548 



THE COMMUNITY 



that the photosynthetic process, one of the 

 two key industries, takes place during the 

 diurnal hours. The result of plant photosyn- 

 thesis in the community is the formation of 

 sugars. These carbohydrates pass freely as 

 solutes from cell to cell, and during the 



the working cells (Coulter, Barnes, and 

 Cowles, 1911, p. 528; Transeau, Sampson, 

 and TifiFany, 1940). In terrestrial communi- 

 ties at least, the upper strata of a com- 

 munity are involved generally in diurnal 

 carbohydrate manufacture, and nocturnal 



Fig. 189. Dial periodicity in sonification at dawn and dusk of forest animals (cicadas, 

 orthopterans, frogs, birds, and monkeys) on Barro Colorado Island, Panama Canal Zone. 

 White squares represent sounds made by mainly diurnal animals, and black squares represent 

 those made by mainly nocturnal animals. One square represents sonification for one species 

 for one minute. Light intensity is in foot-candles. (After O. Park, Barden, and Williams.) 



day such compounds are manufactured 

 more rapidly than they can be transported, 

 and the excess sugar is converted into 

 starches. The starch accumulates in the 

 chloroplasts of the plant, and during the 

 night many of these stored products are 

 reconverted into sugars, and removed from 



transport of the excess products of this 

 activity. 



There are many similar diel rhythms in 

 the community, and the rate and character 

 of these periodic activities affect the sev- 

 eral trophic levels directly and indirectly, 

 usually in proportion to the ecological dis- 



