Dimorf1 natural theology: nature precisely tuned for some function, traits perfectly adapted by the Creator („argument from design“) ´ traits often suboptimal (cf. inverse eye, laryngeal nerve) if fitness depends on abundance of other species, interactions between individuals or frequences of other genotypes, selection may not necessarily result in fitness increase (see frequency-dependent sel.) ie. there may be no „best“ solution selection can result in the decrease of fitness of all organisms – contradiction to Fisher´s fundamental theorem of natural selection ® in this situation we cannot use simple arguments of optimization ® GAME THEORY 1944 (John von Neumann a Oskar Morgenstern), 1950s in biology William Hamilton (1967), John Maynard Smith economy, applied mathematics, politology, philosophy, informatics,... 8 game theory experts were Nobel Prize winners biology: J. Maynard Smith (Crafoord Prize) http://upload.wikimedia.org/wikipedia/commons/e/e2/John_Maynard_Smith.jpg J. Maynard Smith Game theory Evolutionary game theory: phenotype, not corresponding genes assumption: asexual population, ignoring species biology contrary to other branches (eg. economy) obvious advantage in that benefit can be expressed as the number of genome copies in next generations, ie. a strategy increasing player´s fitness will spread in the population by natural selection strategy = phenotype eg. body size, growth rate, behaviour, growth in varied environments etc. payoff matrix: benefit = more offspring = higher fitness strategy: pure ® only 1 type of behaviour mixed ® more types of behaviour games: symmetric ® all players same asymmetric ® different players John Maynard Smith, George Price (1973): evolutionarily stable strategy (ESS) = strategy which, if fixed in a population, does not allow any alternative strategy to invade it (due to natural selection) evolution to a particular ESS depends on initial conditions skenovat0001 Ritualization: traditional explanation of ritualization as species´ advantage individual advantage? dominant male subordinate male increased expression of subordination Why don´t males try to kill other males? AGGRESSION AND ALTRUISM Hawk: always attacking Dove: never attacking H D H (V-C)/2 V D 0 V/2 both attacking, one loses (zero benefit), both losing due to risk of injury Hawk is attacking (gain) both Doves are waiting, then one escapes (no gain) and the other wins (V) Dove is escaping (no gain) Is Hawk or Dove ESS? Symmetric models – Hawk and Dove payoff matrix: H D H -1/2 1 D 0 1/2 Conclusion: neither Hawk nor Dove are evolutionarily stable Þ mixed strategy (in this case D : H = 1 : 1) average gain of H: (1 – 1/2)/2 = 1/4 Eg.: V = 1, C = 2 payoff matrix: average gain of D: (1/2 – 0)/2 = 1/4 if we add a delay penalty of -1/4 to both Doves, the average Dove payoff will be (1/2 – 0 – 1/4)/2 = 1/8 Þ the Hawk strategy will be more favourable and its frequency will increase ® in this case equilibrium of a mixed strategy or D : H polymorfism would be 1 : 2 group selection (Dove population): works only in the case of conscious behaviour (conspiracy) – mostly only in humans and only theoretically (in practice usually betraying) Þ Doves is never ESS ... ... but what about Hawk? ® only if V > C eg. V = 2, C = 1 payoff matrix: H D H 1/2 2 D 0 1 average gain of H: (2 – 1/2)2 = 3/4 average gain of D: (1 – 0)/2 = 1/2 Eg.: pinnipeds: though frequent injuries but payoff high (harem system Þ the winner takes all) therefore aggressiveness pays off males but sometimes alternative strategies Výsledek obrázku pro Southern elephant seal image https://c402277.ssl.cf1.rackcdn.com/photos/561/images/story_full_width/sea-lion-threat-07162012-HI_ 257952.jpg.jpg?1345574127 http://www.grantdixonphotography.com.au/lib_images/SG_EleSealFight1.jpg