Suppose that kin selection has evolved in a group of rodents. The average female typically has four offspring in her lifetime. If, instead of raising her own offspring, a female helps her sister raise her offspring (i.e., her nieces and nephews) how many nieces and nephews would her sister have to have in order for her to experience no net loss in fitness?

Question

Quizplus · Accepted Answer

In order for the female to experience no net loss in fitness, she would have to help raise enough nieces and nephews to equate to the fitness benefit she would have received if she had raised her own offspring. Since the average female has four offspring, the female would need to help raise four nieces or nephews to break even. However, since she is helping her sister, who shares 50% of her genes, she effectively gains half of the fitness benefit from each of her sister's offspring. Therefore, she would need to help raise eight nieces or nephews (4 x 2) in order to experience no net loss in fitness. Since her sister would have to have two litters of four offspring each, the total number of nieces and nephews would be 8 x 2 = 16. Therefore, the correct answer is B.

Suppose That Kin Selection Has Evolved in a Group of Rodents