Origin of Species Variorum

→ only at 1872

often only at 1859 1860 1861

generally at only 1866

in effecting changes, at 1869

→ results accord 1872

action of natural selection accords perfectly 1859 1860 1861 1866

results of natural selection accord perfectly 1869

→ OMIT 1869 1872

his powers of 1859 1860 1861 1866

→ selection, that is by the survival of the fittest. 1872

selection. 1859 1860 1861 1866

selection or the survival of the fittest. 1869

→ Extinction caused by Natural Selection. 1866 1872

Extinction .— 1859

Extinction. — 1860 1861

Extinction caused by Natural Selection. 1869

→ Owing to 1869 1872

But as from 1859 1860

From 1861 1866

→ inhabitants; 1872

inhabitants, 1859 1860

the full number of its existing inhabitants, and as most areas are already stocked with a great diversity of forms, 1861 1866 1869

→ and it follows from this, 1872

it follows 1859 1860 1861 1866 1869

→ the 1872

each selected and 1859 1860 1861 1866 1869

→ which is represented 1872

represented 1859 1860 1861 1866 1869

→ run a good chance of utter extinction, during great 1872

during 1859 1860 1861 1866 1869

→ nature of the seasons, or from a temporary increase 1872

seasons or 1859 1860 1861 1866 1869

→ OMIT 1872

continually and slowly being 1859 1860 1861 1866 1869

→ OMIT 1872

the number of 1859 1860 1861 1866 1869

→ can go on 1872

goes on perpetually and almost 1859 1860 1861 1866 1869

→ in number, many old forms 1872

numbers inevitably 1859 1860 1861

many inevitably 1866 1869

→ plainly tells us; and we shall presently attempt to show why it is that 1872

shows us plainly; and indeed we can see reason why they should not have thus increased, for 1859 1860

tells us plainly; and we shall presently attempt to show why it is that 1861 1866 1869

→ species throughout the world has not become immeasurably great. 1861 1866 1869 1872

places in the polity of nature is not indefinitely great,— not that we have any means of knowing that any one region has as yet got its maximum of species. 1859 1860

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

Probably no region is as yet fully stocked, for at the Cape of Good Hope, where more species of plants are crowded together than in any other quarter of the world, some foreign plants have become naturalised, without causing, as far as we know, the extinction of any natives.

→ and diffused or dominant species which offer 1872

species which afford 1859 1860

species which offer 1861 1866 1869

→ and improved descendants 1872

descendants 1859 1860 1861 1866 1869

do believe that natural selection

will always

always

generally

will generally

acts

act

very

slowly

slowly,

→only at long intervals of time, and

generally

only

....

very

....

few of the inhabitants of the same

region

the

same

time.

I further

believe,

believe

that

this very

this

these

slow,

intermit- tent

inter- mittent

intermittent

→results accord

~~well~~

well

with what geology tells us of the rate and manner at which the inhabitants of

this

the

world have changed.

Slow though the process of selection may be, if feeble man can do much by →OMIT artificial selection, I can see no limit to the amount of change, to the beauty and

infinite

....

complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may

have been

effected

affected

in the long course of time

through

nature's power of →selection, that is by the survival of the fittest.

→ Extinction caused by Natural Selection.

This subject will be more fully discussed in our chapter on Geology; but it must

be here

here be

alluded to from being intimately connected with natural selection. Natural selection acts solely through the preservation of variations in some way advantageous, which consequently endure. →Owing to the high geometrical

powers

ratio

rate

of increase of all organic beings, each area is already

~~fully~~

fully

stocked with →inhabitants; →and it follows from this,

that,

that

as →the favoured

form

increases

in number,

generally will

the less favoured

forms

....

decrease and become rare. Rarity, as geology tells us, is the precursor to extinction. We

can,

can

also,

....

see that any form →which is represented by few individuals

will,

will

→run a good chance of utter extinction, during great fluctuations in the →nature of the seasons, or from a temporary increase in the number of its

enemies,

run

good

chance

utter

extinction.

But we may go further than this;

for

for,

as new forms are →OMIT produced, unless we

believe

admit

that →OMIT specific forms →can go on indefinitely

increasing,

increasing

→in number, many old forms must become extinct. That the number of specific forms has not indefinitely increased, geology →plainly tells us; and we shall presently attempt to show why it is that the number of →species throughout the world has not become immeasurably great. ↑

We have seen that the species which are most

nume- rous

numerous

in individuals have the best chance of producing favourable variations within any given period. We have evidence of this, in the facts

given

stated

in the second chapter, showing that it is the common →and diffused or dominant species which offer the greatest number of recorded

varieties,

varieties.