desired end. ↑1 blocks not present in 1859 1860 1861 1866 1869; present in 1872 | Breeders of cattle wish the flesh and fat to be well marbled together: an animal thus characterised has been slaughtered, but the breeder has gone with confidence to the same stock and has succeeded.
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Thus, a well-flavoured vegetable is cooked, and the individual is destroyed;
but the horticulturist sows seeds of
the same
family, family, 1861 | stock, 1859 1860 | stock 1866 1869 |
and
confidently expects to get nearly the same variety: breeders of cattle wish the flesh and fat to be well marbled together; the animal has been slaughtered, but the breeder goes with confidence to the same stock. confidently expects to get nearly the same variety: breeders of cattle wish the flesh and fat to be well marbled together; the animal has been slaughtered, but the breeder goes with confidence to the same stock. 1861 |
confidently expects to get nearly the same variety; breeders of cattle wish the flesh and fat to be well marbled together; the animal has been slaughtered, but the breeder goes with confidence to the same family. 1859 |
confidently expects to get nearly the same variety: breeders of cattle wish the flesh and fat to be well marbled together; the animal has been slaughtered, but the breeder goes with confidence to the same family. 1860 |
has succeeded. 1866 1869 |
I have
such
faith in
the powers
of selection, that I do not doubt that
a breed of cattle, always yielding oxen with extraordinarily long horns, could
be slowly
formed by carefully watching which individual bulls and cows, when matched, produced oxen with the longest horns; and yet no one ox could
ever have propagated its kind. ↑2 blocks not present in 1859 1860 1861; present in 1866 1869 1872 | Here is a better and real illustration: according to M. Verlot, some varieties of the double annual stock
of various colours,
from having been long carefully
selected to the right degree, always produce by seed
a large proportion of plants
bearing double and quite sterile flowers; so that, if the variety had not yielded others, it would at once have become extinct; but it likewise always
yields
some single and fertile plants,
which differ only in their power of producing which differ only in their power of producing two forms, from ordinary single varieties.
Thus
these single and fertile plants
may
be compared with the males
and females
of an ant-community,
and the sterile double-flowered plants, which are regularly produced in large numbers,
with the many sterile
neuters of the same community.
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↑1 blocks not present in 1859 1860 1861 1866 1869; present in 1872 | As with the varieties of the stock, so with social insects, selection has been applied to the family, and not to the individual, for the sake of gaining a serviceable end.
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Thus I believe it has been with social insects: a
slight modification
of structure,
or instinct,
correlated with the sterile condition of certain members of the community, has been advantageous to the community:
consequently the fertile males and females of the same community
flourished, and transmitted to their fertile offspring a tendency to produce sterile members having
the same modification. And I believe that
this
process has
been repeated,
until
that prodigious amount of difference between the fertile and sterile females of the same species has been produced, which we see in many
social insects. |
But we have not as yet touched on the climax of the difficulty; namely, the fact that the neuters of several ants differ, not only from the fertile females and males, but from each other, sometimes to an almost incredible degree, and are thus divided into two or even three castes. The castes, moreover, do not generally
graduate into each other, but are perfectly well defined; being as distinct from each other,
as are any two species of the same genus, or rather as any two genera of the same family. Thus in Eciton, there are working and soldier neuters, with jaws and instincts extraordinarily
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