EvoluTion And SoCiETy 593
2016, the U.S. Food and Drug Administration instituted a policy to phase out the
use of antibiotics for promoting growth in livestock.)individuAl HEAlTH And PuBliC HEAlTH Many characteristics that are
advantageous to individual organisms are harmful at the population level, and
vice versa (see Chapters 3 and 12). This conflict arises in public health. Farmers
who use antibiotics to promote livestock growth may profit economically, but
perhaps at great cost to the entire population. If most (say, 90 percent) of the
members of a population are vaccinated against an infectious disease such as
measles, the pathogen will not spread, and the few unvaccinated members will
remain healthy, protected by “herd immunity.” But if the proportion of unvac-
cinated individuals is too great, the pathogen will spread readily, leading to an
outbreak. Outbreaks of some childhood diseases are correlated with geographic
regions where a large percentage of people refused to let their children be vacci-
nated [86]. These situations are among the many in which there must be arbitra-
tion between what individuals consider to be their rights, and the greater good.Evolution and Human Behavior
No topic in evolutionary biology is more intriguing or more controversial than
the genetic and evolutionary foundations of human behavior. Resistance to
hypotheses about human behavioral evolution, or even research on the subject,
is widespread for several reasons. Many people are emotionally reluctant to see
human abilities as extensions of those of other species, and they justify making
a sharp distinction by pointing to the immense difference between the mental
capacities of humans and those of any other mammal (see Chapter 21). A lmost
every aspect of our behavior varies greatly among individuals and among popu-
lations because of learning and cultural differences, so the hypothesis that there
is any genetic basis for human behaviors is viewed with skepticism, especially
by many social scientists. Finally, any intimation of biological determinism sum-
mons memories of Social Darwinism, a political philosophy that ascribed pov-
erty, illiteracy, and crime to genetic inferiority, rather than the social conditions
that exclude much of society from education and economic self-sufficiency [58].
Social Darwinism was developed by the philosopher Herbert Spencer, who
coined the term “survival of the fittest” before Darwin wrote On the Origin of
Species. Spencer was a fierce individualist who believed that competition was the
driving force for improvement in nature and society. Darwin, who voiced the
optimistic view that the evolution of cooperativeness in humans would lead to
greater compassion and inclusiveness, did not espouse Spencer’s view, but his
idea of natural selection, and therefore his name, became applied to Spencer’s
social philosophy. Social Darwinism became linked with the idea of eugenics, a
movement (largely initiated by one of Darwin’s cousins) that advocated encour-
aging “superior” people to have more children and discouraging or preventing
“inferior” people from doing so [63]. There is no basis for the common belief
that Hitler used evolution to support his racist, anti-Semitic rhetoric; instead, he
rejected the idea of Darwinian evolution and invoked racist ideologies that had a
long pre-Darwinian history and were rampant in Europe [98]. It is true, though,
that evolution has been used to support racist beliefs that some populations are
“higher” or “superior” to others. These abuses were based on misunderstanding
or twisting of the data and theory of evolution and genetics. To their credit, some
evolutionary biologists and geneticists said so at the time, and in the last few
decades they have been prominent in warning of misinterpretations of scientific
information. A proper understanding of evolutionary biology, as of any science,
is necessary to prevent it from being misused.22_EVOL4E_CH22.indd 593 3/22/17 1:49 PM