Share to: share facebook share twitter share wa share telegram print page

Unit of selection

David Sloan Wilson and Elliott Sober's 1994 Multilevel Selection Model, illustrated by a nested set of Russian matryoshka dolls. Wilson himself compared his model to such a set.

A unit of selection is a biological entity within the hierarchy of biological organization (for example, an entity such as: a self-replicating molecule, a gene, a cell, an organism, a group, or a species) that is subject to natural selection. There is debate among evolutionary biologists about the extent to which evolution has been shaped by selective pressures acting at these different levels.[1][2][3]

There is debate over the relative importance of the units themselves. For instance, is it group or individual selection that has driven the evolution of altruism? Where altruism reduces the fitness of individuals, individual-centered explanations for the evolution of altruism become complex and rely on the use of game theory,[4][5] for instance; see kin selection and group selection. There also is debate over the definition of the units themselves,[6] and the roles for selection and replication,[2] and whether these roles may change in the course of evolution.[7]

Fundamental theory

Two useful introductions to the fundamental theory underlying the unit of selection issue and debate, which also present examples of multi-level selection from the entire range of the biological hierarchy (typically with entities at level N-1 competing for increased representation, i.e., higher frequency, at the immediately higher level N, e.g., organisms in populations or cell lineages in organisms), are Richard Lewontin's classic piece The Units of Selection[8] and John Maynard-Smith and Eörs Szathmáry's co-authored book, The Major Transitions in Evolution. As a theoretical introduction to units of selection, Lewontin writes:

The generality of the principles of natural selection means that any entities in nature that have variation, reproduction, and heritability may evolve. ...the principles can be applied equally to genes, organisms, populations, species, and at opposite ends of the scale, prebiotic molecules and ecosystems." (1970, pp. 1-2)

Elisabeth Lloyd's book The Structure and Confirmation of Evolutionary Theory provides a basic philosophical introduction to the debate. Three more recent introductions include Samir Okasha's book Evolution and the Levels of Selection, Pierrick Bourrat's book Facts, Conventions, and the Levels of Selection, and Elisabeth Lloyd and Javier Suárez book Units of Selection.

Selection at each level

Below, cases of selection at the genic, cellular, individual and group level from within the multi-level selection perspective are presented and discussed.

Nucleic acid

George C. Williams in his influential book Adaptation and Natural Selection was one of the first to present a gene-centered view of evolution with the gene as the unit of selection, arguing that a unit of selection should exhibit a high degree of permanence.

Richard Dawkins has written several books popularizing and expanding the idea. According to Dawkins, genes cause phenotypes and a gene is 'judged' by its phenotypic effects. Dawkins distinguishes entities which survive or fail to survive ("replicators") from entities with temporary existence that interact directly with the environment ("vehicles"). Genes are "replicators" whereas individuals and groups of individuals are "vehicles". Dawkins argues that, although they are both aspects of the same process, "replicators" rather than "vehicles" should be preferred as units of selection. This is because replicators, owing to their permanence, should be regarded as the ultimate beneficiaries of adaptations. Genes are replicators and therefore the gene is the unit of selection. Dawkins further expounded this view in an entire chapter called 'God's utility function' in the book River Out of Eden where he explained that genes alone have utility functions.[9]

Some clear-cut examples of selection at the level of the gene include meiotic drive and retrotransposons. In both of these cases, gene sequences increase their relative frequency in a population without necessarily providing benefits at other levels of organization. Meiotic-drive mutations (see segregation distortion) manipulate the machinery of chromosomal segregation so that chromosomes carrying the mutation are later found in more than half of the gametes produced by individuals heterozygous for the mutation, and for this reason the frequency of the mutation increases in the population.

Retrotransposons are DNA sequences that, once replicated by the cellular machinery, insert themselves in the genome more or less randomly. Such insertions can be very mutagenic and thus reduce drastically individual fitness, so that there is strong selection against elements that are very active. Meiotic-drive alleles have also been shown strongly to reduce individual fitness, clearly exemplifying the potential conflict between selection at different levels.

