Parental Care and Investment: An Evolutionary Perspective, Slides of Psychology of Sex

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Parental Care and

Investment

Psychology 3107

Introduction

In many species, eggs are lad after reproduction and the young are left to fend for themselves Parents can go make more… However, parents do care for young in varying degrees and ways in a number of species

Sex Differences

So, why is it then that, as a rule, females give more investment than males?  Reliability of paternity Pretty obvious  Gamete release ‘my work here is done’  Association with young The females are there at birth

Parent Offspring Conflict

If there is investment, the offspring would like it to go on forever, the parents, eventually want to have more babies OK, look at this genetically, the mother and daughter/son share .5 of their genes At some point, the mother would be better served by having another child.

Sex Allocation

‘Shall we have girls or boys dear?’ Not as odd a question as it seems Think evolutionarily Proximate mechanisms?  Stress  X v y sperm  Temperature

Parent Offspring Conflict

The second kid would be related to the mom by .5, to the other kid by. This is NOT in the best interests of kid no. It shares 1.0 of its genes with itself, only .5 with new kid The offspring are only ½ as interested in parental costs as the parent is

Conclusions

Trivers (1974) parent offspring conflict model is an amazing thing You must think evolutionarily This stuff dovetails nicely with the stuff on mating systems