Question

question 13

According to Hamilton’s rule (rB – C > 0), and assuming that B = 20 and C = 5, helping which of the following relatives would yield the greatest inclusive fitness return on investment?

Group of answer choices

a.) aunt or uncle

b.) niece

c.) mother-in-law (the mother of your mate)

d.) brother or sister

e.) grandchild

Answer 1

Answer: (13)

A simple but powerful formalization of inclusive fitness theory is provided by Hamilton's rule. This states that a gene for any social action will undergo selection when the sum of indirect fitness (rb) and direct fitness (c) exceeds zero, where r is the relatedness of the social actor and recipient and c and b are the changes brought about by the social action in the offspring numbers of, respectively, the actor and the recipient.

From Hamilton's rule follow the well-known conditions for the four possible types of social action as defined by the signs of c and b, namely cooperation or mutual benefit (+, +), altruism (−, +), selfishness (+, −) and spite (−, −). Specifically, in its most celebrated application, Hamilton's rule states that altruism (net loss of direct fitness) is selected if rb – c > 0.

By identifying this condition, inclusive fitness theory solved the problem of altruism. Because of its grounding in fundamental theory, its incorporation of the four types of social action and its universal taxonomic scope, the theory provides the best current basis for a unified understanding of social evolution.

For example, it enables conflict within family groups and intragenomic conflict to be understood in the same terms. When applied to the major transitions, it provides an explanation of the biological hierarchy itself.

Kin selection would favour the altruistic act if rB - C > 0.

In the given question.

If the coefficient of relatedness should be 0.5 or more.
Then, 0.5 x 20 - 5 > 0

10 - 5 > 0

5 > 0

While if it is aunt or uncle, niece, mother-in-law (the mother of your mate) and grandchild, the coefficient of relatedness would be 0.25.
Then 0.25 x 20 - 5 > 0

5 - 5 = 0

Hence the following Hamilton's Rule the act should be performed if the relative is only brother or sister.

Therefore, the correct answer is (d) brother or sister.