In biology, evolution is the change in heritable characteristics of biological populations over successive generations.[1][2] Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations.[3] The process of evolution has given rise to biodiversity at every level of biological organisation.[4][5]

The theory of evolution by natural selection was conceived independently by Charles Darwin and Alfred Russel Wallace in the mid-19th century as an explanation for why organisms are adapted to their physical and biological environments. The theory was first set out in detail in Darwin's book On the Origin of Species.[6] Evolution by natural selection is established by observable facts about living organisms: (1) more offspring are often produced than can possibly survive; (2) traits vary among individuals with respect to their morphology, physiology, and behaviour; (3) different traits confer different rates of survival and reproduction (differential fitness); and (4) traits can be passed from generation to generation (heritability of fitness).[7] In successive generations, members of a population are therefore more likely to be replaced by the offspring of parents with favourable characteristics for that environment.

In the early 20th century, competing ideas of evolution were refuted and evolution was combined with Mendelian inheritance and population genetics to give rise to modern evolutionary theory.[8] In this synthesis the basis for heredity is in DNA molecules that pass information from generation to generation. The processes that change DNA in a population include natural selection, genetic drift, mutation, and gene flow.[3]

All life on Earth—including humanity—shares a last universal common ancestor (LUCA),[9][10][11] which lived approximately 3.5–3.8 billion years ago.[12] The fossil record includes a progression from early biogenic graphite[13] to microbial mat fossils[14][15][16] to fossilised multicellular organisms. Existing patterns of biodiversity have been shaped by repeated formations of new species (speciation), changes within species (anagenesis), and loss of species (extinction) throughout the evolutionary history of life on Earth.[17] Morphological and biochemical traits tend to be more similar among species that share a more recent common ancestor, which historically was used to reconstruct phylogenetic trees, although direct comparison of genetic sequences is a more common method today.[18][19]

Evolutionary biologists have continued to study various aspects of evolution by forming and testing hypotheses as well as constructing theories based on evidence from the field or laboratory and on data generated by the methods of mathematical and theoretical biology. Their discoveries have influenced not just the development of biology but also other fields including agriculture, medicine, and computer science.[20]

  1. ^ Hall & Hallgrímsson 2008, pp. 4–6
  2. ^ "Evolution Resources". Washington, DC: National Academies of Sciences, Engineering, and Medicine. 2016. Archived from the original on 3 June 2016.
  3. ^ a b Scott-Phillips, Thomas C.; Laland, Kevin N.; Shuker, David M.; et al. (May 2014). "The Niche Construction Perspective: A Critical Appraisal". Evolution. 68 (5): 1231–1243. doi:10.1111/evo.12332. ISSN 0014-3820. PMC 4261998. PMID 24325256. Evolutionary processes are generally thought of as processes by which these changes occur. Four such processes are widely recognized: natural selection (in the broad sense, to include sexual selection), genetic drift, mutation, and migration (Fisher 1930; Haldane 1932). The latter two generate variation; the first two sort it.
  4. ^ Hall & Hallgrímsson 2008, pp. 3–5
  5. ^ Voet, Voet & Pratt 2016, pp. 1–22, Chapter 1: Introduction to the Chemistry of Life
  6. ^ Darwin 1859
  7. ^ Lewontin, Richard C. (November 1970). "The Units of Selection" (PDF). Annual Review of Ecology and Systematics. 1: 1–18. doi:10.1146/annurev.es.01.110170.000245. JSTOR 2096764. Archived (PDF) from the original on 6 February 2015.
  8. ^ Futuyma & Kirkpatrick 2017, pp. 3–26, Chapter 1: Evolutionary Biology
  9. ^ Kampourakis 2014, pp. 127–129
  10. ^ Doolittle, W. Ford (February 2000). "Uprooting the Tree of Life" (PDF). Scientific American. 282 (2): 90–95. Bibcode:2000SciAm.282b..90D. doi:10.1038/scientificamerican0200-90. ISSN 0036-8733. PMID 10710791. Archived from the original (PDF) on 7 September 2006. Retrieved 5 April 2015.
  11. ^ Glansdorff, Nicolas; Ying Xu; Labedan, Bernard (9 July 2008). "The Last Universal Common Ancestor: emergence, constitution and genetic legacy of an elusive forerunner". Biology Direct. 3: 29. doi:10.1186/1745-6150-3-29. ISSN 1745-6150. PMC 2478661. PMID 18613974.
  12. ^ Cite error: The named reference Origin1 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference NG-20131208 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference AP-20131113 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference TG-20131113-JP was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference AST-20131108 was invoked but never defined (see the help page).
  17. ^ Futuyma 2004, p. 33
  18. ^ Panno 2005, pp. xv-16
  19. ^ NAS 2008, p. 17 Archived 30 June 2015 at the Wayback Machine
  20. ^ Futuyma, Douglas J., ed. (1999). "Evolution, Science, and Society: Evolutionary Biology and the National Research Agenda" (PDF) (Executive summary). New Brunswick, New Jersey: Office of University Publications, Rutgers, The State University of New Jersey. OCLC 43422991. Archived from the original (PDF) on 31 January 2012. Retrieved 24 November 2014.

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