http://www.leeabbamonte.com/wp-content/uploads/2013/11/IMG_4373-1024x768.jpg https://naturalunseenhazards.files.wordpress.com/2013/05/northern_elephant_seal_mikebairdwc.jpg Conditional symmetric strategies: For example we can imagine the following alternative strategies: Retaliator: starts as Dove, if attacked ® retaliation if you meet Dove behave as Dove, if you meet Hawk play Hawk Bully: starts as Hawk, when retaliated – escape play Hawk but if you meet Hawk, play Dove Prober-retaliator: retaliator which sometimes tries conflict closest to ESS is a mixed strategy of Retaliator, Prober-retaliator, and Dove Conclusion: don´t behave as Bully, repay good with good but repay aggression with aggression! one opponent weaker or smaller one opponent has less to lose one opponent sooner at the locality = Lord of the Mountain principle Assymetric models burgeois strategy: if you are the resident, attack (play Hawk); if you are the intruder, retreat (play Dove) ... eg. territory defence (passerines, sticklebacks) male B male A female D male A female C male B Three strategies in the population: there may be no equilibrium ® cycles eg. „rock-paper-scissors“ game: rock beats scissors, scissors beats paper, paper beats rock rock scissors paper rock e 1 -1 scissors -1 e 1 paper 1 -1 e depends on e value: payoff matrix: rock scissors paper rock e 1 -1 scissors -1 e 1 paper 1 -1 e JMS population state given by intersection of p, r, s, ie. sum of frequencies p + r + s = 1 rock paper If game cost is low (e < 0) ® stable polymorphism or mixed strategy http://40.media.tumblr.com/32eacb0615d1234a5b9e1e48b895db00/tumblr_mjp9fk3bgm1rprj1yo2_r1_500.jpg scissors JMS If game payoff is low (e > 0) ® strategies are cycling, no ESS genetically unstable polymorphism trajectory http://40.media.tumblr.com/32eacb0615d1234a5b9e1e48b895db00/tumblr_mjp9fk3bgm1rprj1yo2_r1_500.jpg rock scissors paper rock e 1 -1 scissors -1 e 1 paper 1 -1 e Eg.: Uta stansburiana: orange throat: large territory, several females blue throat: small territory, one female ® but easier defence against sneakers yellow throat: no territory, „stealing“ of copulations orange throat: big, territorial, several females yellow throat: non-territorial, mimics females – stealing copulations blue throat: smaller, territorial, single female http://trv-science.ru/uploads/162-0035.jpg each strategy prevails for 4-5 years ® cycles http://static1.squarespace.com/static/5311f659e4b0e179eafde666/t/5316265ae4b035ad03327dbd/139396053 9245/UtaAmmonCorl.jpg image trajectory of cycles http://static1.squarespace.com/static/5311f659e4b0e179eafde666/t/5316265ae4b035ad03327dbd/139396053 9245/UtaAmmonCorl.jpg kin altruism (kin selection) altruism between non-relatives sometimes altruism only imaginary (benefit for „altruists“, manipulation etc.) Robert Trivers (1971): reciprocal altruism especially in stable groups reciprocal altruism between species = mutualism RECIPROCAL ALTRUISM Eg. removing parasites ® possible strategies: Sucker: always helps Cheat: never helps, abuses others Grudger: helps only in some situations http://academic.reed.edu/biology/professors/srenn/pages/teaching/web_2008/dklj_site_final/images/al logroom.jpg https://uscworkandfamilylife.files.wordpress.com/2012/10/monkey-grooming.jpg http://1funny.com/wp-content/uploads/2009/09/picdump_91.jpg Prisoner´s dilemma https://web.natur.cuni.cz/student/sites/default/files/styles/large/public/images/prisoner.jpg?itok= krD3MkMq http://3.bp.blogspot.com/-jS8DNUcMriE/UVwCqIIH0hI/AAAAAAAAAQA/_fMS5N4yASk/s1600/interrogation.jpg http://i.dailymail.co.uk/i/pix/2014/04/08/article-2599889-1CF0340100000578-952_634x405.jpg http://cdn04.cdn.justjared.com/wp-content/uploads/2012/11/dicaprio-arrested/leonardo-dicaprio-arres ted-on-wolf-of-wall-street-set-15.jpg http://crooksandliars.com/files/vfs/2013/02/interrogation.jpg Conclusion: when we don´t know what other player does it is better to defect defect § § coope- rate © © ? 