According to the RNA world hypothesis, RNA sequences performing both enzymatic and information storage roles in autocatalytic sets were an early unit of selection and evolution that would later transition into living cells.[10] It is possible that RNA-based evolution is still taking place today. Other subcellular entities such as viruses, both DNA-based and RNA-based, do evolve.

The gene-centered view of evolution normally refers to selection among different alleles of the same gene. However, gene families also differ in their tendency to diversify and avoid loss during evolution.[11] This latter form of selection more closely resembles clade selection of groups of species.

Epigene

There is also view that evolution is acting on epigenes.[12]

Cell

Leo Buss in his book The Evolution of Individuality proposes that much of the evolution of development in animals reflects the conflict between selective pressures acting at the level of the cell and those acting at the level of the multicellular individual. This perspective can shed new light on phenomena as diverse as gastrulation and germ line sequestration.

This selection for unconstrained proliferation is in conflict with the fitness interests of the individual, and thus there is tension between selection at the level of the cell and selection at the level of the individual. Since the proliferation of specific cells of the vertebrate immune system to fight off infecting pathogens is a case of programmed and exquisitely contained cellular proliferation, it represents a case of the individual manipulating selection at the level of the cell to enhance its own fitness. In the case of the vertebrate immune system, selection at the level of the cell and individual are not in conflict.

Some view cancer stem cells as units of selection.[13]

Behavioural

Gene–culture coevolution was developed to explain how human behavior is a product of two different and interacting evolutionary processes: genetic evolution and cultural evolution.

Organism

Selection at the level of the organism can be described as Darwinism, and is well understood and considered common. If a relatively faster gazelle manages to survive and reproduce more, the causation of the higher fitness of this gazelle can be fully accounted for if one looks at how individual gazelles fare under predation.

The speed of the faster gazelle could be caused by a single gene, be polygenic, or be fully environmentally determined, but the unit of selection in this case is the individual since speed is a property of each individual gazelle.

When speaking about individual organism evolution an extended phenotype and superorganism must be also mentioned.

Group

If a group of organisms, owing to their interactions or division of labor, provides superior fitness compared to other groups, where the fitness of the group is higher or lower than the mean fitness of the constituent individuals, group selection can be declared to occur.[14]

Specific syndromes of selective factors can create situations in which groups are selected because they display group properties which are selected-for. Many common examples of group traits are reducible to individual traits, however. Selection of these traits is thus more simply explained as selection of individual traits.

Some mosquito-transmitted rabbit viruses are only transmitted to uninfected rabbits from infected rabbits which are still alive. This creates a selective pressure on every group of viruses already infecting a rabbit not to become too virulent and kill their host rabbit before enough mosquitoes have bitten it, since otherwise all the viruses inside the dead rabbit would rot with it. And indeed in natural systems such viruses display much lower virulence levels than do mutants of the same viruses that in laboratory culture readily outcompete non-virulent variants (or than do tick-transmitted viruses since ticks do bite dead rabbits).

In the previous passage, the group is assumed to have "lower virulence", i.e., "virulence" is presented as a group trait. One could argue then that the selection is in fact against individual viruses that are too virulent. In this case, however, the fitness of all viruses within a rabbit is affected by what the group does to the rabbit. Indeed, the proper, directly selected group property is that of "not killing the rabbit too early" rather than individual virulence. In situations such as these, we would expect there to be selection for cooperation amongst the viruses in a group in such a way that the group will not "kill the rabbit too early". It is of course true that any group behavior is the result of individual traits, such as individual viruses suppressing the virulence of their neighbours, but the causes of phenotypes are rarely the causes of fitness differences.

