Which concept explains how behavior can evolve to favor traits that increase the genetic relatives' reproductive success?

Which concept explains how behavior can evolve to favor traits that increase the genetic relatives' reproductive success?

• A. Group selection
• B. Inclusive fitness
• C. Adaptationism
• D. Kin selection

Answer: (D)

Kin selection explains how behavior can evolve to favor traits that increase the genetic relatives’ reproductive success. The idea is that an organism can pass on its genes not only through its own offspring but also by helping relatives, who share a portion of its genes, to have more offspring themselves. This makes altruistic or costly behaviors advantageous if they boost the relatives’ reproduction enough to outweigh the cost to the actor. A useful way to think about it is through inclusive fitness, which combines direct fitness (your own offspring) with indirect fitness (the offspring your relatives produce with your help). The condition under which such helping behavior should spread is often summarized by Hamilton’s rule: relatedness to the beneficiary (r) times the benefit to that relative’s reproduction (B) must exceed the cost to the actor’s own reproduction (C). When rB > C, the behavior can be favored by natural selection because it increases the actor’s genetic representation in the next generation via relatives. Examples help illustrate: a helping behavior that costs an individual a bit of personal reproduction but substantially increases a relative’s offspring can spread if that relative shares many of the same genes. This is why parental care, alarm calls that warn relatives, or sterile helpers in social groups can evolve even though they seem costly to the individual. This concept is distinct from group selection, which emphasizes effects at the level of groups rather than genetic relatedness, and from adaptationism, which is a broad view about traits as adaptations. The idea that ties behavior to relatives’ reproductive success is kin selection, with inclusive fitness providing the framework to understand how those gene-level advantages accumulate.

Kin selection explains how behavior can evolve to favor traits that increase the genetic relatives’ reproductive success. The idea is that an organism can pass on its genes not only through its own offspring but also by helping relatives, who share a portion of its genes, to have more offspring themselves. This makes altruistic or costly behaviors advantageous if they boost the relatives’ reproduction enough to outweigh the cost to the actor.

A useful way to think about it is through inclusive fitness, which combines direct fitness (your own offspring) with indirect fitness (the offspring your relatives produce with your help). The condition under which such helping behavior should spread is often summarized by Hamilton’s rule: relatedness to the beneficiary (r) times the benefit to that relative’s reproduction (B) must exceed the cost to the actor’s own reproduction (C). When rB > C, the behavior can be favored by natural selection because it increases the actor’s genetic representation in the next generation via relatives.

Examples help illustrate: a helping behavior that costs an individual a bit of personal reproduction but substantially increases a relative’s offspring can spread if that relative shares many of the same genes. This is why parental care, alarm calls that warn relatives, or sterile helpers in social groups can evolve even though they seem costly to the individual.

This concept is distinct from group selection, which emphasizes effects at the level of groups rather than genetic relatedness, and from adaptationism, which is a broad view about traits as adaptations. The idea that ties behavior to relatives’ reproductive success is kin selection, with inclusive fitness providing the framework to understand how those gene-level advantages accumulate.