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{{mergefrom|Niche adaptation|discuss=Talk:Niche_adaptation|date=July 2018}}{{About|the evolutionary process}}{{distinguish|Adoption|Acclimatization}}{{Evolutionary biology}}In [[biology]], Top title on a page is surrounded by a double 'equals'sign=====First subtitle is surrounded by a triple 'adaptationequals''' has three related meanings. Firstly, it sign=======Second subtitle is the dynamic evolutionary process that fits [[organism]]s to their environment, enhancing their [[Fitness (biology)|evolutionary fitness]]. Secondly, it is a state reached surrounded by the population during that process. Thirdly, it is a [[phenotypic trait|phenotypic]] or quadruple 'equals''adaptive trait''', with a functional role in each individual organism, that is maintained and has been [[evolution|evolved]] by [[natural selection]].sign====

Organisms face a succession of environmental challenges as they grow, and show adaptive [[Phenotypic plasticity|plasticity]] as traits [[ontogeny|develop]] '''Text in response to the imposed conditions. This gives them resilience to varying environments.bold is surrounded by triple aporstrophe's'''''Italicised text is surrounded by double aporstrophe's''

==History ==To turn a word into a link use [[ this double bracket at the start and end.{{MainTo turn a word into a link, but have it link to a different page then use the |History symbol to separate the word to be displayed from the title of evolutionary thought}}the page.For example (I've added spaces to demonstrate what it would look like) [ [ evaporation | evaporating ] ]. Removing the spaces would make a link to the page called 'evaporation' while displaying the word 'evaporating'[[Evaporation|evaporating]]

Adaptation is an observable fact of life accepted by philosophers and natural historians from ancient times, independently of their views on [[evolution]], but their explanations differed. [[Empedocles]] did not believe that adaptation required To start a [[final cause]] (~ purpose), but thought that it "came about naturally, since such things survived." [[Aristotle]] did believe in final causes, but assumed that [[Aristotle's biology#Scale of being|species were fixed]].<ref>{{cite book |authorlink=Armand Marie Leroi |last=Leroi |first=Armand Marie |title=The Lagoon: How Aristotle Invented Science |titlelink=Aristotle's Lagoon |publisher=Bloomsbury |date=2015 |isbn=978-1408836224 |pages=91–92, 273, 288}}</ref>new paragraph you can simply press enter twice

[[File:Lamarck's Two-Factor Theory.svg|thumb|upright=1.7|The second of [[Jean-Baptiste Lamarck]]'s two factors (Or you can use : at the first being a complexifying force) was an adaptive force that causes animals with a given [[body plan]] to adapt to circumstances by [[inheritance of acquired characteristics]], creating a diversity start of [[species]] and [[genus|genera]]each new paragraph which will also indent it.]]

In [[natural theology]], adaptation was interpreted : The * symbol can be used as the work of a deity and as evidence for bullet point at the existence of God.<ref>{{harvnb|Desmond|1989|pp=31–32, fn 18}}</ref> [[William Paley]] believed that organisms were perfectly adapted to the lives they led, an argument that shadowed [[Gottfried Wilhelm Leibniz]], who had argued that God had brought about "[[best of all possible worlds|the best of all possible worlds]]." [[Voltaire]]'s Dr. Pangloss<ref>{{cite book |author=Voltaire |title=Candide |publisher=Cramer et al |date=1759}}</ref> is a parody of this optimistic idea, and [[David Hume]] also argued against design.<ref>{{harvnb|Sober|1993|loc=chpt. 2}}</ref> The ''[[Natural theology#The Bridgewater Treatises|Bridgewater Treatises]]'' are a product start of natural theology, though some of the authors managed to present their work in a fairly neutral mannerline. The series was lampooned by [[Robert Knox]], who held quasi-evolutionary views, as the ''Bilgewater Treatises''. [[Charles Darwin]] broke with the tradition by emphasising the flaws and limitations which occurred in the animal and plant worlds.<ref>{{harvnb|Darwin|1872|p=[http://darwin-online.org.uk/content/frameset?pageseq=425&itemID=F391&viewtype=side 397: "Rudimentary, Atrophied, and Aborted Organs"]}}</ref>

[[Jean-Baptiste Lamarck]] proposed a tendency * Like this**or this for organisms to become more complex, moving up a ladder subclause of progress, plus "the influence of circumstances," usually expressed as ''use first bullet point**and again**and disuse''.<ref>{{cite book |last1=Bowler |first1=Peter J. |title=Evolution The History of an Idea|date=1989 |publisher=University of California Press |isbn=0-520-06386-4 |page=86 |edition=Revised |origyear=1983}}</ref> This second, subsidiary element of his theory is what is now called [[Lamarckism]], again***or this for a proto-evolutionary hypothesis subclause of the [[inheritance third subclause of acquired characteristics]], intended to explain adaptations by natural means.<ref>See, for example, the discussion in {{harvnb|Bowler|2003|pp=86–95}}: "Whatever the true nature of Lamarck's theory, it was his mechanism of adaptation that caught the attention of later naturalists." (p. 90)</ref> original bullet point

Other natural historians, such as [[Georges-Louis Leclerc, Comte de Buffon|Buffon]], accepted adaptation, and some also accepted evolution, without voicing their opinions as The # symbol can be used to the mechanism. This illustrates the real merit of Darwin and [[Alfred Russel Wallace]], and secondary figures such as [[Henry Walter Bates]], for putting forward number things#like this#or this#or this##or a mechanism whose significance had only been glimpsed previously. A century later, experimental field studies and breeding experiments by people such as [[E. B. Ford]] subclause##like this##and [[Theodosius Dobzhansky]] produced [[Evidence of common descent|evidence that natural selection]] was not only the 'engine' behind adaptation, but was a much stronger force than had previously been thought.<ref name="Provine 1986">{{harvnb|Provine|1986}}</ref><ref>{{harvnb|Ford|1975}}</ref><ref name="Orr_2005">{{cite journal |last=Orr |first=H. Allen |authorlink=H. Allen Orr |date=February 2005 |title=The genetic theory of adaptation: a brief history |journal=[[Nature Reviews Genetics]] |volume=6 |issue=2 |pages=119–127 |doi=10.1038/nrg1523 |pmid=15716908}}</ref>this

{{Quotation|''The significance of an adaptation can only be understood in relation to the total biology of the species:*# like this:*# and this.''|[[Julian Huxley]]|''[[Evolution: The Modern Synthesis]]''<ref>{{harvnb|Huxley|1942|p=449}}</ref>}}

