Comparison with 1872 |
|
return in a future chapter to the preservation and perpetuation of
single or single or 1872 | single or 1869 |
occasional variations. ↑4 blocks not present in 1859 1860 1866 1869 1872; present in 1861 | I have not, at least, been able to find good cases of species in a state of nature presenting modifications of structure resembling monstrosities observed in allied forms.
If such have occurred, their perpetuation will have been due to their beneficial nature, so that natural selection will have come into play.
Many cases are known of plants which regularly produce on different branches, or on the circumference and in the centre of umbels, &c., flowers of a widely different structure; and if the plant ceased to produce flowers of the one kind, a great change might perhaps suddenly be effected in the specific character; but then we do not at present know by what steps, or for what good, a plant produces two kinds of flowers.
With cultivated plants, in the few cases known of a variety habitually bearing flowers or fruit slightly different from each other, the production of the variety has been sudden.
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|
Individual
Differences.
↑1 blocks not present in 1866 1869 1872; present in 1859 1860 1861 | Again, we have many slight differences which may be called individual differences, such as are known frequently
to appear in the offspring from the same parents, or which may be presumed to have thus arisen, from being frequently observed in the individuals of the same species inhabiting the same confined locality.
|
The many slight differences which
....... 1872 | frequently 1866 1869 |
appear in the offspring from the same parents, or which
it may
be presumed
..
have thus arisen, from being
....... 1872 | frequently 1866 1869 |
observed in the individuals of the same species inhabiting the same confined locality, may be called individual differences. No one supposes that all the individuals of the same species are cast in the very
same mould. These individual differences are highly
important
for us, as
they afford
materials for natural selection to accumulate,
in the same manner as man can
accumulate
in any given direction individual differences in his domesticated productions. These individual differences generally affect what naturalists consider unimportant parts; but I could show by a long catalogue of facts, that parts which must be called important, whether viewed under a physiological or classificatory point of view, sometimes vary in the individuals of the same species. I am convinced that the most experienced naturalist would be surprised at the number of the cases of variability, even in important parts of structure, which he could collect on good authority, as I have collected, during a course of years. It
should be remembered that systematists are far from pleased
at finding variability in important characters, and that there are not many men who will laboriously examine internal and important organs, and compare them in many specimens of the same species. I should
never have expected
that the branching of the main nerves close
|
return in a future chapter to the preservation and perpetuation of
..
occasional variations. ↑4 blocks not present in 1859 1860 1866 1869 1872; present in 1861 | I have not, at least, been able to find good cases of species in a state of nature presenting modifications of structure resembling monstrosities observed in allied forms.
If such have occurred, their perpetuation will have been due to their beneficial nature, so that natural selection will have come into play.
Many cases are known of plants which regularly produce on different branches, or on the circumference and in the centre of umbels, &c., flowers of a widely different structure; and if the plant ceased to produce flowers of the one kind, a great change might perhaps suddenly be effected in the specific character; but then we do not at present know by what steps, or for what good, a plant produces two kinds of flowers.
With cultivated plants, in the few cases known of a variety habitually bearing flowers or fruit slightly different from each other, the production of the variety has been sudden.
|
|
Individual
Differences.
↑1 blocks not present in 1866 1869 1872; present in 1859 1860 1861 | Again, we have many slight differences which may be called individual differences, such as are known frequently
to appear in the offspring from the same parents, or which may be presumed to have thus arisen, from being frequently observed in the individuals of the same species inhabiting the same confined locality.
|
The many slight differences which
frequently frequently 1866 1869 | frequently 1872 |
appear in the offspring from the same parents, or which
may
be presumed
to
have thus arisen, from being
frequently frequently 1866 1869 | frequently 1872 |
observed in the individuals of the same species inhabiting the same confined locality, may be called individual differences. No one supposes that all the individuals of the same species are cast in the
....... 1866 1869 1872 | very 1859 1860 1861 |
same
actual mould. actual mould. 1866 1869 1872 | mould. 1859 1860 1861 |
These individual differences are
of the highest of the highest 1869 1872 |
highly 1859 1860 1861 1866 |
importance importance 1869 1872 | important 1859 1860 1861 1866 |
for us,
for for 1861 1866 1869 1872 | as 1859 1860 |
they
are often inherited, as must be familiar to every one; and they thus afford are often inherited, as must be familiar to every one; and they thus afford 1869 1872 |
afford 1859 1860 |
are often inherited, as must be familiar to every one; and thus they afford 1861 1866 |
materials for natural selection to
act on and accumulate, act on and accumulate, 1866 1869 1872 |
accumulate, 1859 1860 1861 |
in the same manner as man
....... 1861 1866 1869 1872 | can 1859 1860 |
accumulates accumulates 1861 1866 1869 1872 | accumulate 1859 1860 |
in any given direction individual differences in his domesticated productions. These individual differences generally affect what naturalists consider unimportant parts; but I could show by a long catalogue of facts, that parts which must be called important, whether viewed under a physiological or classificatory point of view, sometimes vary in the individuals of the same species. I am convinced that the most experienced naturalist would be surprised at the number of the cases of variability, even in important parts of structure, which he could collect on good authority, as I have collected, during a course of years.
It It 1859 1860 1861 1869 1872 | I 1866 |
should be remembered that systematists are far from
being pleased being pleased 1866 1869 1872 | pleased 1859 1860 1861 |
at finding variability in important characters, and that there are not many men who will laboriously examine internal and important organs, and compare them in many specimens of the same species.
It would It would 1861 1866 1869 1872 | I should 1859 1860 |
never have
been expected been expected 1861 1866 1869 1872 | expected 1859 1860 |
that the branching of the main nerves close
|