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36. What is the difference between a discrete (Mendelian) trait and a continuous (polygenic) trait?37. Be able to calculate relative fitness and selection coefficients.Relative fitness (W) = actual survival/largest survival Selection coefficient = 1-W38. Be able to use the equations h2= vg/vp, and R = h2S to calculate heritabilitiesresponses to selection and selection differentials for polygenic traits., Handout Sociobiology12
Altruism- behavior by an individual that increases the fitness of another individual while decreasing the fitness of the individual itself.Kin selection- evolutionary force favoring helping behavior by relatives/kin•Individuals increase their inclusive fitness by helping increase the survival and reproduction of genetic relatives that are not offspring•Tend to help kin that are more closely related versus more distant kinHaplodiploidy- system where males develop from unfertilized eggs and are haploid (N), while females develop from fertilized eggs and are diploid (2N)•Inheritance system found in leafcutter ants •Consequence: worker ants within a colony can be very similar genetically (75% genetic similarity) - drone workers more related to their sisters than their offspringGroup selection- sociality in diploid organisms- not as strong as individual selectionPrides- female lions live in groups of related individuals•2 males, 3+ females, 4+ subadults, numerous cubs•Males ejected after 2 years, must take over new pride as brothers - kill cubs of old males•More than 2 males requires kin selection•Higher ranked males sire more cubs than lower ranked males•Male coalitions of 2-3 - often unrelated Large male coalitions - rarely unrelatedHelpers at the nest- “Colonial nesters”—most common habitat is open woodlands with trees large enough to provide cavities for nesting and roosting and providing protection from climate and predation•Cooperative breeders- siblings help provide for young rather than dispersing•Limiting cavities- kin selection favors cooperation rather than dispersal•Higher rainfall during the dry season reduces reproduction of green woodhoopoe flocks•Reproduction was higher in high quality territories•Red-cockaded woodpeckers= colonial nesters in longleaf forestso2 breeding adults + up to 4 helpers (usually sons)oNest cavities in larger trees are limitingoBetter to inherit your parents nest is nests are limiting—natal territoriesoBirds colonized 18 of 20 experimentally drilled tree holes•Positive relationship between large trees and the openness and grass cover•