Encyclopedia of Evolution.pdf - Online Reading Center

eugenics
grieving, or experiencing inspiration) have shown that nearly
every activity involves more than one part of the brain, and
individuals differ at least a little bit in which parts of their
brains are active during certain functions.
Brainlike properties can emerge from a computer.
When computer subroutines or algorithms interact with one
another, and learn from each other, complex outputs can be
produced, even though each algorithm is simple and has no
information about what the rest of the computer is doing (see
evolutionary algorithms). This is particularly true of
neural net computing, which is designed to imitate the way
neurons interact within a brain.
Emergent properties of human interactions. Groups of
interacting humans, who learn from one another and alter
their behavior accordingly, show emergent properties. This
is why cities and whole societies take on spontaneous structures
even when no individual or government agency imposes
the order. The emergent properties are unplanned and frequently
surprising. One would expect the World Wide Web
to produce emergent properties. It usually does not do so,
however, because most of the interactions are one-way: Users
access information, but the Web sites that they access remain
unchanged by the users. Some Web sites gather information
about the users or solicit feedback from the users and apply
this information to modify themselves; in these cases, emergent
properties begin to appear. This is how Web sites can
recommend other Web sites to users, without any human
being supervising the process.
Some scientists study evolution not by studying the natural
world or designing laboratory experiments but by using
computer models that explore the kinds of complexity that
can emerge from the seeming chaos of simpler interacting
components. The Santa Fe Institute in New Mexico attracts
scientists who wish to explore the evolutionary implications
of what they call complexity theory.
Emergence explains how complexity can arise from
simplicity rather than having to be imposed by a complex
information structure. No cell is in charge of embryonic
development, no ant is in charge of the colony, no cluster of
neurons is in charge of the brain, and no person is in charge
of a human society. Yet complexity emerges from all of them.
natural selection acts upon the results of the complexity.
This is one reason that natural selection usually cannot act
upon a single gene: No gene acts in isolation, but as part of a
network of interactions.
Further Reading
Barabási, Albert-László. Linked: How Everything Is Connected to
Everything Else and What It Means for Business, Science, and
Everyday Life. New York: Penguin, 2003.
Buhl, J., et al. “From disorder to order in marching locusts.” Science
312 (2006): 1,402–1,406.
Franks, N. R. “Army ants: A collective intelligence.” American Scientist
77 (1989): 138–145.
Johnson, Steven. Emergence: The Connected Lives of Ants, Brains,
Cities, and Software. New York: Scribner, 2001.
Kaufmann, Stuart A. The Origins of Order: Self-Organization and
Selection in Evolution. New York: Oxford University Press, 1993.
Prigogine, Ilya. Order out of Chaos: Man’s New Dialogue with
Nature. New York: Bantam, 1984.
Santa Fe Institute. “Santa Fe Institute: Celebrating 20 Years of Complexity
Science.” Available online. URL: http://www.santafe.edu.
Accessed March 28, 2005.
eugenics Eugenics was a pseudoscience that attempted to
use genetics to justify delusions of racial superiority or to
promote genetic improvements in human populations. Eugenics
(from the Greek for “good breeding”) grew together with
the young science of genetics (see Mendelian genetics). But
while genetics has grown into a major science, the underpinning
of evolutionary biology, eugenics has fallen into disrepute
in the popular mind as well as among scientists, both for
its injustice and its erroneous science.
Theories of “good breeding” predated both genetics
and evolutionary theory. For many centuries, some societies
viewed “purity of blood” as an important virtue, especially
among its elite classes, who eschewed interbreeding with people
of lower estate. Royal and aristocratic families bred only
among themselves, and sometimes cousin marriages were
common, although few went as far as the sibling marriages of
the Pharaohs. Scientists now understand that interbreeding of
close relatives results in inbreeding depression, the expression
of numerous detrimental genes that would have otherwise
remained hidden. Some scholars suggest that the illnesses
both of Charles Darwin (see Darwin, Charles) and his
daughter Annie resulted from the close inbreeding between
the Darwin and Wedgwood families (Charles Darwin’s father
and mother were cousins, and he married his cousin).
Not everyone in previous centuries shared the opinion
that royal and aristocratic blood needed to be kept pure.
The embarrassing problems of royal families were an open
secret in late medieval and early modern Europe. The infamous
“Hapsburg lip” of one of Europe’s royal families was
so striking that even flattering portraits could not hide it, and
it passed through 23 generations. The Hapsburg Charles II of
Spain could not even chew his own food, because of it, and
was in addition a complete invalid and incapable of having
children. Several British kings were insane for reasons now
known to be genetic. George III (who lost the American colonies)
had periodic bouts of madness variously attributed to
genetic diseases porphyria or alkaptonuria. Thomas Jefferson,
when visiting Europe, became convinced that something
was biologically wrong with the European royals, which
reinforced his belief that democracy was necessary not only
for justice but even for physical health. As Jefferson wrote in
1810 in a letter to Governor John Langdon:
… take any race of animals, confine them in idleness
and inaction, whether in a sty, a stable, or a
state-room, pamper them with high diet, gratify all
their sexual appetites, immerse them in sensualities
… and banish whatever might lead them to think,
and in a few generations they become all body and
no mind … and this too … by that very law by
which we are in constant practice of changing the
characters and propensities of the animals that we