Specialized 



Refers to an organism, or part thereof, that is adapted to 

 a particular kind of life or to a certain combination of 

 environmental conditions; more limited than an unspecial- 

 ized organism. 



Speciation 



The processes in evolution by which new species are 

 formed, cf. Mutation, Natural selection. Sub spe elation. 



Species 



A unit of classification of plants and animals, consisting 

 of the largest and most inclusive array of sexually reproduc- 

 ing and cross-fertilizing individuals which share a common 

 gene pool; the most inclusive Mendelian population (q. v.), 

 e.g., the white pine (Pinus strobus) and ponderosa pine 

 (Pinus ponderosa) are two species in the genus Pinus. cf. 

 Jordanon, Ecospecies, Coenospecies, Taxon, Syngameon, 

 Superspecies. 



Species-area Curve 



A graph showing the number of species on the vertical 

 axis and the area of the sampling-unit or Quadrat on the 

 horizontal axis; used to determine the most suitable area 

 of quadrat to use in sampling vegetation. 



Specific Gravity (Soils) 



The ratio of the weight of a given volume of soil, pore 

 space excluded, to the weight of an equal volume of water; 

 the average specific gravity of tilled surface soil is about 2.65. 



Specificity 



The limitation of an organism to restricted, definite set 

 of environmental conditions, a single kind of food plant or 

 animal host, or other set of circumstances. 



Spectrum, Biological 



See Biological spectrum. 



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