→ those naturally and those artificially produced, 1866 1869 1872 |
natural and artificial, 1859 1860 1861 |
|
→ has at some periods probably been 1866 1869 1872 |
is probably 1859 1860 1861 |
|
→ species have 1866 1869 1872 |
the number of species has 1859 1860 1861 |
|
→
i.e.
1866 1869 1872 |
i
.
e
.
1859 |
I. e.
1860 1861 |
|
when much improved it is transported far and near, like our short-horn cattle, and takes the place of other breeds in other countries. Thus the appearance of new forms and the disappearance of old forms, both
→those naturally and those artificially produced,
are bound together. In
flourishing groups, the number of new specific forms which have been produced within a given time
→has at some periods probably been
greater than
of the old
which have been exterminated; but we know that
→species have
not gone on indefinitely increasing, at least during the later geological
so
looking to later
we may believe that the production of new forms has caused the extinction of about the same number of old forms. |
|
The competition will generally be most severe, as formerly explained and illustrated by examples, between the forms which are most like each other in all respects. Hence the improved and modified descendants of a species will generally cause the extermination of the parent-species; and if many new forms have been developed from any one species, the nearest allies of that species,
→
i.e.
the species of the same genus, will be the most liable to extermination. Thus, as I believe, a number of new species descended from one species, that is a new genus, comes to supplant an old genus, belonging to the same family. But it must often have happened that a new species belonging to some one group
seized on the place occupied by a species belonging to a distinct group, and thus
its
allied forms be developed from the
many will have to yield their places; and it will generally be
forms, which will suffer from some inherited inferiority in common. But whether it be species belonging to the same or to a distinct class,
|