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.