Levels of Selection Explored

Hamilton's rule states that altruism can evolve if the benefit to the recipient (B) multiplied by the coefficient of relatedness (r) is greater than the cost to the altruist (C), expressed as Br > C.

Examples of altruistic behavior in nature include alarm calls in prairie dogs, helping behavior in birds like white-throated bee-eaters, and food sharing in vampire bats.

Inclusive fitness is the sum of an individual's direct fitness (through its own offspring) and indirect fitness (through helping relatives reproduce).

The weaning conflict arises when offspring demand more resources from parents than the parents are willing to provide, balancing the needs of current offspring with the potential for future offspring.

The 'selfish gene' theory argues that natural selection and evolution are best considered from the perspective of the gene, where genes and alleles that promote their own propagation are favorably selected.

Reciprocal altruism is a form of cooperation where individuals help others with the expectation that the favor will be returned in the future, often seen in stable groups with good memory of past interactions.

Vampire bats exhibit reciprocal altruism by sharing blood meals with other bats that have shared with them in the past, ensuring mutual survival in times of food scarcity.

Group selection refers to the selection acting on traits that benefit groups of organisms over individuals, though it is often considered a weaker force than individual selection.

Segregation distorters are genetic elements that manipulate the segregation of chromosomes during meiosis, often leading to a higher transmission rate of certain alleles over others.

Eusociality is an extreme form of social organization where individuals sacrifice their own reproduction to assist in the rearing of close relatives, often involving specialized castes and cooperative brood care.

Siblicide is the act of one sibling killing another to gain more resources from the parents, often seen in birds where stronger siblings push weaker ones out of the nest.

Biased gene conversion occurs when, during chromosome repair or recombination, the gene that is fixed is converted to the other allele, often due to biases in binding preferences between nucleotides.

Kin selection is a form of natural selection that favors altruistic behaviors towards close relatives, increasing the indirect fitness of the altruist.