Origin of Species Variorum

→ specialised 1859 1860 1861

in part or in whole specialised 1866 1869 1872

↑ 2 blocks not present in 1859 1860 1861; present in 1866 1869 1872

We have seen in two beings widely remote from each other in the natural scale, that an organ serving in both for the same purpose and appearing closely similar may have been separately and independently formed; but when such organs are closely examined, essential differences in their structure can almost always be detected; and this naturally follows from the principle of natural selection. On the other hand, the common rule throughout nature is infinite diversity of structure for gaining the same end; and this again naturally follows on the same great principle.

→ We 1859 1860 1861

In almost every case we 1866 1869

In many cases we 1872

→ in almost every case, 1859 1860 1861

OMIT 1866 1869 1872

→ But we may confidently believe that many modifications, wholly due to 1859 1860 1861 1866 1869

In many other cases, modifi- cations are probably the direct result of 1872

→ growth, and at first in no way advantageous to a species, have been subsequently taken advantage of by the still further modified descendants of this species. 1859 1860 1861 1866 1869

variation or of growth, independently of any good having been thus gained. 1872

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

But even such structures have often, as we may feel assured, been subsequently taken advantage of, and still further modified, for the good of species under new conditions of life.

→ natural selection,— a power which acts solely by the preservation of profitable variations in the struggle for life. 1859 1860 1861

natural selection,—a power which acts solely by the preservation of profitable variations in the struggle for life. 1866

natural selection,—a power which acts solely through the survival of the best-fitted individuals in the struggle for life. 1869

means of natural selection. 1872

→ Natural selection in 1859 1860 1861 1866 1869

In 1872

→ must act chiefly 1859 1860 1861 1866 1869

natural selection acts 1872

→ one with another, 1859 1860 1861 1866 1869

OMIT 1872

→ will produce perfection, or strength 1859 1860 1861 1866 1869

leads to success 1872

→ according to 1859 1860 1861 1866 1869

in accordance with 1872

→ as we see they do yield, 1859 1860 1861

OMIT 1866 1869 1872

simultaneously very different functions, and then having been →specialised for one function; and two

~~very~~

very

distinct organs having performed at the same time the same function, the one having been perfected whilst aided by the other, must often have largely facilitated transitions. ↑

→We are far too

ignorant

ignorant,

→in almost every case, to be enabled to assert that

any

part or organ is so unimportant for the welfare of a species, that modifications in its structure could not have been slowly accumulated by means of natural selection. →But we may confidently believe that many modifications, wholly due to the laws of →growth, and at first in no way advantageous to a species, have been subsequently taken advantage of by the still further modified descendants of this species. ↑ We may, also, believe that a part formerly of high importance has

frequently

often

been retained (as the tail of an aquatic animal by its terrestrial descendants), though it has become of such small importance that it could not, in its present state, have been acquired by →natural selection,— a power which acts solely by the preservation of profitable variations in the struggle for life.

Natural selection

can

will

produce nothing in one species for the exclusive good or injury of another; though it may well produce parts, organs, and excretions highly useful or even indispensable, or

again highly

highly

injurious to another species, but in all cases at the same time useful to the

possessor.

owner.

→Natural selection in each well-stocked

country

country,

→must act chiefly through the competition of the

inhabitants,

inhabitants