294 Self and the Phenomenon of Life
b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity “9x6”one are called haploids. Normally, animal cells are diploids. Hymenoptera
are unusual in that they have diploid females and haploid males, a phenom-
enon called “haplodiploidy.”- Wilson DS. (1975) A theory of group selection. Proc Natl Acad Sci USA
72: 143–146; Wilson DS. (1997) Altruism and organism: Disentangling the
themes of multilevel selection theory. Am Naturalist 150 (suppl.): S122–
S134; Nowak MA, Tarnita CE, Wilson EO. (2010) The evolution of euso-
ciality. Nature 466: 1057–1062. - Wilson DS, Wilson EO. (2007) Rethinking the theoretical foundation of
sociobiology. Quart Rev Biol 82: 327–348. - In simple cases, Hamilton’s model has explanatory power, but in real life,
which is complex and multivariate, it loses its elegance. E.O. Wilson’s col-
league C. Tarnita presented the following hypothetical situation. Suppose
your cousin is drowning and you want to risk your life to save him, not
knowing that he is competing with your brother for the same girl. If your
cousin survives to marry that girl, you may be depriving your brother of
having progeny to carry on his genes, which are closer to yours than your
cousin’s are. (Quoted with permission from Lehrer J. (2012) Kin and kind.
The New Yorker, March 5 2012, pp. 36–42.) What this story illustrates is
that Hamilton’s model works in isolation, but, like many other biological
situations, there are numerous variables, many of which are not known to
us. Aside from kinship, other factors also contribute to insect eusociality,
among them a defensible nest (territory), genetic mutation, and selection
by environmental forces. See Nowak MA, Tarnita CE, Wilson EO. (2010)
The evolution of eusociality. Nature 466: 1057–1062. - In an experiment set up to test the importance of touch to a youngster,
infant monkeys were given a choice between a wire shaped in the form of
a body and one covered with a piece of soft, velvet cloth as their surrogate
mother. Whenever threatened, the monkey would cling to the surrogate
covered with a piece of soft cloth. See: Harlow HF, Zimmermann RR.
(1958) The development of affective responses in infant monkeys. Proc Am
Philos Soc 102: 501–509; Harlow HF. (1958) The nature of love. Am Psy-
chologist 13: 673–685. - Both oxytocin and vasopressin are peptides of nine amino acids, with slight
differences in sequence. Both have peripheral and central actions. Those