impact of functional information on understanding variation. Nature (journal)