The Selfish Gene: 40th Anniversary edition (Oxford Landmark Science) — 6. Genesmanship

1. 1. A gene can assist replicas of itself in other bodies, which appears as individual altruism but is driven by gene selfishness.
2. 2. The Green Beard Altruism Effect is theoretically possible but unlikely, as a single gene would need to produce both a visible label and altruistic behavior toward that label.
3. 3. Close relatives share a greater-than-average chance of having the same genes, explaining why altruism toward kin, including siblings and cousins, evolves similarly to parental care.
4. 4. The relatedness between any two individuals can be calculated by counting generation distance via common ancestors, with each step multiplying by 1/2.
5. 5. A suicidal altruistic gene must save more than two siblings, four half-siblings, or eight first cousins to become more numerous in the gene pool.
6. 6. Kin selection is a consequence of gene selection, not a special case of group selection, contrary to E. O. Wilson's definition.
7. 7. Animals behave as if they perform cost-benefit calculations weighted by relatedness, life expectancy, and certainty of kinship, without conscious arithmetic.
8. 8. Parental care is more common than sibling altruism because parents have greater certainty of relatedness and longer life expectancy, giving them a selective advantage.
9. 9. Cuckoos exploit the built-in rule of host birds to care for any chick in their nest, leading to an evolutionary arms race of egg mimicry and host discrimination.
10. 10. In lion prides, natural selection favors altruism appropriate to the average relatedness of 0.22 for males and 0.15 for females, as estimated from reproductive patterns.
11. 11. Individual selfishness has an advantage over kin altruism due to certainty of self-identity, making it evolutionarily stable against mistakes and exploitation.