| → tropical and temperate South 1866 1869 1872 |
| South 1859 1860 1861 |
|
| → On the other hand, these 1859 1860 1861 1866 |
| This similarity 1869 1872 |
|
|
inherited for a very long period; for in this case it will have been rendered constant by long-continued natural selection. |
|
| Glancing at instincts, marvellous as some are, they offer no greater difficulty than
corporeal
on the theory of the natural selection of successive, slight, but profitable modifications. We can thus understand why nature moves by graduated steps in endowing different animals of the same class with their several instincts. I have attempted to show how much light the principle of
throws on the admirable architectural powers of the hive-bee. Habit no doubt
comes into play in modifying instincts; but it certainly is not indispensable, as we
in the case of neuter insects, which leave no progeny to inherit the effects of long-continued habit. On the view of all the species of the same genus having descended from a common parent, and having inherited much in common, we can understand how it is that allied species, when placed under
different conditions of life, yet
follow nearly the same instincts; why the
of
→tropical and temperate South
America, for instance,
with mud like our British species. On the view of instincts having been slowly acquired through natural
we need not marvel at some instincts being
not perfect and liable to mistakes, and at many instincts causing other animals to suffer. |
|
| If species be only well-marked and permanent varieties, we can at once see why their crossed offspring should follow the same complex laws in their degrees and kinds of resemblance to their parents,— in being absorbed into each other by successive crosses, and in other such points,— as do the crossed offspring of acknowledged varieties.
→On the other hand, these
|
