Origin of Species Variorum

→ having 1869 1872

new varieties arising, which have 1859 1860 1861 1866

→ would be the most likely to give birth to the greatest number of 1869

would naturally oftenest give rise to 1859 1860 1861 1866

give birth to the greatest number of 1872

→ and 1861 1866 1869 1872

in their own homes, and are 1859 1860

→ producing 1869 1872

having produced 1859 1860

compared with other plants within their own homes, having produced 1861

compared with other less dominant plants, producing 1866

→ and on the gradual acclimatisation of new species to the various climates through which they might have to pass, but 1869 1872

but 1859 1860

or on the gradual acclimatisation of new species to the various climates through which they must pass, but 1861

or on the gradual acclimatisation of new species to the various climates through which they have to pass, but 1866

→ course of time 1866 1869 1872

long run 1859 1860 1861

→ spreading and would ultimately prevail. 1869 1872

spreading. 1859 1860 1861 1866

→ land than with those of the sea. 1869 1872

sea. 1859 1860 1861 1866

↑ 6 blocks not present in 1869 1872; present in 1859 1860 1861 1866

Dominant species spreading from any region might encounter still more dominant species, and then their triumphant course, or even their existence, would cease. We know not at all precisely what are all the conditions most favourable for the multiplication of new and dominant species; but we can, I think, clearly see that a number of individuals, from giving a better chance of the appearance of favourable variations, and that severe competition with many already existing forms, would be highly favourable, as would be the power of spreading into new territories. A certain amount of isolation, recurring at long intervals of time, would probably be also favourable, as before explained. One quarter of the world may have been most favourable for the production of new and dominant species on the land, and another for those in the waters of the sea. If two great regions had been for a long period favourably circumstanced in an equal degree, whenever their inhabitants met, the battle would be prolonged and severe; and some from one birthplace and some from the other might be victorious. But in the course of time, the forms dominant in the highest degree, wherever produced, would tend everywhere to prevail.

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

As they prevailed, they would cause the extinction of other and inferior forms; and as these inferior forms would be allied in groups by inheritance, whole groups would tend slowly to disappear; though here and there a single member might long be enabled to survive.

look to some special law. We shall see this more clearly when we treat of the present distribution of organic beings, and find how slight is the relation between the physical conditions of various

countries

countries,

and the nature of their inhabitants.

This great fact of the parallel succession of the forms of life throughout the world, is explicable on the theory of natural selection. New species are formed by →having some advantage over older forms; and

those

the

forms, which are already dominant, or have some advantage over the other forms in their own country, →would be the most likely to give birth to the greatest number of new varieties or incipient

species;

for

these

latter

must

victorious

still

higher

degree

order

preserved

and

survive.

We have distinct evidence on this head, in the plants which are dominant, that is, which are commonest →and most widely diffused, →producing the greatest number of new varieties. It is also natural that the

domi- nant,

dominant,

varying, and far-spreading species, which

have already

already have

invaded to a certain extent the territories of other species, should be those which would have the best chance of spreading still further, and of giving rise in new countries to

new

other new

varieties and species. The process of diffusion

may

would

often be very slow,

being

....

dependent

depending

on climatal and geographical changes,

....

on strange accidents, →and on the gradual acclimatisation of new species to the various climates through which they might have to pass, but in the →course of time the dominant forms

will

would

generally succeed in →spreading and would ultimately prevail. The diffusion would, it is probable, be slower with the terrestrial inhabitants of distinct continents than with the marine inhabitants of the continuous sea. We might therefore expect to find, as we

apparently

....

do find, a less strict degree of

parallel

parallelism

succession

....

in the

productions

succession

of the

land than

productions

of the →land than with those of the sea. ↑ ↑

Thus, as it seems to me, the parallel, and, taken in a