| → so marvellous an instinct as that 1859 1860 1861 1866 1869 |
| the instinct 1872 |
|
| → which has 1860 1861 1866 1869 |
| which have 1859 |
| and which has 1872 |
|
| → shall be here discussed— Instinct 1859 1860 1861 |
| shall be here discussed—Instinct 1866 1869 |
| will here be discussed; some miscellaneous objections in the following chapter; Instinct 1872 |
|
| → separate 1859 1860 1861 1866 1869 |
| the two succeeding 1872 |
|
| → will, as we have seen, 1859 1860 1861 |
| OMIT 1866 1869 1872 |
|
| → hand. 1859 1860 1861 1866 1869 |
| hand. Hence, if we look at each species as descended from some unknown form, both the parent and all the transitional varieties will generally have been exterminated by the very process of the formation and perfection of the new form. 1872 |
|
|
as the
|
|
| Thirdly, can instincts be acquired and modified through natural selection? What shall we say to
→so marvellous an instinct as that
which leads the bee to make cells,
→which has
practically anticipated the discoveries of profound mathematicians? |
|
| Fourthly, how can we account for species, when crossed, being sterile and producing sterile offspring, whereas, when varieties are crossed, their fertility is unimpaired? |
|
| The two first heads
→shall be here discussed— Instinct
and Hybridism in
→separate
chapters. |
|
|
| As natural selection acts solely by the preservation of profitable modifications, each new form will tend in a fully-stocked country to take the place of, and finally to exterminate, its own less improved
other less-favoured forms with which it comes into competition. Thus extinction and natural selection
→will, as we have seen,
go hand in
→hand. Hence, if we look at each species as descended from some other unknown form, both the parent and all the transitional varieties will generally have been exterminated by the very process of
and perfection of the new form. |
|
| But, as by this theory innumerable transitional forms must have existed, why do we not find them embedded in countless numbers in the crust of the
It will be
more convenient to discuss this question in the chapter on the Imperfection of the
and I will here only state that I believe the answer mainly lies in the record being incomparably less perfect than is generally
|
