[Campbell Biology P.1207] In the provided text's surf rescue scenario involving a brother and... | Practice Question

In the provided text's surf rescue scenario involving a brother and sister, the altruistic act was favored by natural selection. If the same altruistic act were performed by the sister to rescue her first cousin, assuming the surf conditions remain the same C = 0.5 and the cousin's potential reproductive output is still 2 offspring B = 2 , would natural selection favor this act?

  • A: Yes, because the rB term (0.125 * 2 = 0.25) is still greater than C (0.5).
  • B: No, because the rB term (0.125 * 2 = 0.25) is less than C (0.5).
  • C: Yes, because the cost C (0.5) is less than the benefit B (2).
  • D: No, because Hamilton's rule only applies to direct siblings.

Explanation

For first cousins, the coefficient of relatedness r is 0.125. Given B=2 and C=0.5, rB = 0.125 2 = 0.25. Since 0.25 is not greater than 0.5 rB < C , Hamilton's rule is not satisfied. Therefore, natural selection would not favor this altruistic act under these specific conditions.