|
which allowed certain forms and not others to enter, either in greater or lesser numbers; according or not, as those which entered happened to come
more or less direct competition with each other and with the
and according as the immigrants were capable of varying more or less rapidly, there would ensue in
→different
regions, independently of their physical conditions, infinitely diversified conditions of life,— there would be an almost endless amount of organic action and reaction,— and we should
→as we do find,
some groups of beings greatly, and some only slightly
some
in great force, some existing in scanty numbers—
→in the different
great geographical provinces of the world. |
| On these same
we can understand, as I have endeavoured to show, why oceanic islands should have few inhabitants, but
a
should be endemic or peculiar; and why, in relation to the means of migration, one group of
→even within the same class,
should have all its species
and another
→should
have all its species
→common to other
of the world. We can see why whole groups of organisms, as batrachians and terrestrial mammals, should be absent from oceanic islands, whilst the most isolated islands
their own peculiar species of
mammals or bats. We can see
→there
should be some relation between the
→of
mammals, in a more or less modified
→and
the depth of the sea between
and the mainland. We can clearly see why all the inhabitants of an archipelago, though specifically distinct on the several islets, should be closely related to each
and
be related, but less closely, to those of the nearest
or other source whence immigrants
→were probably
We can see
→in
two areas, however distant from each other,
|
