- A Selection that specifically favors behaviors benefiting mainly largely unrelated individuals, the opposite of what kin selection theory actually predicts, which favors helping genetic relatives according to most researchers
- B Natural selection that favors behaviors increasing the reproductive success of relatives even at cost to the individual; Hamilton's rule: altruism evolves when rB > C, explaining eusociality in bees and ants
- C Kin selection is sometimes considered functionally identical to group selection theory, despite kin selection operating through individual relatedness coefficients rather than whole-group fitness in the majority of cases studied
- D Hamilton's rule is sometimes thought to apply mainly to flowering plant species, rarely to animal behavior, despite being formulated specifically to explain altruistic behaviors like eusociality as widely reported
Correct answer: B. Natural selection that favors behaviors increasing the reproductive success of relatives even at cost to the individual; Hamilton's rule: altruism evolves when rB > C, explaining eusociality in bees and ants
Explanation: Kin selection: individuals share genes with relatives (r = 0.5 for siblings, 0.25 for half-siblings). Altruistic act towards kin increases 'inclusive fitness' (direct + indirect fitness). Hamilton's rule: rB > C → behavior evolves. J.B.S. Haldane joked 'I'd lay down my life for two brothers or eight cousins' (both r equivalent to 1 of yourself). Explains: bee workers sacrificing reproduction to raise sisters (r=0.75 due to haplodiploidy), alarm calls in ground squirrels.
Concept context
Origin of life, Darwin's theory, natural selection, speciation, and evidence for evolution.