==Key Stage 1=What adaptation is={| border="0" style="border-collapse:collapse"||||||Adaptation is primarily a process rather than a physical form or part of a body||[[File:HydrogenSymbol1.<ref>{{harvnbpng|Mayrcenter|198231px|plink=483}}Hydrogen]]||||||||||[[File: "AdaptationHeliumSymbol1.png|center|31px|link=Helium]]|-|[[File:LithiumSymbol1.png|center|31px|link=Lithium]]|[[File:BerylliumSymbol1. could no longer be considered a static condition, a product of a creative past, and became instead a continuing dynamic processpng|center|31px|link=Beryllium]]|||||||||||[[File:BoronSymbol1."</ref> An internal png|center|31px|link=Boron]]|[[parasiteFile:CarbonSymbol1.png|center|31px|link=Carbon]] (such as a |[[liver flukeFile:NitrogenSymbol1.png|center|31px|link=Nitrogen]]) can illustrate the distinction|[[File: such a parasite may have a very simple bodily structure, but nevertheless the organism is highly adapted to its specific environmentOxygenSymbol1. From this we see that adaptation is not just a matter of visible traitspng|center|31px|link=Oxygen]]|[[File: in such parasites critical adaptations take place in the FluorineSymbol1.png|center|31px|link=Fluorine]]|[[biological life cycleFile:NeonSymbol1.png|center|31px|life cyclelink=Neon]], which is often quite complex|-|[[File:SodiumSymbol1.<ref>{{harvnb png|center|Price 31px|1980}}</ref> However, as a practical term, "adaptation" often refers to a ''product''link=Sodium]]|[[File: those features of a MagnesiumSymbol1.png|center|31px|link=Magnesium]]|||||||||||[[speciesFile:AluminiumSymbol1.png|center|31px|link=Aluminium]] which result from the process|[[File:SiliconSymbol1. Many aspects of an animal or plant can be correctly called adaptations, though there are always some features whose function remains in doubtpng|center|31px|link=Silicon]]|[[File:PhosphorusSymbol1. By using the term ''adaptation'' for the evolutionary ''process'', and ''adaptive trait'' for the bodily part or function (the product), one may distinguish the two different senses of the wordpng|center|31px|link=Phosphorus]]|[[File:SulphurSymbol1.<ref>{{cite encyclopedia png|center|31px|editor1-lastlink=Daintith Sulphur]]|editor1-first[[File:ChlorineSymbol1.png|center|31px|link=John Chlorine]]|[[File:ArgonSymbol1.png|center|31px|editor2-lastlink=Martin Argon]]|editor2-first|[[File:PotassiumSymbol1.png|center|31px|link=Elizabeth APotassium]]|[[File:CalciumSymbol1. png|encyclopediacenter|31px|link=A Dictionary of Science Calcium]]|[[File:ScandiumSymbol1.png|titlecenter|31px|link=adaptation Scandium]]|[[File:TitaniumSymbol1.png|center|31px|origyearlink=First published 1984 as ''Concise Science Dictionary'' Titanium]]|edition[[File:VanadiumSymbol1.png|center|31px|link=6th Vanadium]]|[[File:ChromiumSymbol1.png|yearcenter|31px|link=2010 Chromium]]|publisher[[File:ManganeseSymbol1.png|center|31px|link=Manganese]]|[[Oxford University PressFile:IronSymbol1.png|center|31px|link=Iron]] |[[File:CobaltSymbol1.png|center|series31px|link=Oxford Paperback Reference Cobalt]]|[[File:NickelSymbol1.png|center|31px|isbnlink=978-0-19-956146-9 Nickel]]|[[File:CopperSymbol1.png|center|31px|lccnlink=2010287468 Copper]]|oclc[[File:ZincSymbol1.png|center|31px|link=444383696 Zinc]]|[[File:GalliumSymbol1.png|center|31px|pagelink=13 Gallium]]|[[File:GermaniumSymbol1.png|center|31px|quotelink=Any change in the structure or functioning of successive generations of a population that makes it better suited to its environmentGermanium]]|[[File:ArsenicSymbol1.}}</ref><ref>{{harvnb png|Bowler center|2003 31px|plink=10}}</ref><ref>{{harvnb Arsenic]]|[[File:SeleniumSymbol1.png|Patterson center|1999 31px|plink=1}}</ref><ref>{{harvnb Selenium]]|[[File:BromineSymbol1.png|Williams center|1966 31px|plink=5}}Bromine]]|[[File: "Evolutionary adaptation is a phenomenon of pervasive importance in biologyKryptonSymbol1."</ref>png|center|31px|link=Krypton]]|}

Adaptation is one of the two main processes that explain the observed diversity of species, such as the different species of [[Darwin's finches]]. The other process is [[speciation]], in which new species arise, typically through [[reproductive isolation]].<ref>{{harvnb |Mayr |1963}}</ref><ref>{{harvnb |Mayr |1982 |pp=562–566}}</ref> A favourite example used today to study the interplay of adaptation and speciation is the evolution of [[cichlid]] [[fish]] in African lakes, where the question of reproductive isolation is complex.<ref name="Salzburger">{{cite journal |last1=Salzburger |first1=Walter |last2=Mack |first2=Tanja |last3=Verheyen |first3=Erik |last4=Meyer |first4=Axel |authorlink4=Axel Meyer |date=February 21, 2005 |title=Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes |url=httphttps://wwwmediawiki.biomedcentral.com/content/pdf/1471-2148-5-17.pdf |journal=[[BMC Evolutionary Biology]] |location=London |publisher=[[BioMed Central]] |volume=5 |number=17 |doi=10.1186/1471-2148-5-17 |pmc=554777 |pmid=15723698 |accessdate=2015-08-15}}</ref><ref name="Kornfield">{{cite journal |last1=Kornfield |first1=Irv |last2=Smith |first2=Peter F. |date=November 2000 |title=African Cichlid Fishes: Model Systems for Evolutionary Biology |journal=[[Annual Review of Ecology, Evolution, and Systematics |Annual Review of Ecology and Systematicsorg MediaWiki]] |volume=31 |pages=163–196 |doi=10.1146/annurev.ecolsys.31.1.163}}</ref>

All adaptations help organisms survive in their [[ecological niche]]s.<ref>{{harvnb|Hutchinson|1965}}. The niche ===Meaning==='''Testpage''' is to show the central concept in evolutionary ecology; see especially part II: "The niche: an abstractly inhabited hypervolume." (pp. 26–78)</ref> The adaptive traits may be structural, behavioural or [[Physiology|physiological]]. Structural adaptations are physical features of an organism, such as shape, body covering, armament, and [[comparative anatomy |internal organization]]. [[Ethology|Behavioural]] adaptations are inherited systems type of behaviour, whether inherited errors in detail as [[instinct]]s, or as a [[neuropsychology|neuropsychological]] capacity for [[learning]]this wiki that need correcting. Examples include [[Foraging |searching for food]], [[mating]], and [[Animal communication |vocalizations]]File:AppleFruit. Physiological adaptations permit the organism to perform special functions such as making [[venom]], secreting [[Snail slime png|slime]], and [[phototropism]]), but also involve more general functions such as [[developmental biology right|growth and development]], [[Thermoregulation 100px|temperature regulation]], [[ions thumb|ionic]] balance and other aspects A picture of [[homeostasisa dragon.]]. Adaptation affects all aspects of the life of an organism.

The following definitions are given by the evolutionary biologist [[Theodosius Dobzhansky]]::1. ''Adaptation'' is the evolutionary process whereby an organism becomes better able to live in its [[habitat]] or habitats.<ref name="Dobzhansky T 1968">{{harvnb |Dobzhansky |1968 |pp=1–34}}</ref><ref>{{cite book |last1=Wang |first1=G |title=Analysis of Complex Diseases: A Mathematical Perspective |publisher=Taylor Francis |year=2014 |chapter=Chapter 5.6—Zero Order Adaptivity |pages=69 |isbn=9781466572232 |url={{Google books |plainurl=yes |id=DmDSBQAAQBAJ |page=69}}}}</ref><ref>{{cite book |title=Climate Change Impact on Livestock: Adaptation and Mitigation |publisher=Springer |editor1-last=Sejian |editor1-first=V. |editor2-last=Gaughan |editor2-first=J. |editor3-last=Baumgard |editor3-first=L. |editor4-lastAbout Error checking in Testpage=Prasad |editor4-first=C. |year=2015 |pages=515 |isbn=9788132222651 |url={{Google books |plainurl=yes |id=D-G9BwAAQBAJ |page=515}}}}</ref>:2. *There is an extra '='Adaptednessin the title 'About Error checking in Testpage' is the state of being adapted: the degree to which an organism is able to live and reproduce in a given set of habitats.<ref>{{harvnb |Dobzhansky |1970 |pp=4–6; 79–82}}</ref>:3. An ''adaptive trait'' is an aspect of *In the developmental pattern of the organism which enables or enhances the probability of that organism surviving and reproducing.<ref>{{cite journal |last=Dobzhansky |first=Theodosius |authorlink=Theodosius Dobzhansky |date=March 1956 |title=Genetics of Natural Populations. XXV. Genetic Changes in Populations of sentence ''Drosophila pseudoobscura'testpage' and ''Drosophila persimilis'' in Some Localities should have been in California |journal=[[Evolution (journal) |Evolutionbold]] |publisher=[[John Wiley & Sonsbecause it is the title of this page.*The ']] for ' show that the [[Society for word 'bold' was supposed to be a link but the Study of Evolution]] |volume=10 |issue=1 |pages=82–92 |doi=10first brackets were not included.2307/2406099 |jstor=2406099}}</ref>

===What adaptation : '''Testpage is to show the type... *The last sentence should not===have been completely in bold type. It happened because the the sentence began with three apostrophe's but more should have been added after the word '''testpage'''.*TestPage is the title of this page so it should never appear as a link to another page. This happens sometimes when brackets [[File:Tampering_W_Nature_Guacharacasare used because they can also make the page bold, but if the word is spelled wrong or there is a capital in the wrong place it becomes a link.jpg|right|thumb|*Some links may be 'red' when there is already a page with a similar name that they should be linked to. [[Generalist and specialist species|generalistsPollinate]], such as and [[birdPollination]]s, have can both be fit on the flexibility same page so if you know there is a page that it could link to adapt to [[urban area]]s, then it shouldn't be red.]]

