| → descent with slow modification 1859 1860 1861 1866 1869 |
| evolution 1872 |
|
| → of 1859 1860 1861 1866 1869 |
| by this means of 1872 |
|
| ↑ 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.
|
|
| → or some few 1859 1860 1861 1866 1869 |
| OMIT 1872 |
|
| → species 1859 1860 |
| groups of species 1861 1866 1869 |
| groups or species 1872 |
|
| → but 1859 1860 |
| and consequently that the transitional forms would often long remain confined to some one region; but 1861 1866 1869 1872 |
|
| → had 1859 1860 |
| adaptation had once 1861 1866 1869 1872 |
|
| → be able to 1859 1860 1861 1866 |
| OMIT 1869 1872 |
|
|
started into life
at once, the fact would be fatal to the theory of
→descent with slow modification
through natural selection. For the development
→of
a group of forms, all of which
descended from some one progenitor, must have been an extremely slow process; and the
must have lived long
before their modified descendants. But we continually
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. ↑
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
and have slowly
before they invaded the ancient archipelagoes of Europe and
the United States. We do not make due allowance for the
intervals of
which have
elapsed between our consecutive formations,— longer perhaps in
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
and in the succeeding
such
→species
will appear as if suddenly created. |
|
| I may here recall a remark formerly made,
that it might require a long succession of ages to adapt an organism to some new and peculiar line of life, for
to fly through the air;
→but
when this
→had
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
spread rapidly and widely throughout the world.
|
|
| I will now give a few examples to illustrate
|
