started into life
all all 1859 1860 | all 1861 1866 1869 1872 |
at once, the fact would be fatal to the theory of
descent with slow modification descent with slow modification 1859 1860 1861 1866 1869 |
evolution 1872 |
through natural selection. For the development
of of 1859 1860 1861 1866 1869 |
by this means of 1872 |
a group of forms, all of which
have have 1859 1860 1861 1866 1869 | are 1872 |
descended from some one progenitor, must have been an extremely slow process; and the
progenitors progenitors 1859 1860 1861 1866 1872 | progenitors, 1869 |
must have lived long
ages ages 1859 1860 1861 1866 1869 | ages 1872 |
before their modified descendants. But we continually
over-rate over-rate 1859 1860 1861 | overrate 1866 1869 1872 |
the perfection of the geological record, and falsely infer, because certain genera or families have not been found beneath a certain stage, that they did not exist before that stage. ↑1 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | In all cases positive palæontological evidence may be implicitly trusted; negative evidence is worthless, as experience has so often shown.
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We continually forget how large the world is, compared with the area over which our geological formations have been carefully examined; we forget that groups of species may elsewhere have long
existed existed 1859 1860 | existed, 1861 1866 1869 1872 |
and have slowly
multiplied multiplied 1859 1860 | multiplied, 1861 1866 1869 1872 |
before they invaded the ancient archipelagoes of Europe and
of of 1859 1860 | of 1861 1866 1869 1872 |
the United States. We do not make due allowance for the
enormous enormous 1859 1860 1861 1866 1869 | enormous 1872 |
intervals of
time, time, 1859 1860 | time 1861 1866 1869 1872 |
which have
probably probably 1859 1860 | probably 1861 1866 1869 1872 |
elapsed between our consecutive formations,— longer perhaps in
most most 1860 | some 1859 | many 1861 1866 1869 1872 |
cases than the time required for the accumulation of each formation. These intervals will have given time for the multiplication of species from some one
or some few or some few 1859 1860 1861 1866 1869 |
OMIT 1872 |
parent-forms; parent-forms; 1859 1860 1861 1866 1869 | parent-form: 1872 |
and in the succeeding
formation formation 1859 1860 1861 1866 1869 | formation, 1872 |
such
species species 1859 1860 |
groups of species 1861 1866 1869 |
groups or species 1872 |
will appear as if suddenly created. |
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I may here recall a remark formerly made,
namely namely 1859 1860 | namely, 1861 1866 1869 1872 |
that it might require a long succession of ages to adapt an organism to some new and peculiar line of life, for
instance instance 1859 1860 | instance, 1861 1866 1869 1872 |
to fly through the air;
but but 1859 1860 |
and consequently that the transitional forms would often long remain confined to some one region; but 1861 1866 1869 1872 |
that that 1859 1860 1861 | that, 1866 1869 1872 |
when this
had had 1859 1860 |
adaptation had once 1861 1866 1869 1872 |
been effected, and a few species had thus acquired a great advantage over other organisms, a comparatively short time would be necessary to produce many divergent forms, which would
be able to be able to 1859 1860 1861 1866 |
OMIT 1869 1872 |
spread rapidly and widely throughout the world.
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I will now give a few examples to illustrate
these these 1859 1860 | the foregoing 1861 1866 1869 1872 |
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