Adaptation differs from flexibility***Bullet points should only have one bullet, [[acclimatization]], and [[learning]]. Flexibility deals with the relative capacity of an organism to maintain itself in different habitats: its degree of [[Generalist and specialist species|specialization]]. Acclimatization describes automatic [[physiology|physiological]] adjustments during life;<ref name="Rymer2013">{{cite journal | last=Rymer | first=Tasmin | last2=Pillay | first2=Neville | last3=Schradin | first3=Carsten | title=Extinction or Survival? Behavioral Flexibility in Response to Environmental Change not two in the African Striped Mouse Rhabdomys | journal=Sustainability | volume=5 | issue=1 | date=2013 | doi=10.3390/su5010163 | pages=163–186}}</ref> learning means improvement in behavioral performance during life.<ref>{{cite book |last=Gross |first=Richard |title=Psychology: The Science of Mind and Behaviour |edition=6th |url=https://books.google.com/books?id=Cle1Fcr_6_QC&pg=PT335 |year=2012 |publisher=Hodder |isbn=978-1-4441-6436-7 |page=335}}</ref> These terms are preferred to adaptation for changes during life which are not inherited by the next generationa row.

Flexibility stems from [[phenotypic plasticity]]Sometimes a sentence is far too long, or they have some parts to them which make it more complicated, or too many different ways of saying the same thing and this can make it difficult for people, especially young children, to read the ability of an organism with sentence and get the meaning from that sentence because there's too much going on and maybe they're a little tired or have difficulty staring at a given [[genotype]] screen, which makes it harder to change its [[phenotype]] in response pay attention, so you lose track of what the sentence was originally trying to changes in its [[habitat]], or say before you reach the end and have to move go back over it to a different habitatmake sure what you read makes sense.*That sentence is way too long and complicated.<ref>{{cite journal |last1=Price |first1=Trevor DIf you have to go back to re-read anything, then it is too complicated and needs correcting. |last2=Qvarnström |first2=Anna |last3=Irwin |first3=Darren E*Most pictures and diagrams will have a description. |date=July 2003 |title=The role of phenotypic plasticity in driving genetic evolution |journal=[[Proceedings of If the Royal Society#Proceedings of description doesn't match the Royal Society B|Proceedings of image then it needs correcting.*Some pictures are too small to see the Royal Society B]] |volume=270 |issue=1523 |pages=1433–1440 |doi=10important detail.1098/rspbSome may be too large to fit on the screen.2003These need to be resized.2372 *Some tables with pictures in have small pictures but a large box:{|pmcclass=1691402 'wikitable'|pmid=12965006}}</ref><ref>{{cite journal -|last=Price |first=Trevor D[[File:MusicalInstruments. png|date=June 2006 |title=Phenotypic plasticity, sexual selection and the evolution of colour patterns center|journal=[[The Journal of Experimental Biology200px]] |volume=209 -|issue=12 |pages=2368–2376 |doi=10.1242/jeb.02183 |pmid=16731813}}</ref> The degree of flexibility is inherited, and varies between individuals. A highly specialized animal or plant lives only in I did a well-defined habitat, eats a specific type of food, and cannot survive if its needs are not met. Many [[herbivore]]s are like this; extreme examples are [[koala]]s which depend on ''[[Eucalyptus]]'test', and [[giant panda]]s which require [[bamboo]]. A generalist, on the other hand, eats a range of food, and can survive in many different conditions. Examples are humans, [[rat]]s, [[crab]]s and many carnivores. The ''tendency'' to behave in a specialized or exploratory manner is inherited—it is an adaptation. Rather different is developmental flexibility: "An animal or plant is developmentally flexible if when it is raised in or transferred to new conditions, it changes in structure so that it is better fitted to survive in find out which instrument makes the new environment," writes [[evolutionary biology|evolutionary biologist]] [[John Maynard Smith]]deepest sound.<ref>{{harvnb|Maynard Smith|1993|p=33}}</ref>

If humans move to a higher altitude, respiration and physical exertion become a problem, but after spending time in high altitude conditions they acclimatize to the reduced partial pressure of oxygen, such as by producing more [[red blood cell]]s. The ability to acclimatize is an adaptation, but the acclimatization itself is not. Fecundity goes down, but deaths from some tropical diseases also go down. Over a longer period of time, some people are better able to reproduce at high altitudes than others. They contribute more heavily to later generations, and gradually by natural selection the whole population becomes adapted to the new conditions. This has demonstrably occurred, as the observed performance of long-term communities at higher altitude is significantly better than the performance of new arrivals, even when the new arrivals have had time to acclimatize.<ref>{{cite journal |last1=Moore |first1=Lorna G. |last2=Regensteiner |first2=Judith G. |date=October 1983 |title=Adaptation to High Altitude |journal=[[Annual Review of Anthropology]] |volume=12 |pages=285–304 |doi=10.1146/annurev.an.12.100183.001441}}</ref>table should look like this:

{| class===Adaptedness and fitness ==='wikitable'|-|[[File:fitness-landscape-cartoonMusicalInstruments.png|thumbcenter|In this sketch of a [[fitness landscape200px]], |-| style="height:20px; width:200px; text-align:center;" |I did a population can evolve by following the arrows '''test''' to find out which instrument makes the adaptive peak at point B, and the points A and C are local optima where a population could become trappeddeepest sound.]]{{Main|Fitness (biology)|Fitness landscape}}

