and Ricardo and Malthus and Mill, until the marginalist revolution shifted focus from objectives to the mechanics in supply, demand and price. Bioeconomics awoke a century later, largely it seems in response to the challenge of Hamilton’s rule. Now
I will look at it too.
My term “lineage survival” is unusual. It is meant not to take sides between “kin selection” and “group selection.” The kin selection idea was another word for Hamilton’s rule from his doctorial thesis in 1964. It said that genes encoding investment in close kin encode investment in likeliest sharers of those genes, and should tend to entrench and perpetuate themselves. His condition for investment
was r)bc.r here meant relatedness: ¥% for offspring or siblings, % for nephews or
nieces or grandoffspring, and so forth. b meant benefit to the donee, and c meant cost to the investor. The sign > means “greater than”. The cost and benefit were measured in fitness itself, meaning chances to survive and breed. But that too meant “inclusive fitness” where investing in kin counted as breeding when adjusted for relatedness. The idea was that I give up some of my chances if I can increase yours to my net genic advantage in the long run. Hamilton allowed for exceptions including meiotic drive, which sometimes forecloses gene competition. His rule prevailed because it made mostly good predictions. Humans and creatures in general usually care for their own young first, if they have any, and for closely
related young if not.
Hamilton made it clear that cost c and benefit b in his hurdle rb>c respectively meant fitness given up by the investor and fitness grained by the investee. He further made it clear that fitness could be measured as R. A. Fisher’s “reproductive
value” V(x) published in 1930 and 1957. V(x) meant likelihood at age x of reaching each successive age times expected offspring at that age. V(x), or Bob Trivers’ “reproductive success” RS, which simplifies V(x) to expected remaining
offspring, is implicitly constant at the population scale unless there is population
growth (Fisher’s “Malthusian parameter”). For creatures other than us, the
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