Encyclopedia of Evolution.pdf - Online Reading Center

genetic inferiority of the lower classes and nonwhite races
(see eugenics). Wallace saw this as an abuse of science and
an attempt to justify oppression.
In the late 1860s, Wallace became an adherent of spiritualism,
with which he remained for the rest of his life. As a scientist
he sought experimental confirmation but was satisfied
with demonstrations that more skeptical scientists would not
accept. He wrote more than 100 publications on spiritualism.
His lecture on life after death, delivered mainly during his
California speaking tour, was one of his most popular. His
outspoken association with spiritualism, however, did not
prevent him from receiving a continuous stream of scientific
awards and honors.
Related to his belief in spiritualism was his acceptance
of what is now called the anthropic principle, in which
he believed that the universe was designed for man—a perfect
universe in which humans were intended to evolve. The
rebuttal written by Samuel Clemens (Mark Twain), “Was the
World Made for Man?” has become much more famous than
Wallace’s original writings on the subject.
The publication of Wallace’s first article about natural
selection jointly with Charles Darwin in 1858 created
the impression that Darwin and Wallace believed the same
things about evolution. Wallace’s publications about evolution
were to prove that this was not the case at least with
human evolution. Wallace distinguished between the material
process of natural selection that produced the human
body, and a spiritual one that produced the human mind, a
distinction Darwin never made. Today, nearly all evolutionary
scientists explain the origin of human behavior patterns
in terms of evolutionary processes acting upon the brain (see
altruism; sociobiology). Many scholars assume that Wallace’s
rejection of natural selection as an explanation for the
origin of the human mind resulted from his irrational attraction
to spiritualism. However, evolutionary biologist Stephen
Jay Gould and others have pointed out a different possibility.
Both Darwin and Wallace were aware that tribal peoples had
intelligence equal to that of civilized peoples—Darwin knew
this from his experience with the Fuegians, and Wallace from
the Amazonians and Indonesians. But Wallace pointed out,
further, that the tribal peoples did not need or use the high
levels of intelligence of which they proved themselves capable
when given European education. Wallace reasoned that
if natural selection were the sole explanation of the origin of
the human mind, then scientists would see tribal peoples with
low intelligence. Why did these people have so much more
intelligence than they used? (This argument is now rejected
by anthropologists, who recognize that tribal peoples have
very complex languages, customs, and oral traditions.) Wallace,
in other words, was taking natural selection more seriously,
not less seriously, than Darwin. Of course, Wallace’s
acceptance of spiritualism made his rejection of the evolution
of mind much easier.
Wallace remained intellectually active well into his old
age. Between 1898 and 1910, mostly in his ninth decade, he
published more than 4,000 pages of material. Wallace died
November 7, 1913.
whales, evolution of
Further Reading
Brackman, Arnold C. A Delicate Arrangement: The Strange Case of
Charles Darwin and Alfred Russel Wallace. New York: Times
Books, 1980.
Camerini, Jane, ed. The Alfred Russel Wallace Reader: A Selection of
Writings from the Field. Baltimore, Md.: Johns Hopkins University
Press, 2001.
Fichman, Martin. An Elusive Victorian: The Evolution of Alfred Russel
Wallace. Chicago: University of Chicago Press, 2004.
Raby, Peter. Alfred Russel Wallace: A Life. Princeton, N.J.: Princeton
University Press, 2002.
Smith, Charles H. “The Alfred Russel Wallace Page.” Available
online. URL: http://www.wku.edu/~smithch/index1.htm. Accessed
May 13, 2005.
Wallace’s line See biogeography; Wallace, Alfred
Russel.
whales, evolution of Whales and other cetaceans (such
as dolphins) evolved from land-dwelling mammalian ancestors
(see mammals, evolution of). Cetaceans are spectacularly
well adapted to life in the oceans, so well that they
were considered fishes until the last couple of centuries.
Among the adaptations that were necessary in the evolution
of whales are:
• Front flippers and a tail fluke. Pinnipeds such as seals and
walruses crawl onto land for mating and childbirth, but
cetaceans spend their entire lives in water. An animal that
spends all of its time in the water does not need to walk,
and hind legs are only a hindrance. Flippers provide a large
surface area with which the front limbs can propel the
cetacean through water, and the horizontal fluke on the tail
also allows propulsion. Cetaceans move their tails up and
down in typical mammalian fashion, unlike the side-to-side
motion of the tails of fishes.
• Nostrils on the top of the head. Cetaceans, being mammals,
need to breathe air. It is much more convenient to emerge
from the ocean for breathing if the nostrils are on the top
of the head.
• Change in eating. While many cetaceans (such as killer
whales and dolphins) have teeth and pursue prey, some of
the largest whales live off of plankton, which they strain
from the water with baleen or whalebone, which they have
instead of teeth.
• Ability to hold its breath. When diving deeply for long periods
of time, whales must take as much oxygen with them
as possible. Whenever they emerge, they can exchange up
to 90 percent of the air in their lungs with the atmosphere,
compared to the typical human breath that exchanges only
50 percent. Their muscles contain a great deal of myoglobin,
a protein similar to hemoglobin that releases oxygen
into muscle tissue.
• Changes in ear structure. The structure of the ear that is
best for hearing in air is quite different from that which is
best for hearing underwater.
• Changes in birth. Most mammals are born headfirst, to
allow the newborn to begin breathing as soon as possible.