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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

a good many 1859 1860 1861
some of the 1866 1869 1872

in the several islands. This difference might indeed have been expected
if
on
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
plant,
plant
to another island.
Hence,
Hence
when in former times an immigrant settled on any one or more of the islands, or when it subsequently spread from one
island
island
to another, it would undoubtedly be exposed to different conditions
of life
of life
in the different islands, for it would have to compete with
a different
different
set
sets
of
organisms;
organisms:
a
plant
plant,
for instance, would find the
best-fitted
best-fitted
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
on continents
on continents
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
cases,
instances,
is that
each
the
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
between
across
the
islands,
archipelago,
and gales of wind are extraordinarily rare; so that the islands are far more effectually separated from each other than they appear
to be
to be
on a map. Nevertheless a good many species, both
of those
those
found in other parts of the world and
of those
those
confined to the archipelago, are common to