Chapter 2: Evolution
Chapter 2: Evolution BIOL 515
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This 4 page Study Guide was uploaded by Erica Leonard on Sunday October 11, 2015. The Study Guide belongs to BIOL 515 at Kansas State University taught by Eva A Horne in Summer 2015. Since its upload, it has received 41 views. For similar materials see Behavioral Ecology in Biology at Kansas State University.
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Date Created: 10/11/15
Chapter 2 The Evolution of Behavior Prehistoric animal behavior 0 Diet bone structure habitat and behavior leads to hypotheses on animals in present day Artificial selection 0 Manually chosen for reproduction based on desired traits 0 Chemical traits o Corticosteroids produced by adrenal gland response to stress I After 12 generation levels are almost 12 of control group after 24 generations levels are almost of control group 0 Serotonin neurotransmitter inhibiting aggression I Levels are higher in experimental brains compared to controls Natural selection 0 Variation exists in population variation is genetic based 0 Individuals with beneficial traits leave more offspring and those offspring have beneficial traits and leave more of their own offspring etc 0 Only works on expressed traits not directly on genes but a trait needs to have a genetic basis to be selected Relative fitness 0 of offspring produced that survive to reproduce relative to others in population Most fit individual with most offspring genes in next generation Direct fitness all an individual s own offspring Indirect fitness offspring in next generation contain genes as a direct result of individuals actions 0 Inclusive offspring direct indirect fitness Sources of variation in population 0 Mutation 0 Change in gene or chromosome 0 Gene mutation mistake during replication resulting in altered protein 0 Chromosome mutation broken deleted or added chromosome 0 Alleles code for proteins Somatic mutation 0 Change in gene or chromosome during development not in germ tissue 0 Not heritable can t be affected by natural selection Recombination o Mixing alleles during meiosis 0 Due to random mixing of chromosomes produces 4 cells with 2 different types from 4 pairs of diploid chromosomes 0 Due to crossing over between homologous chromosomes produces 4 different cells Gene flow 0 Movement of alleles from 1 population to another with movement of individuals random Genetic drift 0 Random loss of alleles due to chance events random Maintenance of variation 0 Frequency dependent selection rare traits have advantage 0 Negativeassortative mating choosing mates from quotoppositequot type 0 Environmental variation different traits favored under different conditions o Involves selection 9 non random 0 Frequencydependent predation 0 Selection on prey 0 Blue jays hunt moths based on some character until they become scare 9 switch to a different type 0 Maintains and increases variability 29 increase in mean cripticity o Frequencydependent reproduction 0 Selection on mates 0 Negativeassortative mating 0 Individuals choose to mate with phenotype most unlike their own 0 Whitestriped females outcompete tanstriped females to mate with tanstriped males tanstriped females settle for white striped males 0 Environmental variation 0 Some phenotypes do better in some environments than others 0 Riparian spider populationssmall territory I Riparian areasmove web sites and prey I Spider can catch all it needs to in a smaller area I Uses less energy and risk less injury protecting larger area Adaption o Trait that allows individual to leave more offspring and increase relative fitness 0 Natural selection 0 Works at individual level 0 Works only on phenotypes available 0 Works only with in particular environments 0 Future generation is product of selection on current population Maintenance on nonadaptive traits 0 Linkage o Nonadaptive genes located on chromosome close to adaptive one Pleiotropy o 1 gene with multiple effects Gene flow 0 Individuals with alleles adapted to particular environments move around Evolutionary time lag 0 Natural selection chooses traits for current conditions but offspring live in future 0 Environment changes but individuals do not adjust Heterozygote effect 0 Heterozygous individuals have adaptive advantage 0 Heterozygotes survive better and produce more offspring Natural selection 0 Example guppies in river with predator transplanted to 1 with and without 0 Natural population in high risk areas did not approach predator as closely as those from low risk areas 0 Introduced guppies behaved same way 9 they evolved to be less cautious in low risk areas Inferring evolution of behavior 0 Defn Compare populations of same species in different environments 0 To find out if there is a genetic component to lifestyle switch habitats amp see if behavior changes then bring spiders into lab and breed in equal conditions 0 Example 0 Arid spider habitat I Desert I Lo prey lo predation I Aggressive not cautious o Riparian habitat I Trees along streams I Hi prey hi predation I Not aggressive cautious I Lo competition 0 Arid moved 9 Riparian habitat with gene flow I Hi prey hi predation I Aggressive not cautious Behavioral phylogeny o Defn Compare related species to infer evolution of a behavior 0 Different species of flies in family Empididae congregate in swarms where each male carries a large empty silk balloon to offer to female before mating other species 0 Offer captures prey to female before mating 0 Form a swarm after capturing prey female chooses a mate eats prey and mates 0 Wrap prey up in a silk like a box of chocolates before joining swarm 0 Wrap prey up entirely in silk 0 Suck all the juices out of prey before wrapping it in silk and joining group nonnutritious gift 0 Feed on nectar find insect fragments or small objects to wrap up in silk and create a large balloon to present to female 0 Transformation series 0 Defn arrange different behaviors of extant species along gradient 0 Gives insight to how a complex behavior evolved 0 Don t know order of stages or if current function for behavior is the initial reason behavior evolved or if all stages evolved in final species 0 Primitive 9 advanced most common 0 Test hypothesis about evolution of a behavior Speciation o Allopatric population physically separated by river or road in space amp time become different species 0 Sympatric populations are not separated become different species least common 0 Isolating mechanisms 0 Prezygotic before zygotes are formed before mating occurs usually behavioral 0 Example different song occurs different pitchspeed keeps species apart similar habitat and notes keep songs similar active at different time of day 0 Postzygotic after zygotes are formed 0 Example mules sterile The PhyloCode o Defn proposed classification scheme based on nested clades o Monophyletic everything in clade shares 1 main common ancestor Strategy behavior or group of behaviors used to gain some resource mating strategy of males in a population Tactic1 behavior of a strategy defend a territory or be satellite Evolution stable strategy ESSbehavior which when adopted by most of population cannot be replaced or invaded if stable tactic cant mess it up 0 Pure strategyall individuals play rare 0 Mixed strategyseveral alternatives tactics exist in stable equilibrium 0 Play tactic you are genetically programmed to play each individual can play all tactics with particular frequency for each is able to change behavior based on what others do Mixed E55 0 Female digger wasps lay eggs in katydid burrows 2 choices I quotdigquot dig own burrow costly in timeenergy may lose to invader I quotenterquot enter already existing burrow less timeenergy risky if owner returns I Most enter amp steal a diggers burrow if there are too many diggers some switch to enter amp vis versa I Dig fitness increases as enter fitness decreases 0 Male sideblotched lizards 3 colors of males each with a different mating tactic I Red defends many females polygamous 0 Can mate with many females a time steals females from blues I Yellow steals copulation quotside steals a female 0 Steals females from reds unnoticed because red has so many females I Blue defends a single female 0 Keeps yellows away because they can keep an eye on their only mate
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