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GLOSSARY 



tion is by producers at the base and that there is pro- 

 gressive marked reduction in successive consumers. 



food web an illustration of all interconnecting food chains 

 in a community. 



foot in liverworts, mosses, and many vascular plants, the 

 basal part of the developmental sporophyte, which 

 attaches to and obtains nutrients from the gameto- 

 phyte. 



forb an herb other than a grass; sometimes restricted to 

 herbs that are distinctly not grasslike. 



forest a community having a dense growth of trees, 

 usually over various shorter plants. 



formation (1) in geology, the fundamental unit of rock 

 classification; any group of similar rocks formed with- 

 out interruption under similar conditions at approxi- 

 mately but not exactly the same time; formations 

 need not be continuously distributed geographically; 

 (2) in ecology, plant communities, serai or climax, oc- 

 cupying either a single or similar climatic regions; a 

 very large unit of vegetation composed of similar- 

 appearing communities in similar environments; a 

 biome minus its animals. 



fossil any evidence of past life, including remains of 

 organisms that have just died and such things as tracks 

 or burrows of dead organisms. 



fragmentation asexual reproduction by the breaking of a 

 multicellular organism into two or more segments, 

 with most to all segments regenerating a new in- 

 dividual. 



front any boundary between air masses of different 

 temperatures. 



fruit a plant structure consisting of one or more 

 ripened ovaries and any enveloping parts that may 

 be associated with them. 



fruiting body any reproductive structure in plants. 



gamete a mature reproductive (sex or germ) cell that is 

 capable of uniting with another in sexual reproduction 

 to form a zygote. 



gametophore loosely, one of the two gametophyte 

 stages in the life cycle of certain bryophytes; 

 specifically, the second and true gametophyte stage 

 because it bears the sex organs and produces gametes; 

 the budding product of a protonema, the first 

 gametophyte stage. 



gametophyte specifically, the gamete-forming adult stage 

 in the diplobiontic life cycle, in a loose sense, any 

 gamete-forming plant. 



ganglion a group of nerve cell bodies, generally set 

 apart from other nerve cell bodies and acting as an 

 independent source of nervous influence. 



gas one of the three states of matter (solid, liquid, and 

 gas); the state of matter that completely fills a con- 

 tainer (theoretically, even one of infinite size) without 

 regard to the amount of matter. 



gastrovascular pertaining to or serving both digestive 

 and circulatory functions. 



gastrula an early stage in animal development in which 

 surface cells migrate into the embryonic mass and in- 

 ternal cells become oriented into germ layers. 



geanticline a gigantic and elongate arching fold of the 

 earth's crust; a gigantic anticline. 



gemma an asexual, multicellular outgrowth by budding of 

 a parental body, as in liverworts, capable of developing 

 into an individual like the parent. 



gemmule generally considered a bud (but usually a group 

 of cells formed inside a parental sponge) that is re- 

 leased upon decay of the parent, and grows into a new 

 adult. 



gene definable only in functional terms; the unit of 

 heredity; the chromosomal site of a unit of genetic 

 information. 



gene pool the total genetic material (genes) of a species; 

 any definable segment of a species or an individual. 



generalized pertaining to any organism at an early stage 

 (not a time concept) of evolutionary development; 

 primitive; an organism lacking complex structures, 

 functions, and/or behavior. 



genetics the study of heredity. 



genus (1) a taxon ranking above a species and below a 

 family; composed of a closely related group of species 

 or a species; (2) a category below a family in the 

 classification of clouds and certain other things. 



geoflora an extremely large unit of vegetation, diagnosed 

 on the basis of growth form, that evolves but retains 

 its identity through time; three were (and are) im- 

 portant in the development of North American vege- 

 tation. 



geology the study of the history of the earth and its life 

 as recorded in rocks. 



geomorphic pertaining to the form of the earth. 



geomorphology the study of the form and changes in form 

 of the earth. 



geosyncline a gigantic syncline, generally submerged and 

 acting as a collecting basin, especially for sedimentary 

 deposits. 



germ cell a gamete. 



germ layer any of the two or three basic cell layers (ecto- 

 derm, mesoderm, and endoderm) in the embryo of 

 most animals (Subkingdom Eumetazoa). 



germ plasm roughly, genes. 



germination the beginning of growth of a plant spore, 

 seed, or other reproductive structure. 



gill an animal organ for underwater respiration. 



gill pouch an outpocketing of the pharynx in all chordate 

 embryos; the precursor of the gill slits of fishes and 

 certain amphibians but only of temporary gill slits in 

 other vertebrates. 



gill slit an opening for the pharynx to the outside of the 