300 -100 500 -10 C B C B JÁ: a type of so called Nash equilibrium = situation when none of the players can unilaterally improve his/her position (it depends on action of other players) Soubor:John f nash 20061102 3.jpg John Forbes Nash basic scheme of the game: problem: we don´t know other player´s step In other words, in the Prisoner´s dilemma defect is the only Nash equilibrium http://im.tiscali.cz/press/2012/11/07/47352-vyhra-v-loterii-653x367.jpg http://cestovnikancelar.org/wp-content/uploads/2010/08/bankrot.jpg Eg.: bird mobbing http://www.thefreequark.com/wp-content/uploads/2012/07/eaglecrow1750.jpg https://projectfeederwatch.files.wordpress.com/2012/05/img_5361_accipiter-fight.jpg help only to those which helped previously http://img.metro.co.uk/i/pix/2008/12/Hawk_450x300.jpg raxelrod Robert Axelrod Robert Axelrod: in the 1970s and 1980s computer tournament 14 programs = 13 strategies + 1 random (7 „bad“ strategies) each game: 200 random encounters with other strategies including own strategy 225 independent games points based on Prisoner´s dilemma: 5, 3, 1, 0 Þ min. 0, max. 15 000 points winner = Tit for Tat (TfT): during first encounter cooperation, then repeating the step of a previous opponent subsequently Tit for Two Tats (J. Maynard Smith): first two steps cooperation, then normal TfT ® if it would be included in the original tournament it would win R. Axelrod – 2nd tournament: 62 + 1 strategies, only 15 „good“ winner = again Tit for Tat Why Tit for Two Tats did not win? 3rd tournament: same strategies as in 2nd tournament instead of points increasing/decreasing of the number of program copies (simulation of evolution) always victory of „good“ strategies, in 5 of 6 games TfT Caution! Tit for Tat is not ESS! (possible coexistence with other strategies, eg. Tit for Two Tats) „Good“ strategies must be at a certain critical frequency: random drift relativeness viscosity Computer simulations and existence of altruism in nature itself seem to be in contradiction both to results of Prisoner´s dilemma and psychological practice Non-zero-sum games zero-sum game: eg. football matches (but not always – see R. Dawkins: Premier League 1977) non-zero-sum game: divorce common vampire bat (Desmodus rotundus) Desmodus rotundus Time perspective Axelrod´s tournament: repeating games = repeated Prisoner´s Dilemma we don´t know end of the game Þ cooperation we know end of the game Þ defection Eg.: World War I – strategy „Live-and-let-live strategy“ Battle_of_Verdun_map wwi14 Protection-against SEXUAL SELECTION o-pohlavnim-vyberu Why are males so conspicuous? Darwin (1871): sexual selection „chuck“ Engystomops pustulosus Trachops cirrhosus chuck! http://globe-views.com/dcim/dreams/peacock/peacock-04.jpg Sexual reproduction ® cooperation but also conflict between individuals of the same sex as well as between sexes If the partners are not relatives none of them is interested in survival or reproductive success of the other!! http://i2.wp.com/www.avoiceformen.com/wp-content/uploads/sites/2/2015/01/battle.png?resize=750%2C42 0 http://www.magic4walls.com/wp-content/uploads/2013/12/couple-in-love-wide-1.jpeg http://conflictcrusaders.yolasite.com/resources/02bfcadd51c67fea43a92c33e423a5ad.jpeg sexual conflict sib-sib conflict parent-offspring conflict mother father sibling 1 sibling 2 https://timcourtois.files.wordpress.com/2010/11/p648029-sperm_fertilizing_egg-spl1.jpg Primary cause of sexual selection = different parental investments cheap sperm ´ expensive eggs cheap sperm cell expensive ovum operational sex ratio = number