If then our diagram be assumed to represent a considerable amount of
modification, species (A) and all the earlier varieties will have
become extinct, having been replaced by eight new species (a14 to
m14); and (I) will have been replaced by six (n14 to z14) new species.
But we may go further than this. The original species of our genus
were supposed to resemble each other in unequal degrees, as is so
generally the case in nature; species (A) being more nearly related to
B, C, and D, than to the other species; and species (I) more to G, H,
K, L, than to the others. These two species (A) and (I), were also
supposed to be very common and widely diffused species, so that they
must originally have had some advantage over most of the other species
of the genus. 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, to me 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.
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