L07 and L08 Notes
L07 and L08 Notes BIOL 4700
Popular in Behavioral Ecology
Popular in Biology
This 3 page Class Notes was uploaded by Hiba Kouser on Monday March 7, 2016. The Class Notes belongs to BIOL 4700 at Clemson University taught by Michael J Childress in Fall 2016. Since its upload, it has received 14 views. For similar materials see Behavioral Ecology in Biology at Clemson University.
Reviews for L07 and L08 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/07/16
L07 Notes: Darwin’s One Special Difficulty: how can selection favor an individual that could never reproduce? (in this case, talking about individuals that are in the sterile, working class, ex. bees) Reasoned individuals in hive are relatives of another so as long as someone is reproducing, there is the possibility to pass on that sterility trait to other generations I. Kin Selection Theory A. Our fitness doesn’t end with our own offspring and instead deals with the propagation of our genes with our close relatives (ex. Worker bees are working altruistically) Consequence to actor Consequence to recipient Beneficial Harmful Beneficial Mutual Benefit (+,+) Selfish (+,) Harmful Altruistic (,+) Spiteful (,) B. Inclusive Fitness 1. When is altruism ever favored by natural selection? When should individuals discriminate kin from nonkin? W =ia +i (b * rj ij (direct fitness) + (indirect fitness) a = effect of i’s behavior on i’s fitness i bj= effect of I’s behavior on the fitness of relative j rij coefficient of relatedness of i to j 2. Direct fitness: the genes contributed to next generation by personal reproduction 3. Indirect fitness: the genes contributed to the next generation by helping non descendant kin’s reproduction 4. Inclusive fitness: the sum of an individual’s direct and indirect fitness C. Hamilton’s Rule Inclusive Fitness Direct Fitness Indirect Fitness NonAltruist W 11 ==== a11 Altruist W a C + rB 12 === 11 1. C= cost to actor, B= benefit to relative, r= relatedness 2. W > 12 hen11 c > 0 when rB > C D. Ex. Belding’s Ground Squirrels 1. Live in colonies 2. Give alarm calls to snake and bird predators 3. Alarm caller is at increased risk of predation 4. Females remain close to home and males disperse 5. Prediction 1: females should make more alarm calls than males a. Yes, females are more likely to make alarm calls 6. Prediction 2: females should only call if relatives are in danger a. Yes alarm calls are more likely if relative present ( meaning that the genetic relatedness is high) E. Measuring Relatedness 1. Coefficient of relatedness (r): proportion of genes shared with another individual due to descent form a common ancestor 2. ParentOffspring (r = 0.5) 3. HalfSiblings (r = 0.5^2) 4. Full siblings: r= (0.5^2)+(0.5^2) 5. NieceUncle: r= 0.25 6. Cousins: r=0.125 7. Grandchildren: r=0.25 8. Greatgrandchildren: r = .125 II. Kin Recognition A. Recognition Alleles 1. “Greenbeard effect” a. Altruism directed only toward individuals with the same altruism gene b. The gene must code the behavior, the signal and the recognition c. Fire ants accept new queens that have the “b”allele at the GP9 locus B. Genetic 1. “armpit effect” 2. Altruism directed only toward individuals hat share many genes 3. Different genes may code the behavior, signal, and recognition 4. Slime models cells from different lines (lag genes) aggregate before segregating cells for reproduction 5. Ex. Honeybees: a. Honeybees guard allow workers to pass based on their genetic relatedness b. Recognition is by cuticle hydrocarbons that match specific receptors c. Males are haploid and females are diploid (i.e. so sisters are related by 0.75) i. Could explain Darwin’s one special difficulty if kin selection favors sterile workers d. Does haploidiploidy explain the presence of sterile workers (Eusociality)? i. Hymenoptera insects are all haplodiploid ii. But sterile workers occur in only five groups (1 ants, 2 bees, 2 wasps) iii. Eusociality is more likely the result of limited nests and queen manipulation of workers C. Environmental 1. “Nest mate effect” 2. Altruisms directed toward individuals that were raised together 3. Does not require any genetic similarity 4. Belding’s ground squirrels accept nest mates regardless of relatedness a. Both siblings (S) and nonsiblings (NS) raised together show low aggression b. However, full siblings fight less and assist more than half sibs c. Females are able to distinguish genetic relatedness of equality familiar females d. Males do not distinguish genetic relatedness III. Kin Discrimination A. Offspring Provisioning 1. Ex. Whitefronted bee eaters a. Live in colonies b. Nest sites limited and nests tend to have many extra adults c. Helpers don’t breed and just assist by feeding fledglings of the mated pair d. Due to kin selection or due to delayed benefits of direct selection? e. Prediction 1: Helpers at the nest will increase fledgling survival i. Yes more helpers, more fledglings f. Prediction 2: only related helpers should help at the nest i. Yes, related helpers are much more likely to help ii. No, unrelated helpers also help g. Prediction 3: helpers should help close relatives more than distant relatives i. Yes, more likely to help siblings over cousins in the nest ii. No help unrelated sibling more than never h. Evidence for indirect fitness benefit of helping close kin and for delayed direct benefit of helping regardless of kinship i. More likely to inherit the territory B. Avoiding Cannibalism 1. Ex. Spadefoot toads, wood frogs, tiger salamanders, cannibalize smaller larvae 2. Herbivorous tadpoles prefer to swim with siblings 3. More likely to become a cannibal morph if raised with fewer siblings 4. More likely to cannibalize a cousin than a sibling 5. Herbivorous morphs prefer schooling with siblings 6. Cannibal morphs avoid schooling with siblings a. However, will eat siblings if hungry C. Avoiding Inbreeding 1. Ex. Rodents a. Female rodents prefer to mate with males that have different MHC alleles b. Female rodents prefer to share nests with females that share MHC alleles c. Males learn to avoid mating with close kin by environmental recognition (learning mother’s phenotype) rather than genetic recognition d. Females learn to avoid mating with close kin by genetic recognition (choosing opposite of self) rather than environmental recognition e. Females in estrous prefer males of opposite of MHC alleles (unrelated), lactating females prefer nest mate females over the same MHC alleles (close relatives) IV.Spite A. When is spite ever favored by selection? 1. If you harm a recipient that is less related to you than others in a population and its benefits those that remain 2. Soldiers are altruists because they are sterile 3. They kill others such that their close relatives can benefit
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'