that certain Brachiopods have been but slightly modified from an extremely remote geological
epoch; and that certain land and fresh-water shells have remained nearly the same, from the time when, as far as is known, they first appeared. epoch; and that certain land and fresh-water shells have remained nearly the same, from the time when, as far as is known, they first appeared. 1872 |
period, although no explanation can be given of this fact. 1866 |
epoch. 1869 |
It is not an insuperable difficulty that Foraminifera have
not,
...OMIT 1869 1872 |
progressed in organisation, 1866 |
as insisted on by Dr. Carpenter,
progressed in organisation since even progressed in organisation since even 1869 1872 |
since that most ancient of all epochs 1866 |
the Laurentian
epoch; epoch; 1869 1872 |
formation of Canada; 1866 |
for some organisms would have to remain fitted for simple conditions of life, and what
could be better fitted could be better fitted 1869 1872 |
better 1866 |
for this end than these lowly organised Protozoa? ↑1 blocks not present in 1859 1860 1861 1872; present in 1866 1869 | It is no great difficulty that fresh-water shells, as Professor Phillips has remarked,
have remained almost unaltered from the time when they first appeared to the present day; but in this case we can see that
these shells will have been subjected to less severe competition than the molluses
which
inhabit
the far
more extensive area of the sea with its innumerable inhabitants.
|
Such objections as the above would be fatal to
my
view,
if it if it 1872 | which 1866 1869 |
included advance in organisation as a necessary contingent. They would
likewise be fatal, if the above likewise be fatal, if the above 1872 |
be fatal to my view if 1866 |
likewise be fatal to my view if 1869 |
Foraminifera, for instance, could be proved to have first come into existence during the Laurentian epoch, or
the above Brachiopods the above Brachiopods 1872 |
Brachiopods 1866 1869 |
during the
Cambrian Cambrian 1869 1872 | lower Silurian 1866 |
formation; formation; 1869 1872 | formations; 1866 |
for
in
this
case, case, 1869 1872 | were proved, 1866 |
there would not have been time sufficient for the development of these organisms up to the standard which they
had
then reached. When
..
advanced up to any given point, there is no
necessity, necessity, 1872 | necessity 1866 1869 |
on the theory of natural
selection, selection, 1872 | selection 1866 1869 |
for their further continued progress; though they will, during each successive age, have to be slightly modified, so as to hold their places in relation to
slight changes in their conditions. slight changes in their conditions. 1872 |
their changing conditions of life. 1866 |
the changing conditions of life. 1869 |
The foregoing The foregoing 1872 | All such 1866 1869 |
objections hinge on the question whether we
really know how old really know how old 1869 1872 |
have any sufficient knowledge of the antiquity of 1866 |
the world
is, and at what period is, and at what period 1872 |
and of the periods when 1866 |
is, and at what periods 1869 |
the various forms of life first appeared; and this may
well be well be 1872 | be boldly 1866 | be 1869 |
disputed. |
The problem
whether organisation on the whole has advanced is whether organisation on the whole has advanced is 1866 1869 1872 |
is 1861 |
in many ways excessively intricate. The geological record, at all times imperfect, does not extend far enough back,
...OMIT 1872 |
as I believe, 1861 1866 1869 |
to show with unmistakeable clearness that within the known history of the world organisation has largely advanced. Even at the present day, looking to members of the same class, naturalists are not unanimous which forms
ought to be ranked as ought to be ranked as 1872 |
are 1861 1866 1869 |
highest: highest: 1861 1872 |
to be ranked as highest: 1866 1869 |
thus, some look at the selaceans or
sharks, sharks, 1866 1869 1872 | sharks 1861 |
from their approach in some important points of structure to
reptiles, reptiles, 1866 1869 1872 | reptiles 1861 |
as the highest fish; others look at the teleosteans as the highest. The ganoids stand
intermediate intermediate 1861 1866 1872 | in- termediate 1869 |
between the selaceans and teleosteans; the latter at the present day are largely preponderant in number; but formerly selaceans and ganoids alone existed; and in this case, according to the standard of highness chosen, so will it be said that fishes have advanced or retrograded in organisation. To attempt to compare
members of distinct types in the scale of highness members of distinct types in the scale of highness 1872 |
in the scale of highness members of distinct types 1861 1866 1869 |
seems seems 1861 1866 1872 | seemed 1869 |
hopeless; hopeless; 1872 | hopeless: 1861 1866 1869 |
who will decide whether a
cuttle-fish cuttle-fish 1866 1869 1872 | cuttlefish 1861 |
be higher than a bee— that insect which the great Von Baer believed to be "in fact more highly organised than a fish, although upon another type"? In the complex struggle for life it is quite credible that crustaceans,
....... 1866 1869 1872 | for instance, 1861 |
not very high
|