Origin of Species Variorum

→ insuperable; though they often are 1859 1860 1861 1866

far from insuperable; though 1869 1872

→ extremely great. 1860 1861 1866

extremely grave. 1859

they are often great. 1869 1872

→ has been the influence of the modern 1859 1860 1861 1866

a part the 1869

a part the last 1872

→ which I am fully convinced simultaneously affected the whole world, or at least great longitudinal belts. 1861 1866

which I am fully convinced simultaneously affected the whole world, or at least great meridional belts. 1859 1860

has played, which affected even the equatorial regions, and which, during the alternations of the cold in the north and south, allowed the productions of opposite hemispheres to mingle, and left some of them stranded in all parts of the world on the mountain-summits. 1869

has played, which affected even the equatorial regions, and which, during the alternations of the cold in the north and south, allowed the productions of opposite hemispheres to mingle, and left some of them stranded on the mountain-summits in all parts of the world. 1872

→ allied species, 1859 1860 1861 1866

the several species belong- ing to the same genus, 1869

the several species belonging to the same genus, 1872

→ (generally of the more dominant forms of life), 1859 1860 1861 1866

OMIT 1869 1872

→ which separate our 1859 1860 1861 1866

in not only separating, but in apparently forming the 1869 1872

→ sub-genera, genera, and families; 1859 1860 1861 1866

related species within the same areas; 1869 1872

→ in 1859 1860 1861 1866

linked together in 1869 1872

→ linked together by affinity, 1859 1860 1861

linked together, 1866

OMIT 1869 1872

→ region; according to the nature of the 1859 1860 1861

of the regions, or both; according to the nature of the 1866 1869 1872

difficulties are →insuperable; though they often are in this case,

and

in that of the individuals of the same species, →extremely great.

As exemplifying the effects of climatal changes on distribution, I have attempted to show how important →has been the influence of the modern Glacial

period

period,

→which I am fully convinced simultaneously affected the whole world, or at least great longitudinal belts. As showing how diversified are the means of occasional transport, I have discussed at some little length the means of dispersal of fresh-water productions.

If the difficulties be not insuperable in admitting that in the long course of time

all the

the

individuals of the same species, and likewise of →allied species, have proceeded from some one source; then

I think

....

all the grand leading facts of geographical distribution are explicable on the theory of

migration,

migration

→(generally of the more dominant forms of life), together with subsequent modification and the multiplication of new forms. We can thus understand the high importance of barriers, whether of land or water, →which separate our several zoological and botanical provinces. We can thus understand the

concentration

localisation

of →sub-genera, genera, and families; and how it is that under different latitudes, for instance in South America, the inhabitants of the plains and mountains, of the forests, marshes, and deserts, are →in so mysterious a

manner,

manner

→linked together by affinity, and are likewise linked to the extinct beings which formerly inhabited the same continent. Bearing in mind that the mutual

relations

relation

of organism to organism

are

of the highest importance, we can see why two areas having nearly the same physical conditions should often be inhabited by very different forms of life; for according to the length of time which has elapsed since

new colonists

the colonists

new inhabitants

entered one →region; according to the nature of the communication