27 terms


the sum of all the organisms living within its boundaries and the abiotic factors with which they interact
conservation of energy
energy cannot be created nor destroyed but transferred or transformed
primary producers
the trophic level that ultimately supports all others, consists of autotrophs
primary consumers
herbivores. eat plants and other primary producers
secondary consumers
carnivores that eat herbivores
tertiary consumers
carnivores that eat other carnivores
decomposers that get their energy from detritus
nonliving organic material, such as the remains of dead organisms, feces, fallen leaves
primary production
amount of light energy converted to chemical energy by autotrophs during a given time period
gross primary production
the amount of light energy that is converted to chemical energy by photosynthesis per unit time
net primary production
equal to gross primary production minus the energy used by the primary producers for respiration
standing crop
total biomass of photosynthetic autotrophs present at a given time, whereas NPP is the amount of new biomass added in a given period of time
light limitation
depth of light penetration affects primary production through the photic zone of an ocean or lake
nutrient limitation
element that must be added for production to increase. adding other elements will do little to nothing to increase production
when cyanobacteria and algae surge because of excess nutrients added to water. reduce oxygen and clarity of water
actual evapotranspiration
annual amount of water transpired by plants and evaporated from a landscape
secondary production
the amount of chemical energy in a consumer's food converted to their own new biomass during a given time period
production efficiency
the percentage of energy stored in assimilated food that is not used for respiration
trophic efficiency
the percentage of production transferred from one trophic level to the next.
pyramid net production
representation of energy transfer in a food chain
biomass pyramid
the total of the physical mass of all the organisms at each trophic level
turnover time
the time it takes for the standing crop to develop or to be used up
green world hypothesis
states that terrestrial herbivores are held in check by various factors, like plant defenses that prevent herbivores from eating up all the plants`
biochemical cycles
nutrient cycles involving both biotic and abiotic elements
critical load
the amount of added nutrient, usually nitrogen or phosphorus that can be absorbed by plants without damaging ecosystem integrity
acid precipitation
lowers the pH of streams and lakes and affects soil chemistry and nutrient availability
biological magnification
the accumulation of toxins up the trophic levels