of reproducing males and females ® male-biased because males copulate more often Þ males limited by number of females, females limited by number of eggs or offspring Þ conflict of reproductive interests (Trivers 1972) Conclusion: sexes differ in reproductive behaviour: males are (mostly) competitive females are (mostly) choosy range of reproductive success in males almost always higher than in females http://www.unique-canvas.com/media/images/popup/rowlandson-thomas--der-harem-793069.jpg http://cdn1.arkive.org/media/11/11A0C3D5-71CD-48B6-B781-E09D444632DE/Presentation.Large/White-taile d-deer-mating-with-second-male-attempting-to-mount.jpg http://www.gorilla-safari.net/wp-content/uploads/2012/11/gorilla-family1.jpg Strength of sexual selection is not the same in various species: monogamous species: weak selection, no or moderate dimorphism polygamous species: strong selection, strong dimorphism polygyny polyandry promiscuity polygynandry gorilla: polygynous gibbon: monogamous … what about humans? http://www.chimpanzeefacts.org/wp-content/uploads/chimpanzee-3.jpg chimp: promiscuous Výsledek obrázku pro Red phalarope image Výsledek obrázku pro Red phalarope image Výsledek obrázku pro Red-necked phalarope image Red-necked Phalaropes mating - Stock Image Sometimes females brighter, eg. phalaropes: red-necked phalarope red phalarope Intrasexual selection Males compete – directly ... direct combat http://stockfresh.com/files/c/cquigley/m/46/493185_stock-photo-wild-goats-play-fighting.jpg http://i.ytimg.com/vi/60SZ7Hk0wdQ/hqdefault.jpg http://www.thehindu.com/multimedia/dynamic/00005/IN28-SNAKE6_5940g.jpg Males compete – directly ... displaying eg. mating calls, leks manakin dances bowers of bowerbirds etc. 1138709748 32154075_b242c23aa8 http://www.birdforum.net/opus/images/thumb/f/f8/Long-tailed-Manakin_V0A0192.jpg/550px-Long-tailed-M anakin_V0A0192.jpg Alternative strategies: marine iguana: fast transmission of sperm during short copulation of subordinate males display23 Lamprologus callipterus (Lake Tanganyika) sneakers 0406-12 bitterling non-territorial males – „stealing“ of copulations („sneakers“): Uta stansburiana, salmons, sunfish, cichlids, bitterling http://www.tethys.cz/gal/_obr_k_clankum/r2013galapagy2.jpg consequences of existence of non-territorial males: for territorial (dominant) males negative for females negative (reduction of offspring fitness), ambivalent but also positive (increased number of fertilized eggs, variation of offspring, and genetic compatibility) mimic2 bluegill Lepomis macrochirus (North America) satellite male female often mimicking females (smaller size, colouration): cichlids, salmons … and indirectly prevention of fertilisation by other males guarding of female copulatory plugs (rodents, insects, scorpions) http://www.neoperceptions.com/snakesandfrogs.com/scbirds/images/mallard_duck-male-female-1.jpg http://www.thefunmouse.com/info/images/plug.jpg https://c2.staticflickr.com/6/5252/5402342800_1f63063bbc_b.jpg Vaejovis punctatus hooked plugs … and indirectly prevention of fertilisation by other males breaking of copulatory organ in female´s duct (spiders): eg. spider Tidarren argo breaks off one of his pedipalps, adhers to female´s epigyne ~ 4 h chemical repelents in sperm (Drosophila, snakes) https://c2.staticflickr.com/4/3009/2992496261_c8b0ff209f.jpg http://rsbl.royalsocietypublishing.org/content/8/4/512/F1.large.jpg Nephilengys malabarensis https://c2.staticflickr.com/4/3009/2992496261_c8b0ff209f.jpg 4 transgenic lineages Tr. 1 a 2: no sperm Drosophila: proteins of accessory glands in sperm ® increase of egg production, plug, repellent effects Tr. 3: sperm, copulation effect of seminal proteins decreases female survival Tr. 4: sperm, no copulation conflict between reproductive