Question

What is total reproductive success of an individual, including reproduction by the individual and also reproduction by related kin?

A. greenbeard effect
B. indirect fitness
C. inclusive fitness
D. direct fitness
E. eusociality
F. kin selection

Answer 1

The total reproductive success of an individual, accounting for both direct offspring and the reproductive success of relatives, is called inclusive fitness. Kin selection, a subset of inclusive fitness, describes behavior that supports relatives, potentially at a cost to the individual, but aids in the propagation of shared genes.

Step-by-step explanation:

The total reproductive success of an individual, which includes the ability to produce offspring and the addition of the reproductive success of related kin, is described as the individual's inclusive fitness. Inclusive fitness is not only concerned with an individual's direct offspring but also with the success of relatives that share common genes.

The reasoning behind this concept is that by assisting related individuals (kin), an individual can increase the proportion of shared genetic material that is passed on to the next generation. Therefore, even if the individual does not produce its own offspring, it may still contribute to the gene pool via kin.

A key component of inclusive fitness is kin selection, a form of natural selection that favors behaviors that increase the reproductive success of relatives, even at a cost to the individual's own survival and direct reproduction. This can explain seemingly altruistic behaviors, as observed in social insects like bees and ants, where sterile workers support the reproductive queen thereby indirectly ensuring the propagation of shared genes.

Answer 2

Inclusive fitness encompasses both the direct reproduction by an individual and reproduction by their kin, considering the shared genes within a family. It is a crucial element in the study of evolutionary biology, particularly in social species where kin selection plays a significant role in fitness strategies. Therefore, the correct option is c).

Step-by-step explanation:

The term that describes the total reproductive success of an individual, including both the direct reproduction by the individual and reproduction by related kin, is known as inclusive fitness. Inclusive fitness takes into account not only the offspring an individual produces (direct fitness) but also the offspring that their relatives (sharing common genes) produce. This concept is essential in understanding evolutionary strategies, as behaviors that might seem altruistic on the surface may increase an individual's inclusive fitness. For instance, in eusocial species like bees, wasps, ants, and termites, sterile workers contribute to the colony by supporting the queen who shares their genes. Although these workers do not reproduce directly, they enhance their inclusive fitness by ensuring gene propagation through the queen's reproduction, a concept evolved through kin selection.

By supporting relatives, an individual can ensure that the genes he shares with their kin are passed on to subsequent generations. This is particularly evident in species with complex social structures, where even the good genes hypothesis and the handicap principle can play roles in displaying one's genetic fitness indirectly by presenting certain traits that signal robust health or advantageous attributes. The interplay of these different factors illustrates the complex nature of evolutionary fitness strategies, encompassing direct and indirect genetic contributions to the gene pool.