Their modified
descendants, fourteen in number at the fourteen-thousandth generation, will
probably have inherited some of the same advantages: they have also been
modified and improved in a diversified manner at each stage of descent, so
as to have become adapted to many related places in the natural economy of
their country. It seems, therefore, extremely probable that they will have
taken the places of, and thus exterminated, not only their parents (A) and
(I), but likewise some of the original species which were most nearly
related to their parents. Hence very few of the original species will have
transmitted offspring to the fourteen-thousandth generation. We may
suppose that only one (F) of the two species (E and F) which were least
closely related to the other nine original species, has transmitted
descendants to this late stage of descent.
The new species in our diagram, descended from the original eleven species,
will now be fifteen in number. Owing to the divergent tendency of natural
selection, the extreme amount of difference in character between species
a14 and z14 will be much greater than that between the most distinct of the
original eleven species. The new species, moreover, will be allied to each
other in a widely different manner. Of the eight descendants from (A) the
three marked a14, q14, p14, will be nearly related from having recently
branched off from a10; b14 and f14, from having diverged at an earlier
period from a5, will be in some degree distinct from the three first-named
species; and lastly, o14, e14, and m14, will be nearly related one to the
other, but, from having diverged at the first commencement of the process
of modification, will be widely different from the other five species, and
may constitute a sub-genus or a distinct genus.
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