An Evolutionary Paradox...
"Evolution, by favoring fitness, drives truth to extinction." - Donald Hoffman
"Trust isn't about content, it's about process" - Macomb Gladwell
Evolutionary biologists use the word fitness to describe how good a particular genotype is at leaving offspring in the next generation relative to other genotypes. So if brown beetles consistently leave more offspring than green beetles because of their color, you’d say that the brown beetles had a higher fitness. In evolution, fitness is about success at surviving and reproducing, not about exercise and strength.
Of course, fitness is a relative thing. A genotype’s fitness depends on the environment in which the organism lives. The fittest genotype during an ice age, for example, is probably not the fittest genotype once the ice age is over.
Fitness is a handy concept because it lumps everything that matters to natural selection (survival, mate-finding, reproduction) into one idea. The fittest individual is not necessarily the strongest, fastest, or biggest. A genotype’s fitness includes its ability to survive, find a mate, produce offspring — and ultimately leave its genes in the next generation.
Caring for your offspring, producing thousands of young — many of whom won’t survive — and sporting fancy feathers that attract females are a burden to the health and survival of the parent. These strategies do, however, increase fitness because they help the parents get more of their offspring into the next generation.