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See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1866
1872

→ work. 1859 1860 1861 1866 1869
work will completely fail. 1872
→ a large amount of crossing with inferior animals. 1859 1860 1861 1866 1869
that there is no separation of selected individuals. 1872
→ natural selection will always tend to preserve 1869
as might be, natural selection will always tend to preserve 1859 1860 1861 1866
OMIT 1872
→ so as better to fill up the unoccupied place. 1859 1860 1861 1866 1869
will tend to be preserved. 1872
→ then, 1866 1869 1872
then 1859 1861
then if natural selection be modifying and improving a species in the several districts, there will be intercrossing with the other individuals of the same species on the confines of each. 1860
↑ 1 blocks not present in 1860 1869 1872; present in 1859 1861 1866
if natural selection be modifying and improving a species in the several districts, there will be intercrossing with the other individuals of the same species on the confines of each.
→ whether the result 1869
will in the long run generally be supplanted by one 1872
→ crossing of other varieties, or originally formed with an intermediate character, will in the long run generally be supplanted by one of the varieties on either hand. 1869
adjoining varieties. 1872
→ affect those animals most 1869
most affect those animals 1859 1860 1861 1866
chiefly affect those animals 1872
→ and afterwards spread, so that the crossing would be chiefly between 1869
so that whatever intercrossing took place would be chiefly between 1859 1860 1861 1866
and afterwards spread, so that 1872
→ new variety living together in the same place. 1869
same new variety. 1859 1860 1861 1866
new variety would chiefly cross together. 1872
his →work. But when many men, without intending to alter the breed, have a nearly common standard of perfection, and all try to
get
procure
and breed from the best animals,
much
much
improvement
and modification
....
surely but slowly
follow
follows
from this unconscious process of selection, notwithstanding →a large amount of crossing with inferior animals. Thus it will be
under
in
nature; for within a confined area, with some place in
the natural
its
polity not
so
....
perfectly
occupied
occupied,
→natural selection will always tend to preserve all the individuals varying in the right direction, though in different degrees, →so as better to fill up the unoccupied place. But if the area be
large,
very large,
its several districts will almost certainly present different conditions of life; and →then, ↑ if the same species undergoes modification in different
districts,
parts,
the newly-formed varieties will intercross on the confines of
each.
each
district.
district.
But we shall see in the
sixth
seventh
chapter that intermediate varieties, inhabiting
an
an
intermediate
districts,
district,
→whether the result of the →crossing of other varieties, or originally formed with an intermediate character, will in the long run generally be supplanted by one of the varieties on either hand.
The
....
intercrossing
Intercrossing
will →affect those animals most which unite for each
birth,
birth
which
and
wander much, and which do not breed at a very quick rate. Hence
in
with
animals of this nature, for
instance,
instance
in
....
birds, varieties will generally be confined to separated countries; and this I
believe
find
to be the case.
In
With
hermaphrodite organisms which cross only occasionally, and likewise
in
with
animals which unite for each birth, but which wander little and
which
....
can increase at a
very
very
rapid rate, a new and improved variety might be quickly formed on any one spot, and might there maintain itself in a
body,
body
→and afterwards spread, so that the crossing would be chiefly between the individuals of the →new variety living together in the same place. On
the above
this
principle, nurserymen