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→ insect. 1859 1860 1861 1866
insect; 1869
insect; and these modifications may affect, through correlation, the structure of the adult. 1872
→ These modifications will probably 1866
These modifications will no doubt 1859 1860 1861
and these modifications may 1869
→ the laws of 1859 1860 1861 1866
OMIT 1869
→ will probably often 1859 1860 1861 1866
may 1869 1872
→ modifications consequent on other modifications at a different period of life, 1859 1860 1861 1866
they 1869 1872
→ in the least degree 1859 1860 1861 1866
OMIT 1869 1872
→ would cause the extinction of the species. 1859 1860 1861 1866
species would become extinct. 1869 1872
→ community; if each in consequence 1859 1860 1861 1866
whole community; if this in consequence 1869
whole community; if the community 1872
and agricultural plants; in the caterpillar and cocoon stages of the
va- rieties
varieties
of the silkworm; in the eggs of poultry, and in the colour of the down of their chickens; in the horns of our sheep and cattle when nearly adult;— so in a state of nature, natural selection will be enabled to act on and modify organic beings at any age, by the accumulation of
profitable variations
variations profitable
at that age, and by their inheritance at a corresponding age. If it profit a plant to have its seeds more and more widely disseminated by the wind, I can see no greater difficulty in this being effected through natural selection, than in the cotton-planter increasing and improving by selection the down in the pods on his
cotton trees.
cotton-trees.
Natural selection may modify and adapt the larva of an insect to a score of contingencies, wholly different from those which concern the mature →insect. →These modifications will probably affect, through →the laws of correlation, the structure of the
adult.
adult;
and
and
probably
perhaps
perhaps
in
in
the
the
case
case
of
of
those
those
insects
insects
which
which
live
live
only
only
for
for
a
a
few
few
hours,
hours,
and
and
which
which
never
never
feed,
feed,
a
a
large
large
part
part
of
of
their
their
structure
structure
is
is
merely
merely
the
the
correlated
correlated
result
result
of
of
successive
successive
changes
changes
in
in
the
the
structure
structure
of
of
their
their
larvæ.
larvæ.
So, conversely, modifications in the adult →will probably often affect the structure of the larva; but in all cases natural selection will ensure that →modifications consequent on other modifications at a different period of life, shall not be →in the least degree injurious: for if they
were
became
so,
the
they
→would cause the extinction of the species.
Natural selection will modify the structure of the young in relation to the parent, and of the parent in relation to the young. In social animals it will adapt the structure of each individual for the benefit of the →community; if each in consequence profits by the selected change. What natural selection cannot do, is