Biogeography 



The branch of biology that deals with the geographic 

 distribution of plants and animals, cf. Plant geography, 

 Zoogeography, Chorology. 



Biointization 



Preliminary treatment for seeds with chemicals to stim- 

 ulate growth. 



Biological Clock 



The rhythmic occurrence of processes in organisms at 

 periodically timed intervals, e.g., the ejection of spores by 

 the fungus Pilobolus sphaerosporus. 



Biological Control 



The use of organisms or viruses to control parasites, 

 weeds, or other pests, e.g. control of the cottony-cushion scale 

 by the lady beetle, prickly pear cactus in Australia by the 

 insect Cactoblastis cactorum. 



Biological Efficiency 



The ratio of the productivity of an organism, or a group 

 of organisms, to that of its supply of energy, cf. Productivity. 



Biological Equilibrium 



See Biotic balance. 



Biological Factor 



An influence resulting from biological as distinct from 

 physical and chemical agents, including both Biotic factors 

 (q. v.) and physiologic factors such as Hormones. 



Biological Race (Strain) 



A group of organisms which differ only in their physio- 

 logical or ecological behaviour from other groups in the same 

 species. 



Biological Spectrum 



A tabulation by percentages of the plants of a community 



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