Provide a pivotal insight into evolution of altruistic behavior by pointing out that altruistic acts directed toward relative produce an importent kind of reproductive compensation. By enhancing the reproduction of relatives, a gene that increases the probability that its bearer provide help indirectly propagates copiesof itself in those same relative. when the relative are the helper's offspring, the help is refered to as "parental care" and the enhancement of propagation of the helping genes as a positive direct effect of those genes. But hamilton's theory showed that help-inducing gene benefit in an essentially identical
why when the help is direct toward nondescendant relative, such as siblings. when the latter "indirect effect" is sufficiently strong, the helping gene can spread (increase in frequency in the population) despite decreases in its propagation through the offspring of the individual in which it reside