Annelid 



An animal belonging to the phylum Annelida such 

 as earthworms, leeches, and marine worms; showing 

 segmentation. 



Annual Heat Budget 



See Heat budget. 



Annual Plant 



A plant which completes its life-cycle and dies in one 

 year or less; a winter annual starts growth in late summer or 

 fall and completes its life-cycle the following spring or early 

 summer, a summer annual begins growth in the spring or 

 early summer and completes its life-cycle before the follow- 

 ing winter, cf. Biennial, Perennial. 



Annual Production 



The amount of substance formed in a year by an organ- 

 ism or a group of organisms. 



Annual Ring 



The layer of wood (Xylem) added each year to stems and 

 roots of woody plants, which indicate the age of the plant. 

 Occasionally more than one layer may be formed in one 

 year. See Growth layer. 



Annual Seasons 



The chief climatic periods of the year; Vernal/ Estival, 

 Autumnal. (Serotinal), and Hibernal (q. v.). 



Annual Succession 



The successive occurrence of plants or animals in an area, 

 or their activities, during the year, such as summer-flowering 

 plants replacing the spring-flowering ones; or the various 

 reproductive stages in animals. 



Annual Turnover 



The total quantity of living organisms (Biomass) (q. v.) 

 produced in one year in an area. 



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