SECTION VII 



ORGANIC GROWTH : THE MORPHOLOGICAL AND PHYSIOLOGICAL 

 EVOLUTION OF THE LIVING WORLD AS THE RESULT OF 

 FUNCTION 



In Section IV., under the heading " Characters acquired by 

 Use," I have abeady indicated in a general way the influence 

 of use in the modification of organic forms. I have now to 

 show in detail that all organisation, and above all, the first 

 development of organs, and further, all higher physiological 

 evolution depends on use, is to be traced to the inheritance 

 of acquired characters. 



The Origin of Organisation in Unicellular Animals 

 — The Fundamental Biological Law 



Whoever assumes that complexity of organisation has 

 arisen in consequence of the gradual evolution of the living 

 world must also assume that all living beings, both plants 

 and animals, have been derived from the simplest beginnings, 

 from unorganised particles of protoplasm ; in other words, 

 from organisms which were destitute of organs. 



The term organism was first employed by Aristotle, and 

 was based upon the fact that each part of a living being is 

 an instrument, opyavov, for the whole. In his time organisms 