interests of males and females!! http://i.ytimg.com/vi/aVjg2Olw_W4/maxresdefault.jpg … and indirectly prevention of fertilisation by other males prolonged coupling after copulation (canids) removing sperm of preceding male(s) copulatorz organ of Argia damseflies: http://s3.amazonaws.com/pik.pikcam.com/780/original.jpg?1368339933 male female http://www.dontdodumbthings.com/wp-content/uploads/2010/04/gorillas.jpg … and indirectly sperm competition prolonged intercourse larger ejaculate ® larger testes: chimp > human > gorilla > gibbon promiscuous primates (blue) monogamous primates (red) polygynous primates (green) human http://cdn.phys.org/newman/gfx/news/hires/2014/largetesticl.jpg https://wilkma11.files.wordpress.com/2014/02/female-monogamy.jpg https://c1.staticflickr.com/1/53/115454013_7d47534cbc.jpg … and indirectly infanticide killing youngsters: felids (lion, domestic cat) rodents (mouse, brown rat, lemmings, hamsters, meadow vole): Bruce effect = abortion triggered by odour of unfamiliar male although male benefit is clear it is female strategy – prevention of probable future infanticide (thwarted investment) Females choose... … but based on what? 1. direct benefit male care for offspring: larger territory (Þ more sources) bringing food nest building Intersexual selection http://www.naturesavannah.org/wp-content/uploads/2013/07/CourtingRoyalTerns-wFish1-929x484.jpg http://www.birdphoto.cz/photos/8803_v.jpg http://www.zvirenaprodej.cz/images/blog/zvireci_architekti_20.jpg http://davidkanigan.files.wordpress.com/2014/03/bird-singing.jpg How to secure male care? ® delaying copulation – „the Concord fallacy“ 3 possible male strategies: „Daddy“ – remains with the female „If not you, then other“ – escapes before copulation, looks for more permissive females „Lad“ – escapes after copulation http://static.planetminecraft.com/files/resource_media/screenshot/1237/concord-crash-jul-25-17_3564 430.jpg http://img.ihned.cz/attachment.php/890/32263890/aiovBCDFJMNOjlPQWbefghpqrx0TUw9m/_MG_0396.JPG http://www.birdphoto.cz/photos/8803_v.jpg hiding eggs 2. sensory bias = preference occurs before emergence of the male trait eg. stronger response to superstimuli Eg.: swordtails of the genus Xiphophorus: females of „non-sworded“ species prefer males with the „sword“ preference of females of the genus Priapella stronger than preference of own species´ females Xiphophorus helleri Priapella intermedia Eg. túngara frogs of the genus Engystomops: II.15.tif chuck! “chuck“ emerges preference emerges 3. indirect benefit male investment = only genes contributed „sexy sons“ hypothesis: R. A. Fisher (1915, 1930): runaway sexual selection a male trait may not render a benefit to an individual but for some reason it is preferred by females Þ it is advantageous to produce offspring with such males (sons will be attractive for other females) http://coachingpositivity.com/wp-content/uploads/2010/01/bright-colored-love-birds.jpg http://news.xinhuanet.com/english/photo/2012-03/19/131475775_101n.jpg http://riverbanktales.com/wp-content/uploads/2012/07/male-and-female-stickleback-three-spinned.jpg prerequisite = strong linkage between the gene for female preference and that for male trait (both genes in both sexes but different expression) „snowball effect“ – runaway process Þ origin of extraggerated or eccentric structures this process ends when ekvilibrium between female selection and normal (environmental) selection correlation between intensity of red colour and preference for red in three-spined stickleback „good genes“ hypothesis: preferred trait indicates high genetic quality of the offspring Eg.: three-spined stickleback, great tit, scarlet rosefinch, barn swallow peacock (Pavo cristatus): correlation between size and number of „eyes“ and fitness of descendants http://imgc.allpostersimages.com/images/P-473-488-90/21/2142/NMRED00Z/posters/ashok-jain-close-up-o f-the-eye-of-a-peacock-feather-pavo-cristatus.jpg http://previews.123rf.com/images/enjoylife25/enjoylife250804/enjoylife25080400174/2919700-beautiful -male-indian-peacock-showing-its-feathers-Pavo-cristatus--Stock-Photo.jpg Anders Pape Møller: barn swallow (Hirundo rustica) shorter pre-copulatory phase more second egg-laying more offspring Melamine_Plate handicap principle: Amotz Zahavi (1975) indication of high viability („good genes“) despite the handicap handicap necessary for the information to be reliable, ie. to prevent the male from “lying“ Amotz Zahavi babbler Arabian babbler (Turdoides squamiceps) the ornament helps to easily uncover a defect handicap model: bright coloration, complex ornaments, structures filled with blood, toxic nature of chemical signals etc. waterbuck (Kobus ellipsiprymnus) http://upload.wikimedia.org/wikipedia/commons/a/a1/Namibie_Etosha_Leopard_01edit.jpg http://img.photobucket.com/albums/v714/tileman/Canon%20XSL/IMG_4149.jpg http://www.themoviescene.co.uk/reviews/_img/721-2.jpg Malte Andersson: long-tailed widowbird (Euplectes progne) http://www.hlasek.com/foto/euplectes_progne_bb1151.jpg highest reproductive success in males with elongated tail feathers increasing fitness relatively lower costs for genetically high-quality males handicap model – bright males hypothesis William Hamilton and Marlene Zuk (1982): problem of repeated preference of certain trait ® depletion of variation = the “lek paradox“ a solution can be variation of a selective optimum – eg. pathogens sexual selection favours “fairly“ signalizing traits state of health, ie. the ability to cope with parasites and pathogens animals with “bad genes“ cannot effectively struggle with infection hypothesis: males of more parasitized species are, in general, brighter ® some passerine species Eg.: bald uakari (Cacajao calvus) http://cdn2.arkive.org/media/D1/D11C4A5B-2326-4309-8A0E-783414A030E3/Presentation.Small/Bald-headed -uakari-male---sick-with-malaria-loss-of-red-face-colouring.jpg in healthy individuals red colour in individuals with malaria pale colour https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTNWtfaejHjnNu3VmGiLtf007Zv79Ksf3VQSOr-sVEBuXj ztGmQMw in species from non-malarial areas dark coloration Extra-pair copulations, EPC (extra-pair paternity, EPP; extra-pair fertilization, EPF) males: increase number of fertilized eggs females: increase quality of offspring by mating with males possessing better genes than their partners Þ increase of offspring fitness 34_EVOW_CH20 Eg.: great reed warbler: span of song repertoire correlated with fitness ® in all observed EPPs biological fathers had broader song repertoire than partners Þ indirect benefit of females through higher fitness of descendants great reed warbler (Acrocephalus arundinaceus) acquiring good or complementary genes? EPC in humans: Univ. of Western Australia: 28% males, 22% females – extramarital sex France, Great Britain, USA: 5–52% EPP: difficult estimate, overal ~2 %, Yanomami ~10 %, Himba (Namibia) ~17 % ethnic differences: eg. Michigan: 1,4% in Caucasians, 10,1% in Afro-Americans South-American Indians (eg. Mehinaku, Kaingang, Araweté, Curripaco, Tapirapé, Yanomami, Bari, Matis, Aché): partible paternity Canelo (central Brazil): generally more than 12 potential fathers 60% males transiently in polyandric bonds copulation with multiple males is often part of public ritual intersexual differences in jealousy: males: physical cuckoldry (risk of EPP) females: spiritual affinity (risk of mate´s leaving) Výsledek obrázku pro jealousy http://www.asset1.net/tv/pictures/show/shakespeare/Shakespeare-Othello-16x9-1.jpg