Species and higher levels

It remains controversial among biologists whether selection can operate at and above the level of species.[15] Proponents of species selection include R. A. Fisher (1929);[15] Sewall Wright (1956);[15] Richard Lewontin (1970);[15] Niles Eldredge & Stephen Jay Gould (1972); Steven M. Stanley (1975).[16][15] Gould proposed that there exist macroevolutionary processes which shape evolution, not driven by the microevolutionary mechanisms of the Modern Synthesis.[17] If one views species as entities that replicate (speciate) and die (go extinct) within a clade, then species could be subject to selection and thus could change their occurrence over geological time, much as heritable selected-for traits change theirs over generations. For evolution to be driven by species selection, differential success must be the result of selection upon species-intrinsic properties, rather than for properties of genes, cells, individuals, or populations within species. Such properties include, for example, population structure, their propensity to speciate, extinction rates, and geological persistence. While the fossil record shows differential persistence of species, examples of species-intrinsic properties subject to natural selection have been much harder to document.

One issue with selection among clades is that they are not independent, i.e. all species are descended from the same last universal common ancestor and are thus part of the same clade.[1] This criticism does not apply to selection among different gene families that are not evolutionarily related, and which are duplicated and lost at different rates rather than speciating and going extinct at different rates.[11]

In the microbial realm, it has been interpreted that the unit of selection is a blend of ecological and functional behaviors, or guilds, beyond the species-level.[18]

References

  1. ^ a b Okasha, S. (2006) Evolution and the levels of selection. Oxford University Press.
  2. ^ a b Hull, David L.; Langman, Rodney E.; Glenn, Sigrid S. (2001). "Chapter 3: A general account of selection". Science and Selection: Essays on biological evolution and the philosophy of science. Cambridge University Press. ISBN 9780521644051.
  3. ^ Zee, Peter; Dyken, J. David Van; Bever, James D.; Richerson, Peter J.; Fletcher, Jeffrey A.; Linksvayer, Timothy A.; Breden, Felix; Fields, Peter; Edmund D. Brodie Iii (February 2010). "Multilevel and kin selection in a connected world". Nature. 463 (7283): E8–E9. Bibcode:2010Natur.463....8W. doi:10.1038/nature08809. ISSN 1476-4687. PMC 3151728. PMID 20164866.
  4. ^ Maynard Smith, John (1986). "The evolution of animal intelligence". In Hookway, Christopher (ed.). Minds, Machines and Evolution. CUP Archive. p. 64. ISBN 9780521338288.
  5. ^ Dugatkin, Lee Alan (1998). "§3.2.3 Category III: Group selection". In Dugatkin, Lee Alan; Reeve, Hudson Kern (eds.). Game Theory and Animal Behavior. Oxford University Press. p. 52. ISBN 9780195350203. group-selected cooperation can always be cast within some broad-based individual selection model
  6. ^ Bourrat, Pierrick (August 2021). Facts, Conventions, and the Levels of Selection. doi:10.1017/9781108885812. ISBN 9781108885812. S2CID 238732212. Retrieved 2021-08-23. {{cite book}}: |website= ignored (help)
  7. ^ von Sydow, Momme (2012). From Darwinian Metaphysics towards Understanding the Evolution of Evolutionary Mechanisms. A Historical and Philosophical Analysis of Gene-Darwinism and Universal Darwinism. Universitaetsverlag Goettingen Press. p. 481. ISBN 978-3863950064.
  8. ^ Lewontin, Richard 1970. The Units of Selection. Annual Review of Ecology and Systematics 1: 1-18.
  9. ^ See the chapter God's utility function in Dawkins, Richard (1995). River Out of Eden. Basic Books. ISBN 0-465-06990-8.
  10. ^ Bernhardt, Harold S. (2012). "The RNA world hypothesis: The worst theory of the early evolution of life (except for all the others)a". Biology Direct. 7: 23. doi:10.1186/1745-6150-7-23. PMC 3495036. PMID 22793875.
  11. ^ a b James, Jennifer E; Nelson, Paul G; Masel, Joanna (4 April 2023). "Differential Retention of Pfam Domains Contributes to Long-term Evolutionary Trends". Molecular Biology and Evolution. 40 (4). doi:10.1093/molbev/msad073. PMC 10089649.
  12. ^ Hunter, P. (2009). "Extended phenotype redux. How far can the reach of genes extend in manipulating the environment of an organism?". EMBO Rep. 10 (3): 212–5. doi:10.1038/embor.2009.18. PMC 2658563. PMID 19255576.
  13. ^ Greaves, Mel (2013). "Cancer stem cells as 'units of selection'". Evolutionary Applications. 6 (1): 102–108. doi:10.1111/eva.12017. PMC 3567475. PMID 23396760.
  14. ^ "Group selection | biology".
  15. ^ a b c d e Vrba, Elisabeth S. (1984). "What is Species Selection?". Systematic Zoology. 33 (3): 318–328. doi:10.2307/2413077. JSTOR 2413077.
  16. ^ Stanley, SM (1975). "A theory of evolution above the species level". Proceedings of the National Academy of Sciences of the United States of America. 72 (2): 646–650. Bibcode:1975PNAS...72..646S. doi:10.1073/pnas.72.2.646. PMC 432371. PMID 1054846.
  17. ^ Lieberman, Bruce S.; Vrba, Elisabeth S. (Spring 2005). "Stephen Jay Gould on species selection: 30 years of insight" (PDF). Paleobiology. 31 (2 Suppl): 113–121. doi:10.1666/0094-8373(2005)031[0113:SJGOSS]2.0.CO;2. S2CID 14801676. Archived from the original (PDF) on 2012-09-18. Retrieved 2012-07-08.
  18. ^ Shapiro, B. Jesse; Polz, Martin F. (May 2014). "Ordering microbial diversity into ecologically and genetically cohesive units". Trends in Microbiology. 22 (5): 235–247. doi:10.1016/j.tim.2014.02.006. ISSN 0966-842X. PMC 4103024.

