Ch. 54

163767721	Ecosystem	A level of ecological study that includes all the organisms in a given area as well as the abiotic factors with which they interact; a community and its physical environment
163767722	Secondary Consumers	Carnivores that eat herbivores
163767723	Food Chain	Pathway along which food is transferred from trophic level to trophic level
163767724	Primary Productivity	The rate at which light energy or inorganic chemical energy is converted to the chemical energy of organic compounds by autotrophs in an ecosystem
163767725	Limiting Nutrient	single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem
163767726	Pyramid of Productivity	shows that productivity is highest at the bottom, or first, trophic level and decreases dramatically
163767727	Production	Rate of incorporation of energy and materials into bodies of organisms
163767728	Trophic Structure	The different feeding relationships in an ecosystem that determine the route of energy flow and the pattern of chemical cycling
163767729	Tertiary Consumers	A member of a trophic level of an ecosystem consisting of carnivores that eat mainly other carnivores
163767730	Food Web	A community of organisms where there are several interrelated food chains
163767731	Gross Primary Productivity	The total primary productivity of an ecosystem
163767732	Secondary Productivity	Rate at which consumers convert chemical energy in the food they eat into their own biomass
163767733	Ecological Efficiency	Ratio of net productivity at one trophic level compared to net productivity at the trophic level below
163767734	Trophic Level	The division of species in an ecosystem on the basis of their main nutritional source; an organism's feeding status in an ecosystem.
163767735	Detritivores	Decomposers; derive energy from detritus and dead organisms from other trophic levels; major link between primary producers and consumers
163767736	Consumption	Metabolic use of assimilated organic molecules for growth & reproduction
163767737	Biomass Pyramid	Tiers that symbolize the total dry weight of all organisms in a trophic level; narrow sharply from base to top level carnivores; aquatic may be inverted b/c of short turnover time
163767738	Nitrification	Metabolic process by which certain aerobic soil bacteria use ammonium as an energy source by oxidizing it to nitrite then nitrate; returns nitrogen to the atmosphere
163767739	Primary Producers	An autotroph, which collectively make up the trophic level of an ecosystem that ultimately suuports all other levels; usually a photosynthetic organisms
163767740	Detritus	Dead organic matter
163767741	Decomposition	Breakdown of organic molecules into inorganic molecules
163767742	Net Primary Productivity	The gross primary productivity minus the energy used by the producers for cellular resperation; represents chemical energy in an ecosystem available to consumers
163767743	Biological Magnification	Process by which toxiins become more concentrated with each successive trophic level; top-level carnivores most affected
163767744	Pyramid of Numbers	Blocks which are proportional in size to the number of individuals present at each trophic level
163767745	Primary Consumers	Herbivores that eat primary producers
163767746	Denitrification	Only returns a small amount of N2; nitrate reduction into nitrogen
163767747	Greenhouse Effect	Warming of Earth due to atmospheric accumulation of carbon dioxide, which absorbs infaredd radiation
163767748	Biomass	The dry weight of organic matter comprising a group of organisms in a particular habitat
163767749	Ammonification	Decomposition of organic nitrogen back into ammonium; bacteria & fungi; recycles large amounts of N2
163767750	Nitrogen Fixation	The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants