Origin of Species Variorum

→ though ranked as distinct species, being closely related, 1859 1860 1861 1866

being closely related, though ranked as distinct species, 1869 1872

→ two 1859 1860 1861

in any two 1866 1869 1872

→ Forms .— 1859 1860

compared with Living Forms. — 1861

compared with Living Forms. 1866

compared with Living Forms. 1869

compared with Living Forms . 1872

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

We have seen in the fourth chapter that the degree of differentiation and specialisation of the parts in all organic beings, when arrived at maturity, is the best standard, as yet suggested, of their degree of perfection or highness. We have also seen that, as the specialisation of parts and organs is an advantage to each being, so natural selection will tend to render the organisation of each being more specialised and perfect, and in this sense higher; not but that it may and will leave many creatures with simple and unimproved structures fitted for simple conditions of life, and in some cases will even degrade or simplify the organisation, yet leaving such degraded beings better fitted for their new walks of life.

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

formations, by the physical conditions of the ancient areas having remained nearly the same. Let it be remembered that the forms of life, at least those inhabiting the sea, have changed almost simultaneously throughout the world, and therefore under the most different climates and conditions. Consider the

pro- digious

prodigious

vicissitudes of climate during the pleistocene period, which includes the whole glacial

epoch,

period,

and note how little the specific forms of the inhabitants of the sea have been affected.

On the theory of descent, the full meaning of the

~~fact of~~

fact of

fossil remains from closely consecutive

formations

formations,

→though ranked as distinct species, being closely related, is obvious. As the accumulation of each formation has often been interrupted, and as long blank intervals have intervened between successive formations, we ought not to expect to find, as I attempted to show in the last chapter, in any one or →two

formations,

formations

all the intermediate varieties between the species which appeared at the commencement and close of these

periods:

periods;

but we ought to find after intervals, very long as measured by years, but only moderately long as measured geologically, closely allied forms, or, as they have been called by some authors, representative species; and these

assuredly we

we assuredly

do find. We find, in short, such evidence of the slow and scarcely sensible

mutations

mutation

of specific forms, as we have

the

a just

right to

expect.

expect

~~find.~~

find.

the

State

state

Development

Ancient

→ Forms .— ↑ There has been much discussion whether recent forms are more highly developed than ancient. I will not here enter on this subject, for naturalists have not as yet defined to each other's satisfaction what is meant by high and low forms. ↑ But in one particular sense the