| → kind. 1859 1860 1861 1866 1869 |
| of its existing inhabitants. 1872 |
|
| ↑ 1 blocks not present in 1859 1860 1861 1866 1872; present in 1869 |
| But the effects of natural selection will probably still oftener depend on some few of the inhabitants becoming slowly modified; the mutual relations of the other inhabitants being thus disturbed.
|
|
| → On the other hand, 1859 1860 1861 1866 |
| But 1869 1872 |
|
| → generally at only 1866 |
| often only at 1859 1860 1861 |
| in effecting changes, at 1869 |
| only at 1872 |
|
| → action of natural selection accords perfectly 1859 1860 1861 1866 |
| results of natural selection accord perfectly 1869 |
| results accord 1872 |
|
| → his powers of 1859 1860 1861 1866 |
| OMIT 1869 1872 |
|
| → selection. 1859 1860 1861 1866 |
| selection or the survival of the fittest. 1869 |
| selection, that is by the survival of the fittest. 1872 |
|
| →
Extinction caused by Natural Selection. 1866 1872 |
|
Extinction
.—
1859 |
|
Extinction.
—
1860 1861 |
|
Extinction caused by Natural Selection.
1869 |
|
|
of some
→kind. The existence of such places will often depend on physical changes, which are generally very slow, and on the immigration of better adapted forms
checked. ↑ But the action of natural selection will probably still oftener depend on some
the inhabitants becoming slowly modified; the mutual relations of many of the other inhabitants being thus disturbed. Nothing can be effected, unless favourable variations occur, and variation itself is apparently always a
slow process. The process will often be greatly retarded by free intercrossing. Many will exclaim that these several causes are amply sufficient
to
the
of natural selection. I do not believe so.
→On the other hand,
I do believe that natural selection
very
→generally at only
long intervals of time, and
on
a
few of the inhabitants of the same
I further
that
slow,
→action of natural selection accords perfectly
with what geology tells us of the rate and manner at which the inhabitants of
world have changed. |
|
| Slow though the process of selection may be, if feeble man can do much by
→his powers of
artificial selection, I can see no limit to the amount of change, to the beauty and
complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may
in the long course of time
nature's power of
→selection.
|
|
→
Extinction caused by Natural Selection.
|
| This subject will be more fully discussed in our chapter on Geology; but it must
alluded to from being intimately connected with natural selection.
|
