Bio-assay 



The employment of living organisms to test the effects 

 of a substance such as feeding rats with food containing 

 herbicide residues. 



Biocenose 



See Biocoenosis. 



Biochemical Oxygen Demand (B.O.D.) 



A test for the detection and measurement of pollution in 

 which the quantity of oxygen that has been used by oxidiz- 

 able materials under standardized conditions is determined. 



Biochore 



A subdivision of the Biocycle (q. v.) It comprises a group 

 of Biotopes (q. v.) which resemble one another. The princi- 

 pal biochores are grassland, forest, savanna, and desert. The 

 desert biochore includes sandy desert and stony desert bio- 

 topes, cf. Biosphere. 



Bioclimate 



See Microclimate. 



Bioclimatic Law (Hopkins) 



The generalization that in temperate North America 

 Phenological events generally occur at the average rate of 

 four days to each degree of latitude, 5 of longitude, and 

 400 feet of altitude; later northward, eastward, or upward 

 in spring and early summer, and earlier in late summer and 

 autumn. 



Bioclimatology 



The study of the interrelations of organisms and climate. 



Biocoenology 



The study of communities including qualitative and 

 quantitative analyses; the Synecology, Synchorology, Dynam- 

 ics, and classification of communities. 



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