| → in some necessary manner correlated. 1872 |
| correlated in some necessary manner. 1859 1860 1861 1866 1869 |
|
| → can alone act. 1872 |
| acts. 1869 |
|
| ↑ 1 blocks not present in 1869 1872; present in 1859 1860 1861 1866 |
| So, again, I do not doubt that some apparent
correlations, occurring throughout whole orders, are entirely
due to the manner alone in which natural selection can act.
|
|
| → impossibility of seeds gradually becoming 1869 1872 |
| fact that seeds could not gradually become 1859 1860 1861 1866 |
|
| → unless the capsules were open: for in this case alone could the 1872 |
| except in fruits which opened; so that the individual plants producing 1859 1860 1861 1866 |
| unless the capsules first opened themselves; for in this case alone could the 1869 |
|
| → by the wind, gain 1869 1872 |
| further, might get 1859 1860 1861 1866 |
|
| → others less well 1872 |
| those producing seed less 1859 1860 1861 1866 |
| those less well 1869 |
|
| → wide dispersal. 1869 1872 |
| dispersal; and this process could not possibly go on in fruit which did not open. 1859 1860 1861 1866 |
|
|
truth are simply due to inheritance; for an ancient progenitor may have acquired through natural selection some one modification in structure, and, after thousands of generations, some other and independent modification; and these two modifications, having been transmitted to a whole group of descendants with diverse habits, would naturally be thought to be
→in some necessary manner correlated. Some
are apparently due to the manner in which natural selection
→can alone act.
↑
For instance, Alph.
Candolle has remarked that winged seeds are never found in fruits which do not
I should explain
rule by the
→impossibility of seeds gradually becoming
winged through natural selection,
→unless the capsules were open: for in this case alone could the
which were a little better
to be wafted
→by the wind, gain
an advantage over
→others less well
fitted for
→wide dispersal.
|
| Compensation
and
Economy
of
|
| The elder Geoffroy and Goethe propounded, at about the same
their law of compensation or balancement of growth; or, as Goethe expressed it, "in order to spend on one side, nature is forced to economise on the other side." I think this holds true to a certain extent with our domestic productions: if nourishment flows to one part or organ in excess, it rarely flows, at least in excess, to another part; thus it is difficult to get a cow to give much milk and to fatten readily. The same varieties of the cabbage do not yield abundant and nutritious foliage and a copious supply of oil-bearing seeds. When the seeds in our fruits become atrophied, the fruit itself gains largely in size and quality. In our poultry, a large tuft of feathers on the head is generally accompanied by a diminished comb, and a large beard by diminished wattles. With species in a state of nature it can hardly be maintained that the law is of universal application; but many good observers, more especially botanists, believe in its truth. I will not, however, here give any instances, for I see hardly any way of distinguishing between the effects, on the one hand, of a part being largely developed through natural selection and another and adjoining part being reduced by this same process or by disuse, and, on the other hand, the actual withdrawal of nutriment from one part owing to the excess of growth in another and adjoining part. |
|
| I suspect, also, that some
cases of compensation which have been advanced, and likewise some other facts, may be merged under a more general principle, namely, that natural selection is continually trying to economise
every part of the organisation. If under changed conditions of life a
before
becomes
|
