DIRECTORY 339
contained in its genetic code. Its
phenotype is that which results
from the expression of that code.
While individual genes may simply
code for the synthesis of different
substances in an organism’s
body, the phenotype should be
considered to be everything that
results from that synthesis. For
example, a termite mound may be
considered to be part of a termite’s
extended phenotype. Dawkins
views the extended phenotype
as the means by which genes
maximize their chances of
survival to the next generation.
See also: Charles Darwin
14 2– 49 ■ Lynn Margulis 300–01 ■
Michael Syvanen 318–19JOCELYN BELL BURNELL
1943–In 1967, while working as a
research assistant at Cambridge
University, British astronomer
Jocelyn Bell was monitoring
quasars (distant galactic nuclei)
when she discovered a strange
series of regular radio pulses
coming from space. The team she
was working with jokingly called
the pulses LGM (Little Green Men),
referring to the remote chance
that they were an attempt at
extraterrestrial communication.
They later determined that the
sources of the pulses were rapidly
spinning neutron stars, which
were dubbed pulsars. Two of Bell’s
senior colleagues were awarded
the 1974 Nobel Prize in Physics
for the discovery of pulsars, but Bell
missed out because she was only a
student at the time. Many leading
astronomers, including Fred Hoyle,
objected publicly to her omission.
See also: Edwin Hubble 236–41 ■
Fred Hoyle 270MICHAEL TURNER
1949–American cosmologist Michael
Turner’s research focuses on
understanding what happened
directly following the Big Bang.
Turner believes that the structure
of the universe today, including
the existence of galaxies and the
asymmetry between matter and
antimatter, can be explained by
quantum-mechanical fluctuations
that took place during the rapid
burst of expansion called cosmic
inflation, which occurred moments
after the Big Bang. In 1998, Turner
coined the term “dark energy” to
describe the hypothetical energy
that permeates the whole of space
and explains the observation that
the universe is expanding in all
directions at an accelerating rate.
See also: Edwin Hubble 236–41 ■
Georges Lemaître 242–45 ■
Fritz Zwicky 250–51TIM BERNERS-LEE
1955–Few living scientists have had
as much impact on everyday life as
British computer scientist Tim
Berners-Lee, who invented the
World Wide Web. In 1989, Berners-
Lee was working at CERN, the
European Organization for Nuclear
Research, when he had the idea
of establishing a network of
documents that could be shared
across the world via the Internet.
A year later, he wrote the first
web client and server, and in
1991, CERN built the first website.
Today, Berners-Lee campaigns for
open access to the Internet, free
from government control.
See also: Alan Turing 252–53STEPHEN JAY GOULD
1941–2002
American paleontologist Stephen
Jay Gould’s specialized area of
research concerned the evolution
of land snails in the West Indies,
but he wrote widely about many
aspects of evolution and science.
In 1972, Gould and colleague Niles
Eldredge proposed the theory of
“punctuated equilibrium,” which
proposed that, rather than being
a constant, gradual process
as Darwin had imagined, the
evolution of new species took place
in rapid bursts over periods as short
as a few thousand years, which
were followed by long periods of
stability. To back up their claim,
they cited evidence from the
fossil record, in which patterns
of evolution in various organisms
support their theory. In 1982,
Gould coined the term “exaptation”
to describe the way in which a
particular trait may be passed
on for one reason, and then later
come to be coopted for a very
different function. His work
widened understanding of the
mechanisms by which natural
selection takes place.
See also: Charles Darwin
14 2– 49 ■ Lynn Margulis 300–01 ■
Michael Syvanen 318–19
RICHARD DAWKINS
1941–
British zoologist Richard Dawkins
is best known for his popular
science books, including The
Selfish Gene (1976). His most
significant contribution to his field
is his concept of the “extended
phenotype.” An organism’s genotype
is the sum of the instructions