There is a relationship between adaptedness and the concept of fitness used in [[population genetics]]. Differences in fitness between [[genotype]]s predict the rate of evolution by natural selection. Natural selection changes the relative frequencies of alternative phenotypes, insofar as they are [[Heritability|heritable]].<ref name="Endler 33">{{harvnb|Endler|1986|pp=[https://books.google.com/books?ul id=MYk1XbelDssC&lpg=PA27&pg=PA33#v=onepage&q&f=false 33–51]}}</ref> However, a phenotype with high adaptedness may not have high fitness. Dobzhansky mentioned the example of the [[Sequoia sempervirens|Californian redwood]], which is highly adapted, but a [[Relict (biology)|relict]] species in danger of [[extinction]].<ref name="Dobzhansky T 1968nav" /> [[Elliott Sober]] commented that adaptation was a retrospective concept since it implied something about the history of a trait, whereas fitness predicts a trait's future.<ref name="Sober2"li>{{harvnb|Sober|1984|p=210}}</ref> :1. Relative fitness. The average contribution to the next generation by a genotype or a span class of genotypes, relative to the contributions of other genotypes in the population.<ref name="Futuyma_Evolutionplainlinks">{{harvnb|Futuyma|1986|p=552}}</ref> This is also known as ''Darwinian fitness'', ''[[selection coefficient]]'', and other terms.:2. Absolute fitness. The absolute contribution to the next generation by a genotype or a class of genotypes. Also known as the [[Malthusian growth model|Malthusian parameter]] when applied to the population as a whole.<ref name="Endler 33" /><ref>{{harvnb|Fisher|1930|p=25}}</ref>:3. Adaptedness. The extent to which a phenotype fits its local ecological niche. Researchers can sometimes test this through a [[Transplant experiment|reciprocal transplant]].<ref>{{cite journal | last=de Villemereuil | first=P. | last2=Gaggiotti | first2=O. E. | last3=Mouterde | first3=M. | last4=Till-Bottraud | first4=I | title=Common garden experiments in the genomic era: new perspectives and opportunities | journal=Heredity | volume=116 | issue=3 Main_Page| date=2015-10-21 | doi=10.1038/hdy.2015.93 | pages=249–254| pmc=4806574 }}</ref> [[Sewall WrightShortcuts]] proposed that populations occupy ''adaptive peaks'' on a fitness landscape. To evolve to another, higher peak, a population would first have to pass through a valley of maladaptive intermediate stages, and might be "trapped" on a peak that is not optimally adapted.<ref>{{harvnb|Wright|1932|pp=[http://www.esp.org/books/6th-congress/facsimile/contents/6th-cong-p356-wright.pdf 356–366]}}</refspan> ===Genetic basis===A large diversity of genome [[DNA]]s in a species is the basis for adaptation and differentiation. A large population is needed to carry sufficient diversity. According to the misrepair-accumulation aging theory,<reful>{{cite arXiv |last1=Wang |first1=Jicun |last2=Michelitsch |first2=Thomas M. |last3=Wunderlin |first3=Arne |last4=Mahadeva |first4=Ravi |eprint=0904.0575 |title=Aging as a consequence of misrepair—A novel theory of aging |class=q-bio.TO |year=2009}}</refli><ref>{{cite arXiv |last1=Wang-Michelitsch |first1=Jicun |last2=Michelitsch |first2=Thomas M. |eprint=1503.07163 |title=Aging as a process of accumulation of misrepairs |span class=q-bio.TO |year=2015}}</ref> The misrepair mechanism is important in maintaining a sufficient number of individuals in a species.<ref>{{cite arXiv |last1=Wang-Michelitsch |first1=Jicun |last2=Michelitsch |first2=Thomas M. |eprint=1505.03900 |title=Misrepair mechanism: a mechanism essential for individual adaptation, species adaptation and species evolution |class=q-bio.TO |year=2015}}</ref"plainlinks"> misrepair is a way of repair for increasing the surviving chance of an organism when it has severe injuries. Without misrepairs, no individual could survive to reproduction age. Thus misrepair mechanism is an essential mechanism for the survival of a species and for maintaining the number of individuals. Although individuals die from aging, genome DNAs are being recopied and transmitted by individuals generation by generation. In addition, the DNA misrepairs in germ cells contribute also to the diversity of genome DNAs. ==Types=={{Quotation|''Adaptation is the heart and soul of evolution.''|[[Niles EldredgeCarnivore]]|Reinventing Darwin: The Great Debate at the High Table of Evolutionary Theory<ref>{{harvnb|Eldredge|1995|p=33}}</ref>}} ===Changes in habitat ===Before Darwin, adaptation was seen as a fixed relationship between an organism and its habitat. It was not appreciated that as the [[climate]] changed, so did the habitat; and as the habitat changed, so did the [[Biota (ecology)|biota]]. Also, habitats are subject to changes in their biota: for example, [[Invasive species|invasions]] of species from other areas. The relative numbers of species in a given habitat are always changing. Change is the rule, though much depends on the speed and degree of the change.When the habitat changes, three main things may happen to a resident population: habitat tracking, genetic change or extinction. In fact, all three things may occur in sequence. Of these three effects only genetic change brings about adaptation.When a habitat changes, the resident population typically moves to more suitable places; this is the typical response of flying [[insect]]s or oceanic organisms, which have wide (though not unlimited) opportunity for movement.<ref>{{harvnb|Eldredge|1985|p=136: "Of glaciers and beetles"}}</ref> This common response is called ''habitat tracking''. It is one explanation put forward for the periods of apparent stasis in the [[Fossil#Fossil record|fossil record]] (the [[punctuated equilibrium]] theory).<ref>{{harvnb|Eldredge|1995|p=64}}</refspan> === Genetic change ===Genetic change occurs in a population when natural selection and [[mutation]]s act on its [[genetic variability]].<ref>{{cite encyclopedia |last=Hogan |first=C. Michael |editor-last=Monosson |editor-first=Emily |encyclopedia=[[Encyclopedia of Earth]] |title=Mutation |url=http://www.eoearth.org/view/article/159530/ |accessdate=2015-08-18 |date=October 12, 2010 |publisher=Environmental Information Coalition, [[National Council for Science and the Environment]] |oclc=72808636}}</refli> The first pathways of enzyme-based metabolism may have been parts of [[Purine metabolism|purine nucleotide metabolism]], with previous metabolic pathways being part of the ancient [[RNA world]]. By this means, the population adapts genetically to its circumstances.<ref name="Orr_2005" /li> Genetic changes may result in visible structures, or may adjust physiological activity in a way that suits the habitat. Habitats and biota do frequently change. Therefore, it follows that the process of adaptation is never finally complete.<ref>{{harvnb|Mayr|1982|ppspan class=481–483}}: This sequence tells how Darwin's ideas on adaptation developed as he came to appreciate it as "a continuing dynamic process.plainlinks"</ref> Over time, it may happen that the environment changes little, and the species comes to fit its surroundings better and better. On the other hand, it may happen that changes in the environment occur relatively rapidly, and then the species becomes less and less well adapted. Seen like this, adaptation is a genetic ''tracking process'', which goes on all the time to some extent, but especially when the population cannot or does not move to another, less hostile area. Given enough genetic change, as well as specific demographic conditions, an adaptation may be enough to bring a population back from the brink of [[extinctionHerbivore]] in a process called [[evolutionary rescue]]. It should be noted that adaptation does affect, to some extent, every species in a particular [[ecosystem]].<ref>{{harvnb|Sterelny|Griffiths|1999|p=217}}</ref><ref>{{harvnb|Freeman|Herron|2007|p=364}}</ref> [[Leigh Van Valen]] thought that even in a stable environment, competing species constantly had to adapt to maintain their relative standing. This became known as the [[Red Queen hypothesis]], as seen in host-[[parasite]] interaction.<ref>{{cite journal |doi=10.1126/sciadv.1501548 |last=Rabajante |first=J |title=Host-parasite Red Queen dynamics with phase-locked rare genotypes|journal=[[Science Advances]] |year=2016 |volume=2|pages=e1501548 |url=http://advances.sciencemag.org/content/2/3/e1501548 |display-authors=etal|bibcode=2016SciA....2E1548R}}</ref> === Co-adaptation ==={{main|Co-adaptation}} [[File:Plumpollen0060.jpg|thumb|Pollinating insects are co-adapted with flowering plants.]]In [[coevolution]], where the existence of one species is tightly bound up with the life of another species, new or 'improved' adaptations which occur in one species are often followed by the appearance and spread of corresponding features in the other species. These [[co-adaptation]]al relationships are intrinsically dynamic, and may continue on a trajectory for millions of years, as has occurred in the relationship between [[flowering plant]]s and [[pollination|pollinating]] insects.