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GLOSSARY 



hydrophyte a plant growing partly to completely sub- 

 merged in water and usually displaying specializa- 

 tions for its habitat. 



hydrosphere the water upon the earth's surface. 



hypho a threadlike structure basic to the body organiza- 

 tion of many fungi. 



hypolimnion in temperature-layered lake, the water at the 

 bottom and below the thermocline. 



hypothesis a tentative and reasonable explanation of 

 observed phenomena; an intelligent guess adopted for 

 the purpose of critical experimental testing to de- 

 termine its validity. 



igneous pertaining to fire or to rocks formed from the 

 solidification of magma. 



immigration the movement of an organism into a pre- 

 viously unoccupied area. 



indusium a fern epidermal tissue often found covering 

 a sorus (q.v.). 



influent any organism, usually an animal, that is not a 

 dominant but has important effects upon its physical 

 and/or biological environment. 



inorganic pertaining to matter formed by natural physical 

 processes and not by an organism. 



insolation energy received from the sun as by the earth. 



instar any stage of an immature insect between any two 

 successive molts, but excluding a pupa. 



integument (1) any outer covering of an organism; (2) the 

 outer covering of a plant ovule that develops into a 

 seed coat; (3) generally restricted to living coverings. 



internode any plant stem region between any two succes- 

 sive nodes; sometimes applied to jointlike parts in 

 stemlike structures of animals. 



intertidal the ocean zone from the highest level of land 

 struck by spray of the highest high tide surf to the 

 lowest point uncovered by the lowest low tide. 



invertebrate any animal without a backbone (vertebral 

 column). 



ion an atom or group of atoms bearing positive or nega- 

 tive charge; one of the particles formed by ionization. 



ionization the dissociation of a molecule into two or more 

 charged particles (ions) ; the addition or substraction of 

 charged particles from atoms. 



isogamy fusion of gametes of like appearance, isogametes. 



joint ( 1) in geology, an essentially flat break or separation 

 between rocks along which there was little or no move- 

 ment as in a fault; (2) in biology, the movable or im- 

 movable, junction between separate body parts. 



kame a small hill deposited in front of a glacier by a 

 stream leaving the interior of the glacier and entering a 

 lake. 



kelp loosely, any of the large marine algae, a seaweed; 

 more specifically, any large, marine brown alga, a 

 rock weed. 



kettle hole a depression in a glaciated area believed to 



have formed by melting of a block of ice once covered 

 by glacial debris. 



kingdom the largest taxonomic subdivision of life; Monera, 

 Protista, Plantae, or Animalia. 



labial pertaining to the lip. 



laccolith a dome mountain formed by underground in- 

 jection of a lens-shaped body of igneous rock. 



lanceolate shaped like a lancehead. 



larva an immature, often wormlike, life cycle stage 

 between embryo and adult stages in many organisms; 

 generally, an immature organism that hatches from 

 an egg, is active and mobile, is quite different from 

 the adult in appearance, carries on most life processes 

 of adults, but usually does not reproduce. 



lateral pertaining to the side of a structure. 



layer society a group of organisms within a particular 

 layer of plants, e.g., trees, shrubs, or herbs. 



leaflet any distinct unit in a compound leaf. 



lichen an intimate grouping of a fungus and a green or 

 blue-green alga into a single mass that functions in 

 many respects like a single organism. 



Life Belt an altitudinal subdivision of a Biotic Province, 

 distinguished by ecological diflferences of lesser im- 

 portance than those separating Biotic Provinces. 



life cycle (1) the series of stages or phases in structure and 

 mode of life of an organism from zygote to natural 

 death; (2) any regular sequence of stages or phases of 

 an inanimate feature from its origin to disappearance; 

 (3) generally, life history. 



life form the characteristic appearance of an organism 

 or species at maturity. 



life history pertaining to the record or history of a life 

 cycle. 



life spectrum the range in organization of living structures 

 and organisms. 



Life Zone a region characterized by distinctive plants and 

 animals and the distribution scheme using such 

 regions. 



limestone a sedimentary rock composed mostly of calcium 

 carbonate which yields lime (CaO) when burned. 



limiting factor any physical or biological feature of the 

 environment that restricts one or more functions 

 (hence, distribution) of an organism. 



limnetic pertaining to open water in a lake. 



liquid the fluid state of matter in which shape is dependent 

 upon shape of the container but volume is independent 

 thereof. 



lithosphere the solid rock of the earth, usually limited to 

 the earth's crust. 



littoral pertaining to water-covered areas near the shore; 

 often defined in terms of depth of light penetration or 

 wave or tide action. 



lophophore a structure surrounding the mouth and bear- 

 ing ciliated tentacles; found in certain aquatic in- 



