172 THE ORIGIN OF SPECIES 



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 

 ditfused 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, extremely probable that 

 they will have taken the places of, and thus extermi- 

 nated, 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 

 a'* and z'* 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 a'\ q'\ p'*, will be nearly related from 

 having recently branched off from a'°; 6'\ and /'*, from 

 having diverged at an earlier period from a*, will be in 



