Belt Transect 



A strip of vegetation, usually a few inches or feet wide, 

 in which the constituent plants are recorded or mapped. 



Bench Mark 



A point of reference used in elevation surveys. 



Bench Terrace 



A shelf-like embankment of earth constructed along the 

 contour of sloping land to control run-off and erosion, cf. 

 Ridge terrace. 



Benthic 



Refers to the bottom of any body of water. In the ocean 

 the benthic division is divided into the Littoral, Sublittoral, 

 Archibenthic, Abyssal-benthic zones, (q. v.). cf. Pelagic. 



Benthos 



Organisms which live on or in the bottom of the ocean or 

 bodies of fresh water, from the water's edge down to the 

 greatest depths, cf. Nekton. 



Bergmann's Principle (Rule) 



The generalization which states that Homoiothermal 

 (q. v.) animals such as birds and mammals in cold regions 

 tend to be larger in size and have a lower ratio of body 

 surface to body weight than related animals in warmer 

 climates. The reverse relationship is shown by Poikilo- 

 thermous animals, especially amphibians and reptiles, cf. 

 Allen's principle. 



Berlese Funnel 



An apparatus in which soil or debris is placed in a funnel, 

 heat and light applied from above as a rule, which forces 

 mites, collembolons, etc., into a vessel below, cf. Baermann 

 funnel, Tullgren funnel. 



Beta Particles 



High-speed electrons given off by radioactive substances. 



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