<ref>{{cite book |title=Coevolution |author=[[Douglas J. Futuyma|Futuyma, D. J.]] and M. Slatkin (editors) |year=1983 |publisher=[[Sinauer Associates]] |isbn=0-87893-228-3 |pages=whole book}}</ref><ref>{{cite book |title=The Coevolutionary Process |author=Thompson, J. N.|year=1994 |publisher=University of Chicago Press |isbn=0-226-79759-7 |pages=whole book}}</ref> === Mimicry ==={{main|Mimicry}}[[File:Wasp mimicry.jpg|thumb|right|A and B show real [[wasps]]; the rest are [[Batesian mimicry|Batesian mimics]]: three [[Hoverfly|hoverflies]] and one [[beetle]].]] Bates' work on Amazonian [[Butterfly|butterflies]] led him to develop the first scientific account of [[mimicry]], especially the kind of mimicry which bears his name: [[Batesian mimicry]].<ref>{{harvnb|Carpenter|Ford|1933}}</ref> This is the mimicry by a palatable species of an unpalatable or noxious species, gaining a selective advantage. A common example seen in temperate gardens is the [[hoverfly]], many of which—though bearing no sting—mimic the warning coloration of [[hymenoptera]] ([[wasp]]s and [[bee]]s). Such mimicry does not need to be perfect to improve the survival of the palatable species.<ref>{{harvnb|Wickler|1968}}</ref> Bates, Wallace and [[Fritz Müller]] believed that Batesian and [[Müllerian mimicry]] provided [[coloration evidence for natural selection|evidence for the action of natural selection]], a view which is now standard amongst biologists.<ref>{{harvnb|Moon|1976}}</ref><ref>{{harvnb|Ruxton|Sherratt|Speed|2004}}</ref><ref>{{cite journal |last=Mallet |first=James |authorlink=James Mallet |date=November 2001 |title=The speciation revolution |url=http://www.ucl.ac.uk/taxome/jim/pap/malletjeb01.pdf |journal=[[Journal of Evolutionary Biology]] |volume=14 |issue=6 |pages=887–888 |doi=10.1046/j.1420-9101.2001.00342.x}}</ref> === Trade-offs ==={{Quotation|''It is a profound truth that Nature does not know best; that genetical evolution... is a story of waste, makeshift, compromise and blunder.''|[[Peter Medawar]]|The Future of Man<ref>{{harvnb|Medawar|1960}}</refspan>}} All adaptations have a downside: [[horse]] legs are great for running on grass, but they can't scratch their backs; [[mammal]]s' hair helps temperature, but offers a niche for [[Parasitism#Types|ectoparasites]]; the only flying [[penguin]]s do is under water. Adaptations serving different functions may be mutually destructive. Compromise and makeshift occur widely, not perfection. Selection pressures pull in different directions, and the adaptation that results is some kind of compromise.<ref>{{cite journal |last=Jacob |first=François |authorlink=François Jacob |date=June 10, 1977 |title=Evolution and Tinkering |journal=[[Science (journal)|Science]] |publisher=[[American Association for the Advancement of Science]] |volume=196 |issue=4295 |pages=1161–1166 |doi=10.1126/science.860134 |pmid=860134|bibcode=1977Sci...196.1161J }}</ref> {{Quotation|''Since the phenotype as a whole is the target of selection, it is impossible to improve simultaneously all aspects of the phenotype to the same degree.''|[[Ernst Mayr]]|[[The Growth of Biological Thought|The Growth of Biological Thought: Diversity, Evolution, and Inheritance]]<refli>{{harvnb|Mayr|1982|p=589}}</refli>}} Consider the antlers of the [[Irish elk]], (often supposed to be far too large; in [[deer]] antler size has an [[Allometry|allometric]] relationship to body size). Obviously, antlers serve positively for defence against [[Predation|predator]]s, and to score victories in the annual [[rut (mammalian reproduction)|rut]]. But they are costly in terms of resource. Their size during the [[last glacial period]] presumably depended on the relative gain and loss of reproductive capacity in the population of elks during that time.<ref>{{cite journal |last=Gould |first=Stephen Jay |authorlink=Stephen Jay Gould |date=June 1974 |title =The Origin and Function of 'Bizarre' Structures: Antler Size and Skull Size in the 'Irish Elk,' ''Megaloceros giganteus'' |journal=Evolution |volume=28 |issue=2 |pages=191–220 |doi=10.2307/2407322 |jstor=2407322}}</ref> As another example, [[camouflage]] to avoid detection is destroyed when vivid [[animal coloration|coloration]] is displayed at mating time. Here the risk to life is counterbalanced by the necessity for reproduction.<ref namespan class="Garcia2013plainlinks">{{cite journal | last=Garcia | first=J. E. | last2=Rohr | first2=D. | last3=Dyer | first3=A. G. | title=Trade-off between camouflage and sexual dimorphism revealed by UV digital imaging: the case of Australian Mallee dragons (Ctenophorus fordi) | journal=Journal of Experimental Biology | volume=216 | issue=22 | date=2013 | doi=10.1242/jeb.094045 | pages=4290–4298}}</ref> Stream-dwelling salamanders, such as [[Caucasian salamander]] or [[Gold-striped salamander]] have very slender, long bodies, perfectly adapted to life at the banks of fast small rivers and mountain [[Stream|brook]]s. Elongated body protects their [[larva]]e from being washed out by current. However, elongated body increases risk of desiccation and decreases dispersal ability of the salamanders; it also negatively affects their [[fecundity]]. As a result, [[fire salamander]], less perfectly adapted to the mountain brook habitats, is in general more successful, have a higher fecundity and broader geographic range.<ref>{{cite journal |last=Tarkhnishvili |first=David N. |year=1994 |title=Interdependences between Populational, Developmental and Morphological Features of the Caucasian salamander, ''Mertensiella caucasica'' |url=http://eprints.iliauni.edu.ge/usr/share/eprints3/data/814/1/Caucasian%20Salamander%20Ecological%20Constraints.pdf |journal=Mertensiella |volume=4 |pages=315–325 |accessdate=2015-08-18}}</ref> [[File:Pfau imponierend.jpg|thumb|left|An [[Indian peafowl|Indian peacock]]'s train<br />in full display]] The [[Peafowl|peacockReptile]]'s ornamental train (grown anew in time for each mating season) is a famous adaptation. It must reduce his maneuverability and flight, and is hugely conspicuous; also, its growth costs food resources. Darwin's explanation of its advantage was in terms of [[sexual selection]]: "This depends on the advantage which certain individuals have over other individuals of the same sex and species, in exclusive relation to reproduction."<ref>{{harvnb|Darwin|1871|p=[http://darwin-online.org.uk/content/frameset?pageseq=269&itemID=F937.1&viewtype=side 256]}}</ref> The kind of sexual selection represented by the peacock is called 'mate choice,' with an implication that the process selects the more fit over the less fit, and so has survival value.<ref>The case was treated by {{harvnb|Fisher|1930|pp=134–139}}</ref> The recognition of sexual selection was for a long time in abeyance, but has been rehabilitated.<refspan>{{harvnb|Cronin|1991}}</refli> The conflict between the size of the human [[Fetus|foetal]] brain at birth, (which cannot be larger than about 400&nbsp;cm<supli>3</sup>, else it will not get through the mother's [[pelvis]]) and the size needed for an adult brain (about 1400&nbsp;cm³), means the brain of a newborn child is quite immature. The most vital things in human life (locomotion, speech) just have to wait while the brain grows and matures. That is the result of the birth compromise. Much of the problem comes from our upright [[Bipedalism|bipedal]] stance, without which our pelvis could be shaped more suitably for birth. [[Neanderthal]]s had a similar problem.<ref>{{cite journal |last=Rosenberg |first=Karen R. |year=1992 |title=The evolution of modern human childbirth |journal=American Journal of Physical Anthropology |location=Hoboken, NJ |publisher=John Wiley & Sons for the [[American Association of Physical Anthropologists]] |volume=35 |issue=Supplement S15 |pages=89–124 |doi=10.1002/ajpa.1330350605}}</ref><ref>{{cite journal |last1=Friedlander |first1=Nancy J. |last2=Jordan |first2=David K. |authorlink2=David K. Jordan |date=October–December 1994 |title=Obstetric implications of Neanderthal robusticity and bone density |journal=Human Evolution |volume=9 |issue=4 |pages=331–342 |doi=10.1007/BF02435519}}</ref><ref>{{harvnb|Miller|2007}}</ref> As another example, the long neck of a [[giraffe]] is a burden and a blessing. The neck of a giraffe can be up to {{convert|2|m|abbr=on}} in length.