F— Continued 



flushing time— The time required to replace 

 all the water in an estuary, harbor, etc., 

 by action of current. 



food chain— The sequence of organisms in 

 wliich each is food for a liigher member 

 of the sequence. Due to energy loss at 

 each level there are usually not more 

 than four or five steps per chain. 



food cycle— Production, consumption and 

 decomposition of food and the energy 

 relationships involved. 



food web— A group of interrelated food 

 chains. See also food chain. 



fouling organism — An organism that 

 attaches to the surface of submerged or 

 introduced objects regardless of whether 

 the objects are natural or man-made. 



--G-- 



genotype— The genetic makeup of an orga- 

 nism regardless of whether the genetic 

 trait is expressed or not. 



geobiocoenois— See biogeocoenois. 



grazing— In aquatic habitats, the consump- 

 tion of phytoplankton by zooplankton. 



growth forms— Populations have character- 

 istic patterns of increase which are called 

 population growth forms. These are rep- 

 resented by two curves: (1) J-shaped and 

 (2) S-shaped. Trees, shrubs and herbs 

 also have characteristic growth forms, 

 patterns, or shapes. 



H-- 



habitat— The place where an organism lives. 



halophyte— A plant that tolerates and lives 

 in salty soil. 



herbivores— Animals that feed primarily on 

 plants. 



heterotrophic— A metabobc process depen- 

 dent on complex organic food origi- 

 nating in other plants and animals. 

 Compare with autotrophic. 



heterotrophic succession— A type of com- 

 munity succession in which respiration 

 exceeds production in early successional 

 stages, but the two tend to equilibrate in 

 more mature stages. Compare with 

 autotrophic succession. 



holocoen— The interactions between envi- 

 ronmental factors and organisms, equiva- 

 lent to ecosystem 



holological approach— Analysis of a system 

 (e.g., as to heat budget) where the 

 system is taken as a whole and treated as 

 a "black box" where only input and 

 output are considered. See also merolog- 

 ical approach. 



holomictic lakes— Lakes where bottom and 

 surface waters are mixed periodically. 



home range— The area which an individual 

 or family uses. It is more or less fixed. If 

 actually defended, it is the animal's 

 territory. 



homeostasis— The tendency of a system to 

 remain at or return to normal, after or 

 during an outside stress. 



