Inclusive Fitness and Parental Care
Some might express concern that parental investment (parental care) is said to contribute to inclusive fitness. The distinctions between the kind of beneficiaries nurtured (collateral versus descendant relatives) and the kind of fitnesses used (inclusive versus personal) in our parsing of nature are orthogonal concepts. This orthogonality can best be understood in a thought experiment: Consider a model of a population of animals such as crocodiles or tangle web spiders. Some species or populations of these spiders and reptiles exhibit parental care, while closely related species or populations lack it. Assume that in these animals a gene, called a, codes for parental care, and its other allele, called A, codes for an absence thereof. The aa homozygotes care for their young, and AA homozygotes don't, and the heterozygotes behave like aa homozygotes if a is dominant, and like AA homozygotes if A is dominant, or exhibit some kind of intermediate behavior if there is partial dominance. Other kinds of animals could be considered in which all individuals exhibit parental care, but variation among them would be in the quantity and quality thereof.
If we consider a lifecycle as extending from conception to conception, and an animal is an offspring of parents with poor parental care, the higher mortality with poor care could be considered a dimunition of the offspring's expected fitness.
Alternatively, if we consider the lifecycle as extending from weaning to weaning, the same mortality would be considered a dimunition in the parents' fecundity, and therefore a dimunition of the parent's fitness.
In Hamilton's paradigm fitnesses calculated according to in the weaning to weaning perspective are inclusive fitnesses, and fitnesses calculated in the conception to conception perspective are personal fitnesses. This distinction is independent of whether the altruism involved in child rearing is toward descendents or toward collateral relatives, as when aunts and uncle rear their nieces and nephews.
Inclusive fitness theory was developed in order to better understand collateral altruism, but this does not mean that it is limited to collateral altruism. It applies just as well to parental care. Which perspective we choose does not affect the animals but just our understanding.
Read more about this topic: Inclusive Fitness
Famous quotes containing the words inclusive, fitness, parental and/or care:
“We are rarely able to interact only with folks like ourselves, who think as we do. No matter how much some of us deny this reality and long for the safety and familiarity of sameness, inclusive ways of knowing and living offer us the only true way to emancipate ourselves from the divisions that limit our minds and imaginations.”
—bell hooks (b. 1955)
“Parentage is a very important profession; but no test of fitness for it is ever imposed in the interest of children.”
—George Bernard Shaw (1856–1950)
“The child who would be an adult must give up any lingering childlike sense of parental power, either the magical ability to solve your problems for you or the dreaded ability to make you turn back into a child. When you are no longer hiding from your parents, or clinging to them, and can accept them as fellow human beings, then they may do the same for you.”
—Frank Pittman (20th century)
“They [creative children] ask more questions than most children. They’re usually spontaneous and enthusiastic. Their ideas are unique and occasionally strike other kids as weird. They’re independent. Not that they don’t care at all what other kids think, but they’re able to do their thing despite the fact that their peers may think it’s strange. And they have lots and lots of ideas.”
—Silvia Rimm (20th century)