<ref>{{harvnb|Williams|2010|p=29}}</ref> This neck can be used for inter-species competition or for foraging on tall trees where shorter [[herbivore]]s cannot reach. However, as previously stated, there is always a trade-off. This long neck is heavy and it adds to the body mass of a giraffe, so the giraffe needs an abundance of nutrition to provide for this costly adaptation.<ref>{{cite journal |last1=Altwegg |first1=Robert E. |last2=Simmons |first2=Res |title=Necks-for-sex or competing browsers? A critique of ideas on the evolution of giraffe |date=September 2010 |journal=[[Journal of Zoology]] |volume=282 |issue=1 |pages=6–12 |doi=10.1111/j.1469-7998.2010.00711.x}}</ref> ==Shifts in function =={{Quotation|''Adaptation and function are two aspects of one problem.''|Julian Huxley|Evolution: The Modern Synthesis<ref>{{harvnb|Huxley|1942|p=417}}</ref>}} ===Pre-adaptation=== Pre-adaptation occurs when a population has characteristics which by chance are suited for a set of conditions not previously experienced. For example, the polyploid [[Spartina|cordgrass]] ''Spartina townsendii'' is better adapted than either of its parent species to their own habitat of saline marsh and mud-flats.<ref>{{cite journal |last=Huskins |first=C. Leonard |authorlink=Charles Leonard Huskins |year=1930 |title=The origin of Spartina Townsendii |journal=[[Genetica]] |publisher=Martinus Nijhoff, The Hague/Kluwer Academic Publishers |volume=12 |issue=6 |pages=531–538 |doi=10.1007/BF01487665}}</ref> Among domestic animals, the [[Leghorn chicken|White Leghorn]] [[chicken]] is markedly more resistant to [[Thiamine|vitamin B₁]] deficiency than other breeds; on a plentiful diet this makes no difference, but on a restricted diet this preadaptation could be decisive.<ref>{{cite journal |last1=Lamoreux |first1=Wilfred F. |last2=Hutt |first2=Frederick B. |date=February 15, 1939 |title=Breed differences in resistance to a deficiency in vitamin B₁ in the fowl |url=http://naldc.nal.usda.gov/download/IND43969284/PDF |journal=Journal of Agricultural Research |publisher=[[United States Department of Agriculture]] |volume=58 |issue=4 |pages=307–316}}</ref> Pre-adaptation may arise because a natural population carries a huge quantity of genetic variability.<ref namespan class="Dobzhansky T 1981plainlinks">{{harvnb|Dobzhansky|1981}}</ref> In [[Ploidy#Diploid|diploid]] [[eukaryote]]s, this is a consequence of the system of [[sexual reproduction]], where mutant alleles get partially shielded, for example, by [[dominance (genetics)|genetic dominance]].<ref>{{cite book |first=R. C. |last=King |date=2006 |title=A Dictionary of Genetics |edition=7th|page=129 |publisher=Oxford University Press |isbn=978-0-19-530761-0 |url=https://books.google.com/books?id=ykp-7oJ5pREC&pg=PA129#v=onepage&f=false|quote=Dominance [refers] to alleles that fully manifest their phenotype when present in the [[zygosity|heterozygous]] ... state. |display-authors=etal}}</ref> [[Microorganism]]s, with their huge populations, also carry a great deal of genetic variability. The first experimental evidence of the pre-adaptive nature of genetic variants in microorganisms was provided by [[Salvador Luria]] and [[Max Delbrück]] who developed the [[Luria–Delbrück experiment|Fluctuation Test]], a method to show the random fluctuation of pre-existing genetic changes that conferred resistance to [[bacteriophage]]s in ''[[Escherichia coli]]''.<ref name="Luria 1943 491–511">{{cite journal |last=Luria |first=S. E. |author2=Delbrück, M. |year=1943 |title=Mutations of Bacteria from Virus Sensitivity to Virus Resistance |journal=[[Genetics (journal)|GeneticsAmphibian]] |volume=28 |issue=6 |pages=491–511 |url=http://www.genetics.org/cgi/reprint/28/6/491}}</ref> ===Co-option of existing traits: exaptation ===[[File:Sinosauropteryxfossil.jpg|thumb|upright=1.2|The feathers of ''[[Sinosauropteryx]]'', a dinosaur with feathers, were used for insulation, making them an [[exaptation]] for flight.]]{{main|Exaptation}} Features that now appear as adaptations sometimes arose by co-option of existing traits, evolved for some other purpose. The classic example is the [[Evolution of mammalian auditory ossicles|ear ossicles of mammals]], which we know from [[Paleontology|paleontological]] and [[Embryology|embryological]] evidence originated in the upper and lower [[jaw]]s and the [[hyoid bone]] of their [[synapsid]] ancestors, and further back still were part of the [[Branchial arch|gill arch]]es of early fish.<ref>{{harvnb|Allin|Hopson|1992|pp=587–614}}</ref><refspan>{{harvnb|Panchen|1992|loc=chpt. 4, "Homology and the evidence for evolution"}}</refli> The word ''exaptation'' was coined to cover these common evolutionary shifts in function.<refli>{{cite journal |last1=Gould |first1=Stephen Jay |author1link=Stephen Jay Gould |last2=Vrba |first2=Elizabeth S. |authorlink2=Elisabeth Vrba |date=Winter 1982 |title=Exaptation–A Missing Term in the Science of Form |journal=[[Paleobiology (journal)|Paleobiology]] |volume=8 |issue=1 |pages=4–15 |jstor=2400563}}</ref> The flight [[feather]]s of birds evolved from the much earlier [[Feathered dinosaur#List of non-avian dinosaur species preserved with evidence of feathers|feathers of dinosaur]]s,<ref namespan class="Ornithoscelidaplainlinks">{{cite journal | last1=Baron | first1=M.G. | last2=Norman | first2=D.B. | last3=Barrett | first3=P.M. | year=2017 | title=A new hypothesis of dinosaur relationships and early dinosaur evolution | journal=Nature | volume=543 | issue=| pages=501–506 | doi=10.1038/nature21700| bibcode=2017Natur.543..501B }}</ref> which might have been used for insulation or for display.<ref name="Dimond et al">{{Cite journal|author1=Dimond, C. C. |author2=Cabin, R. J. |author3=Brooks, J. S. |journal=BIOS |title=Feathers, Dinosaurs, and Behavioral Cues: Defining the Visual Display Hypothesis for the Adaptive Function of Feathers in Non-Avian Theropods |volume=82|year=2011 |pages=58–63 |doi=10.1893/011.082.0302 |issue=3}}</ref><ref>{{Cite journal |author1=Sumida, S. S. |author2=C. A. Brochu |journal=American Zoologist|title=Phylogenetic Context for the Origin of Feathers |volume=40 |issue=4 |year=2000 |pages=485–503 |doi=10.1093/icb/40.4.486}}</ref> ==Non-adaptive traits =={{main|Spandrel (biology)|Vestigiality}} Some traits do not appear to be adaptive, that is, they have a neutral or deleterious effect on fitness in the current environment. Because genes have [[Pleiotropy|pleiotropic]] effects, not all traits may be functional: they may be what [[Stephen Jay Gould]] and [[Richard Lewontin]] called [[Spandrel (biology)|spandrels]], features brought about by neighbouring adaptations, like the triangular areas under neighbouring arches in architecture which began as functionless features.<ref name=Wagner2014>[[Günter P. Wagner|Wagner, Günter P.]], ''Homology, Genes, and Evolutionary Innovation''. Princeton University Press. 2014. Chapter 1: The Intellectual Challenge of Morphological Evolution: A Case for Variational Structuralism. Page 7</ref> Another possibility is that a trait may have been adaptive at some point in an organism's evolutionary history, but a change in habitats caused what used to be an adaptation to become unnecessary or even [[maladaptation|maladaptedMammal]]. Such adaptations are termed [[Vestigiality|vestigial]]. Many organisms have vestigial organs, which are the remnants of fully functional structures in their ancestors. As a result of changes in lifestyle the organs became redundant, and are either not functional or reduced in functionality. Since any structure represents some kind of cost to the general economy of the body, an advantage may accrue from their elimination once they are not functional. Examples: [[Wisdom tooth|wisdom teeth]] in humans; the loss of pigment and functional [[eye]]s in cave fauna; the loss of structure in [[Intestinal parasite|endoparasites]].<ref>{{harvnb|Barrett|Gautrey|Herbert|Kohn|1987}}. Charles Darwin was the first to put forward such ideas.</ref> ==Extinction and coextinction =={{Main|Extinction|Coextinction}} If a population cannot move or change sufficiently to preserve its long-term viability, then obviously, it will become extinct, at least in that locale. The species may or may not survive in other locales. Species extinction occurs when the death rate over the entire species exceeds the birth rate for a long enough period for the species to disappear. It was an observation of Van Valen that groups of species tend to have a characteristic and fairly regular rate of extinction.<ref>{{cite journal |last=Van Valen |first=Leigh |authorlink=Leigh Van Valen |date=July 1973 |title=A New Evolutionary Law |url=https://dl.dropboxusercontent.com/u/18310184/evolutionary-theory/vol-01/Vol.1%2CNo.1%2C1-30%2CL.