| → having been effected through 1869 1872 |
| being effected by 1859 1860 1861 1866 |
|
| → ordinary animal, 1869 1872 |
| animal in the ordinary state, 1859 1860 1861 1866 |
|
| → which were 1869 1872 |
| of structure, this being 1859 1860 1861 1866 |
|
| → and that these 1869 1872 |
| which 1859 1860 1861 1866 |
|
| → inherited structure which are correlated with 1869 1872 |
| structure which have become correlated to 1859 1860 1861 1866 |
|
| → the oxen of 1869 1872 |
| in 1859 1860 1861 1866 |
|
| → relatively to the length of 1869 1872 |
| in comparison with 1859 1860 1861 1866 |
|
|
from both the males and fertile females, and yet, from being sterile, they cannot propagate their kind. |
|
| The subject well deserves to be discussed at great length, but I will here take only a single case, that of working or sterile ants. How the workers have been rendered sterile is a difficulty; but not much greater than that of any other striking modification of structure; for it can be shown that some insects and other articulate animals in a state of nature occasionally become sterile; and if such insects had been social, and it had been profitable to the community that a number should have been annually born capable of work, but incapable of procreation, I can see no
difficulty in this
→having been effected through
natural selection. But I must pass over this preliminary difficulty. The great difficulty lies in the working ants differing widely from both the males and the fertile females in structure, as in the shape of the
and in being destitute of wings and sometimes of eyes, and in instinct. As far as instinct alone is concerned, the
difference in this respect between the workers and the perfect females, would have been
better exemplified by the hive-bee. If a working ant or other neuter insect had been an
→ordinary animal,
I should have unhesitatingly assumed that all its characters had been slowly acquired through natural selection; namely, by
having been born with
slight profitable
→which were
inherited by
→and that these
again varied and
selected, and so
But with the working ant we have an insect differing greatly from its parents, yet absolutely
so that it could never have transmitted successively acquired modifications of structure or instinct to its progeny. It may well be asked how is it possible to reconcile this case with the theory of natural selection? |
|
| First, let it be remembered that we have innumerable instances, both in our domestic productions and in those in a state of nature, of all sorts of differences of
→inherited structure which are correlated with
certain ages, and
either sex. We have differences correlated not only
one sex, but
that short period
when the reproductive system is active, as in the nuptial plumage of many birds, and in the hooked jaws of the male salmon. We have even slight differences in the horns of different breeds of cattle in relation to an artificially imperfect state of the male sex; for oxen of certain breeds have longer horns than
→the oxen of
other breeds,
→relatively to the length of
the horns
the bulls
cows of these same breeds. Hence I can see no
difficulty in any character
correlated with the sterile condition of
|
