Comparison with 1869 |
|
the species of the same genus differ from each other, be more variable than
the the 1859 1860 1861 1866 1869 | the 1872 |
generic characters in which they all agree? Why, for instance, should the colour of a flower be more likely to vary in any one species of a genus, if the other
species, species, 1859 1860 1861 1866 1869 | species 1872 |
supposed to have been created independently, have supposed to have been created independently, have 1859 1860 1861 1866 1869 |
possess 1872 |
differently coloured flowers, than if all
the species of the genus have the species of the genus have 1859 1860 1861 1866 1869 |
possessed 1872 |
the same coloured flowers? If species are only well-marked varieties, of which the characters have become in a high degree permanent, we can understand this fact; for they have already varied since they branched off from a common progenitor in certain characters, by which they have come to be specifically distinct from each other; and
therefore these same characters would be more likely still
to be variable
than the generic characters which have been inherited without change for an
enormous enormous 1859 1860 1861 1866 1869 | immense 1872 |
period. It is inexplicable on the theory of creation why a part developed in a very unusual manner in
any any 1859 1860 1861 1866 1869 | any 1872 |
one species
of of 1859 1860 1861 1866 1869 | alone of 1872 |
a genus, and therefore, as we may naturally infer, of great importance to the
species, should be eminently liable to variation; but, on my
view, this part has
undergone undergone 1869 | undergone, 1859 1860 1861 1866 1872 |
since the several species branched off from a common progenitor, an unusual amount of variability and modification, and therefore we might expect this
part generally to be still variable. But a part may be developed in the most unusual manner, like the wing of a bat, and yet not be more variable than any other structure, if the part be common to many subordinate forms, that is, if it has been inherited for a very long period; for in this case it will have been rendered constant by long-continued natural selection. |
|
Glancing at instincts, marvellous as some are, they offer no greater difficulty than
does does 1859 1860 1861 1866 1869 | do 1872 |
corporeal
structure structure 1859 1860 1861 1866 1869 | structures 1872 |
on the theory of the natural selection of successive, slight, but profitable modifications. We can thus understand why nature moves by graduated steps in endowing different animals of the same class with their several instincts. I have attempted to show how much light the principle of gradation
throws on the admirable architectural powers of the hive-bee. Habit no doubt
sometimes sometimes 1859 1860 1861 1866 1869 | often 1872 |
comes into play in modifying instincts; but it certainly is not indispensable, as we see,
in the case of neuter insects, which leave no progeny to inherit the effects of long-continued habit. On the view of all the species of the same genus having descended from a common parent, and having inherited much in common, we can understand how it is that allied species, when placed under considerably
different conditions of life, yet should
follow nearly the same instincts; why the thrush
of South
America, for instance, lines
her
nest
with mud like our British species. On the view of instincts having been slowly acquired through natural selection
we need not marvel
|
the species of the same genus differ from each other, be more variable than
....... 1872 | the 1859 1860 1861 1866 1869 |
generic characters in which they all agree? Why, for instance, should the colour of a flower be more likely to vary in any one species of a genus, if the other
species species 1872 | species, 1859 1860 1861 1866 1869 |
possess possess 1872 |
supposed to have been created independently, have 1859 1860 1861 1866 1869 |
differently coloured flowers, than if all
possessed possessed 1872 |
the species of the genus have 1859 1860 1861 1866 1869 |
the same coloured flowers? If species are only well-marked varieties, of which the characters have become in a high degree permanent, we can understand this fact; for they have already varied since they branched off from a common progenitor in certain characters, by which they have come to be specifically distinct from each other;
....... 1869 1872 | and 1859 1860 1861 1866 |
therefore these same characters would be more likely
again again 1869 1872 | still 1859 1860 1861 1866 |
to
vary vary 1869 1872 | be variable 1859 1860 1861 1866 |
than the generic characters which have been inherited without change for an
immense immense 1872 | enormous 1859 1860 1861 1866 1869 |
period. It is inexplicable on the theory of creation why a part developed in a very unusual manner in
....... 1872 | any 1859 1860 1861 1866 1869 |
one species
alone of alone of 1872 | of 1859 1860 1861 1866 1869 |
a genus, and therefore, as we may naturally infer, of great importance to
that that 1866 1869 1872 | the 1859 1860 1861 |
species, should be eminently liable to variation; but, on
our our 1869 1872 | my 1859 1860 1861 1866 |
view, this part has
undergone, undergone, 1859 1860 1861 1866 1872 | undergone 1869 |
since the several species branched off from a common progenitor, an unusual amount of variability and modification, and therefore we might expect
the the 1866 1869 1872 | this 1859 1860 1861 |
part generally to be still variable. But a part may be developed in the most unusual manner, like the wing of a bat, and yet not be more variable than any other structure, if the part be common to many subordinate forms, that is, if it has been inherited for a very long period; for in this case it will have been rendered constant by long-continued natural selection. |
|
Glancing at instincts, marvellous as some are, they offer no greater difficulty than
do do 1872 | does 1859 1860 1861 1866 1869 |
corporeal
structures structures 1872 | structure 1859 1860 1861 1866 1869 |
on the theory of the natural selection of successive, slight, but profitable modifications. We can thus understand why nature moves by graduated steps in endowing different animals of the same class with their several instincts. I have attempted to show how much light the principle of
gradation gradation 1859 1860 1861 1869 1872 | graduation 1866 |
throws on the admirable architectural powers of the hive-bee. Habit no doubt
often often 1872 | sometimes 1859 1860 1861 1866 1869 |
comes into play in modifying instincts; but it certainly is not indispensable, as we
see see 1869 1872 | see, 1859 1860 1861 1866 |
in the case of neuter insects, which leave no progeny to inherit the effects of long-continued habit. On the view of all the species of the same genus having descended from a common parent, and having inherited much in common, we can understand how it is that allied species, when placed under
widely widely 1866 1869 1872 | considerably 1859 1860 1861 |
different conditions of life, yet
....... 1869 1872 | should 1859 1860 1861 1866 |
follow nearly the same instincts; why the
thrushes thrushes 1866 1869 1872 | thrush 1859 1860 1861 |
of
tropical and temperate South tropical and temperate South 1866 1869 1872 |
South 1859 1860 1861 |
America, for instance,
line line 1866 1869 1872 | lines 1859 1860 1861 |
their their 1866 1869 1872 | her 1859 1860 1861 |
nests nests 1866 1869 1872 | nest 1859 1860 1861 |
with mud like our British species. On the view of instincts having been slowly acquired through natural
selection, selection, 1869 1872 | selection 1859 1860 1861 1866 |
we need not marvel
|