Disfunction 



See Discontinuity. 



Disjunctive Symbiosis 



See Symbiosis. 



Disoperation 



An interaction between organisms in which one or all 

 are harmed, e. g. Competition resulting in stunted growth. 



Dispersal 



(1) The actual transfer or movement of Disseminules or 

 organisms from one place to another. (2) The history of the 

 movement of a group of organisms, cf. Migration, Establish- 

 ment, Spread. 



Dispersion 



The pattern of Distribution of individuals of a Popula- 

 tion, especially in regard to probability. 



Dispersion (Soil) 



The breaking down of soil aggregates, resulting in single 

 grain structure; usually the more easily a soil is dispersed 

 the more credible it is. 



Disphotic Zone 



The depths in bodies of water where light is inadequate 

 for photosynthesis in plants but adequate for animal life. cf. 

 Aphotic zone, Euphotic zone. 



Displacement Theory 



See Continental drift hypothesis. 



Dissemination 



The processes by which organisms or their parts, espe- 

 cially spores, seeds, or fruits are scattered, cf. Diaspore, Dis- 

 persal, Disseminule. 



Ill 



