Unit 8

8.1 Responses to the Environment

altruism in animals (such as predator warnings) can be explained by kin selection and inclusive fitness

kin selection: the value of a gene is not based on whether it promotes survival in a single individual, but also how it affects survival in the individual’s relatives

inclusive fitness: if an allele promotes sacrificing oneself for the benefit of one’s close relatives (who also share that allele) then the allele might increase in frequency

Altruism reaches its peak in eusociality

social structure in which some organisms breed and others don’t

example: bees, ants, wasps, termites, one species of shrimp, 2 species of mole rats

queen bee reproduces, and thousands of non-reproductive

females are workers, and males (drones) leave nest to mate and then die

haplodiploidy is the concept where males develop from unfertilized eggs (results in haploid chromosomes) and females develop from fertilized eggs (results in diploid chromosomes)

sisters are 75% related to each other, as they inherit 100% from father and 50% from mother. They’re more related to each other than their own offspring. So it makes mo sense for workers to help their queen make more sisters who are more related than their own offspring would be.

eusociality can exist independent of haplodiploidy