118 THE ORIGIN OF SPECIES 



we can clearly see that if we wish in imagination to give 

 the plant the power of increasing in number, we should 

 have to give it some advantage over its competitors, or 

 over the animals which prey on it. On the confines 

 of its geograpiiical range, a change of constitution with 

 respect to climate would clearly be an advantage to our 

 plant; but we have reason to believe that only a few 

 plants or animals range so far that they are destroyed 

 exclusively by the rigor of the climate. Not until we 

 reach the extreme confines of life, in the Arctic regions 

 or on the borders of an utter desert, will competition 

 cease. The land may be extremely cold or dry, yet there 

 will be competition between some few species, or between 

 the individuals of the same species, for the warmest or 

 dampest spots. 



Hence we can see that when a plant or animal is 

 placed in a new country among new competitors, the 

 conditions of its life will generally be changed in an 

 essential manner, although the climate may be exactly 

 *" the same as in its former home. If its average numbers 

 are to increase in its new home, we should have to 

 modify it in a different way to what we should have had 

 to do in its native country; for we should have to give 

 it some advantage over a different set of competitors or 

 enemies. 



It is good thus to try in imagination to give to any 



one species an advantage over another. Probably in no 



single instance should we know what to do. This ought 



■X to convince us of our ignorance on the mutual relations 



'^ of all organic beings; a conviction as nece'ssary as it is 



, difficult to acquire. All that we can do is to keep 



I steadily in mind that each organic being is striving to 



f 



