Our l.ivini^ Restmrces — Glos.scin 



479 



All definitions (except those followed by an 

 asterisk) are from The Dictionaiy of Ecology 

 and Emimnmental Science, edited by Henry W. 

 Art, published by Henry Holt and Company, 

 Inc., copyright 1993 by Storey Communica- 

 tions, Inc.. Pownal. Vermont, and are used with 

 permission. 



acidification. The process of making a sub- 

 stance acidic, lowering its pH or making it 

 "sour." 



adaptive radiation. The evolutionary diver- 

 gence of a species into a variety of different 

 forms, usually as an ancestral fonn encounters 

 new resources or habitats. 



adventive. A species that is not native and has 

 been introduced into the area but has not 

 become permanently established. 



agent. Something that produces or is capable of 

 producing an effect: an active or efficient cause 

 or a chemically, physically, or biologically 

 active principle. 



albedo. Fraction of light reflected by a surface, 

 such as ice, or by an entire planet. Studying a 

 planet's albedo can help determine the compo- 

 sition of its surface. 



allele. One of a pair or series of genes that occu- 

 pies a specific physical position in a specific 

 chromosome; any of the alternative forms of a 

 given gene.* 



allozymes. One of several possible forms of an 

 enzyme that is the product of a particular allele 

 at a given gene locus. 



anadromous. Describing a fish life cycle in 

 which adult individuals travel upriver from the 

 sea to spawn, usually returning to the area 

 where they were born. Salmon and shad are 

 anadromous species. 



anthropogenic. Caused by human action, such 

 as changes in vegetation, an ecosystem, or an 

 entire landscape. 



architomy. Reproduction by fission followed 

 by bodily reorganization. 



bioaccumulation. The absoiption and concen- 

 tration of toxic chemicals in living organisms. 

 Heavy metals and pesticides, such as DDT, are 

 stored in the fatty tissues of animals and passed 

 along to predators of those animals. The result 

 is higher and higher concentrations of the pesti- 

 cide in fatty tissue, eventually reaching harmful 

 levels in predators at the top of the food chain, 

 such as eagles. Also called biomagnification. 



bioassay. Testing the strength of a drug or other 

 substance by examining its effects on a living 

 organism and comparing it with those of a stan- 

 dard substance. 



biodiversity. Number and variety of living 

 organisms; includes genetic diversity, species 

 diversity, and ecological diversity. 



biome. Regional land-based ecosystem type 

 such as a tropical rainforest, tiaga, temperate 

 deciduous forest, tundra, grassland, or desert. 

 Biomes are characterized by consistent plant 

 foims and are found over a large climatic area.* 



bole. Trunk of a tree above the root collar and 

 extending along the main axis.* 



broth. A tluid culture medium.* 



cirque. A deep steep-walled basin high on a 

 mountain usually shaped like half a bowl and 

 often containing a small lake.* 



clutch. The group of eggs laid at one time by 

 either a bird or a reptile. 



community. All the groups of organisms living 

 together in the same area, usually interacting or 

 depending on each other for existence. Also 

 called biological community. 



confidence intervals. An interval formulated to 

 have specific probability of containing the real 

 value of an unknown parameter. A 95 percent 

 confidence interval has a 95 percent probability 

 of containing the parameter being estimated. 



cytological. Describing cytology, a branch of 

 biology dealing with the structure, function, 

 multiplication, pathology, and life history of 

 cells.* 



diadromous. Adjective describing organisms 

 that migrate between fresh and salt water, such 

 as eels and carp. 



double clutching. When an egg-laying individ- 

 ual produces two clutches of eggs in the same 

 season.* 



ecosystem. A functioning unit of nature that 

 combines biotic communities and the abiotic 

 environments with which they interact. 

 Ecosystems vary greatly in size and characteris- 

 tics.* 



ecotones. A transitional area between two (or 

 more) distinct habitats or ecosystems, which 

 may have characteristics of both or its own dis- 

 tinct characteristics. The edge of a woodland, 

 next to a field or lawn, is an ecotone, as are 

 some savanna areas between forests and grass- 

 lands. 



ectomycorrhiza(e) or ectotrophic mycor- 

 rhizae. A symbiotic condition between a fungus 

 and the root of a plant in which the fungus 

 forms a sheath around the root. Some hyphae 

 connecting to this sheath penetrate the host root 

 and spread through the soil surrounding the 

 roots. Ectomycorrhizae form between tree 

 species and basidiomyctete fungi. 



Glossary 



