Origin of Species Variorum

→ each. 1866 1869 1872

each. By my theory these allied species have descended from a common parent; and during the process of modification, each has become adapted to the conditions of life of its own region, and has supplanted and exterminated its original parent and all the transitional varieties between its past and present states. 1859 1860 1861

→ By my theory these allied species are descended from a common parent; and during the process of modification, each has become adapted to the conditions of life of its own region, and has supplanted and exterminated its original parent-form and all the 1869 1872

Hence we ought not to expect at the present time to meet with numerous 1859 1860 1861

By my theory these allied species have descended from a common parent; and during the process of modification, each has become adapted to the conditions of life of its own region, and has supplanted and exterminated its original parent-form and all the 1866

→ between its past and present states. 1866 1869 1872

in each region, though they must have existed there, and may be embedded there in a fossil condition. 1859 1860 1861

→ Hence we ought not to expect at the present time to meet with numerous transitional varieties in each region, though they must have existed there, and may be embedded there in a fossil condition. 1869 1872

But in the intermediate region, having intermediate conditions of life, why do we not now find closely-linking intermediate varieties? 1859 1860 1861

Hence we ougth not to expect at the present time to meet with numerous transitional varieties in each region, though they must have existed there, and may be embedded there in a fossil condition. 1866

→ But in the intermediate region, having intermediate conditions of life, why do we not now find closely-linking intermediate varieties? 1866 1869 1872

This difficulty for a long time quite confounded me. 1859 1860 1861

→ This difficulty for a long time quite confounded me. 1866 1869 1872

But I think it can be in large part explained. 1859 1860 1861

→ most continents have 1869 1872

almost every continent has 1859 1860 1861 1866

But it may be urged that when several closely-allied species inhabit the same

territory

territory,

we surely ought to find at the present time many transitional forms. Let us take a simple case: in travelling from north to south over a continent, we generally meet at successive intervals with closely allied or representative species, evidently filling nearly the same place in the natural economy of the land. These representative species often meet and interlock; and as the one becomes rarer and rarer, the other becomes more and more frequent, till the one replaces the other. But if we compare these species where they intermingle, they are generally as absolutely distinct from each other in every detail of structure as are specimens taken from the metropolis inhabited by →each. →By my theory these allied species are descended from a common parent; and during the process of modification, each has become adapted to the conditions of life of its own region, and has supplanted and exterminated its original parent-form and all the transitional varieties →between its past and present states. →Hence we ought not to expect at the present time to meet with numerous transitional varieties in each region, though they must have existed there, and may be embedded there in a fossil condition. →But in the intermediate region, having intermediate conditions of life, why do we not now find closely-linking intermediate varieties? →This difficulty for a long time quite confounded me. But I think it can be in large part explained.

In the first place we should be extremely cautious in inferring, because an area is now continuous, that it has been continuous during a long period. Geology would lead us to believe that →most continents have been broken up into islands even during the later tertiary periods; and in such islands distinct species