PAPERS OX ZOOLOGY 257 



PHYSIOLOGICAL LIFE HISTORIES OF TEEEES- 



TEIAL AXIMALS AXD MODEEX METHODS 



OF EEPEESEXTIXCx CLBIATE^ 



Br Victor E. Shelfobd, Uxiversity of Illixois 



I. IXTEODTCTIOX 



Modern ecology had its beginning with the publication 

 of Warming's work on the sand dunes of Denmark. He 

 discovered in these studies that it is possible to classify 

 and arrange the various plant communities which he 

 found there in a natural order. This is the distinctive 

 thing about modern ecology: the ecology of communi- 

 ties of organisms is known as synecology. It enables 

 us in our studies of the pecuharities of various domestic 

 species and pest species to refer them back to the original 

 conditions in which they were found. In other words, 

 it has made it possible for us to locate organisms in their 

 natural environments correctly and in a manner which 

 other trained ecologists can understand. From time to 

 time one hears biologists, particularly zoologists, asking 

 why the term ecology is used and what modern ecology is 

 all about, an^-way, but these people have merely neglected 

 to become acquainted with its distinctive features which 

 are synecological or have to do with the ecology of com- 

 munities. 



Perhaps the second distinctive feature of n.odern ecol- 

 ogy lies in the attempt of ecologists to study what are 

 know^l as physiological life-histories of organisms. By 

 this is meant all physiological changes during the life 

 cycle or during an annual cycle in the case of animals 

 with several generations, and the relations of these 

 physiological changes to external conditions. Ganong 

 (1917) expressed the view that if we could learn the 

 physiological hfe-history of the plant we world be well 

 on the road to the solution of the ecological roblem. 



^ Contribution from the Illinois Xatural History Su^^ .• and from 

 the Department of Zoology of the University of Illinois X . 161. For 

 details regarding the ^ork on insect pests referred to herei see Bulle- 

 tin of the Illinois Xatural History Survey. This paper s the sub- 

 stance of an address befo'- the American Society of Zoologists at its 

 St. Louis meeting Dec. 31. . ^9 and the Illinois chapter of Sigma Xi. Jan. 

 11. 1920. and an address betore the meeting of the Illinois Academy of 

 Sciences at Danville, Feb. 21, 1920. 



