Encyclopedia of Evolution.pdf - Online Reading Center

though the eugenics to which Galton applied them has now
been discredited. Galton also developed the use of percentile
scores and the survey method of psychological research.
He was the first to use identical (monozygotic) and fraternal
(dizygotic) twins in the study of human inheritance patterns
even though the eugenic conclusions he reached are no longer
believed (see essay, “How Much Do Genes Control Human
Behavior?”). Therefore Galton’s techniques, although not his
scientific theories, pervade modern genetic and psychological
research.
Galton’s 1869 book Hereditary Genius outlined his
conviction that intelligence was primarily inherited. Galton
believed that the rapid population growth of the lower
classes, and the declining fertility of the upper classes, would
lead to a national loss of intelligence. (It is interesting that
Galton, who considered himself one of the intelligent elite,
had no children.) He even advocated restrictions that would
prohibit reproduction by people whom his tests identified as
feebleminded. His statistical methods did, in fact, prove that
there was a significant correlation between intelligence and
heredity. What he seems to have ignored is that it is not just
genes that are inherited in human societies. Culture is passed
on through families as well. The lower classes may have
scored lower on Galton’s tests of mental ability not because
of inferior genes but because, generation after generation,
they had been denied access to economic and educational
opportunities. This would have explained his significant
correlations just as well as the eugenic explanations Galton
offered. Moreover, the very questions that were asked on his
surveys presupposed a knowledge of English culture and language;
Africans scored as low on his English tests as Englishmen
would have on tests conducted in Swahili about African
culture. Today, all scientists recognize what Galton apparently
did not: Correlation is not the same as causation.
Although Galton’s principal scientific accomplishments
have been discredited, many of his techniques, from fingerprints
to statistics, play an essential role in the world today.
He died February 17, 1911.
Further Reading
Allen, G. “The measure of a Victorian polymath: Pulling together the
strands of Francis Galton’s legacy to modern biology.” Nature
145 (2002): 19–20.
Bynum, W. F. “The childless father of eugenics.” Science 296 (2002):
472.
Gillham, Nicholas Wright. A Life of Sir Francis Galton: From African
Exploration to the Birth of Eugenics. New York: Oxford, 2001.
Tredoux, Gavan. “Galton.org Home Page.” Available online. URL:
http://www.mugu.com/galton/index.html. Accessed March 28,
2005.
gene See DNA (raw material of evolution).
gene-culture coevolution Gene-culture coevolution refers
to the influence of cultural innovation on genes in a population,
and the effects of those genes on culture. The term
coevolution is usually restricted to the mutual evolutionary
effects of one species on another. In this case, one of the par-
gene-culture coevolution
ticipants in coevolution is the culture of a species, and the
other is the genes within its populations. Some evolutionary
scientists (see Wilson, Edward O.; sociobiology)
use gene-culture coevolution as an important mechanism for
explaining the evolution of societies and intelligence. Geneculture
coevolution is a more modern form of a concept
known as the Baldwin Effect, which evolutionary biologist
George Gaylord Simpson named after a concept proposed in
the late 19th century by evolutionary scientist James Mark
Baldwin.
In order to explain this process, consider one famous
example of it. In Britain, some individual blue tits (Parus
caeruleus, a species of bird) figured out how to peck the foil
caps off of milk bottles left on doorsteps and drink the milk
inside. Other birds watched the ones that could perform this
trick and began doing it themselves. The first part of the process,
therefore, was cultural: The birds learned a new behavior
from one another. The existence of this behavior causes
a selective advantage for those birds that have the appropriate
physical and behavioral abilities to do this action well:
the ones that are best at recognizing the foil, at performing
the movements to remove the foil. A new resource, unlocked
by behavior, now becomes a selective force that can influence
the gene frequencies of the bird population (see natural
selection). The second part of the process, then, is genetic.
In turn, these new gene frequencies might allow yet more
cultural innovations, in which the birds can more effectively
steal milk from bottles. It is important to note that the behavior
itself is culturally transmitted, rather than instinctual. The
new behavior cannot imprint itself on the genes; this would
be Lamarckism. No one will ever know what further genetic
changes might have occurred in the bird populations, because
dairies began using bird-proof caps on milk bottles.
Another example, more familiar to modern Americans,
is that birds such as grackles are often observed to pick
recently killed insects from automobile grilles in parking lots.
This behavior is beneficial because the birds can eat insects
without using energy to pursue them, do so safely because
the automobiles are not moving, and do so efficiently because
many automobiles are in one location. This behavior creates
a situation in which natural selection favors birds that have
an innate preference for parking lots over natural insect habitats.
The behavior is now cultural, but in later centuries may
become genetic.
Another famous example involves Imo, a very smart Japanese
macaque monkey. Imo learned how to wash food items
before eating them. This allowed Imo to eat the food more
efficiently. Other monkeys began imitating Imo. Now there
is a selective advantage for those monkeys that are capable of
learning and efficiently executing this behavior. The monkeys
that cannot do so might find themselves lower in the social
hierarchy, with reduced or nonexistent reproduction as their
reward.
On the Galápagos Islands, Darwin’s finches have
undergone adaptive radiation into numerous species that
specialize on different foods. Another Pacific island, Cocos,
off the coast of Costa Rica, shares one of these species of
finches (Pinaroloxias inornata) with the Galápagos. But