| → view of the islands having 1859 1860 1861 1866 |
| islands have 1869 1872 |
|
| → island. 1859 1860 1861 1866 |
| island, though all proceeding from the same general source. 1869 1872 |
|
| → settled on any one or more 1859 1860 1861 1866 |
| first settled on one 1869 1872 |
|
| → more perfectly 1859 1860 1861 1866 |
| best fitted for it 1869 1872 |
|
| → distinct plants in one island than in another, and it 1859 1860 1861 1866 |
| somewhat different species in the different islands, and 1869 1872 |
|
| → and 1859 1860 1861 1866 |
| throughout a continent and 1869 1872 |
|
| → formed in the separate islands have not quickly spread 1859 1860 1861 1866 |
| after being formed in any one island, did not quickly spread 1869 |
| after being formed in any one island, did not spread quickly 1872 |
|
| → some of the 1866 1869 1872 |
| a good many 1859 1860 1861 |
|
|
in the several islands. This difference might indeed have been expected
the
→view of the islands having
been stocked by occasional means of transport— a seed, for instance, of one plant having been brought to one island, and that of another
to another
→island.
when in former times an immigrant
→settled on any one or more
of the islands, or when it subsequently spread from one
to another, it would undoubtedly be exposed to different conditions
in the different islands, for it would have to compete with
of
a
for instance, would find the
ground
→more perfectly
occupied by
→distinct plants in one island than in another, and it
would be exposed to the attacks of somewhat different enemies. If then it varied, natural selection would probably favour different varieties in the different islands. Some species, however, might spread and yet retain the same character throughout the group, just as we see
some species spreading widely
→and
remaining the same. |
|
| The really surprising fact in this case of the Galapagos Archipelago, and in a lesser degree in some analogous
is that
new species
→formed in the separate islands have not quickly spread
to the other islands. But the islands, though in sight of each other, are separated by deep arms of the sea, in most cases wider than the British Channel, and there is no reason to suppose that they have at any former period been continuously united. The currents of the sea are rapid and sweep
the
and gales of wind are extraordinarily rare; so that the islands are far more effectually separated from each other than they appear
on a map. Nevertheless
→some of the
species, both
found in other parts of the world and
confined to the archipelago, are common to
|