Sources

External links

Baca informasi lainnya yang berhubungan dengan : article

Article 19 Article 20

Read other articles:

?Тюлька звичайна Охоронний статус Найменший ризик (МСОП 3.1) Біологічна класифікація Домен: Ядерні (Eukaryota) Царство: Тварини (Animalia) Підцарство: Справжні багатоклітинні (Eumetazoa) Тип: Хордові (Chordata) Підтип: Черепні (Craniata) Надклас: Щелепні (Gnathostomata) Клас: Променепері (Ac…

Romaine Sawyers Sawyers con el Walsall en 2014Datos personalesNombre completo Romaine Theodore SawyersNacimiento Birmingham, Inglaterra2 de noviembre de 1991 (32 años)País Reino UnidoNacionalidad(es) Británica SancristobaleñaAltura 1,75 m (5′ 9″)Carrera deportivaDeporte FútbolClub profesionalDebut deportivo 2011(Port Vale F. C.)Club Cardiff City F. C.Liga EFL ChampionshipPosición CentrocampistaDorsal(es) 19Selección nacionalSelección SKN San Cristóbal y NievesDebut 20…

Ця стаття є частиною Проєкту:Населені пункти України (рівень: невідомий) Портал «Україна»Мета проєкту — покращувати усі статті, присвячені населеним пунктам та адміністративно-територіальним одиницям України. Ви можете покращити цю статтю, відредагувавши її, а на сторін…

Genre of written material Part of a series onJewish culture Languages Hebrew Modern Ashkenazi Sephardi Mizrahi Yemenite Tiberian Medieval Mishnaic Biblical Samaritan Babylonian Palestinian Judeo-Aramaic Hulaulá Lishana Deni Lishán Didán Barzani Betanure Lishanid Noshan Targum Biblical Talmudic Palestinian Galilean Judeo-Arabic Yahudic Judeo-Baghdadi Judeo-Moroccan Judeo-Tripolitanian Djerbian Yemenite Other Jewish diaspora languages Yiddish Ladino Haketia Tetuani Yevanic Catalanic Italkian Pi…

2016 single by Martin Solveig featuring Ina WroldsenPlacesSingle by Martin Solveig featuring Ina WroldsenReleased25 November 2016Genre Future house[1] Length3:22LabelSpinnin' RecordsBig BeatSongwriter(s)Ina WroldsenMartin PicandetProducer(s)Martin SolveigMartin Solveig singles chronology Do It Right (2016) Places (2016) All Stars (2017) Ina Wroldsen single singles chronology Lay It on Me(2016) Places(2016) Mary's Story(2016) Music videoPlaces on YouTube Places is a song by French…

