EVOLUTION AND ANIMAL LIFE 



CHAPTER I 

 EVOLUTION DEFINED 



Grau, theurer Freund, 1st alle Theorie, 

 Und grim des Lebens gold'ner Baum. 



GOETHE. 



Men of science repudiate the opinion that natural laws are rulers 

 and governors of nature, looking with suspicion on all " necessary " and 

 universal laws. BROOKS. 



THIS volume treats of the elements of the science of Organic 

 Evolution. To this science belongs the consideration of the 

 forces which govern the changes in organisms. It includes the 

 influences which control development in the individual and in 

 the species which is the succession of individuals, together with 

 the laws or observed sequences of events which development 

 exhibits. From another point of view, this is the science of 

 life adaptation. The term Bionomics (/3i'6s, life, vo/xos, order 

 or custom), first suggested by Prof. Patrick Geddes, is essen- 

 tially equivalent to the older term Organic Evolution, the 

 science of the facts, processes, and laws involved in the mutation 

 of organisms. For many reasons, this new name, Bionomics, 

 with its technically exact meaning, should be preferred to the 

 phrase Organic Evolution, as, unlike the latter, it involves no 

 philosophic assumptions. 



That organs and organisms do change from day to day, and 

 place to place, and from generation to generation is an observed 

 fact, which now admits of no doubt. The orderly arrangement 

 of our knowledge of this process constitutes a branch of science. 

 To use the word evolution in regard to this process is to use a 

 philosophic term in connection with a group of scientific facts. 

 For the word evolution means unrolling. It carries the thought 



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