BIO2022 Lecture Notes - Lecture 5: Frequency-Dependent Selection, Cytoplasmic Incompatibility, Amphiprioninae
7 Aug 2018
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Parental strategies should evolve towards equal investment in offspring of both sexes assuming they a(cid:396)e e(cid:395)ually (cid:272)ostly to p(cid:396)odu(cid:272)e. fishe(cid:396)"s s(cid:272)e(cid:374)a(cid:396)io: In a population where there are more males than females born youd want to be a male as youd have more mating opportunities and females would have to compete. Therefore parents who carry an allele encoding male bias will have more grandchildren born to them due to higher evolutionary fitness. Therefore the allele for male bias spreads and male births are more common. It will then go the other way as a ratio of 1:1 is reached and the advantage of being a male wanes. Mechanisms of sex determination: genetic x y chromosomes or haploid vs diploid (e. g. bees, environment temperature dependent sex allocation, clownfish change sex, parasites when infected, sex determination can be decided by parasites. Haploidiploidy sex determined by the number of chromosomes they receive, females are diploid.
