| → in their affinities they 1860 1861 1866 1869 1872 |
| they 1859 |
|
| → which 1859 1860 1861 |
| both of which 1866 1869 |
| both 1872 |
|
| → all species first existed as 1859 1860 1861 |
| each existed first as a 1866 1869 1872 |
|
|
view we can understand how it is that in
region 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
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
→in their affinities they
are clustered in little groups round other species— in
→which
respects
varieties. These are strange relations on the view
each species
independently created, but are intelligible if
→all species first existed as
|
|
| As each species tends by its geometrical
of reproduction to increase inordinately in number; and as the modified descendants of each species will be enabled to increase by
much
as they become
diversified in habits and structure, so as to be
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.
during a long-continued course of modification, the slight
characteristic of varieties of the same species, tend to be augmented into the greater differences characteristic of
of the same genus. New and improved varieties will inevitably supplant and exterminate the older, less
and intermediate varieties; and thus species are rendered to a large extent defined and distinct objects. Dominant species belonging to the
|
