The morning call., 1893-11-23
Struggle for Existence of
All Things.
JORDAN ON EVOLUTION.
The Process of Natural Selec-
ton.
ONLY THE FITTEsT SURVIVES.
Unchecked Geometrical Increase OF
Animal and Plant Would Result
in Terrestrial Anarchy.

evening
by the large audience. He said:
81 be great motive force in evolution is
the process of natural selection. which
brings about order in life by removing all
those creatures not adapted to the condi-
tions in much the same way as the law of
gravitatiOn brings about cOsmc order By
the simple process Of bringing down to
earth everything that is movable. This is
n OF the only force in evolution, and it is
questionable to what it would lead il ii
were alone, but it is always present. will
always be present, and it is q factor that
must always be calculated upon in any
state of natural affairs. No one doubts ii,
get no one realizes it fully, so il is neces-
sary to 60 into its rudiments in order that
We may be able to discuss it later.
There are Of all kinds of animals and
plants a thousand born for one that
natures. The creatures that perish perish
because they cannot live, and the one who
lives lives because il is best adapted to
the conditions in which 1t finds itself. If
you put flies in bottle they will not all
die; those will live who can best breathe
the impure air. So the destruction is not
iDdlScrimi nate.
Nautilus says that mankind is always
while the food supply increases only on an
arithmeIical ratio.
sNow the world is limited, and any rate
of increase necessarily leads to a struggle
Tor existence. Nor is the ratio of increase
of any special Importance, for all geOmetric
will ultimately outrun all arithmetlcal pro-
gressions. This law is partly true, only it
does not take into account the better ways
of providing food which the human race
Will discover. However, the point
L want 10 make is hat this law
applies to every form of proto-
pIasm. Every one of the 100000 or
SO of animals and of the vastly more
numerous plants is trying just hard as
we are to occupy the whole earth. and
there is not single kind that would not,
if the conditions were suitable, occupy the
whole standing room on the earth in a
short time. OF course 1t would take
longer fol- elephants or sequoias to fill the
earth than bacteria, etc. Miss Mitchell.
the astronomer. had a conversation with
Hrrschell. in which he SAID that he bad
calculated the number of men who would
have been alive at that time on the earth.
if the conditions of life had been favorable
to each one living out his natural life, and
he had found that tier upon tier they
would cover the earth until they reached
he planet Uranus. There would not be
material enough on earth to supply them
with bone material.
"a Goldfish lays 10000 eggs; of these
10000, 5000 are females. and if each one
was guaranteed living, aud conditions
favored their DEVELOPMENT, in five years
the ocean and seas would be mass of cod
fish.
Two English sparrows with their
natural rate OF propagation, under condi-
lions that guaranteed their descendants
the enjoyment Of their natural te rm IF life,
would IN twenty years so cover a 5 ate like
Vx1a fhn$ n J. So
inch of SPACE.
''Linn8us said that three flies. on account
of their rate of multiplication, would de-
YOUR horse as quickly as i lion.
1T is calculated that there are 100 Co.,
O00,000,000 Fl es in the world to-day. If all
except one pair were destroyed in three
NJ onths there would be the same number,
provided only each was guaranteed its eX-
isIence.
ut is not great but continuous destruc-
tions that destroy species. The terrible
wars in Holland made no permanent diff
ference in the population. Malaria and
disease would have been more effective.
In the woods and rivers we see little
change, yet the change Is going on.
Some creatures are just barely able to
hold their own, and If pressed they grad
ually disappear. The Labrador duck has
gone; so too has the graf aux. The sea-
COW has disappeared from Alaska. where
il was numerous in 1850. The buffaloes
exist only in the Yellowstone; the pas
senger pigeon, to whose numbers Wilson
test fed, are gone; gone are the salmon
from the Columbia and so they will go
from the rivers of Alaska unless the Gov
eminent steps in and protects them.
species depend on species, as English
clover depends on cats. The clover is fer
:liZed by humble bees, the field mice eat
the bees, and the cats keep down the mice
and thus enable the bees TO fertlize the
clover. In consequence Huxley said that
the clover depended on the unmarried
women. In New ZEALAND they found the
clover would not 1--we without the bees.
"Spacies are substituted for species
The European rat takes the place of the
California rat. the English flv drives out
the Maori fly, and rabbits. foxes and
Scotch thistles thrive in Australia.
The races seasoned In struggle prevail;
the continental OF more specialized over
the insular or less specialized. A curious
witness is borne to this In Mark TwaIn's
book of the Yankee in King Arthur's
Court and Kipling's Man Who Would Be
KING
THE value of these ideas can be tested
by artificial selection. A man can develop
any kind of sheep which he may wish
along the line of its variations. Artificial
selection is the magician's wand by which
man can summon up almost anything he
ETC., so with patience he could develop a
race Of small elephants. Out of the ordi-
nary pigeon have come pouters. fantails,
umblers, etc. These forms never return
to original species unless the same condi-
tons return.
This name artificial selection gave the
idea TO Darwin OF the expression natural
selection, for just in the same way that
man improves stock SO nature is at work
all the time on every kind Of plant and
animal.
''rhe fittest survives. Nature is not a
respecter OF persons. The fittest is deter
mined by time and place. The best SWIM
mer is sometimes drowned. because be is
holder, more generous, less careful. The
law of natural selection is wasteful and
careless of results.
illustrations of the law are found in
the cottontail rabbits. North of the snow
line In Ohio and Pennsylvania the cotton
tails are white in winter and brown in
summer; In the South they remain brown,
In California the mountain rabbit is " bite.
that of the plains brown. The same
holds GOOD of the weasel. TIE reason ia
obvious. In Norway the further north
one goes the smaller grow the birch trees.
till in the rel deer pastures are found trees