GLOSSARY 



411 



, 



body, typical of chordate developmental stages and 

 adult fish. 



gland a cell, tissue, or organ of secretion or excretion. 



gonad a reproductive organ (ovary, testis, or combina- 

 tion of the two), in which gametes are formed; gen- 

 erally limited to an animal sex organ. 



graben a fault valley depressed between more or less 

 parallel faults. 



granite an igneous rock composed of a mass of visible, 

 mainly interlocking crystals, mostly of feldspars and 

 quartz: 



grass any plant of the Family Poaceae (Subclass Mono- 

 cotyledoneae) ; distinguished by sheating leaves, 

 jointed stems, and fruit in the form of grain. 



grassland loosely, any area containing mostly grasses; 

 specifically, an extensive area of perennial grasses. 



gravity that force of nature observed as a mutual attrac- 

 tion between bodies. 



growth form the appearance or shape of an organism; less 

 restrictive than life form. 



growth formation the appearance of a community, e.g., 

 forest, woodland, and scrub. 



guard cells specialized plant epidermal cells surrounding 

 and controlling the size of opening in a stoma. 



gymnosperm a seed plant that bears naked seeds, those 

 not enclosed in an ovary; once considered a natural 

 group and taxon of plants. 



habitat the natural dwelling place of an organism or 

 group of organisms; sometimes applied to the physical 

 and biological environment of such a place. 



haplobiontic a life cycle having all adults either haploid or 

 diploid; either a haplontic or diplontic life cycle. 



haploid a single set of chromosomes (symbol n) as 

 found in a mature gamete. 



haplontic a life cycle with all haploid adults, the zygote 

 undergoing meiosis. 



haplophase that part of a life cycle in which adults and/or 

 ot her stages have a single set of chromosomes. 



hardwood (1) pertaining to the wood of a broad-leaved 

 deciduous tree as opposed to a conifer; (2) pertaining 

 to any tree with heavy, close-grained resistant wood. 



heat that form of energy into which mechanical energy 

 may be converted; when given to a body, raises its 

 temperature; when removed from a body, lowers its 

 temperature. 



heliotherm an organism whose main source of body heat 

 is the sun. 



hemocoel a portion of a body cavity functioning as part of a 

 circulatory system. 



hemoglobin an iron-containing blood pigment that com- 

 bines with and transports oxygen; a complex chemical 

 compound resembling chlorophyll. 



herb a plant whose aerial parts die back to the ground 

 during the annual period of dormancy; any plant that 



is not woody; a grass or forb in contrast to a tree or 

 shrub. 



herbivore an organism that bulk feeds upon entire plants 

 or parts of plants. 



hermaphrodite a bisexual organism; an individual con- 

 taining both male and female sex organs; also applied 

 to individuals that have one sex organ at a particular 

 time but, during their life cycle, first one then the 

 other sex organ. 



heterogamy union of unlike gametes (heterogametes), 

 usually egg and sperm. 



heterotherm an organism that is an endotherm except 

 during dormancy, when it becomes a heliotherm. 



heterotrophic pertaining to an organism that is unable 

 to synthesize required organic compounds from purely 

 inorganic substances, hence requires complex organic 

 substances as food. 



hibernal pertaining to the winter season. 



hibernation winter dormancy, generally in an animal. 



"High" an anticyclone 



highway in biogeography, any physical or biological 

 feature allowing the movement of an organism out- 

 side its area. 



hogback any cuesta-like ridge formed by difTerential 

 erosion upon rock layers having a dip surpassing 12 

 degrees. 



holdfast the simpler-structured, but rootlike, basal at- 

 tachment device of many algae, especially kelps. 



holozoic pertaining to an organism that feeds upon 

 bulk or solid food; nutrition characteristic of animals; 

 generally pertains to a carnivore, herbivore, 

 omnivore, or scavenger. 



home range that portion of an animal's habitat traversed 

 during its normal activities. 



horst a fault mountain elevated between more or less 

 parallel faults. 



host an organism supplying such things as food and 

 shelter to a parasite. 



humidity the absolute humidity of air. 



humus soil organic matter, dark in color and so decom- 

 posed as to provide no semblance of its original 

 structure. 



hurricane a severe cyclone of tropical origin. 



hydrarch pertaining to a sere beginning in a site of 

 abundant water. 



hydraulicking erosion mechanism by water having great 

 force. 



hydrocarbon an organic compound composed only of car- 

 bon and hydrogen. 



hydrologic pertaining to water; the hydrologic cycle 

 includes the movement of water from the atmosphere 

 by precipitation and back into the atmosphere, mostly 

 by evaporation. 



