Earth in Our Care: Ecology, Economy, and Sustainability

Glossary

247 GLOSSARY abiotic—the nonliving chemical and physical components of the environment. albedo effect—the electromagnetic radiation reflected back into space by the white surface of a growing ice sheet; albedo is Late Latin for whiteness, from the Latin albus, white. autonomous, self-compatible plant—a plant that can fertilize itself without the services of an outside pollinator, such as a bee. benthic—of or pertaining to a benthos, including the organisms that live there. benthos—the biogeographic region at the lowest level of a body of water, such as an ocean or a lake, including the sediment surface and some subsurface layers. biodiversity (see also “biological diversity”)—the diversity of living organisms. biological diversity—the condition of having a variety of biotic characteristics and traits (e.g., genes, species, and community types); life-history stages; structural forms (e.g., stratification, zonation, and the physical structures of plants); biotic patterns (e.g., reproductive, activity, food-web, social, and interactive); and functions (e.g., nutrient cycling, hydrological cycling, and provision of habitat). biomass—the combined weight of all living organisms in a given area. biophysical diversity—the diversity of living and nonliving components of an ecosystem. biotic—composed of plants and animals. boreal—of or pertaining to the northern part of the Northern Hemisphere. calcareous—composed of, containing, or characteristic of calcium carbonate, calcium , or limestone; chalky. calcium—a silvery, moderately hard, metallic element that constitutes approximately  percent of the earth’s crust and is a basic component of bone, shell, and leaves. calcium carbonate—a colorless- or white-crystalline compound that occurs naturally in chalk, limestone, marble, and other forms. cambium—in woody vegetation, the layer of cells that lies between the secondary xylem and secondary phloem cell layers; through a process of cell division, the cambium produces the secondary xylem and the secondary phloem that are also known, respectively, as the wood and the innermost living bark. canopy—the more or less continuous cover of branches and foliage collectively formed by the crowns of adjacent trees and other woody growth; layers of canopy may be called stories. canopy closure—the progressive reduction of space between tree crowns as they spread laterally. carbohydrate—any of a group of chemical compounds, including sugars, starches, and cellulose, containing carbon, hydrogen, and oxygen only. carbon—a naturally abundant nonmetallic element that occurs in many inorganic and all organic compounds. carbon flux—an abbreviated phrase referring to the net difference between the sequestration of carbon dioxide through photosynthesis and the respiration of carbon dioxide by such organisms as plants and microbes. carnivore—a mammal that that preys or feeds on other animals, as opposed to eating plants. carnivorous—flesh-eating. carrying capacity—the maximum number of individuals of a species that an area can sustainably maintain without altering the integrity of the ecosystem that supports them. chemoautotrophs—“chem” from the Greek chemikos, “of or pertaining to juices” ⫹ “auto” from the Greek autos, “self” ⫹ “troph” from the Greek trophos, “one who feeds”; hence, bacteria that derive energy from oxidizing inorganic compounds , such as hydrogen sulfide, ammonium, and ferrous iron. chemotaxis (chemotactic, adj.)—a movement in which bodily cells, bacteria, and other single-cell organisms direct their movements according to certain chemicals in their environment, as when bacteria find food by swimming toward the highest concentration of food molecules or when they flee from poisons. clear-cut—an area of land that was forested but now has all the trees cut down and removed. clear-cutting—the act of cutting down all the trees in a forested area as an economic expedient in order to remove the timber to a mill. GLOSSARY 248 climatic cycle—the cyclic changes in weather patterns in a geographical area over time. climax—the culminating stage in plant succession for a given site where the vegetation is self-reproducing and thus has reached a stable condition through time. colonization—the process or act of establishing a colony or colonies (also see “colony”). colony—a group of the same kind of plants or animals living together. closed canopy—the condition that exists when the canopy created by trees or shrubs or both is dense enough to exclude most of the direct sunlight from the floor of the forest. commensal—of or pertaining to the relationship between two different species from which one derives food and other benefits without negatively affecting the other, such as house sparrows benefiting from their association...