| →
a
14
,
1859 1861 1866 1869 1872 |
|
a
14
1860 |
|
| →
q
14
,
1859 1861 1866 1869 1872 |
| , 1860 |
|
| →
p
14
,
1859 1861 1866 1869 1872 |
|
q
14
,
1860 |
|
| → will 1859 1861 1866 1869 1872 |
|
p
14
, will
1860 |
|
| →
a
10
;
1859 1861 1866 1869 1872 |
|
a
10
1860 |
|
| →
b
14
,
1861 1866 1869 1872 |
|
b
14
1859 |
|
;
b
14
1860 |
|
| →
f
14
,
1859 1861 1866 1869 1872 |
|
f
14
1860 |
|
| →
a
5
,
1859 1861 1866 1869 1872 |
|
a
5
,
1860 |
|
| →
o
14
,
1859 1861 1866 1869 1872 |
|
o
14
1860 |
|
| →
e
14
,
1859 1861 1866 1869 1872 |
|
,
e
14
,
1860 |
|
| →
m
14
,
1859 1861 1866 1869 1872 |
|
m
14
1860 |
|
| → descendants. 1859 1860 1861 1866 1872 |
| descendants. Hence the six new species descended from (I), and the eight descended from (A), will have to be ranked as very distinct genera, or even as distinct sub-families. 1869 |
|
| ↑ 1 blocks not present in 1861 1869; present in 1859 1860 1866 1872 |
| Hence the six new species descended from (I), and the eight descended from (A), will have to be ranked as very distinct genera, or even as distinct sub-families.
|
|
|
transmitted descendants to this late stage of descent. |
|
| The new species in our diagram descended from the original eleven species, will now be fifteen in number. Owing to the divergent tendency of natural selection, the extreme amount of difference in character between species
a
14
and
z
14
will be much greater than that between the most
of the original eleven species. The new species, moreover, will be allied to each other in a widely different
Of the eight descendants from (A) the three marked
→
a
14
,
→
q
14
,
→
p
14
,
→will
be nearly related from having recently branched off from
→
a
10
;
→
b
14
,
and
→
f
14
,
having diverged at an earlier period from
→
a
5
,
will be in some degree distinct from the three first-named species; and lastly,
→
o
14
,
→
e
14
,
and
→
m
14
,
be nearly related one to the other,
from having diverged at the first commencement of the process of modification, will be widely different from the other five species, and may constitute a sub-genus or
a distinct genus. |
|
| The six descendants from (I) will form two
or
genera. But as the original species (I) differed largely from (A), standing nearly at the extreme
of the original genus, the six descendants from (I) will, owing to
considerably from the eight descendants from (A); the two groups, moreover, are supposed to have gone on diverging in different directions. The intermediate species, also (and this is a very important consideration), which connected the original species (A) and (I), have all become, excepting (F), extinct, and have left no
→descendants.
↑
|
|
| Thus it is, as I believe, that two or more genera
|
