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1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1866
1869
1872

→ and, consequently, they will tend to 1861 1866 1869
consequently, they will tend to supplant and 1872
→ exterminate 1861 1872
supplant and exterminate 1866 1869
→ during the long course of ages and under varying 1859 1860 1861 1866
under changing 1869 1872
→ vary at all in the several 1859 1860 1861 1866
present individual differences in all 1869
present individual differences in almost every 1872
→ the high geometrical ratio 1860 1861 1866 1869
the high geometrical powers 1859
their geometrical rate 1872
→ of each species, 1859 1860 1861 1866 1869
a severe struggle for life 1872
→ a severe struggle for life at some age, season, or year, 1860 1861 1866 1869
at some age, season, or year, a severe struggle for life, 1859
at some age, season, or year, 1872
→ preservation 1861 1866
preservation, 1859 1860 1869
pre- servation, or the survival of the fittest, 1872
→ I 1859 1860 1861 1866 1872
or the survival of the fittest, I 1869
→ for the sake of brevity, 1859 1860 1861 1866
OMIT 1869 1872
→ Selection. 1859 1861 1866 1869 1872
Selection; and it leads to the improvement of each creature in relation to its organic and inorganic conditions of life. 1860
→ with 1859 1860 1861 1866
or rivalry with 1872
→ males. 1859 1860 1861 1866
males; and these characters will be transmitted to one sex or to both sexes, according to the form of inheritance which prevails. 1872
↑ 3 blocks not present in 1859 1860 1861 1866 1872; present in 1869
Natural selection, on the principle of qualities being inherited at corresponding ages, can modify the egg, seed, or young, as easily as the adult. Amongst many animals, sexual selection will give its aid to ordinary selection, by assuring to the most vigorous and best adapted males the greatest number of offspring. Sexual selection will also give characters useful only to the males, in their struggles with other males; and these characters will be transmitted to one sex or to both sexes, according to the form of inheritance which prevails.
→ nature, in modifying and 1859 1860 1861 1866
OMIT 1869 1872
help
to
in
exterminate
exterminating
it;
at least
at least
authors have thought that this comes into play in accounting for the deterioration of
the Aurochs
Aurochs
in Lithuania, of Red Deer in Scotland, and of
bears
Bears
in Norway,
&c.
&C.
As
As
far
far
as
as
animals
animals
are
are
concerned,
concerned,
some
some
species
species
are
are
closely
closely
adapted
adapted
to
to
prey
prey
on
on
some
some
one
one
other
other
organism;
being;
being;
but
but
if
if
this
this
other
other
organism
being
being
had
had
been
been
rare,
rare,
it
it
would
would
not
not
have
have
been
been
any
any
advantage
advantage
to
to
the
the
animal
animal
to
to
have
have
been
been
produced
produced
in
in
close
close
relation
relation
to
to
its
its
prey:
prey:
therefore,
therefore,
it
it
would
would
not
not
have
have
been
been
produced
produced
by
by
natural
natural
selection.
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; →and, consequently, they will tend to →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
globe,
world,
the endemic Australian species have been greatly reduced in number. How much weight to attribute to these several considerations I
will
do
not pretend to
say;
assign;
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,
→during the long course of ages and under varying conditions of
life
life,
organic beings →vary at all in the several
part
parts
of their
structure,
organisation,
and
I think
I think
this cannot be disputed; if there be, owing to →the high geometrical ratio of
increase,
increase
→of each species, →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
life,
existence,
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
variations
variation
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
ever do
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,
these
they
will tend to produce offspring similarly characterised. This principle of →preservation →I have
called
called,
→for the sake of brevity, Natural →Selection. It leads to the improvement of each creature in relation to its organic and inorganic conditions of life; and consequently, in most cases, to what must be regarded as an advance in organisation.
Nevertheless,
Nevertheless
low and simple forms
will
would
long endure if well fitted for their simple conditions of
life.
life.
Natural selection, on the principle of qualities being inherited at corresponding ages, can modify the egg, seed, or young, as easily as the adult. Amongst many animals, sexual selection will
have given
give
its aid to ordinary selection, by assuring to the most vigorous and best adapted males the greatest number of offspring. Sexual selection will also give characters useful to the males alone, in their struggles →with other →males. ↑
Whether natural selection has really thus acted in →nature, in modifying and adapting the various forms of life to their several conditions and stations, must be judged
of
of
by the general
tenour
tenor
and balance of
the evidence
evidence
given in the following chapters. But we
have already
already
seen
see
how it entails extinction; and how largely extinction has acted in the
worlds
world's
history, geology plainly declares. Natural selection, also, leads to divergence of