Some naturalists have maintained that all variations are connected with the act of sexual reproduction; but this is certainly an error; for I have given in another work a long list of "sporting
plants;" plants;" 1872 | plants," 1869 |
as they are called by gardeners; — that is, of plants which have suddenly produced a single bud with a new and sometimes widely different character from that of the other buds on the same plant. These
bud variations, bud variations, 1872 | bud-variations, 1869 |
as they may be named, can be propagated by grafts, offsets, &c., and sometimes by seed. They occur rarely under nature, but
are far from rare are far from rare 1872 |
far from rarely 1869 |
under culture. As a single bud out of
..
many
thousands, thousands, 1872 | thousands 1869 |
produced year after year
on the same tree under uniform conditions, on the same tree under uniform conditions, 1872 |
under uniform conditions on the same tree, 1869 |
has been known suddenly to assume a new character; and as buds on distinct trees, growing under different conditions, have sometimes yielded nearly the same variety — for instance, buds on peach-trees producing nectarines, and buds on common roses producing moss-roses — we clearly see that the nature of the conditions is of
..
subordinate importance in comparison with the nature of the organism in determining each particular form of variation; —
perhaps of
not more importance than the nature of the
spark,
by which a mass of
..
combustible combustible 1872 | bustible 1869 |
matter is ignited, has in determining the nature of the flames. ↑Subtitle not present 1859 1860 1861 1866 1869 1872 |
|
↑9 blocks not present in 1869 1872; present in 1859 1860 1861 1866 | Sterility has been said to be the bane of horticulture; but on this view we owe variability to the same cause which produces sterility; and variability is the source of all the choicest productions of the garden.
I may add, that as some organisms will breed most
freely under the most unnatural conditions (for instance, the rabbit and ferret kept in hutches), showing that their reproductive system has not been thus affected; so will some animals and plants withstand domestication or cultivation, and vary very slightly — perhaps hardly more than in a state of nature.
A long list could easily be given of "sporting plants;" by this term gardeners mean a single bud or offset, which suddenly assumes a new and sometimes very different character from that of the rest of the plant.
Such buds can be propagated by grafting, &c., and sometimes by seed.
These "sports" are extremely rare under nature, but far from rare under cultivation; and in this case we see that the treatment of the parent has affected a bud or offset, and not the ovules or pollen.
But it is the opinion of most physiologists that there is no essential difference between a bud and an ovule in their earliest stages of formation; so that, in fact, "sports" support my
view, that variability may be largely attributed to the ovules or pollen, or to both, having been affected by the treatment of the parent prior to the act of conception.
These cases anyhow show that variation is not necessarily connected, as some authors have supposed, with the act of generation.
Seedlings from the same fruit, and the young of the same litter, sometimes differ considerably from each other, though both the young and the parents, as Müller has remarked, have apparently been exposed to exactly the same conditions of life; and this shows how unimportant the direct effects of the conditions of life are in comparison with the laws of reproduction, and
of growth, and of inheritance; for had the action of the conditions been direct, if any of the young had varied, all would probably have varied in the same manner.
To judge how much, in the case of any variation, we should attribute to the direct action of heat, moisture, light, food, &c., is most difficult: my impression is, that with animals such agencies have produced very little direct effect, though apparently more in the case of plants.
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↑1 blocks not present in 1866 1869 1872; present in 1859 1860 1861 | Under this point of view, Mr. Buckman's recent experiments on plants seem
extremely valuable.
|
|
Changed habits produce an inherited effect, Changed habits produce an inherited effect, 1872 |
Habit also has a decided influence, 1859 1860 1861 1866 |
Habits are inherited and have a decided influence; 1869 |
as in the period of
the flowering of the flowering of 1869 1872 |
flowering with 1859 1860 1861 1866 |
plants when transported from one climate to another.
With With 1872 | In 1859 1860 1861 1866 1869 |
animals
the increased use or disuse of parts has had the increased use or disuse of parts has had 1872 |
it has 1859 1860 1861 1866 |
they have 1869 |
a more marked
influence; thus influence; thus 1872 |
effect; for instance, 1859 1860 1861 1866 1869 |
I find in the domestic duck that the bones of the wing weigh less and the bones of the leg more, in proportion to the whole skeleton, than do the same bones in the wild-duck; and
...OMIT 1869 1872 |
I presume that 1859 1860 1861 1866 |
this change may be safely attributed to the domestic duck flying much less, and walking more, than its wild
parents. parents. 1869 1872 | parent. 1859 1860 1861 1866 |
The great and inherited development of the udders in cows and goats in countries where they are habitually milked, in comparison with
...OMIT 1872 |
the state of 1859 1860 1861 1866 1869 |
these organs in other countries, is
probably another probably another 1866 1869 1872 | another 1859 1860 1861 |
instance of the
effects effects 1866 1869 1872 | effect 1859 1860 1861 |
of use. Not
one of our one of our 1869 1872 |
a single 1859 1860 1861 1866 |
domestic
animals animals 1869 1872 | animal 1859 1860 1861 1866 |
can be named which has not in some country drooping ears; and the view
which has been suggested which has been suggested 1866 1869 1872 |
suggested by some authors, 1859 1860 1861 |
that the drooping is due to the disuse of the muscles of the ear, from the animals
....... 1866 1869 1872 | not 1859 1860 1861 |
being
seldom much alarmed, seldom much alarmed, 1872 |
much alarmed by danger, 1859 1860 1861 |
seldom alarmed by danger, 1866 1869 |
seems probable. |