Comparison with 1860 |
|
a greater number of individuals be capable of there supporting themselves. A set of animals, with their organisation but little diversified, could hardly compete with a set more perfectly diversified in structure. It may be doubted, for instance, whether the Australian marsupials, which are divided into groups differing but little from each other, and feebly representing, as Mr. Waterhouse and others have remarked, our carnivorous, ruminant, and rodent mammals, could successfully compete with these
well-pronounced well-pronounced 1859 1860 1861 1866 1869 | well-developed 1872 |
orders. In the Australian mammals, we see the process of diversification in an early and incomplete stage of development. ↑Subtitle not present 1859 1860 1861 |
The
Probable
Effects of
the Action of Natural
Selection through
Divergence
of
Character
and
Extinction
,
on
the
Descendants
of
a
Common
Ancestor.
1866 1869 1872 |
|
After the foregoing discussion, which
ought to have ought to have 1859 1860 1861 1866 |
has 1869 1872 |
been much
amplified, amplified, 1859 1860 1861 1866 | compressed, 1869 1872 |
we
may, may, 1859 1860 | may 1861 1866 1869 1872 |
I think, I think, 1859 1860 | I think, 1861 1866 1869 1872 |
assume that the modified descendants of any one species will succeed
by by 1859 1860 1861 1866 1869 | by 1872 |
so much the better as they become more diversified in structure, and are thus enabled to encroach on places occupied by other beings. Now let us see how this principle of great
benefit being derived from divergence of character, combined with the principles of natural selection and of extinction,
will will 1859 1860 1861 | will 1866 1869 1872 |
tend tend 1859 1860 1861 | tends 1866 1869 1872 |
to act. |
|
The accompanying diagram will aid us in understanding this rather perplexing subject. Let A to L represent the species of a genus large in its own country; these species are supposed to resemble each other in unequal degrees,
as is so generally the case in nature, and as is represented in the diagram by the letters standing at unequal distances. I have said a large genus, because
we have seen we have seen 1859 1860 1861 1866 1869 |
as we saw 1872 |
in the second chapter,
that that 1859 1860 1861 1866 1869 | that 1872 |
on an average more
of the species of of the species of 1859 1860 1861 1866 1869 |
species vary in 1872 |
large genera
vary vary 1859 1860 1861 1866 1869 | vary 1872 |
than
of of 1859 1860 1861 1866 1869 | in 1872 |
small genera; and the varying species of the large genera present a greater number of varieties. We have, also, seen that the species, which are the commonest and the most
widely-diffused, widely-diffused, 1859 1860 | widely diffused, 1861 1866 1869 1872 |
vary more than
rare species with restricted ranges. rare species with restricted ranges. 1859 1860 1861 |
do the rare and restricted species. 1866 1869 1872 |
Let (A) be a common, widely-diffused, and varying species, belonging to a genus large in its own country. The
little fan of little fan of 1859 1860 1861 |
branching and 1866 1869 1872 |
diverging dotted lines of unequal lengths proceeding from (A), may represent its varying offspring. The variations are supposed to be extremely slight, but of the most diversified nature; they are not
supposed all to appear simultaneously, but often after long intervals of time; nor are they all supposed to endure for equal periods. Only those variations which are in some way profitable will be preserved or naturally selected. And here the importance of the principle of benefit
being being 1859 1860 1861 1866 1869 | being 1872 |
derived from divergence of character comes in; for this will generally lead to the most different or divergent variations
|
a greater number of individuals be capable of there supporting themselves. A set of animals, with their organisation but little diversified, could hardly compete with a set more perfectly diversified in structure. It may be doubted, for instance, whether the Australian marsupials, which are divided into groups differing but little from each other, and feebly representing, as Mr. Waterhouse and others have remarked, our carnivorous, ruminant, and rodent mammals, could successfully compete with these
well-developed well-developed 1872 | well-pronounced 1859 1860 1861 1866 1869 |
orders. In the Australian mammals, we see the process of diversification in an early and incomplete stage of development. |
The
Probable
Probable
1866 1872 |
Probable
1869 |
Effects
Effects
1872 |
Action
1866 |
Results
1869 |
of
the Action of
the Action of
1872 |
the Action of
1869 |
OMIT 1866 |
Natural
Natural
1866 1872 |
Natural
1869 |
Selection
Selection
1872 |
Selection,
1866 |
Selection
1869 |
through
through
1866 1872 |
through
1869 |
Divergence
Divergence
1866 1872 |
Divergence
1869 |
of
Character
Character
1866 1872 |
Character
1869 |
and
Extinction
,
Extinction
,
1872 |
Extinction,
1866 |
Extinction,
1869 |
on
the
Descendants
Descendants
1866 1872 |
Descendants
1869 |
of
a
Common
Common
1866 1872 |
Common
1869 |
Ancestor.
Ancestor. 1872 |
Ancestor. 1866 |
Ancestor.
1869 |
|
After the foregoing discussion, which
has has 1869 1872 |
ought to have 1859 1860 1861 1866 |
been much
compressed, compressed, 1869 1872 | amplified, 1859 1860 1861 1866 |
we
may may 1861 1866 1869 1872 | may, 1859 1860 |
....... 1861 1866 1869 1872 | I think, 1859 1860 |
assume that the modified descendants of any one species will succeed
....... 1872 | by 1859 1860 1861 1866 1869 |
so much the better as they become more diversified in structure, and are thus enabled to encroach on places occupied by other beings. Now let us see how this principle of
....... 1860 1861 1866 1869 1872 | great 1859 |
benefit being derived from divergence of character, combined with the principles of natural selection and of extinction,
....... 1866 1869 1872 | will 1859 1860 1861 |
tends tends 1866 1869 1872 | tend 1859 1860 1861 |
to act. |
|
The accompanying diagram will aid us in understanding this rather perplexing subject. Let A to L represent the species of a genus large in its own country; these species are supposed to resemble each other in unequal
degrees, degrees, 1859 1860 1861 1869 1872 | degress, 1866 |
as is so generally the case in nature, and as is represented in the diagram by the letters standing at unequal distances. I have said a large genus, because
as we saw as we saw 1872 |
we have seen 1859 1860 1861 1866 1869 |
in the second chapter,
....... 1872 | that 1859 1860 1861 1866 1869 |
on an average more
species vary in species vary in 1872 |
of the species of 1859 1860 1861 1866 1869 |
large genera
....... 1872 | vary 1859 1860 1861 1866 1869 |
than
in in 1872 | of 1859 1860 1861 1866 1869 |
small genera; and the varying species of the large genera present a greater number of varieties. We have, also, seen that the species, which are the commonest and the most
widely diffused, widely diffused, 1861 1866 1869 1872 | widely-diffused, 1859 1860 |
vary more than
do the rare and restricted species. do the rare and restricted species. 1866 1869 1872 |
rare species with restricted ranges. 1859 1860 1861 |
Let (A) be a common, widely-diffused, and varying species, belonging to a genus large in its own country. The
branching and branching and 1866 1869 1872 |
little fan of 1859 1860 1861 |
diverging dotted lines of unequal lengths proceeding from (A), may represent its varying offspring. The variations are supposed to be extremely slight, but of the most diversified nature; they are
not not 1859 1860 1861 1869 1872 | nor 1866 |
supposed all to appear simultaneously, but often after long intervals of time; nor are they all supposed to endure for equal periods. Only those variations which are in some way profitable will be preserved or naturally selected. And here the importance of the principle of benefit
....... 1872 | being 1859 1860 1861 1866 1869 |
derived from divergence of character comes in; for this will generally lead to the most different or divergent variations
|