Page - 123 - in The Origin of Species

DIVERGENCE OF CHARACTER 123 one nation or district required swifter horses, whilst those of another required stronger and bulkier horses. The early dif- ferences would be very slight ; but, in the course of time, from the continued selection of swifter horses in the one case, and of stronger ones in the other, the differences would become greater, and would be noted as forming two sub-breeds. Ul- timately, after the lapse of centuries, these sub-breeds would become converted into two well-established and distinct breeds. As the differences became greater, the inferior ani- mals with intermediate characters, being neither very swift nor very strong, would not have been used for breeding, and will thus have tended to disappear. Here, then, we see in man's productions the action of what may be called the prin- ciple of divergence, causing differences, at first barely appre- ciable, steadily to increase, and the breeds to diverge in character, both from each other and from their common parent. But how, it may be asked, can any analogous principle apply in nature ? I believe it can and does apply most effi- ciently (though it was a long time before I saw how), from the simple circumstance that the more diversified the de- scendants from any one species become in structure, consti- tution, 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 discern this in the case of animals with simple habits. Take the case of a carnivorous quadruped, of which the number that can be supported in any country has long ago arrived at its full average. If its natural power of increase be allowed to act, it can succeed in increasing (the country not undergoing any change in conditions) only by its varying descendants 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 the descendants of our carnivorous animals become, the more places they will be enabled to occupy. What applies to one animal will apply throughout all time to all animals—that is, if they vary—for