Origin of Species Variorum

→ case of an 1859 1860 1861 1866 1869

OMIT 1872

→ within the body, 1859 1860 1861 1866 1869

OMIT 1872

→ a case of very great difficulty 1859 1860 1861 1866 1869

OMIT 1872

→ but 1859 1860 1861 1866 1869

a case of great difficulty; but 1872

→ in the case of both 1859 1860 1861 1866 1869

both with 1872

→ not rarely, some of them 1859 1860 1861 1866 1869

OMIT 1872

→ with other individuals, 1859 1860 1861 1866 1869

OMIT 1872

→ I am strongly inclined to suspect that, both in the vegetable and animal kingdoms, 1859 1860 1861

I am strongly inclined to suspect, that, both in the vegetable and animal kingdoms, 1866 1869

it appears that with animals and plants 1872

→ law 1859 1860 1861 1866 1869

very general, if not universal, law 1872

→ to Natural Selection .— 1859

to Natural Selection. — 1860 1861

to Natural Selection. 1866

for the production of new forms through Natural Selection. 1869

for the production of new forms through Natural Selection. 1872

→ inheritable and diversified variability is favourable, but I believe mere 1859 1860

variability will evidently be favourable for the work of natural selection, but mere 1861 1866

variability, under which term 1869 1872

→ suffice for the work. 1859 1860

probably suffice. 1861 1866

are always included, will evidently be favourable. 1869 1872

→ for the appearance within any given period of profitable variations, 1859 1860 1861 1866

for the appearance of profitable variations within any given period, 1869

within any given period for the appearance of profitable variations, 1872

→ it may be said, 1859 1860

OMIT 1861 1866 1869 1872

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

Unless favourable variations be inherited by some at least of the offspring, nothing can be effected by natural selection.

→ man's 1859 1860 1861 1866

the case of 1869 1872

→ free intercrossing will wholly stop 1859 1860 1861 1866 1869

if the individuals be allowed freely to intercross, 1872

→ work. 1859 1860 1861 1866 1869

work will completely fail. 1872

→ a large amount of crossing with inferior animals. 1859 1860 1861 1866 1869

that there is no separation of selected individuals. 1872

→ as might be, natural selection will always tend to preserve 1859 1860 1861 1866

natural selection will always tend to preserve 1869

OMIT 1872

→ so as better to fill up the unoccupied place. 1859 1860 1861 1866 1869

will tend to be preserved. 1872

→ then 1859 1861

then if natural selection be modifying and improving a species in the several districts, there will be intercrossing with the other individuals of the same species on the confines of each. 1860

then, 1866 1869 1872

failed, after consultation with one of the highest authorities, namely, Professor Huxley, to discover a single →case of an hermaphrodite animal with the organs of reproduction so perfectly enclosed →within the body, that access from

without,

without

and the occasional influence of a distinct

individual,

individual

can be shown to be physically impossible. Cirripedes long appeared to me to

present,

present

→a case of very great difficulty under this point of

view,

view;

→but I have been enabled, by a fortunate chance,

~~elsewhere~~

elsewhere

to prove that two individuals, though both are self-fertilising hermaphrodites, do sometimes cross.

It must have struck most naturalists as a strange anomaly that, →in the case of both animals and plants,

some species

species

of the same family and even of the same genus, though agreeing closely with each other in

~~almost~~

almost

their whole organisation,

~~yet~~

yet

are →not rarely, some of them hermaphrodites, and some

~~of them~~

of them

unisexual. But if, in fact, all hermaphrodites do occasionally

intercross,

intercross

→with other individuals, the difference between

them

hermaphrodites

and unisexual

species

species,

is, as

far as function is concerned,

~~becomes~~

becomes

very small.

From these several considerations and from the many special facts which I have collected, but which I am

unable

not

here

~~able~~

able

to give, →I am strongly inclined to suspect that, both in the vegetable and animal kingdoms, an occasional intercross

between

with a

distinct

individuals

individual

is a →law of nature. I am well aware that there are, on this view, many cases of difficulty, some of which I am trying to investigate. Finally then, we may conclude that in many organic beings, a cross between two individuals is an obvious necessity for each birth; in many others it occurs perhaps only at long intervals; but in none, as I suspect, can self-fertilisation go on for perpetuity.

Circumstances

favourable

→ to Natural Selection .—

This is an extremely intricate subject. A

great

large

amount of →inheritable and diversified variability is favourable, but I believe mere individual differences →suffice for the work. A large number of individuals, by giving a better chance →for the appearance within any given period of profitable variations, will compensate for a lesser amount of variability in each individual, and is, I believe,

a highly

an extremely

important element of success. Though

Nature

nature

grants

long

vast

periods of time for the work of natural selection, she does not grant an indefinite period; for as all organic beings are

striving

striving,

→it may be said, to seize on each place in the economy of nature, if any one species does not become modified and improved in a corresponding degree with its competitors, it will

~~soon~~

soon

be exterminated. ↑

In →man's methodical selection, a breeder selects for some definite object, and →free intercrossing will wholly stop his →work. But when many men, without intending to alter the breed, have a nearly common standard of perfection, and all try to

procure

get

and breed from the best animals,

~~much~~

much

improvement

~~and modification~~

and modification

surely but slowly

follows

from this unconscious process of selection, notwithstanding →a large amount of crossing with inferior animals. Thus it will be

under

nature; for within a confined area, with some place in

the natural

its

polity not

perfectly

occupied,

occupied

→as might be, natural selection will always tend to preserve all the individuals varying in the right direction, though in different degrees, →so as better to fill up the unoccupied place. But if the area be

very large,

large,

its several districts will almost certainly present different conditions of life; and →then if natural selection be modifying and improving a species in the several districts, there will be intercrossing with the other individuals of the same species on the confines of each. And in this case the effects of intercrossing can hardly be

~~coun-~~

coun-