Origin of Species Variorum

→ under nature— were 1872

in a state of nature— had been 1859 1860 1861

in a state of nature — had been 1866 1869

→ fact of variations and monstrosities occurring much more frequently 1869 1872

much greater variability, as well as the greater frequency of monstrosities, 1859 1860 1861 1866

→ and the greater variability of species having wide ranges than of those with restricted ranges, lead 1872

leads me to believe that deviations of structure are in some way due 1859 1860

leads to the belief that deviations of structure are in some way due 1861 1866

and the greater variability of species having wide ranges than of those having restricted ranges, lead 1869

→ conclusion that variability is generally related to 1872

nature of 1859 1860 1861 1866

conclusion that variability is directly related to 1869

→ each species has 1869 1872

the parents and their more remote ancestors have 1859 1860 1861 1866

→ In 1869 1872

I have remarked in 1859 1860 1861 1866

→ chapter I attempted 1869 1872

chapter— but a long catalogue of facts which cannot be here given would be necessary 1859 1860 1861

chapter — but a long catalogue of facts which cannot be here given would be necessary 1866

→ that changed conditions act in two ways, directly on the whole organisation or on certain parts alone, and indirectly through 1872

the truth of the remark— that 1859 1860 1861

the truth of the remark — that 1866

that changed conditions act in two ways, directly on the whole organization or on certain parts alone, and indirectly through 1869

↑ 5 blocks not present in 1869 1872; present in 1859 1860 1861 1866

The male and female sexual elements seem to be affected before that union takes place which is to form a new being. In the case of "sporting" plants, the bud, which in its earliest condition does not apparently differ essentially from an ovule, is alone affected. But why, because the reproductive system is disturbed, this or that part should vary more or less, we are profoundly ignorant. Nevertheless, we can here and there dimly catch a faint ray of light, and we may feel sure that there must be some cause for each deviation of structure, however slight. How much direct effect difference of climate, food, &c., produces on any being is extremely doubtful.

CHAPTER V.

LAWS OF VARIATION.

Effects of

external

changed

conditions — Use and disuse, combined with natural selection; organs of flight and of vision — Acclimatisation —

Correlation

Correlated

of growth

variation

— Compensation and economy of growth — False correlations — Multiple, rudimentary, and lowly organised structures variable — Parts developed in an unusual manner are highly variable: specific characters more variable than generic: secondary sexual characters variable — Species of the same genus vary in an analogous manner — Reversions to

long lost

long-lost

characters — Summary.

I HAVE hitherto sometimes spoken as if the

variations —

variations—

so common and multiform

with

organic beings under domestication, and in a lesser degree

with

those →under nature— were due to chance. This, of course, is a wholly incorrect expression, but it serves to acknowledge plainly our ignorance of the cause of each particular variation. Some authors believe it to be as much the function of the reproductive system to produce individual differences, or

very

....

slight deviations of structure, as to make the child like its parents. But the →fact of variations and monstrosities occurring much more frequently under domestication

or cultivation,

....

than under nature, →and the greater variability of species having wide ranges than of those with restricted ranges, lead to the →conclusion that variability is generally related to the conditions of

life,

life

to which →each species has been exposed during several

generations.

successive generations.

→In the first →chapter I attempted to show →that changed conditions act in two ways, directly on the whole organisation or on certain parts alone, and indirectly through the reproductive

system

eminently

susceptible

changes

the

conditions

life;

and

this

system

being

functionally

disturbed

the

parents,

chiefly

attribute

the

varying

plastic

condition

the

offspring.

In all cases there are two factors, the nature of the organism, which is much the most important of the two, and the nature of the conditions. The direct action of changed conditions leads to definite or indefinite results. In the latter case the organisation seems to become plastic, and we have much fluctuating variability. In the former case the nature of the organism is such that it yields readily, when subjected to certain conditions, and all, or nearly all the individuals become modified in the same way. ↑

It is very difficult to decide how far changed conditions, such as of climate, food, &c., have acted in a definite manner. There is