102 ON THE ORIGIN OF SPECIES 



stronger and more bulky horses. The early differences 

 would be very slight ; in the course of time, from the 

 continued selection of swifter horses by some breeders, 

 and of stronger ones by others, the differences would 

 become greater, and would be noted as forming two 

 sub-breeds ; finally, after the lapse of centuries, the 

 sub-breeds would become converted into two well- 

 established and distinct breeds. As the differences 

 slowly become greater, the inferior animals with inter- 

 mediate characters, being neither very swift nor very 

 strong, will have been neglected, and will have tended 

 to disappear. Here, then, we see in man's productions 

 the action of what may be called the principle of diver- 

 gence, causing differences, at first barely appreciable, 

 steadily to increase, and the breeds to diverge in char- 

 acter both from each other and from their common 

 parent. 



But how, it may be asked, can any analogous prin- 

 ciple apply in nature ? I believe it can and does apply 

 most efficiently, from the simple circumstance that the 

 more diversified the descendants from any one species 

 become in structure, constitution, and habits, by so 

 much will they be better enabled to seize on many and 

 widely diversified places in the polity of nature, and so 

 be enabled to increase in numbers. 



We can clearly see this in the case of animals with 

 simple habits. Take the case of a carnivorous quadru- 

 ped, of which the number that can be supported in any 

 country has long ago arrived at its full average. If its 

 natural powers of increase be allowed to act, it can 

 succeed in increasing (the country not undergoing any 

 change in its conditions) only by its varying descen- 

 dants seizing on places at present occupied by other 

 animals : some of them, for instance, being enabled to 

 feed on new kinds of prey, either dead or alive ; some 

 inhabiting new stations, climbing trees, frequenting 

 water, and some perhaps becoming less carnivorous. 

 The more diversified in habits and structure tha 

 descendants of our carnivorous animal became, the 

 more places they would be enabled to occupy. What 



