176 SELECTION. 



autogamy etc.) whether the total variability of a group will 

 continue to reduce itself, whether it wiU remain approximately 

 stationary, or whether the status of the group as a species 

 is insecure. 



Theoretically, the automatic 'reduction of the potential var- 

 iability of a group goes on, ind^endently of any selection. 

 But the advocates of natural selection as the main cause of 

 evolution, have shown that, as only a fraction of the number 

 of individuals produced in any group, have a chance to grow 

 up, it is natural to suppose that the. survivers are a selected 

 group, and are in the main surviving because they are better 

 fitted to their environment. We will later discuss whether the 

 life or death of the individuals really depends, on the average 

 of their constitution and on their suitable situation. 



In the first place, is it absolutely necessary to assume that 

 very organism which we observe to be well-fitted to the cir- 

 cumstances under which it exists, has been made fit for those 

 circumstances by natural selection? In most cases there seems 

 to be no mysterious force compelling a group of organisms to 

 remain in an environment to which they are only moderately 

 weU-adapted, when another enviromnent is open to them into 

 which their present constitution makes them fit better. Either 

 an organism happens to have a genotjT)e which makes it so 

 constituted, that it can live and procreate in a certain set of 

 conditions, in which case that particular organism will be 

 found to be living right there, or else it cannot exist at all. 

 Adaptation, is certainly not the right name for every case in 

 which we find an organism hving in surroundings in which its 

 germinal constitution allows it to live. On the other hand, it is 

 perfectly obvious that there are cases in which a plant or ani- 

 mal is so constitued, that it is securely tied to special con- 

 ditions, such as a fish to hfe in water. 



On the whole, the striking suitabihty of organisms for the 

 conditions in which we find them, has resulted far more from a 

 selection (by the method of trial and error) by the organism 

 of a suitable environment, than from the selection of the organ- 