%20Van%20Valen%2C%20A%20new%20evolutionary%20law..pdf |journal=Evolutionary Theory |volume=1 |pages=1–30}}</ref> Just as there is co-adaptation, there is also coextinction, the loss of a species due to the extinction of another with which it is coadapted, as with the extinction of a [[parasitism|parasitic]] insect following the loss of its host, or when a flowering plant loses its pollinator, or when a [[food chain]] is disrupted.<ref name="Koh">{{cite journal |last1=Koh |first1=Lian Pin |last2=Dunn |first2=Robert R. |authorlink2=Robert Dunn (biologist) |last3=Sodhi |first3=Navjot S. |last4=Colwell |first4=Robert K. |last5=Proctor |first5=Heather C. |last6=Smith |first6=Vincent S. |display-authors=3 |title=Species Coextinctions and the Biodiversity Crisis |date=September 2004 |journal=Science |volume=305 |issue=5690 |pages=1632–1634 |doi=10.1126/science.1101101 |pmid=15361627|bibcode=2004Sci...305.1632K }}</ref><ref>{{harvnb|Darwin|1872|pp=[http://darwin-online.org.uk/content/frameset?pageseq=84&itemID=F391&viewtype=side 57–58]}}. Darwin in tells the story of "a web of complex relations" involving heartsease (''[[Viola tricolor]]''), red clover (''[[Trifolium pratense]]''), [[bumblebee]]s, mice and cats.</refspan> ==Philosophical issues=={{main|Adaptationism|Teleology in biology}} Adaptation raises [[Philosophy of biology|philosophical issues]] concerning how biologists speak of function and purpose, as this carries implications of evolutionary history – that a feature evolved by natural selection for a specific reason – and potentially of supernatural intervention – that features and organisms exist because of a deity's conscious intentions.<ref name="Sober1">{{harvnb|Sober|1993|pp=85–86}}</refli><ref>{{harvnb|Williams|1966|pp=8–10}}</reful> [[Aristotle's biology|In his biology, Aristotle]] introduced [[teleology]] to describe the adaptedness of organisms, but without accepting the supernatural intention built into [[Plato]]'s thinking, which Aristotle rejected.<ref>{{cite journal |last=Nagel |first=Ernest |authorlink=Ernest Nagel |date=May 1977 |title=Goal-Directed Processes in Biology |journal=[[The Journal of Philosophy]] |volume=74 |issue=5 |pages=261–279 |doi=10.2307/2025745 |jstor=2025745}} Teleology Revisisted: The Dewy Lectures 1977 (first lecture)</ref><refli>{{cite journal |last=Nagel |first=Ernest |date=May 1977 |title=Functional Explanations in Biology |journal=The Journal of Philosophy |volume=74 |issue=5 |pages=280–301 |doi=10.2307/2025746 |jstor=2025746}} Teleology Revisisted: The Dewy Lectures 1977 (second lecture)</reful> Modern biologists continue to face the same difficulty.<ref>{{harvnb|Pittendrigh|1958}}</ref><ref>{{harvnb|Mayr|1965|pp=33–50}}</ref><ref>{{harvnb|Mayr|1988|loc=chpt. 3, "The Multiple Meanings of Teleological"}}</ref><reful>{{harvnb|Williams|1966|loc="The Scientific Study of Adaptation"}}</ref><ref>{{harvnb|Monod|1971}}</ref><ref>{{cite encyclopedia |editor-last=Allaby |editor-first=Michael |editor-link=Michael Allaby |encyclopedia=A Dictionary of Zoology |title=teleonomy |url=https://books.google.com/books?id=1_UO957htTwC&pg=PA530&lpg=PA530 |accessdate=2015-08-24 |edition=Reissued with new cover and corrections |year=2003 |publisher=Oxford University Press |series=Oxford Paperback Reference |isbn=0-19-860758-X |oclc=444678726}}</ref> On the one hand, adaptation is obviously purposeful: natural selection chooses what works and eliminates what does not. On the other hand, biologists want to deny conscious purpose in evolution. The dilemma gave rise to a famous joke by the evolutionary biologist [[J. B. S. Haldane|Haldane]]: "Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.'" [[David Hull]] commented that Haldane's mistress "has become a lawfully wedded wife. Biologists no longer feel obligated to apologize for their use of teleological language; they flaunt it."<ref>{{harvnb|Hull|1982}}</ref> ==See also=={{Div col|colwidth=30em}}* [[Adaptive evolution in the human genome]]* [[Adaptive memory]]* [[Adaptive mutation]]* [[Adaptive system]]* [[Anti-predator adaptation]]* [[Body reactivity]]* [[Ecological trap]]* [[Evolutionary pressure]]* [[Evolvability]]* [[Intragenomic conflict]]* [[Neutral theory of molecular evolution]]{{div col end}} ==References=={{Reflist|30em}} ==Sources=={{Refbegin|30em}}* {{cite book |last1=Allin |first1=Edgar F. |last2=Hopson |first2=James A. |authorlink2=James Hopson |year=1992 |chapter=Evolution of the Auditory System in Synapsida ("Mammal-Like Reptiles" and Primitive Mammals) as Seen in the Fossil Record |editor1-last=Webster |editor1-first=Douglas B. |editor2-last=Fay |editor2-first=Richard R. |editor3-last=Popper |editor3-first=Arthur N. |title=The Evolutionary Biology of Hearing |publisher=[[Springer Science+Business Media|Springer-Verlag]] |doi=10.1007/978-1-4612-2784-7_37 |isbn=0-387-97588-8 |oclc=23582549 |ref=harv}} "Based on a conference held at the [[Mote Marine Laboratory]] in Sarasota, Fla., May 20–24, 1990."* {{cite book |editor1-last=Barrett |editor1-first=Paul H. |editor2-last=Gautrey |editor2-first=Peter J. |editor3-last=Herbert |editor3-first=Sandra |editor4-last=Kohn |editor4-first=David |editor5-last=Smith |display-editors=3 |editor5-first=Sydney |year=1987 |title=Charles Darwin's Notebooks, 1836-1844: Geology, Transmutation of Species, Metaphysical Enquiries |publisher=[[Cornell University Press]] |isbn=0-521-09975-7 |oclc=16224403 |ref=harv}}* {{cite book |last=Bowler |first=Peter J. |authorlink=Peter J. Bowler |year=2003 |title=Evolution: The History of an Idea |edition=3rd completely rev. and expanded |publisher=[[University of California Press]] |isbn=0-520-23693-9 |oclc=49824702 |ref=harv}}* {{cite book |last1=Carpenter |first1=G.D. Hale |authorlink1=Geoffrey Douglas Hale Carpenter |last2=Ford |first2=E. B. |authorlink2=E. B. Ford |year=1933 |title=Mimicry. With a Section on Its Genetic Aspect by E. B. Ford |series=Methuen's Monographs on Biological Subjects |publisher=[[Methuen Publishing|Methuen]] |oclc=875481859 |ref=harv}}* {{cite book |last=Cronin |first=Helen |authorlink=Helena Cronin |year=1991 |title=The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today |others=Foreword by [[John Maynard Smith]] |publisher=[[Cambridge University Press|Press Syndicate of the University of Cambridge]] |isbn=0-521-32937-X |oclc=23144516 |ref=harv}}* {{cite book |last=Darwin |first=Charles |authorlink=Charles Darwin |year=1871 |title=[[The Descent of Man, and Selection in Relation to Sex]] |publisher=[[John Murray (publisher)|John Murray]] |oclc=550912 |ref=harv}}* {{cite book |last=Darwin |first=Charles |authorlink=Charles Darwin |year=1872 |title=The Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life |url=http://darwin-online.org.uk/content/frameset?pageseq=1&itemID=F391&viewtype=side |edition=6th |publisher=John Murray |oclc=1185571 |accessdate=2015-08-17 |ref=harv}}* {{cite book |last=Desmond |first=Adrian |authorlink=Adrian Desmond |year=1989 |title=The Politics of Evolution: Morphology, Medicine, and Reform in Radical London |series=Science and its Conceptual Foundations|publisher=[[University of Chicago Press]] |isbn=0-226-14346-5 |oclc=709606191 |ref=harv}}* {{cite book |last=Dobzhansky |first=Theodosius |authorlink=Theodosius Dobzhansky |year=1968 |chapter=On Some Fundamental Concepts of Darwinian Biology |editor1-last=Dobzhansky |editor1-first=Theodosius |editor2-last=Hecht |editor2-first=Max K. |editor3-last=Steere |editor3-first=William C. |title=Evolutionary Biology |volume=2 |publisher=[[Appleton-Century-Crofts]] |doi=10.1007/978-1-4684-8094-8_1 |oclc=24875357 |ref=harv}}* {{cite book |last=Dobzhansky |first=Theodosius |authorlink=Theodosius Dobzhansky |year=1970 |title=Genetics of the Evolutionary Process |publisher=[[Columbia University Press]] |isbn=0-231-02837-7 |oclc=97663 |ref=harv}}* {{cite book |last=Dobzhansky |first=Theodosius |authorlink=Theodosius Dobzhansky |year=1981 |editor1-last=Lewontin |editor1-first=Richard C. |editor1-link=Richard Lewontin |editor2-last=Moore |editor2-first=John A. |editor2-link=John Alexander Moore |editor3-last=Provine |editor3-first=William B. |editor3-link=Will Provine |editor4-last=Wallace |editor4-first=Bruce| display-editors =3 |title=Dobzhansky's Genetics of Natural Populations I-XLIII |publisher=Columbia University Press |isbn=0-231-05132-8 |oclc=7276406 |ref=harv}} "Papers by Dobzhansky and his collaborators, originally published 1937-1975 in various journals."