Comparison with 1860 |
|
that we are as yet very ignorant
of of 1859 1860 1861 1866 1869 | as to 1872 |
the full extent of the various climatal and geographical changes which have affected the earth during modern periods; and such changes will
obviously obviously 1859 1860 1861 1866 1869 | often 1872 |
have
greatly greatly 1859 1860 1861 1866 | greatly 1869 1872 |
facilitated migration. As an example, I have attempted to show how potent has been the influence of the Glacial period on the distribution
both both 1859 1860 1861 1866 | both 1869 1872 |
of the same and of
representative representative 1859 1860 1861 1866 | allied 1869 1872 |
species throughout the world. We are as yet profoundly ignorant of the many occasional means of transport. With respect to distinct species of the same genus inhabiting
very very 1859 1860 1861 | very 1866 1869 1872 |
distant and isolated regions, as the process of modification has necessarily been slow, all the means of migration will have been possible during a very long period; and consequently the difficulty of the wide diffusion of
species species 1859 1860 1861 | the species 1866 1869 1872 |
of the same genus is in some degree lessened. |
|
As
on on 1859 1860 1861 1866 | according to 1869 1872 |
the theory of natural selection an interminable number of intermediate forms must have existed, linking together all the species in each group by gradations
as fine as
our present our present 1859 1860 1861 |
are our present 1866 1869 |
are our existing 1872 |
varieties, it may be asked, Why do we not see these linking forms all around us? Why are not all organic beings blended together in an inextricable chaos? With respect to existing forms, we 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
are are 1859 1860 |
of a genus ever 1861 1866 1869 1872 |
undergoing undergoing 1859 1860 | undergo 1861 1866 1869 1872 |
change change 1859 1860 | change; 1861 1866 1869 1872 |
at any one period; and all changes are slowly effected. at any one period; and all changes are slowly effected. 1859 1860 |
the other species becoming utterly extinct and leaving no modified progeny. 1861 1866 1869 1872 |
↑1 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | 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
|
that we are as yet very ignorant
as to as to 1872 | of 1859 1860 1861 1866 1869 |
the full extent of the various climatal and geographical changes which have affected the earth during modern periods; and such changes
will will 1859 1860 1861 1866 1872 | may 1869 |
often often 1872 | obviously 1859 1860 1861 1866 1869 |
have
....... 1869 1872 | greatly 1859 1860 1861 1866 |
facilitated migration. As an example, I have attempted to show how potent has been the influence of the Glacial period on the distribution
....... 1869 1872 | both 1859 1860 1861 1866 |
of the same and of
allied allied 1869 1872 | representative 1859 1860 1861 1866 |
species throughout the world. We are as yet profoundly ignorant of the many occasional means of transport. With respect to distinct species of the same genus inhabiting
....... 1866 1869 1872 | very 1859 1860 1861 |
distant and isolated regions, as the process of modification has necessarily been slow, all the means of migration will have been possible during a very long period; and consequently the difficulty of the wide diffusion of
the species the species 1866 1869 1872 | species 1859 1860 1861 |
of the same genus is in some degree lessened. |
|
As
according to according to 1869 1872 | on 1859 1860 1861 1866 |
the theory of natural selection an interminable number of intermediate forms must have existed, linking together all the species in each group by
gradations gradations 1859 1860 1861 1869 1872 | graduations 1866 |
as fine as
are our existing are our existing 1872 |
our present 1859 1860 1861 |
are our present 1866 1869 |
varieties, it may be asked, Why do we not see these linking forms all around us? Why are not all organic beings blended together in an inextricable chaos? With respect to existing forms, we 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
climatic climatic 1872 | climate 1859 1860 1861 1866 1869 |
and other conditions of life change insensibly in
proceeding proceeding 1869 1872 | going 1859 1860 1861 1866 |
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
zones. zones. 1872 | zone. 1859 1860 1861 1866 1869 |
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
probably probably 1869 1872 | will 1859 1860 1861 1866 |
at first
....... 1869 1872 | probably 1859 1860 1861 1866 |
existed existed 1869 1872 | exist 1859 1860 1861 1866 |
in the intermediate zones,
would would 1869 1872 | will 1859 1860 1861 1866 |
be liable to be supplanted by the allied forms on either hand;
for for 1869 1872 | and 1859 1860 1861 1866 |
the latter, from existing in greater numbers,
would would 1869 1872 | will 1859 1860 1861 1866 |
generally be modified and improved at a quicker rate than the intermediate varieties, which
existed existed 1869 1872 | exist 1859 1860 1861 1866 |
in lesser numbers; so that the intermediate varieties
would, would, 1869 1872 | will, 1859 1860 1861 1866 |
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
|