Comparison with 1859 |
|
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
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 at some instincts being apparently
not perfect and liable to mistakes, and at many instincts causing other animals to suffer. |
|
If species be only well-marked and permanent varieties, we can at once see why their crossed offspring should follow the same complex laws in their degrees and kinds of resemblance to their parents,— in being absorbed into each other by successive crosses, and in other such points,— as do the crossed offspring of acknowledged varieties. On the other hand, these
would be strange
facts
if species have
been independently created,
and varieties have
been produced by
secondary laws. |
|
If we admit that the geological record is imperfect in
an extreme degree, then such
facts
as
the record
gives, gives, 1859 1860 |
gives 1861 |
does give, strongly 1866 1869 1872 |
support the theory of descent with modification. New species have come on the stage slowly and at successive intervals; and the amount of change, after equal
|
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
sometimes sometimes 1859 1860 1861 1866 1869 | often 1872 |
comes into play in modifying instincts; but it certainly is not indispensable, as we
see, see, 1859 1860 1861 1866 | see 1869 1872 |
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 considerably 1859 1860 1861 | widely 1866 1869 1872 |
different conditions of life, yet
should should 1859 1860 1861 1866 | should 1869 1872 |
follow nearly the same instincts; why the
thrush thrush 1859 1860 1861 | thrushes 1866 1869 1872 |
of
South South 1859 1860 1861 |
tropical and temperate South 1866 1869 1872 |
America, for instance,
lines lines 1859 1860 1861 | line 1866 1869 1872 |
her her 1859 1860 1861 | their 1866 1869 1872 |
nest nest 1859 1860 1861 | nests 1866 1869 1872 |
with mud like our British species. On the view of instincts having been slowly acquired through natural
selection selection 1859 1860 1861 1866 | selection, 1869 1872 |
we need not marvel at some instincts being
apparently apparently 1859 1860 1861 1866 1869 | apparently 1872 |
not perfect and liable to mistakes, and at many instincts causing other animals to suffer. |
|
If species be only well-marked and permanent varieties, we can at once see why their crossed offspring should follow the same complex laws in their degrees and kinds of resemblance to their parents,— in being absorbed into each other by successive crosses, and in other such points,— as do the crossed offspring of acknowledged varieties.
On the other hand, these On the other hand, these 1859 1860 1861 1866 |
This similarity 1869 1872 |
would be
strange strange 1859 1860 1861 1866 | a strange 1869 1872 |
facts facts 1859 1860 1861 1866 | fact, 1869 1872 |
if species
have have 1859 1860 1861 1866 1869 | had 1872 |
been independently
created, created, 1859 1860 1861 1866 | created 1869 1872 |
and varieties
have have 1859 1860 1861 1866 1869 | had 1872 |
been produced
by by 1859 1860 1861 1866 | through 1869 1872 |
secondary laws. |
|
If we admit that the geological record is imperfect
in in 1859 1860 1861 1866 1869 | to 1872 |
an extreme degree, then
such such 1859 1860 1861 | the 1866 1869 1872 |
facts facts 1859 1860 1861 | facts, 1866 1869 1872 |
as as 1859 1860 1861 | which 1866 1869 1872 |
the record
gives gives 1861 |
gives, 1859 1860 |
does give, strongly 1866 1869 1872 |
support the theory of descent with modification. New species have come on the stage slowly and at successive intervals; and the amount of change, after equal
|