Reproductive success of an organism plus the fitness of its close kin is called what?

• A. Inclusive fitness
• B. Kin selection
• C. Group selection
• D. Adaptationism

Answer: (A)

Inclusive fitness is the sum of direct fitness (your own reproductive success) and indirect fitness (the effect your actions have on the reproductive success of related individuals who share genes). This directly matches the idea of adding an organism’s own reproductive success to the fitness of its close kin. It explains why organisms might help relatives at a cost to themselves, because assisting kin can still propagate shared genes. Kin selection is the mechanism that leads to inclusive fitness gains, while group selection looks at groups rather than just related individuals, and adaptationism is about attributing traits to adaptive functions rather than measuring fitness components.