36 terms

AP Biology Ch 54: Ecosystems Vocabulary

AP Biology Chapter 54: Ecosystems Vocabulary
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Ecosystem
a community and its physical environment, including biotic and abiotic components. All organisms in a given area as well as the abiotic factors with which they interact; a community and it's physical environment. P1198
Heterotrophs
an organism that obtains organic food molecules by eating other organisms or their byproduct. P 1199
Primary producers
an autotroph, which collectively make up the trophic level of an ecosystem that ultimately supports all other levels in the ecosystem; usually a photosynthetic organism which use light energy to make sugars and other organic compounds. P1199
Primary consumers
consumers that eat producers. Ex: herbavors.
Secondary consumers
a member of the trophic level of an ecosystem consisting of carnivores that eat herbivores. p1199
Tertiary consumers
a member of the trophic level of an ecosystem consisting of carnivores that eat other carnivores. p1199
Detritivores / Decomposers
A consumer that derives it's energy from nonliving organic material.
Detritus
dead organic material. p1199
Primary production
amount of light energy converted to chemical energy (organic compounds) during a given time period in an ecosystem; the photosynthetic output of an ecosystem's autotrophs. p1200
Gross primary production (GPP)
the total primary production of an ecosystem. The amount of light energy that is converted to chemical energy by photosynthesis per unit time. Not all is stored as organic material because plants use some to fuel their own chemical respiration. p1200
Net Primary Production (NPP)
it represents the storage of chemical energy that is available to consumers in the ecosystem. It is equal to the gross primary production (GPP) of an ecosystem minus the energy used by the producers for respiration (R); [NPP=GPP-R]. p1200
Biomass
dry weight of organic matter comprising a small group of organisms in a particular habitat. p1201
Standing crop
the total biomass of photosynthetic autotrophs present at a given time. p1201
Limiting nutrient
the nutrient that must be added for production to increase; often is nitrogen or phosphorus. p1203
Eutrophication
the shift in composition of phytoplankton communities in lakes from dominations by green algae and diatoms to blooms of cyanobacteria. p1204
Secondary production
amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period. p1205
Production efficiency
fraction of food energy that is not used for respiration. p1206
Trophic efficiency
the percentage of production transferred from one trophic level to the next.p1206
Pyramid of production
is a pyramid in which the trophic levels are staked in blocks, with primary producers forming the foundation of the pyramid. It shows the multiplicative loss of energy caused by trophic efficiency. p1206
Biomass pyramid
Each tier represents the standing crop in a trophic level. p1206
Turnover time
standing crop biomass compared to production; thus turnover time equals the standing crop biomass (mg/m2) divided by production (mg/m2/day). P1207
Pyramid of numbers
the size of each block is proportional to the number of individual organisms present in each trophic level. p1207
Green world hypothesis
states that herbivores consume relatively little plant biomass because they are held in check by a variety of factors including predators, parasites and disease. p1208
Biogeochemical cycles
any of the various nutrient circuits, which involve both biotic and abiotic components of the ecosystem. Chemical elements are passed between abiotic and biotic components of the ecosystem through the biogeochemical cycle. p1209
Nitrogen fixation
the assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants. Nitrogen can enter the ecosystem when certain prokaryotes convert N2 to minerals that can be used to synthesize nitrogenous organic compounds like amino acids. p1210
Nitrification
An activity that oxidizes ammonium to nitrite and then to nitrate by soil bacteria (making nitrogen available to plants). p1211
Denitrification
The conversion of nitrates back into nitrogen . p1211
Ammonification
the process in which the decomposition of organic nitrogen back to ammonium; carried out by bacterial and fungal decomposers. p1211
Long-term ecological research (LTER)
research conducted to follow dynamics of natural ecosystems over relatively long time periods. p1213
Critical load
the amount of added nitrogen that can be absorbed by plants without damaging ecosystem integrity. p1216
Cultural eutrophication
human intrusion that has disrupted freshwater ecosystems. Eutrophication that occurs as a result of sewage, factory wastes, and runoff of animal wastes and fertilizers from agricultural lands. p1216
Acid precipitation
rain, snow, or fog that has a pH less than 5.6. p1216
Biological magnification
a trophic process in which retained substances (poisons) become more concentrated with each level in the food chain. p1217
Greenhouse effect
the warming of planet Earth due to the atmospheric accumulation of carbon dioxide, water vapor, and other gases, which reflect infrared radiation back toward Earth. p1219
Actual Evapotranspiration
The amount of water annually transpired by plants and evaporated from a landscape, usually measured in millimeters.
Law of Conservation of Mass
mass cannot be created/destroyed, although it may be rearranged in space, and be changed into different types of particles.