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Huntington Beach Pier – news · newspapers · books · scholar · JSTOR (August 2011) (Learn how and when to remove this template message) United States historic placeHuntington Beach Municipal PierU.S. National Register of Historic Places LocationMain St. and Pacific…

Hoseynabad-e Kordehha Rural District دهستان حسین‌آباد کردها التقسيم الإداري الإيراني الإحداثيات 34°48′03″N 52°37′45″E / 34.800833333333°N 52.629166666667°E / 34.800833333333; 52.629166666667  تقسيم إداري  الدولة  إيران  المحافظة سمنان  المقاطعة مقاطعة آرادان  الناحية Central عدد السكان (2006)  المجم

National Football League playoffs 1988–89 NFL playoffsThe Eagles playing against the Bears in the famous Fog Bowl NFC Divisional Playoff game.DatesDecember 24, 1988 – January 22, 1989Season1988Teams10Games played9Super Bowl XXIII siteJoe Robbie StadiumMiami, FloridaDefending championsWashington Redskins(did not qualify)ChampionsSan Francisco 49ersRunners-upCincinnati BengalsConferencerunners-upBuffalo BillsChicago Bears NFL playoffs ← 1987–88 1989–90 → The National Football League pl…

العلاقات المجرية التنزانية المجر تنزانيا   المجر   تنزانيا تعديل مصدري - تعديل   العلاقات المجرية التنزانية هي العلاقات الثنائية التي تجمع بين المجر وتنزانيا.[1][2][3][4][5] مقارنة بين البلدين هذه مقارنة عامة ومرجعية للدولتين: وجه المقارنة المجر …

Промінчик світлатур. Bir Küçük Gün Işığı Тип телесеріал Телеканал(и) atvЖанр драмаТривалість серії 135 хв.Компанія NG MedyaСценарист Озгур Еврен ХептюркРежисер Емре КабакусакПродюсери Назлі ГептюркУ головних ролях Серай Кая Берк ОктайКомпозитор Альп ЄньєрКраїна-виробник  Ту…

برنارد برودي   معلومات شخصية اسم الولادة (بالإنجليزية: Bernard Beryl Brodie)‏  الميلاد 1907ليفربول, المملكة المتحدة الوفاة 1989شارلوتسفيل، فيرجينيا الجنسية بريطاني عضو في الأكاديمية الوطنية للعلوم  الحياة العملية المؤسسات جامعة نيويورك 1935-1950 المدرسة الأم جامعة مكغيل المهنة عال…

Television channel Pittsburgh Cable News ChannelTypeDigital subchannelCountryUnited StatesBroadcast areaPittsburgh Media MarketOwnershipOwnerCox Media GroupSister channelsWPXIHistoryLaunchedJanuary 1, 1994; 29 years ago (1994-01-01)AvailabilityTerrestrialWPXI 11.4 The Pittsburgh Cable News Channel (PCNC) is a cable news channel and digital subchannel of WPXI serving the Western Pennsylvania area. It is owned by Cox Media Group. PCNC simulcasts or replays much of WPXI's programm…

Girl guide association in Bolivia Asociación de Guías Scouts de BoliviaGirl Guide Association of BoliviaCountryBoliviaFounded1958Membership390AffiliationWorld Association of Girl Guides and Girl Scouts  Scouting portal The Asociación de Guías Scouts de Bolivia (AGSB, Girl Guide Association of Bolivia) is the national Guiding organization of Bolivia. It serves 390 members (as of 2006).[1] Guiding was introduced to Bolivia in 1915. Founded in 1958, the girls-only organization beca…

