Which statement best describes kin selection and inclusive fitness?

Which statement best describes kin selection and inclusive fitness?

• A. Kin selection focuses only on individual reproduction; inclusive fitness ignores relatives.
• B. Kin selection favors helping relatives reproduce; inclusive fitness combines direct reproduction with indirect genetic contributions via relatives.
• C. Kin selection is unrelated to Hamilton's rule.
• D. Inclusive fitness measures only a population-level effect.

Answer: (B)

Kin selection centers on the idea that helping relatives can spread an individual’s genes because relatives share copies of those genes. Inclusive fitness then combines two sources of genetic propagation: direct fitness from one's own offspring and indirect fitness gained when helping relatives reproduce, weighted by how closely related those relatives are. This aligns with Hamilton's rule, which says altruistic behavior is favored when the relatedness times the benefit to the relative exceeds the cost to the actor. So the statement is correct because it explicitly describes kin selection as promoting relatives’ reproduction and defines inclusive fitness as the sum of direct reproduction plus indirect genetic contributions via relatives. The other options miss these relationships: kin selection isn’t about ignoring relatives, Hamilton’s rule is central to kin selection, and inclusive fitness isn’t limited to population-level effects but concerns an individual's genetic contribution that includes relatives.

Kin selection centers on the idea that helping relatives can spread an individual’s genes because relatives share copies of those genes. Inclusive fitness then combines two sources of genetic propagation: direct fitness from one's own offspring and indirect fitness gained when helping relatives reproduce, weighted by how closely related those relatives are. This aligns with Hamilton's rule, which says altruistic behavior is favored when the relatedness times the benefit to the relative exceeds the cost to the actor. So the statement is correct because it explicitly describes kin selection as promoting relatives’ reproduction and defines inclusive fitness as the sum of direct reproduction plus indirect genetic contributions via relatives. The other options miss these relationships: kin selection isn’t about ignoring relatives, Hamilton’s rule is central to kin selection, and inclusive fitness isn’t limited to population-level effects but concerns an individual's genetic contribution that includes relatives.