Behavioural Ecology

Natural selection is a fundamental concept in evolutionary biology. It is the process by which certain traits or behaviors become more or less common in a population over time, based on their impact on an organism's survival and reproductive success. Behaviors that enhance an animal's chances of survival and reproduction are more likely to be passed on to future generations, while behaviors that hinder these processes are less likely to be inherited. Therefore, it is true that natural selection has resulted in behaviors that help animals to survive and reproduce.

E.g. Animals assessing rivals before fighting or fleeing, as seen in toads

Example:
The bizarre courtship behaviour of the balloon fly could have evolved in small steps, like the differences among species within the empidid fly family

Kin selection is a theory in evolutionary biology that suggests that individuals can increase their own genetic success by helping their relatives, even if it means sacrificing their own reproductive success. This behavior can extend beyond just offspring and include other kin, such as siblings or cousins. By assisting these relatives, individuals can indirectly pass on their genes through their relatives' reproduction. Therefore, the statement that kin selection favors behavior that spreads genes through any kin, not just offspring, is true.

An altruistic act is defined as an action that immediately benefits another individual at some cost to the performer. In this case, the performer willingly incurs a cost, whether it be time, effort, or resources, in order to benefit someone else. The act is selfless and done with the intention of helping another person, even if it comes at a personal cost.

According to Hamilton's rule, natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist. This means that individuals are more likely to engage in altruistic behavior if the benefit received by the recipient, taking into account their genetic relatedness, is greater than the cost incurred by the individual performing the altruistic act. In other words, altruism is favored when the genetic benefits outweigh the individual costs, promoting the survival and reproduction of related individuals.

The process of natural selection does not mean that animals are selected to act "for the good of the species." Natural selection is a mechanism by which individuals with advantageous traits are more likely to survive and reproduce, passing on their genes to the next generation. It is driven by individual fitness, not the well-being of the species as a whole. Therefore, the statement is false.

Kin selection refers to the enhanced reproduction of related individuals with common alleles through apparently altruistic behavior. This means that individuals may behave in ways that benefit their relatives, even at a cost to themselves, because it increases the chances of their shared genes being passed on to future generations. This concept was developed by W.D. Hamilton and is an important mechanism in evolutionary biology for understanding the evolution of social behaviors.

Altruism can evolve if it entails helping kin, through the process of kin selection, following Hamilton's Rule. Hamilton's Rule states that an organism is more likely to exhibit altruistic behavior towards its kin if the benefits to the recipient multiplied by the degree of relatedness exceeds the cost to the donor. This means that organisms are more likely to help their close relatives because they share a significant amount of genetic material. Therefore, altruistic behavior can be favored by natural selection if it benefits the survival and reproduction of genetically related individuals.

The coefficient of relatedness between two individuals measures the proportion of genes they share due to their common ancestry. In the case of two brothers, they share on average 50% of their genes from their mother and 50% from their father. Therefore, the coefficient of relatedness between two brothers is the same as the coefficient of relatedness between mother and daughter, which is also 0.5 or 50%.

The coefficient of relatedness between siblings is 0.5, and the coefficient of relatedness between an individual and a nephew is 0.25. The total coefficient of relatedness would be 0.5 + (3 × 0.25) = 1.25, a total that is not the lowest of the choices.

Altruistic behavior is expected when it increases the long-term inclusive fitness of the altruists. This means that individuals engage in selfless actions that may incur costs to themselves, but ultimately benefit their own reproductive success and survival. This behavior is favored when it enhances the overall genetic fitness of the altruists, ensuring the propagation of their genes in future generations.