Large language family spoken in Sub-Saharan Africa BantuGeographicdistributionCentral Africa, Southeast Africa, East Africa, Southern Africa, Southern SomaliaLinguistic classificationNiger–Congo?Atlantic–CongoVolta-CongoBenue–CongoBantoidSouthern BantoidBantuProto-languageProto-BantuSubdivisions Zones A–S (geographic) Mbam–Bube–Jarawan Manenguba Sawabantu Basaa Bafia Beti Makaa–Njem Kele–Tsogo Teke–Mbede Mboshi–Buja Bangi–Tetela Mbole–Enya Lega–Binja Boan Lebonya Nyanga…

American drama television series OzGenreCrimeDramaThrillerPrisonsGangsCreated byTom FontanaWritten byTom FontanaBradford WintersSunil NayarSean JablonskiSean WhitesellStarringErnie HudsonTerry KinneyHarold PerrineauEamonn WalkerKirk AcevedoRita MorenoJ. K. SimmonsLee TergesenDean WintersAdewale Akinnuoye-AgbajeTheme music composerRosenDave DarlingtonCountry of originUnited StatesNo. of seasons6No. of episodes56 (list of episodes)ProductionExecutive producersTom FontanaBarry LevinsonJim FinnertyP…

2022 American film by Riley Stearns DualTheatrical release posterDirected byRiley StearnsWritten byRiley StearnsProduced by Nate Bolotin Aram Tertzakian Lee Kim Riley Stearns Nick Spicer Maxime Cottray Starring Karen Gillan Beulah Koale Theo James Aaron Paul CinematographyMichael RagenEdited bySarah Beth ShapiroMusic byEmma Ruth RundleProductioncompanies XYZ Films IPR.VC Resolute Films and Entertainment Distributed byRLJE FilmsRelease dates January 22, 2022 (2022-01-22) (Sunda…

AffluenzaPoster rilis teatrikalSutradara Kevin Asch Produser Morris S. Levy Ditulis oleh Antonio Macia SkenarioAntonio MaciaCeritaKevin AschAntonio MaciaPemeranBen RosenfieldGregg SulkinGrant GustinNicola PeltzPenata musikMJ MynarskiSinematograferTimothy GillisPenyuntingSuzanne SpanglerPerusahaanproduksiLookbook FilmsMega FilmsDistributorFilmbuffTanggal rilis 09 Juli 2014 (2014-07-09) (SVA Theater) 11 Juli 2014 (2014-07-11) (Amerika Serikat) Durasi84 menitNegara Amerika S…

Public college in Leyte, Philippines Palompon Institute of TechnologyInstituto sa Teknolohiya ng PalomponFormer namesPalompon School of Arts and Trade (1961-1972)TypeState CollegeEstablished1961PresidentDr. Norberto C. OlavidesVice-presidentDr. Gregorio S. Ochavillo(VP for Academic Affairs)Dr. Rolando C. Entoma(VP for Administration)Dr. Antonia C. Mendoza(VP for Research, Extension & External Affairs)LocationPalompon, Leyte, PhilippinesColorsRed and whiteNicknamePITiniansMascotPIT MarinersWe…

2018 video game 2018 video gameOne Piece Bounty RushDeveloper(s)Bandai Namco EntertainmentPublisher(s)Bandai Namco Entertainment[3]Producer(s)Tsunehiro Shibata[4]SeriesOne PieceEngineUnityPlatform(s)Android, iOS[5]ReleaseMarch 29, 2018 (initial release)[1]January 31, 2019 (re-release)[2]Genre(s)ActionMode(s)Multiplayer One Piece Bounty Rush is a free-to-play mobile game based on the One Piece franchise, developed and published by Bandai Namco Entertainment…

American television series Big Little LiesGenre Drama Mystery Black comedy[1] Created byDavid E. KelleyBased onBig Little Liesby Liane MoriartyWritten byDavid E. KelleyDirected by Jean-Marc Vallée Andrea Arnold Starring Reese Witherspoon Nicole Kidman Shailene Woodley Alexander Skarsgård Adam Scott Zoë Kravitz James Tupper Jeffrey Nordling Laura Dern Iain Armitage Kathryn Newton Meryl Streep Opening themeCold Little Heart by Michael KiwanukaCountry of originUnited StatesOriginal langu…

Kembali kehalaman sebelumnya