Final answer:
Hamilton's rule states that altruistic behavior evolves if rb > c, where r is relatedness, b is benefit to the recipient, and c is cost to the actor, and this statement is true. Reciprocal altruism and selfish gene theory provide further context for altruistic behaviors in both related and unrelated individuals.
Step-by-step explanation:
The statement regarding Hamilton's rule is indeed true. According to Hamilton's rule, altruistic behavior will evolve in a population if the inequality rb > c is satisfied, where r is the coefficient of relatedness between two individuals, b is the benefit to the recipient of the altruistic act, and c is the cost to the actor of the altruist. This formula helps explain why individuals might act in ways that benefit others at a cost to themselves, especially when the individuals are closely related.
Nonetheless, behaviors that might seem altruistic occur even between unrelated individuals. One mechanism behind such behaviors is reciprocal altruism, where individuals help each other with the expectation of future reciprocation. This type of altruism requires repeated interactions and a system to discourage or punish those who do not reciprocate the altruistic acts (often labeled as cheaters).
The concept of selfish gene theory, proposed by Richard Dawkins, also sheds light on altruistic behaviors. This theory suggests that seemingly selfless acts may often be driven by the underlying 'selfish' motives of the genes, aiming to propagate themselves via related individuals who share those genes.