122 
NATURAL SELECTION. 
Chap. IV. 
modified offspring of a species get into some distinct 
country, or become quickly adapted to some quite new 
station, in which child and parent do not come into 
competition, both may continue to exist. 
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having been replaced by eight new species to ; 
and (I) will have been replaced by six {n to ^ new 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 Gr, H, 
K, L, than to the others. These two species (A) and (I), 
were also supposed to be very common and widely dif¬ 
fused 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. We may suppose 
that only one (F), of the two species which were least 
closely related to the other nine original species, has 
transmitted descendants to this late stage of descent. 