* {{cite book |last=Eldredge |first=Niles |authorlink=Niles Eldredge |year=1985 |title=Time Frames: The Rethinking of Darwinian Evolution and the Theory of Punctuated Equilibria |publisher=[[Simon & Schuster]] |isbn=0-671-49555-0 |oclc=11443805 |ref=harv}}* {{cite book |last=Eldredge |first=Niles |year=1995 |title=Reinventing Darwin: The Great Debate at the High Table of Evolutionary Theory |publisher=[[John Wiley & Sons]] |isbn=0-471-30301-1 |oclc=30975979 |ref=harv}}* {{cite book |last=Endler |first=John A. |authorlink=John Endler |year=1986 |chapter=Fitness and Adaptation |series=Monographs in Population Biology |volume=21 |title=Natural Selection in the Wild |publisher=[[Princeton University Press]] |isbn=0-691-08387-8 |oclc=12262762 |ref=harv}}* {{cite book |last=Fisher |first=Ronald Aylmer |authorlink=Ronald Fisher |year=1930 |title=[[The Genetical Theory of Natural Selection]] |publisher=[[Oxford University Press#The Clarendon Press|The Clarendon Press]] |oclc=493745635 |ref=harv}}* {{cite book |last=Ford |first=E. B. |year=1975 |title=[[Ecological Genetics (book)|Ecological Genetics]] |edition=4th |publisher=[[Chapman & Hall]]; John Wiley & Sons |isbn=0-470-26576-0 |oclc=1890603 |ref=harv}}* {{cite book |last1=Freeman |first1=Scott |last2=Herron |first2=Jon C. |year=2007 |title=Evolutionary Analysis |edition=4th |publisher=[[Prentice Hall|Pearson Prentice Hall]] |isbn=0-13-227584-8 |oclc=73502978 |ref=harv}}* {{cite book |last=Futuyma |first=Douglas J. |authorlink=Douglas J. Futuyma |year=1986 |title=Evolutionary Biology |edition=2nd |publisher=[[Sinauer Associates]] |isbn=0-87893-188-0 |oclc=13822044 |ref=harv}}* {{cite book |last=Hull |first=David L. |authorlink=David Hull |year=1982 |chapter=Philosophy and biology |editor-last=Fløistad |editor-first=Guttorm |editor-link=Guttorm Fløistad |title=Philosophy of Science |series=Contemporary Philosophy: A New Survey |volume=2 |publisher=[[Martinus Nijhoff Publishers]]; [[Springer Science+Business Media|Springer Netherlands]] |doi=10.1007/978-94-010-9940-0 |isbn=90-247-2518-6 |oclc=502399533 |ref=harv}}* {{cite book |last=Hutchinson |first=G. Evelyn |authorlink=G. Evelyn Hutchinson |year=1965 |title=The Ecological Theater and the Evolutionary Play |publisher=[[Yale University Press]]|oclc=250039 |ref=harv}}* {{cite book |last=Huxley |first=Julian |authorlink=Julian Huxley |year=1942 |title=[[Evolution: The Modern Synthesis]] |publisher=[[Allen & Unwin]] |oclc=1399386 |ref=harv}}* {{cite book |editor1-last=Margulis |editor1-first=Lynn |editor1-link=Lynn Margulis |editor2-last=Fester |editor2-first=René |year=1991 |title=Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis |publisher=[[MIT Press]] |isbn=0-262-13269-9 |oclc=22597587 |ref=harv}} "Based on a conference held in Bellagio, Italy, June 25–30, 1989"* {{cite book |last=Maynard Smith |first=John |year=1993 |title=The Theory of Evolution |edition=Canto |publisher=Cambridge University Press |isbn=0-521-45128-0 |oclc=27676642 |ref=harv}}* {{cite book |last1=Mayr |first=Ernst |authorlink=Ernst Mayr |year=1963 |title=Animal Species and Evolution |publisher=[[Harvard University Press|Belknap Press of Harvard University Press]] |isbn=0-674-03750-2 |oclc=899044868 |ref=harv}}* {{cite book |last=Mayr |first=Ernst |authorlink=Ernst Mayr |year=1965 |chapter=Cause and Effect in Biology |editor-last=Lerner |editor-first=Daniel |title=Cause and Effect |series=The Hayden Colloquium on Scientific Method and Concept |publisher=[[Free Press (publisher)|Free Press]] |oclc=384895 |ref=harv}}* {{cite book |last=Mayr |first=Ernst |year=1982 |title=[[The Growth of Biological Thought|The Growth of Biological Thought: Diversity, Evolution, and Inheritance]] |publisher=[[Harvard University Press|Belknap Press]] |isbn=0-674-36445-7 |oclc=7875904 |ref=harv}}* {{cite book |last=Mayr |first=Ernst |authorlink=Ernst Mayr |year=1988 |title=[[Toward a New Philosophy of Biology|Toward a New Philosophy of Biology: Observations of an Evolutionist]] |publisher=Belknap Press of Harvard University Press |isbn=0-674-89665-3 |oclc=17108004 |ref=harv}}* {{cite book |last=Medawar |first=Peter |authorlink=Peter Medawar |year=1960 |title=The Future of Man |series=The BBC [[Reith Lectures]], 1959 |publisher=Methuen |oclc=1374615 |ref=harv}}* {{cite book |last=Miller |first=Geoffrey |authorlink=Geoffrey Miller (psychologist) |year=2007 |chapter=Brain Evolution |editor1-last=Gangestad |editor1-first=Steven W. |editor2-last=Simpson |editor2-first=Jeffry A. |title=The Evolution of Mind: Fundamental Questions and Controversies|publisher=[[Guilford Press]] |isbn=978-1-59385-408-9 |oclc=71005838 |ref=harv}}* {{cite book |last=Monod |first=Jacques |authorlink=Jacques Monod |year=1971 |title=Chance and Necessity: An Essay on the Natural Philosophy of Modern Biology |others=Translation of ''Le hasard et la nécessité'' by [[Austryn Wainhouse]] |edition=1st American |publisher=[[Alfred A. Knopf|Knopf]] |isbn=0-394-46615-2 |oclc=209901 |ref=harv}}* {{cite book |last=Moon |first=Harold Philip |year=1976 |title=Henry Walter Bates FRS, 1825-1892: Explorer, Scientist, and Darwinian |publisher=Leicestershire Museums, Art Galleries, and Records Service |isbn=0-904671-19-4 |oclc=3607387 |ref=harv}}* {{cite book |last=Panchen |first=Alec L. |year=1992 |title=Classification, Evolution and the Nature of Biology|publisher=Cambridge University Press |isbn=0-521-31578-6 |oclc=24247430 |ref=harv}}* {{cite book |last=Patterson |first=Colin |authorlink=Colin Patterson (biologist) |year=1999 |title=Evolution |series=Comstock Book Series |edition=2nd illustrated, revised |publisher=Cornell University Press |isbn=0-8014-8594-0 |oclc=39724234 |ref=harv}}* {{cite book |last=Pittendrigh |first=Colin S. |authorlink=Colin Pittendrigh |year=1958 |chapter=Adaptation, Natural Selection, and Behavior |editor1-last=Roe |editor1-first=Anne |editor2-last=Simpson |editor2-first=George Gaylord |editor2-link=George Gaylord Simpson |title=Behavior and Evolution |publisher=Yale University Press |oclc=191989 |ref=harv}}* {{cite book |last=Price |first=Peter W. |year=1980 |title=The Evolutionary Biology of Parasites |series=Monographs in Population Biology |volume=15 |publisher=Princeton University Press |isbn=0-691-08257-X |oclc=5706295 |ref=harv}}* {{cite book |last=Provine |first=William B. |year=1986 |title=Sewall Wright and Evolutionary Biology |series=Science and its Conceptual Foundations |publisher=University of Chicago Press |isbn=0-226-68474-1 |oclc=12808844 |ref=harv}}* {{cite book |last1=Ruxton |first1=Graeme D. |authorlink1=Graeme Ruxton |last2=Sherratt |first2=Thomas N. |last3=Speed |first3=Michael P. |year=2004 |title=Avoiding Attack: The Evolutionary Ecology of Crypsis, Warning Signals and Mimicry |series=Oxford Biology |publisher=[[Oxford University Press]] |isbn=0-19-852859-0 |oclc=56644492 |ref=harv}}* {{cite book |last=Sober |first=Elliott |authorlink=Elliott Sober |year=1984 |title=The Nature of Selection: Evolutionary Theory in Philosophical Focus |publisher=MIT Press |isbn=0-262-19232-2 |oclc=11114517 |ref=harv}}* {{cite book |last=Sober |first=Elliott |year=1993 |title=Philosophy of Biology |series=Dimensions of Philosophy Series |publisher=[[Westview Press]] |isbn=0-8133-0785-6|oclc=26974492 |ref=harv}}* {{cite book |last=Stebbins |first=G. Ledyard, Jr. |authorlink=G. Ledyard Stebbins |year=1950 |title=[[Variation and Evolution in Plants]] |series=Columbia Biological Series |volume=16 |publisher=Columbia University Press |oclc=294016 |ref=harv}}* {{cite book |last1=Sterelny |first1=Kim |authorlink1=Kim Sterelny |last2=Griffiths |first2=Paul E. |year=1999 |title=Sex and Death: An Introduction to Philosophy of Biology |series=Science and its Conceptual Foundations |publisher=University of Chicago Press |isbn=0-226-77304-3 |oclc=40193587 |ref=harv}}* {{cite book |author=Voltaire |authorlink=Voltaire |year=1759 |title=[[Candide|Candide, ou l'Optimisme]]}} {{Internet Archive|id=Candide_887|name=Candide}} * {{cite book |last=Wickler |first=Wolfgang |authorlink=Wolfgang Wickler |year=1968 |title=Mimicry in Plants and Animals |series=World University Library |others=Translated from the German by R. D. Martin |publisher=[[McGraw-Hill Education|McGraw-Hill]] |oclc=160314 |ref=harv}}* {{cite book |last=Williams |first=Edgar |year=2010 |title=Giraffe |series=Animal (Reaktion Books) |publisher=[[Reaktion Books]] |isbn=978-1-86189-764-0 |oclc=587198932 |ref=harv}}* {{cite book |last=Williams |first=George C. |authorlink=George C. Williams (biologist) |year=1966 |title=[[Adaptation and Natural Selection|Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought]] |series=Princeton Science Library |publisher=Princeton University Press |isbn=0-691-02615-7 |oclc=35230452 |ref=harv}}* {{cite book |last=Wright |first=Sewall |authorlink=Sewall Wright |year=1932 |chapter=The Roles of Mutation, Inbreeding, Crossbreeding and Selection in Evolution |editor-last=Jones |editor-first=Donald F. |editor-link=Donald F. Jones |title=Proceedings of the Sixth International Congress of Genetics |volume=1 |publisher=[[Genetics Society of America]] |oclc=439596433 |ref=harv}}{{Refend}} {{Biology nav}}{{Evolution}}{{Speciation}}{{Portal bar|Evolutionary biology}} [[Category:Evolutionary biology]]