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seem 1859 1860 1861 1866
appear in many cases 1869 1872

to the individual, 1859 1860 1861 1866
OMIT 1869 1872

there are very many other correlations of growth, 1859 1860 1861 1866
many cases of correlated variation, 1869 1872

understand. 1859 1860 1861 1866
understand, undoubtedly occur. 1869 1872

which 1859 1860 1861 1866
standing higher in the scale, and which 1869 1872

will be disregarded 1859 1860 1861 1866
are not regulated 1869 1872

and use in
strengthening
strengthening,
and disuse in weakening and diminishing organs, seem to have been
more
more
potent in their effects. Homologous parts tend to vary in the same
manner,
way,
and homologous parts tend to cohere. Modifications in hard parts and in external parts sometimes affect softer and internal parts. When one part is largely developed, perhaps it tends to draw nourishment from the adjoining parts; and every part of the structure which can be saved without detriment to the individual, will be saved. Changes of structure at an early age
will often
may
will generally
affect parts subsequently developed; and there are very many other correlations of growth, the nature of which we are
utterly
utterly
unable to understand. Multiple parts are variable in number and in structure, perhaps arising from such parts not having been closely specialised
for
to
any particular function, so that their modifications have not been closely checked by natural selection. It
follows
is
probably from this same
cause,
cause
that organic beings low in the scale
of nature
of nature
are more variable than those which have their whole organisation more
specialised.
specialised,
and
and
are
are
higher
higher
in
in
the
the
scale.
scale.
Rudimentary organs, from being useless, will be disregarded by natural selection, and hence
probably
probably
are variable. Specific
characters —
characters—
that is, the characters which have come to differ since the several species of the same genus branched off from a common
parent —
parent—
are more variable than generic characters, or those which have long been inherited, and have not differed within this same period. In these remarks we have referred to special parts or organs being still variable, because they have recently varied and thus come to differ; but we have also seen in the second
chapter
Chapter
that the same principle applies to the whole individual; for in a district where many species of
a
any
genus are
found —
found—
that is, where there has been much former