BIO220H1 Lecture 5: Lecture 5 Cooperation, Conflict, and levels of selection

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azuresquirrel208

11 Apr 2012

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BIO220H1 Full Course Notes

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Lecture 5 bbio220 cooperation, conflict, and levels of selection. Conflict occurs when parent and offspring weigh costs and benefits differently. The trade off (+) b(p) = fitness of current offspring (-) c(p) = number of offspring given up maximize benefit-cost. A gene that causes an offspring to take more resources now will reduce its replication through future offspring. Parents should maximize b(p) c(p) Optimal provisioning rate is greater in offspring than parent. Costs: decrease quality of offspring, decrease probability of survival. Experiment 1: benefit of deserting: release 1 parent and measure the time to re-mate, decreased re-mating time = increased benefit for deserting. Increased remating time = decreased benefit for deserting (long time to re-mate, low benefit: result: increased re-mating time for males, increased female benefit for deserting, decreased benefit for male for deserting. Experiment 2: cost of deserting (uniparental care: manipulated number of parents: f/m/f&m, measured offspring survival, decreased survival = high cost of deserting.

Related Questions

1. Explain why parents and offspring are in conflict (e.g. the Trivers hypothesis). What is meant by parental investment and by conflict? At what points in the development of young might conflict be most evident (and why)?

2. How might parent-offspring conflict drive sibling conflict? Under what conditions is a young bird most likely to attempt to kill its nestling? What are ways in which this conflict can manifest? Why does the conflict occur? Least likely? What costs or benefits is a parent weighing when deciding whether to reduce the size of a brood? Should a parent ever intervene in siblicide (and under what conditions)?

a) Calculate the covariance between parents and offspring.

b) Calculate the deviation of each midparent from the mean forall the mid-parent values, and the deviation of each offspring fromthe mean of all offspring.

c) Calculate the additive genetic variance, and theheritability.

d) What do you predict would be the mean leaf area among theprogeny of this selected group?

Parent	Offspring
51.76	47.69
52.70	27.00
33.16	62.70
45.61	37.23
42.75	53.59
52.17	49.10
68.06	49.61
56.07	46.24
33.12	44.38
34.51	35.61
63.65	51.09
44.67	19.60
46.58	41.47
18.17	41.21