Evening star., 1952-04-29
Sharks Defy Law
|0f Evolution, Study
|By Science Shows
By Thomas R. Henry
Science Editor Of The Stor

SSiO''sS eN''Ss ~ INV SiS'
Evolution's greatest enigma is
the shark.
For more than a million CEN
turies this curious family of fishes
which includes not only the
sharks themselves but the rays
and dogfisheS-has existed, pros
pered, and stood still.
This seems against the first law
of evolution which DEGREES that
life must adjust to change or
perish, DR.. Henry B. Bigelow of
Harvard University. probably the
worlds foremost expert on sharks,
told the Academy of Sciences
when he was awarded the Elliot
medal for biology.
AS fishes the sharks are ex-
tremely primitive. They antedate
the true fishes, which began to
appear in the Eocene. or dawn age,
about so million years ago by an
other SO million years. When they
first appeared in the seas, the
dominant creatures were enor-
nous reptiles, paralleling the di-
nosaurs on land, known as the
ichthysaurs. Long before the dawn
age the monsters had disappeared.
Period Of Great Progress.
The period of great progress
among the sharks, DR.. Bigelow
pointed out, came just before the
dawn age, in the upper cretaceous
geological period about IS million
years ago which marked the end
of the dinosaurs.
The race underwent a burst of
evolution Then, DR.. Bigelow
said, it stopped dead in its tracks.
There are absolutely identical
sharks in the North Atlantic and
the North Pacific. They cannot
endure the cold water of the Arc
tic. So they must have existed.
just as they are today, before the
Arctic existed. There are abso-
Ilutely identical cold water sharks
in the sub-Arctic and sub-Ant-
arctic. They cannot live in tenn
perate waters. Thus they must
have existed before the present
barriers of the temperate seas.
Nearly everything that was in
existence when the sharks started
long since has become extinct, or
has progressed into some form of
life with very little likeness to its
first ancestors.
DR.. Bigelow spoke of 268 known
kinds of sharks. All of them, he
said, apparently lacked nothing
needed for success"
The sharks first great blessing,
he said, probably was that it had
no intelligence-at least it never
has given evidence of using intel
ligence. although it has an ana
tomical brain as good as that of
some of the higher fishes. Else
where, brains seem only to have
gotten animals into trouble.
Good Sight, Smell Senses.
Second, DR.. Bigelow said, the
sharks have unexcelled senses of
sight and smell to follow prey.
Then they have magnificent teeth
often teeth of various shapes in
tended for different purposes
which might be compared to
kitchen equipment.
On top of all this, DR.. Bigelow
said, the Shark-unlike the fishes
lis able to bear living young.
It invented" the placenta long
before the mammals and formed
it out of different tissue, but it
serves its purpose admirably
Some sharks also lay eggs.
The shark is probably about as
evil .as it looks. DR.. Bigelow said
While most of the family are
small, sluggish animals, he ex-
planned, there is little question o1
the dangerous ferocity of larger
species.
The Henry Draper Medal was
awarded posthumously to DR.. Ber-
nard Lyot of the Meudon Observa-
tory, Paris, for his work on the
suns corona.
The Agassiz Medal was awarded
DR.. Harry A. Mariner of the United
States Coast and Geodetic Survey
for his Investigations of the tides.
DR.. H. r. Morgan of Yale Uni
versity, formerly of the Naval OBJ
Servatory here, was awarded the
academy's Watson Medal for his
80 years work in positional as
tronomy.