Comparison with 1860 |
|
plants on Alpine summits, or the thicker fur of an animal from far northwards, would not in some cases be inherited for at least some
few generations? and in this case I presume that the form would be called a variety. ↑2 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | It may perhaps
be doubted whether monstrosities, or such
sudden and great
deviations of structure as
we occasionally see in our domestic productions, more especially with plants, are ever permanently propagated in a state of nature.
Monsters are very apt to be sterile; and
almost
every part of every organic being,
at least with animals,
is so beautifully related to its complex conditions of life that it seems as improbable that any part should have been suddenly produced perfect, as that a complex machine should have been invented by man in a perfect state.
|
↑3 blocks not present in 1859 1860 1861; present in 1866 1869 1872 | Under domestication monstrosities sometimes
occur which resemble
normal structures
in widely different animals. Thus pigs have occasionally
been born with a sort of proboscis,
and if any wild species
of the same genus
had naturally possessed a proboscis, it might have been argued that this had
appeared
as a monstrosity; but I have as yet failed
to find, after diligent search,
cases of monstrosities resembling
normal structures in nearly allied forms, and these alone bear on the question.
If monstrous forms of this kind ever do appear in a state of nature and are capable of reproduction
(which is not always the case), as they occur rarely and singly, their preservation would depend on unusually favourable circumstances.
|
↑1 blocks not present in 1859 1860 1861 1869 1872; present in 1866 | If perpetuated in this crossed state, their preservation will be almost necessarily due to the modification being in some way beneficial to the animal under its then existing conditions of life; so that, even in this case, natural selection will come into play.
|
↑Subtitle not present 1859 1860 1861 |
Individual
Differences. 1866 |
|
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. ↑1 blocks not present in 1859 1860 1861; present in 1866 1869 1872 | The many slight differences which frequently
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, 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 to the great central ganglion of an insect would have been variable in the same species; I should have expected
that changes of this nature could have been effected only
|
plants on Alpine summits, or the thicker fur of an animal from far northwards, would not in some cases be inherited for at least
some some 1859 1860 1861 1866 1869 | a 1872 |
few generations? and in this case I presume that the form would be called a variety. ↑2 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | It may perhaps
be doubted whether monstrosities, or such
sudden and great
deviations of structure as
we occasionally see in our domestic productions, more especially with plants, are ever permanently propagated in a state of nature.
Monsters are very apt to be sterile; and
almost
every part of every organic being,
at least with animals,
is so beautifully related to its complex conditions of life that it seems as improbable that any part should have been suddenly produced perfect, as that a complex machine should have been invented by man in a perfect state.
|
↑3 blocks not present in 1859 1860 1861; present in 1866 1869 1872 | Under domestication monstrosities sometimes
occur which resemble
normal structures
in widely different animals. Thus pigs have occasionally
been born with a sort of proboscis,
and if any wild species
of the same genus
had naturally possessed a proboscis, it might have been argued that this had
appeared
as a monstrosity; but I have as yet failed
to find, after diligent search,
cases of monstrosities resembling
normal structures in nearly allied forms, and these alone bear on the question.
If monstrous forms of this kind ever do appear in a state of nature and are capable of reproduction
(which is not always the case), as they occur rarely and singly, their preservation would depend on unusually favourable circumstances.
|
↑1 blocks not present in 1859 1860 1861 1869 1872; present in 1866 | If perpetuated in this crossed state, their preservation will be almost necessarily due to the modification being in some way beneficial to the animal under its then existing conditions of life; so that, even in this case, natural selection will come into play.
|
↑Subtitle not present 1859 1860 1861 |
Individual
Differences. 1866 |
|
Again, we have many slight differences which may be called individual differences, such as are known
frequently frequently 1859 1860 | fre- quently 1861 |
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.
No one supposes that all the individuals of the same species are cast in the
very very 1859 1860 1861 | very 1866 1869 1872 |
same
mould. mould. 1859 1860 1861 | actual mould. 1866 1869 1872 |
These individual differences are
highly highly 1859 1860 1861 1866 |
of the highest 1869 1872 |
important important 1859 1860 1861 1866 | importance 1869 1872 |
for us,
as as 1859 1860 | for 1861 1866 1869 1872 |
they
afford afford 1859 1860 |
are often inherited, as must be familiar to every one; and thus they afford 1861 1866 |
are often inherited, as must be familiar to every one; and they thus afford 1869 1872 |
materials for natural selection to
accumulate, accumulate, 1859 1860 1861 |
act on and accumulate, 1866 1869 1872 |
in the same manner as man
can can 1859 1860 | can 1861 1866 1869 1872 |
accumulate accumulate 1859 1860 | accumulates 1861 1866 1869 1872 |
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
pleased pleased 1859 1860 1861 | being pleased 1866 1869 1872 |
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 I should 1859 1860 | It would 1861 1866 1869 1872 |
never have
expected expected 1859 1860 | been expected 1861 1866 1869 1872 |
that the branching of the main nerves close to the great central ganglion of an insect would have been variable in the same species;
I should have expected I should have expected 1859 1860 |
it might have been thought 1861 1866 1869 1872 |
that changes of this nature could have been effected only
|