SELECTED ADAPTATIONS 447 
power at all comparable to man’s influence in developing 
artificial varieties? In the first place Darwin pointed to the 
fact that every kind of plant or animal produces more off- 
spring than can possibly come to maturity; for if none died 
without issue, the progeny of one individual or pair of in- 
dividuals would shortly cover the whole earth. Thus fifty 
dandelion plants from one, each bearing fifty-fold, and so on 
for nine generations, would make more than enough dande- 
lions to occupy every foot of dry land on the globe. In- 
numerable individuals of innumerable kinds are continually 
producing offspring in large numbers. Since many more are 
produced than can mature it appears that a competitive 
struggle for life must be going on throughout the living world; 
and, he argued, so intense is this struggle that if some indi- 
viduals had an adaptational peculiarity which gave them 
even a slight advantage over their rivals, such favored in- 
dividuals would be the ones to survive and leave offspring. 
Some of their offspring would be sure (judging from breeders’ 
experience) to inherit the same peculiarity, and these favored 
offspring would in turn transmit it more or less enhanced 
to certain of their descendants, and so on along lines of fa- 
vored individuals in which the peculiarity in question would 
. become more and more pronounced. This improvement 
would continue up to the point of adapting the organism as 
perfectly as possible to its environment. In this way a fa- 
vored race might become a new species through survival of 
the individuals best fitted to a slowly changing or slightly 
changed environment. 
The natural agencies which favor the survival of certain 
races in the struggle for existence Darwin compared in a 
metaphorical way to the human agencies which control the 
production of cultivated varieties. Both Man and Nature, 
he argued, act by selecting through successive generations 
certain peculiarities. Man chooses to encourage what pleases 
him. His method is Artificial Selection. Nature encourages 
only those peculiarities which best fit the organism to its 
environment; her way Darwin called Natural Selection. The 
phrase has been often misunderstood through failing to take 
it merely as a symbol of the way certain natural forces act. 
