KVOLUTION 83 



72. Fitness of the Environment. Biological literature 

 has always taken account of what has been called "adapta- 

 tion," or the fitness of living things for life in the surround- 

 ings or environment where they are placed. But a recent 

 writer, 1 has elaborated the complimentary notion of 

 the fitness of the environment. Recognizing living things as 

 "mechanisms which must be complex, highly regulated, 

 and provided with suitable matter and energy as food," 

 he shows that the present inorganic environment is the 

 best conceivable. Inorganic evolution has resulted, among 

 other things, in the occurrence of large quantities of water 

 and carbon dioxide; their physical and chemical properties, 

 and those of the ocean, together with the chemical properties 

 of the elements, carbon, oxygen, and hydrogen, and their 

 numerous compounds, "are in character or in magnitude 

 either unique or nearly so, and are in their effect favorable ' : 

 to the organisms with which we are familiar, and which 

 possess the three fundamental characteristics of complexity, 

 regulation, and metabolism. The elements carbon, hydro- 

 gen, and oxygen, says Henderson, are uniquely and most 

 highly fitted to be the stuff of which life is formed, and of 

 the environment in which it exists. 



73. Organic Evolution. Developmental changes in 

 living things constitute organic evolution. Such changes 

 are manifested in the development of an individual from 

 a spore or an egg. The development of a mature in- 

 dividual is ontogeny. The development of a group of 

 related forms (genera, families, orders, etc.) is phytogeny. 

 The chief problem of biology is to ascertain and record, 

 in order, the evolutionary changes that have resulted in 



1 Henderson, Lawrence J. The fitness of the environment. New 

 York, 1913. 



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