Origin of Species Variorum

→ best fitted for it 1869 1872

more perfectly 1859 1860 1861 1866

→ somewhat different species in the different islands, and 1869 1872

distinct plants in one island than in another, and it 1859 1860 1861 1866

→ throughout a continent and 1869 1872

and 1859 1860 1861 1866

→ after being formed in any one island, did not spread quickly 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

→ some of the 1866 1869 1872

a good many 1859 1860 1861

→ their present manner of distribution, that they have 1869 1872

certain facts that these have probably 1859 1860 1861 1866

→ intercommunication. Undoubtedly, if one species has any advantage over another, it will in a very brief time wholly or in part supplant it; but if both are equally well fitted for their own places, both will probably hold their separate places for almost any length of time. 1872

intercommunication. 1859 1860 1866 1869

inter-communication. 1861

↑ 1 blocks not present in 1872; present in 1859 1860 1861 1866 1869

Undoubtedly if one species has any advantage whatever over another, it will in a very brief time wholly or in part supplant it; but if both are equally well fitted for their own places in nature, both probably will hold their own places and keep separate for almost any length of time.

→ differ on the different islands; 1872

are distinct on each; 1859 1860 1861 1866 1869

→ mocking-thrush 1859 1860 1861 1866 1872

mocking thrush of 1869

of life

....

in the different islands, for it would have to compete with

different

sets

organisms:

plant,

for instance, would find the

best-fitted

....

ground →best fitted for it occupied by →somewhat different species in the different islands, and 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

....

some species spreading widely →throughout a continent and remaining the same.

The really surprising fact in this case of the Galapagos Archipelago, and in a lesser degree in some analogous

instances,

cases,

is that

the

each

new species →after being formed in any one island, did not spread quickly 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

across

between

the

archipelago,

islands,

and gales of wind are extraordinarily rare; so that the islands are far more effectually separated from each other than they appear

to be

....

on a map. Nevertheless →some of the species, both

those

of those

found in other parts of the world and

those

of those

confined to the archipelago, are common to the several

islands,

islands;

and we may infer from →their present manner of distribution, that they have spread from

some

....

one island to the others. But we often take, I think, an erroneous view of the probability of

closely allied

closely-allied

species invading each

others

other's

territory, when put into free →intercommunication. Undoubtedly, if one species has any advantage over another, it will in a very brief time wholly or in part supplant it; but if both are equally well fitted for their own places, both will probably hold their separate places for almost any length of time. ↑ Being familiar with the fact that many species, naturalised through

mans

man's

agency, have spread with astonishing rapidity over

new countries,

wide areas,

we are apt to infer that most species would thus spread; but we should remember that the

forms

species

which become naturalised in new countries are not generally closely allied to the aboriginal inhabitants, but are very distinct

species,

forms,

belonging in a large proportion of cases, as shown by Alph. de Candolle, to distinct genera. In the Galapagos Archipelago, many even of the birds, though so well adapted for flying from island to island, →differ on the different islands; thus there are three closely-allied species of mocking-thrush, each confined to its own island. Now let us suppose the →mocking-thrush

Chatham Island to be blown to Charles Island, which has its own

mocking-thrush:

mocking-thrush;

why should it succeed in establishing itself there? We