28.pdf - 28 Friday April 3 2020 1:34 PM Q You are studying...

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Q: You are studying a group of birds and observe multipleincidents of allogrooming. You notice that most of thisgrooming involves removing parasites from places that bircannot reach on themselves (e.g. back of head / neck).Grooming costs the actor as it takes energy to do, but itbenefits the recipient because it removes parasites that canimpact their health.You observe that birds will groom relatives and non-relativalike, but will only groom birds that reciprocate in the futuAny birds that attempt to ‘cheat’ by benefiting from groomiand refusing to groom the other bird in return eventuallycannot find any bird willing to remove their parasites withthis group, and are less healthy as a result.Based on this information, which of the potential hypothesbest fits the persistence of allogrooming in the population?A. By-products benefit (grooming must have benefitimmediately both of them)B. ManipulationC. Reciprocal altruism (your helping someone today but gereward later)D. Kin selection (they don’t care if the get repaired or not)
28Friday, April 3, 20201:34 PM
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Ans:C
----------------------------Q: Based on Hamilton’s rule, Br – C is more likely to be greathan 0 if either B or r is high, or if C is low. The r part of thisequation helps explain why social insects like Hymenopterexhibit strong altruism, because they are MORE related to tsisters (r = 0.75 for full sisters) than to any potential offspr(r = 0.5 for all offspring).We know that eusociality has also evolved once or twice inmammals. The naked mole rat is one example of this, and liin colonies that are highly inbred because only one femalereproductive (and mates with only one or two of the malesthe colony).In fact, it looks like the first step for the evolution of eusocibehaviour is MONOGAMY within a breeding pair (and othemembers of the population then opt not to breed, andeventually lose the ability to reproduce).Why do you think monogamy is such an important first stethe evolution of this behaviour (relate this to the Br – Cequation in your answer)?Ans: monogamy will make the value of r be greater, soindividuals will be more likely to display altruism--------------------------Distribution->area over which populations occur (wherefind populations)Distribution can have different scales
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Distribution can have different scalesEg: dots represent fish population in lakes and the white spshows the landGeographic range ->Area in which all populations of a species are foundEach dot might represent an entire population, so scalemattersThere are small areas in the geographic range where thspecies are not found because it is not suitable for thempanmictic -> free mixing of population, widespread
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Subpopulation ->A subset of a larger populationIndividuals hang out in clumpsIndividuals in subpopulations are more likely to breedone anotherIndiviudals to disperse from subpopulation its rareMetapopulation ->a collection of subpopulations that areexchanging genetic information

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