Dr. Lee Dugatkin from the University of Louisville is fascinated by a problem in evolutionary biology: altruism. He offers an example of ground squirrels, who stand on their hind legs and emit loud calls to warn their fellows about predators so they can head to safety. The alarm squirrel eventually runs away as well, but takes a huge risk first, making itself very obvious to the predator while it’s on its hind legs, screaming.
Similar examples of altruism happen throughout the animal kingdom, like chimpanzees sharing food. These examples make little sense at the first evolutionary glance – if you share food, you’ve got less and are less likely to survive and pass on your genes. Why would you do this?
This problem vexed Darwin, who looked at honeybees and found them very disconcerting. Bees sting invaders of the hive and die in the process, paying a very heavy evolutionary price. Darwin thought that this behavior might destroy his entirely evolutionary theory. But defending the hive is protecting many more copies of your genes by protecting your kin. “The problem of altruism disappears when you consider the family, not just the individual.”
Dugatkin takes us through a hundred-year history of arguments on this topic. Thomas Henry Huxley, who famously advanced Darwin’s case on evolution, argued that “the whole planet is a competive bloodbath” and “the only place where you see altruism is blood kin.” Peter Kropotkin, who was an important scientist as well as an anarchist, saw huge amounts of mutualism in his research in Siberia, most of which went beyond kinship. he and Huxley argued publicly about this issue in a series of papers for several years.
This argument continued through Walter Clyde Allee in the 1930s, who did actual experiments on altruism, and JBS Haldane who built mathematical models to explain it. Haldane was the scientists who, asked to comment on God and evolution, said, “God must have an inordinate fondness for beetles.” He also had a useful quip on genetics, arguing that “he would jump into the river to save two or more brothers, or eight or more cousins… but no less.” This actually makes genetic sense, in terms of protecting your genetic matter, as you share roughly half with a sibling. Saving two brothers is the equivalent of saving your genetic information.
The best model came from WD Hamilton, a scientist who grew up near Darwin’s house, literally raised with his mother reading him “Origin of Species”. He developed a mathematical equation with three variables:
– genetic relatedness
– how costly is this altruism
– how much do benefits come from altruism
Altriusm should happen when relatedness times benefit is greater than the cost of that altruism.
This equation suggests that you should always get indirect benefits from helping your close relatives. Honeybees who defend the nest are female. Because of the peculiarities of honeybee genetics, they are closely related to every bee in the hive. Naked mole rats, who have a similar queen structure, despite being mamals, have similar behaviors. The squirrels who sound alarm cries are disproportionately female, and are more closely related to the whole nest, as the males leave the nest to find mates, while females remain at home.
What does this mean? Perhaps we should have tax incentives to let people live in the same neighborhoods with their blood kin,” Dugatin suggests, because we’re biologically wired to treat our blood relations better.
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