dollars, sea urchins) that draws water from the sur-
rounding sea and passes it through a perforated plate
called the madreporite, which is used for locomotion
and food gathering. Extensions of the water vascular
system are called tube feet, which protrude from the
body, usually ending in suckers, and are used for loco-
motion and for holding on to the sea bottom or prey.
wavelength The physical distance between points of
corresponding phase of two consecutive cycles of a
wave.
Wegener, Alfred Lothar (1880–1930) GermanGeo-
physicist, Meteorologist, Climatologist Alfred Wegen-
er was born in Berlin on November 1, 1880, the son of
a minister who ran an orphanage. He obtained his doc-
torate in planetary astronomy in 1904 at the University
of Berlin. In 1905 Wegener took a job at the Royal
Prussian Aeronautical Observatory near Berlin, study-
ing the upper atmosphere with kites and balloons.
Wegener was an expert balloonist, as proved the fol-
lowing year when he and his brother Kurt set a world
record of 52 consecutive hours in an international bal-
loon contest.
In 1911, at the age of 30, Wegener collected his
meteorology lectures and published them as a book
titled The Thermodynamics of the Atmosphere. It
became a standard in Germany, and Wegener received
acclaim. He also noticed the close fit between the coast-
lines of Africa and South America. He was formulating
his theory of continental drift and began to search for
paleontological, climatological, and geological evidence
in support of his theory.
On January 6, 1912, at a meeting of the Geological
Association in Frankfurt, he spoke about his ideas of
“continental displacement” (continental drift), and pre-
sented his theory again days later at a meeting of the
Society for the Advancement of Natural Science in
Marburg.
In 1914 he was drafted into the German army, was
wounded, and served out the war in the army weather-
forecasting service. While recuperating in a military
hospital, he further developed his theory of continental
drift, which he published the following year as Die
Entstehung der Kontinente und Ozeane(The origin of
continents and oceans). Expanded versions of the book
were published in 1920, 1922, and 1929. Wegener
wrote that around 300 million years ago, the conti-
nents had formed a single mass, called Pangaea (Greek
for “all the Earth”), which split apart, and its pieces
had been moving away from each other ever since.
While he was not the first to suggest that the continents
had once been connected, he was the first to present
the evidence, although he was wrong in thinking that
the continents moved by “plowing” into each other
through the ocean floor. His theory was soundly reject-
ed, although a few scientists did agree with his premise.
In November 1930 he died while returning from a
rescue expedition that brought food to a party of his
colleagues camped in the middle of the Greenland ice
cap. His body was not found until May 12, 1931, but
his friends allowed him to rest forever in the area that
he loved.
The theory of continental drift continued to be
controversial for many years, but by the 1950s and
1960s, plate tectonics was all but an accepted fact and
taught in schools. Today, we know that both continents
and ocean floor float as solid plates on underlying rock
that behaves like a viscous fluid due to being under
such tremendous heat and pressure. Wegener never
lived to see his theory proved. Had he lived, most sci-
entists believe he would have been the champion of
present-day plate tectonics.Weller, Thomas Huckle(1915– ) AmericanMicro-
biologist Thomas Huckle Weller was born in Ann
Arbor, Michigan, on June 15, 1915, to Carl Vernon
Weller, who was in the pathology department of the
medical school at the University of Michigan. He
attended this university in 1932 and received a B.A. in
1936 and an M.S. in 1937.
In 1936 he attended Harvard Medical School in
Boston and worked in the facilities in the department
of comparative medicine and tropical medicine. In
1939 he began research on viruses and tissue culture
techniques to study infectious disease. He received an
M.D. in 1940 and began training at the Children’s
Hospital in Boston. After a stint with the Army Medi-
cal Corps during the war, he returned to Boston and
the Children’s Hospital. In 1947 he joined John ENDERS
in the organization of the new research division of
infectious diseases at the Children’s Medical Center. In
1949 he became assistant director of this division andWeller, Thomas Huckle 347