Differentiation 

 and Morphogenesis 



in Insects 



Car roll 3M. Williams 



The Biological Laboratories 

 Harvard University, Cambridge, Massachusetts 



Diversity is introduced into biological systems by the slow-paced 

 events of organic evolution and by the swift unfolding of the individ- 

 ual life. In the diversifications which shape the egg into an organism, 

 what we see is the implementation at the cellular level of species- 

 specific information inherited from the preceding generation. We may 

 think of the genes as supplying a kind of "construction manual" 

 which is translated into action during the course of development. But 

 the construction manual itself is the product of trial-and-error testing 

 in the lives of tens of thousands of individuals over enormous periods 

 of time. Therefore, the two kinds of diversifications, developmental 

 and evolutionary, come together in the management of genetic infor- 

 mation — its genesis, implementation, and testing in the careers of the 

 individual and the species. 



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