should remember that we have no right to expect (excepting in rare cases) to discover
directly
connecting links between them, but only between each and some extinct and supplanted form. Even on a wide area, which has during a long period remained continuous, and of which the
climate climate 1859 1860 1861 1866 1869 | climatic 1872 |
and other conditions of life change insensibly in
going going 1859 1860 1861 1866 | proceeding 1869 1872 |
from a district occupied by one species into another district occupied by a closely allied species, we have no just right to expect often to find intermediate varieties in the intermediate
zone. zone. 1859 1860 1861 1866 1869 | zones. 1872 |
For we have reason to believe that only a few species
of a genus ever of a genus ever 1861 1866 1869 1872 |
are 1859 1860 |
undergo undergo 1861 1866 1869 1872 | undergoing 1859 1860 |
change; change; 1861 1866 1869 1872 | change 1859 1860 |
the other species becoming utterly extinct and leaving no modified progeny. the other species becoming utterly extinct and leaving no modified progeny. 1861 1866 1869 1872 |
at any one period; and all changes are slowly effected. 1859 1860 |
Of the species which do change, only a few within the same country change at the same time; and all modifications are slowly effected. I have also shown that the intermediate varieties which
will will 1859 1860 1861 1866 | probably 1869 1872 |
at first
probably probably 1859 1860 1861 1866 | probably 1869 1872 |
exist exist 1859 1860 1861 1866 | existed 1869 1872 |
in the intermediate zones,
will will 1859 1860 1861 1866 | would 1869 1872 |
be liable to be supplanted by the allied forms on either hand;
and and 1859 1860 1861 1866 | for 1869 1872 |
the latter, from existing in greater numbers,
will will 1859 1860 1861 1866 | would 1869 1872 |
generally be modified and improved at a quicker rate than the intermediate varieties, which
exist exist 1859 1860 1861 1866 | existed 1869 1872 |
in lesser numbers; so that the intermediate varieties
will, will, 1859 1860 1861 1866 | would, 1869 1872 |
in the long run, be supplanted and exterminated. |
|
On this doctrine of the extermination of an infinitude of connecting links, between the living and extinct inhabitants of the world, and at each successive period between the extinct and still older species, why is not every geological formation charged with such links? Why does not every collection of fossil remains afford plain evidence of the
gradation gradation 1859 1860 1861 1869 1872 | graduation 1866 |
and mutation of the forms of life? Although geological research has undoubtedly revealed the former existence of many links, bringing numerous forms of life much closer together, it does not yield the infinitely many fine
gradations gradations 1861 1869 1872 | graduations 1866 |
|