| I attempted also to show that there is a
tendency in the forms which are increasing in number and diverging in character, to supplant and exterminate the
→preceding, less divergent and
less
forms. I request the reader to turn to the diagram illustrating the action, as formerly explained, of these several principles; and he will see that the inevitable result
that the modified descendants proceeding from one progenitor become broken up into groups subordinate to groups. In the diagram each letter on the uppermost line may represent a genus including several species; and
the
→whole of the genera along this upper
form together one class, for all
descended from one ancient
and, consequently, have inherited something in common. But the three genera on the left hand have, on this same principle, much in common, and form a sub-family, distinct from that
the next two genera on the right hand, which diverged from a common parent at the fifth stage of descent. These five genera have also
→in common, though less than when grouped in sub-families;
and they form a family distinct from that
the three genera still
to the right hand, which diverged at
earlier period. And all these genera,
from (A), form an order distinct from the genera descended from (I). So that we here have many species descended from a single progenitor grouped into genera; and the genera
→into
sub-families, families, and orders, all
→under one great
grand fact
→OMIT
of the
→natural subordination of organic beings in
under
which, from its familiarity, does not always sufficiently strike us, is in my judgment
explained. No doubt organic beings, like all other objects, can be classed in
→many
ways, either artificially by single characters or more naturally by a number of characters. We know, for instance, that minerals and the elemental substances can be thus
this case there is of course no relation
→to
genealogical succession, and no cause can
be assigned for their falling into groups. But with organic beings the case is different, and the view above given
their natural arrangement in group under group; and no other explanation has ever been attempted. |
|
→as we have seen, try
to arrange the species, genera, and families in each class, on what is called the Natural System. But what is meant by this system? Some authors look at it merely as a scheme for arranging together those living objects which are most alike, and for separating those which are most unlike; or as
|
