Question

22.A gene will increase in a population, even if it causes an individual's fitness to be immediately decreased, if:

		the individual allows itself to be eaten.
		the individual acquires more relatives.
		that individual can gather more food.
		the individual fails to get reciprocity from others.
		an individual's "sacrificial" behavior leads to reciprocity and an overall fitness increase for that individual.

23.Under what circumstances does reciprocal altruism appear in unrelated individuals?

		When there are repeated interactions with opportunities for all individuals to be the donor and recipient of the altruistic act.
		When one individual gives up something of high value in exchange for frequent low-value returns in the future.
		Reciprocal altruism only appears when there are frequent interactions between close kin, and the outcome is an increase in relative fitness.
		When the benefits to the donor are significantly greater than the costs to the recipient.
		When there is anonymity among individuals in a population, so no one individual can be singled out and recognized.

24.

Why do babies in the United States easily develop a fear of snakes but not a fear of guns?

		There is no known reason for this phenomenon.
		Babies are more likely to encounter snakes than guns as they develop in the United States
		Humans cannot develop fear toward inanimate objects.
		Fewer individuals are killed by guns than by snakes in the United States each year.
		Fear of snakes evolved in early humans with different living conditions, and evolution can be slow in producing populations that are adapted to their newer environments.

Answer 1

Answer 22: A gene will increase in a population, even if it causes an individual’s fitness to be immediately decreased, if: an individual’s sacrificial behaviour leads to reciprocity and an overall fitness increase for that individual.

An individual may sacrifice (a cost) for another individual if the overall fitness of the group increase (the benefit) in an ecosystem. This is called altruism. It serves to benefit the individual’s close relatives or kin.     

Answer 23: The circumstances in which the reciprocal altruism appear in unrelated individuals is – When there are repeated interactions with opportunities for all individuals to be the donor and recipient of the altruistic act.

In reciprocal altruism, the organism acts in a manner that reduces its fitness while increasing the fitness of another organism. Reciprocal altruism is the evolution of altruism among nonkin. Here there is return benefit for an organism, therefore, all the individuals are both the donor and recipient of the altruistic act.

Answer 24: Babies in the United States easily develop a fear of snakes but not a fear of guns because – Fear of snakes evolved in early humans with different living conditions, and evolution can be slow in producing populations that are adapted to their newer environments.

Fear is shaped by evolution. Evolution is a long-term process and the adaptation to the new environment and new behaviour takes time. Long-time back mammals used to survive in a reptile dominated environment and the response to fear has been developed since then. Mammal has developed the perceptive ability to focus on threats.