Precipitation 



(1) A general term for all forms of falling moisture in- 

 cluding rain, snow, hail, sleet, or modifications of them. 

 (2) The quantity of water that is precipitated. (3) The process 

 in which water as a liquid is discharged from the atmosphere 

 upon land or water. 



Precipitation-effectiveness Ratio 



The total amount of precipitation for a certain period of 

 time divided by the total amount of evaporation, both in 

 liquid form. 



Precipitation Rose 



A radial diagram expressing the amounts of precipitation 

 by months or other intervals of time. 



Preclimax 



A Climax community (q. v.) that occurs usually in more 

 Xeric conditions than obtain generally in the region where 

 it is present, often considered a stage in succession preceding 

 the full development of a climax, cf. Postclimax. 



Precocial 



Refers to young animals that do not need parental care 

 after birth or hatching, cf. Altricial. 



Predation 



The behaviour of animals, Predators, in killing other 

 animals, Prey. 



Predator 



An animal that attacks other animals, Prey, e.g., a fox 

 that kills mice or other prey. 



Predominant 



Refers to organisms that are of outstanding abundance 

 or conspicuous importance in a community. 



Preferendum 



The preferred or "selected" conditions of a motile organ- 



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