where many species of a genus have been produced, and where they now flourish, these same species should present many varieties; for where the manufactory of species has been active, we might expect, as a general rule, to find it still in action; and this is the case if varieties be incipient species. Moreover, the species of the larger genera, which afford the
greater greater 1859 1860 1861 1869 1872 | great 1866 |
number of varieties or incipient species, retain to a certain degree the character of varieties; for they differ from each other by a less amount of difference than do the species of smaller genera. The closely allied species also of the larger genera apparently have restricted ranges, and
they they 1859 |
in their affinities they 1860 1861 1866 1869 1872 |
are clustered in little groups round other species— in
which which 1859 1860 1861 |
both of which 1866 1869 |
both 1872 |
respects
they they 1859 1860 1861 1866 1869 | they 1872 |
resemble resemble 1859 1860 1861 1866 1869 | resembling 1872 |
varieties. These are strange relations on the view
of of 1859 1860 1861 | that 1866 1869 1872 |
each species
having been having been 1859 1860 1861 | was 1866 1869 1872 |
independently created, but are intelligible if
all species first existed as all species first existed as 1859 1860 1861 |
each existed first as a 1866 1869 1872 |
varieties. varieties. 1859 1860 1861 | variety. 1866 1869 1872 |
|
|
As each species tends by its geometrical
ratio ratio 1859 1860 1861 1866 1869 | rate 1872 |
of reproduction to increase inordinately in number; and as the modified descendants of each species will be enabled to increase by
so so 1859 1860 1861 1866 1869 | as 1872 |
much
the more the more 1859 1860 1861 1866 1869 | the more 1872 |
as they become
more more 1859 1872 | more 1860 1861 1866 1869 |
diversified in habits and structure, so as to be
enabled enabled 1859 1860 1861 1866 1869 | able 1872 |
to seize on many and widely different places in the economy of nature, there will be a constant tendency in natural selection to preserve the most divergent offspring of any one species.
Hence Hence 1859 1860 1861 | Hence, 1866 1869 1872 |
during a long-continued course of modification, the slight
differences, differences, 1859 1860 1861 1866 1869 | differences 1872 |
characteristic of varieties of the same species, tend to be augmented into the greater differences characteristic of
species species 1859 1860 1861 | the species 1866 1869 1872 |
of the same genus. New and improved varieties will inevitably supplant and exterminate the older, less
improved improved 1859 1860 1861 1866 1869 | improved, 1872 |
and intermediate varieties; and thus species are rendered to a large extent defined and distinct objects. Dominant species belonging to the larger groups
tend tend 1859 1860 |
within each class tend 1861 1866 1869 1872 |
to give birth to new and dominant
|