Origin of Species Variorum

→ This similarity 1869 1872

On the other hand, these 1859 1860 1861 1866

→ does give, strongly 1866 1869 1872

gives, 1859 1860

gives 1861

→ can be classed with all 1869 1872

belong to the same system with 1859 1860 1861 1866

→ naturally 1869 1872

falling either into the same or into intermediate groups, 1859 1860 1861 1866

→ species 1869 1872

the groups which have descended from an ancient progenitor 1859 1860 1861 1866

→ during their long course of descent and modification, 1869 1872

the progenitor with its early descendants will often be intermediate in character in comparison with its later descendants; and thus 1859 1860 1861 1866

→ it is that the 1869 1872

the 1859 1860 1861 1866

→ forms, or early progenitors of each group, so often occupy a position 1869 1872

a fossil is, the oftener it stands 1859 1860 1861 1866

→ on the whole, higher in the scale of organisation 1869 1872

in some vague sense, higher 1859 1860

on the whole, higher 1861 1866

→ must be higher, 1869 1872

are 1859 1860 1861 1866

→ in so far 1869 1872

in so far higher 1859 1860 1861

higher in so far 1866

→ life; they have also generally had their organs more specialised for different functions. 1872

life. 1859 1860

life; they will also generally have had their organs more specialised for different functions. 1861 1866

life; they have also generally had their organs more specialized for different functions. 1869

→ but little improved structures, 1869 1872

little improved organisation 1861 1866

at some instincts being

apparently

....

not perfect and liable to mistakes, and at many instincts causing other animals to suffer.

If species be only well-marked and permanent varieties, we can at once see why their crossed offspring should follow the same complex laws in their degrees and kinds of resemblance to their parents,— in being absorbed into each other by successive crosses, and in other such points,— as do the crossed offspring of acknowledged varieties. →This similarity would be

strange

a strange

facts

fact,

if species

have

had

been independently

created,

created

and varieties

have

had

been produced

through

secondary laws.

If we admit that the geological record is imperfect

an extreme degree, then

such

the

facts

facts,

which

the record →does give, strongly support the theory of descent with modification. New species have come on the stage slowly and at successive intervals; and the amount of change, after equal intervals of time, is widely different in different groups. The extinction of species and of whole groups of species, which has played so conspicuous a part in the history of the organic world, almost inevitably follows

from

the principle of natural selection; for old forms

will be

are

supplanted by new and improved forms. Neither single species nor groups of species

reappear

re-appear

when the chain of ordinary generation

has

once

been

....

broken. The gradual diffusion of dominant

forms

forms,

with the slow modification of their descendants, causes the forms of life, after long intervals of time, to appear as if they had changed simultaneously throughout the world. The fact of the fossil remains of each formation being in some degree intermediate in character between the fossils in the

formation

formations

above and below, is simply explained by their intermediate position in the chain of descent. The grand fact that all extinct

organic

....

beings →can be classed with all recent beings, →naturally follows from the living and the extinct being the

off-spring

offspring

of common parents. As →species have generally diverged in

character,

character

→during their long course of descent and modification, we can

see

understand

why →it is that the more ancient →forms, or early progenitors of each group, so often occupy a position in some degree intermediate between existing

and allied

allied

....

groups. Recent forms are generally looked

upon

as being, →on the whole, higher in the scale of organisation than ancient

and extinct

....

forms; and they →must be higher, →in so far as the later and more improved forms have conquered the older and less improved

organic beings

forms

in the struggle for →life; they have also generally had their organs more specialised for different functions. This fact is perfectly compatible with numerous beings still retaining

....

simple and →but little improved structures, fitted for simple conditions of life; it is likewise compatible with some