Comparison with 1860 |
|
and the consequent extinction of less-favoured
forms almost inevitably follows. It is the same with our domestic productions:
when a new and slightly improved variety has been raised, it at first supplants
the less improved varieties in the same neighbourhood; 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 natural and artificial,
are bound together. In certain
flourishing groups, the number of new specific forms which have been produced within a given time is probably
greater than that
of the old forms
which have been exterminated; but we know that the number of species has
not gone on indefinitely increasing, at least during the later geological periods,
so that
looking to later times
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 will have
seized on the place occupied by a species belonging to a distinct group, and thus
caused caused 1859 1860 | cause 1861 1866 | have caused 1869 1872 |
its extermination;
and if
many
allied forms be developed from the
successful successful 1859 1860 1866 1869 1872 | success- 1861 |
|
and the consequent extinction of
less-favoured less-favoured 1859 1860 1861 | the less-favoured 1866 1869 1872 |
forms almost inevitably follows. It is the same with our domestic
productions: productions: 1859 1860 1861 | productions; 1866 1869 1872 |
when a new and slightly improved variety has been raised, it at first
supplants supplants 1859 1860 1861 1869 1872 | generally supplants 1866 |
the less improved varieties in the same neighbourhood; 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
natural and artificial, natural and artificial, 1859 1860 1861 |
those naturally and those artificially produced, 1866 1869 1872 |
are bound together. In
certain certain 1859 1860 1861 | certain 1866 1869 1872 |
flourishing groups, the number of new specific forms which have been produced within a given time
is probably is probably 1859 1860 1861 |
has at some periods probably been 1866 1869 1872 |
greater than
that that 1859 1860 1861 | the number 1866 1869 1872 |
of the old
specific forms specific forms 1860 1861 1866 1869 1872 | forms 1859 |
which have been exterminated; but we know that
the number of species has the number of species has 1859 1860 1861 |
species have 1866 1869 1872 |
not gone on indefinitely increasing, at least during the later geological
periods, periods, 1859 1860 1861 | epochs, 1866 1869 1872 |
so
that that 1859 1860 1861 | that, 1866 1869 1872 |
looking to later
times times 1859 1860 1861 | times, 1866 1869 1872 |
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.
I. e.
1860 1861 |
i
.
e
.
1859 |
i.e.
1866 1869 1872 |
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
will have will have 1859 1860 1861 1866 | has 1869 1872 |
seized on the place occupied by a species belonging to a distinct group, and thus
cause cause 1861 1866 | caused 1859 1860 | have caused 1869 1872 |
its
extermination; extermination; 1859 1860 1861 | examination; 1866 | extermination. 1869 1872 |
and if and if 1859 1860 1861 1866 | If 1869 1872 |
many many 1859 1860 1861 1869 1872 | any 1866 |
allied forms be developed from the
success- success- 1861 | successful 1859 1860 1866 1869 1872 |
|