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1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1866
1869

→ in any country becomes 1869 1872
become in any country 1861 1866
→ consequently, they will tend to supplant and 1872
and, consequently, they will tend to 1861 1866 1869
→ exterminate 1861 1872
supplant and exterminate 1866 1869
→ under changing 1869 1872
during the long course of ages and under varying 1859 1860 1861 1866
→ present individual differences in almost every 1872
vary at all in the several 1859 1860 1861 1866
present individual differences in all 1869
→ their geometrical rate 1872
the high geometrical powers 1859
the high geometrical ratio 1860 1861 1866 1869
→ a severe struggle for life 1872
of each species, 1859 1860 1861 1866 1869
→ at some age, season, or year, 1872
at some age, season, or year, a severe struggle for life, 1859
a severe struggle for life at some age, season, or year, 1860 1861 1866 1869
→ pre- servation, or the survival of the fittest, 1872
preservation, 1859 1860 1869
preservation 1861 1866
species
will
must
always be
sloW.
slow.
Imagine the extreme case of as many species as individuals in England, and the first severe winter or very dry summer would exterminate thousands on thousands of species. Rare species, and each species will become rare if the number of species →in any country becomes indefinitely increased, will, on the principle often explained, present within a given period few
favourable
favorable
variations; consequently, the process of giving birth to new specific forms
will
would
thus be retarded. When any species becomes very rare, close interbreeding will help
in
to
exterminating
exterminate
it;
at least
....
authors have thought that this comes into play in accounting for the deterioration of
Aurochs
the Aurochs
in Lithuania, of Red Deer in Scotland, and of
Bears
bears
in Norway,
&C.
&c.
As
....
far
....
as
....
animals
....
are
....
concerned,
....
some
....
species
....
are
....
closely
....
adapted
....
to
....
prey
....
on
....
some
....
one
....
other
....
being;
organism;
....
but
....
if
....
this
....
other
....
being
organism
....
had
....
been
....
rare,
....
it
....
would
....
not
....
have
....
been
....
any
....
advantage
....
to
....
the
....
animal
....
to
....
have
....
been
....
produced
....
in
....
close
....
relation
....
to
....
its
....
prey:
....
therefore,
....
it
....
would
....
not
....
have
....
been
....
produced
....
by
....
natural
....
selection.
....
Lastly, and this I am inclined to think is the most important element, a dominant species, which has already beaten many competitors in its own home, will tend to spread and supplant many others. Alph. de Candolle has shown that those species which spread
widely
widely,
tend generally to spread very widely; →consequently, they will tend to supplant and →exterminate several species in several areas, and thus check the inordinate increase of specific forms throughout the world. Dr. Hooker has recently shown that in the
S. E.
S.E.
corner of Australia, where, apparently, there are many invaders from different quarters of the
world,
globe,
the endemic Australian species have been greatly reduced in number. How much weight to attribute to these several considerations I
do
will
not pretend to
assign;
say;
but conjointly they must limit in each country the tendency to an indefinite augmentation of specific forms.
Summary
Summary
of
of
Chapter .—
Chapter. —
Chapter.
If,
If
→under changing conditions of
life,
life
organic beings →present individual differences in almost every
parts
part
of their
organisation,
structure,
and
I think
....
this cannot be disputed; if there be, owing to →their geometrical rate of
increase
increase,
→a severe struggle for life →at some age, season, or year, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of
existence,
life,
causing an infinite diversity in structure, constitution, and habits, to be advantageous to them,
I think
....
it would be a most extraordinary fact if no
variation
variations
ever had
ever
had ever
occurred useful to each
beings
being's
own welfare, in the same
way
manner
as so many variations have occurred useful to man. But if variations useful to any organic being
do
ever do
ever occur,
occur,
assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of
inheritance
inheritance,
they
these
will tend to produce offspring similarly characterised. This principle of →pre- servation, or the survival of the fittest,