Evening star., 1938-05-28
STARS, MEN AND ATOMS
Notebook of Science Progress in Field,
Laboratory and Study.
BY THOMAS R. HENRY.

Interior Alaska seems to have been the
Towering garden Of dead world during
the long winters Of the ages when the
Northern United States was a lifeless
sea of ice thousands OF feet thick.
This thesis is advanced by DR.. Erik
Hulten, botanist of the University of
Lund in Sweden. now studying the COL
lections of the Smithsonian Institution
at the end of an 18-year study OF the
flora of Alaska, the Aleutian Islands and
Kamchatka.
BY interpreting clues afforded by rare
and obscure plants in this area, DR.. Hull
ten is able to reconstruct good deal
of the history Of the glacial and inter-
glacial periods and thus confirm the
findings of geologists. Delicate little
blossoms which appear during the brief
Arctic summer serve as fingerprints OF
a tragic age in the progress Of life on
earth.
During the Pleistocene geological era,
which lasted about 100000 years, there
were four glaciations of large parts of
the North Temperate Zone with three
warm interglacial periods. The present
epoch may be the fourth interglaclal.
Four times resistless oceans OF ice crept
down from the north across Canada
and the northern half of the United
States, crushing out all plant life and
a good deal of animal life before them.
But in each case, 50 far as North Amer
lea was concerned, the progress OF the
glaciation was veered toward the south
east, emptying into the Atlantic ocean.
Because of this, as DR.. Hultens plant
evidence shows, the Yukon Valley and
the slopes of the Northern Alaskan
Mountains were left uncovered, to be-
come the gardens of the dead world.
During the warm, moist interglaclals,
plant life from the central zones would
slowly migrate northward. Alaska would
thus have great variety of species when
the climate again began to change and
the ice to descend. All plant life would
be relentlessly wiped out nearly every
where else. The climate of the Alaskan
life island would become extremely cold.
Now plants, like all forms OF life, are
extremely variable. No two individuals
are exactly alike and there are innu-
merable groupings into varieties and SUBJ
varieties. This is one of the prime
requisites for the mechanism OF evolu-
tion. The effect Of the radical change
of climate in the Alaskan garden must
have been to kill great numbers Of species
and varieties. Only those especially
adapted for cold could have survived
the long epochs of the ice oceans. The
variation within a species or genus was
cut down enormously.
Then would come another interglacial.
The climate would become increasingly
hot and damp. This would result in more
killing, only those surviving which were
able to endure both dry cold and wet
heat in restricted environment. In
other words, the survivors become ex-
traordinarily specialized and non-var1a-
ble-features which, DR.. Hulten believes,
extended to their genetic makeup.
SO today DR.. Hulten finds In the Yu-
kon Valley genetically frozen" varieties,
species and even genera of various IA
miliar plants which either are found no
where else, or south Of the farthest ex-
tent Of the icecaps, or In small areas
like the Gaspe Peninsula Of Quebec or
the northwestern coast Of Norway. which
also escaped the glacial foundations. BY