Fitness, Selection, & Social Evolution

Question 1

Fitness; what is selected for?

Answer 1

• relative probability of survival/reproduction
• debate over what is “directly” acted on
• KEY: species are not selected, individuals are
• with genetically based phenotypes comes the possibility of evolutionary change

Question 2

Deleterious genes

Answer 2

Genes can be linked, meaning deleterious genes may be “hitchhiking” on more advantageous ones, as they aren’t separated during crossing over.

Question 3

Counterexamples

Answer 3

• peacock tail is embellished, meaning less camouflaged, but females choose these slightly exaggerated features up til the point where it is maladaptive
• survival with these traits might indicate a higher fitness

Question 4

Why altruism?

Answer 4

• “Hamilton’s rule”: altruism will occur when the cost to perform altruism is lower than the degree of relatedness and the benefit to the recipient.
• might be explained by origins of many species as highly related small animal groups

Question 5

Haplodiploidy

Answer 5

• in bees, females are diploid and males are haploid
• 2 female siblings will share 75% of their genetic information, as opposed to the 50% between the queen and her offspring
• encourages altruism between siblings