cHAPTER 55 Flashcards
ECOSYSTEM
sum of all organisms living in a given area and the abiotcic factors with which they itneract
primary producers
trophic level that supports all others consists of autotrophs, use light energy
primary consumers
eat primary producers
secondary consumers
carnivores that eat herbivores
tertiary consumers
carnivores that eat other carnivores
detritivores/decomposers
group of heterotrophs, get energy from nonliving organic material
primary production
the amount of light energy converted to chemical energy by autotrophs in a given time
Conservation of mass and energy
govern energy flow and chemical cycling in ecosystems, organisms will cycle energy from the sun
gross primary production (GPP)
amount of energy from light converted to the chemical energy of organic molecules per unit of time. not all of this is stored as organic material
Net primary production (NPP)
equal to GPP minus the energy used by the primary producers for cellular respiration. On average it is about one half of GPP
Net ecosystem Production (NEP)
measure of the total biomass accumulation during that time. defined as gross primary production minus the total respiration of all organisms in the system
limiting nutrient
the element that must be added for production to increase in an ecosystem.
common limiting nutrients
phosphorus and nitrogen
evapotranspiration
the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants.
evapotranspiration effect on biomes
the temperature and moisture can affect the primary production of an ecosystem, net primary production (NPP) increases with evapotranspiration
secondary production
amount of chemical energy in consumers’ food that is converted to their own new biomass during a given period
production efficiency
the percentage of energy stored in assimilated food that is used for growth and reproduction, not respiration (Production Efficiency=net secondary production/assimilation of primary production *100)
Trophic efficiency
percentage of production transferred from one trophic level to the next. must always be less than production efficiencies
10% rules for food chain
only around 10% of energy is received from organisms taking in energy. primary producers convert only about 1% of the energy available to them to net primary production. only about 0.1% of the chemical energy fixed by photosynthesis can flow all the way to a tertiary consumers,
biogeochemical cyclees
nutrient cycles that involve both biotic and abiotic components, consists of the flow of elements into different ecosystems
reservoirs
vital ecosystem elements are typically found in large resevoirs in ecosystems
four factors to focus on for biogeochemical cycles
each chemical’s biological importance, forms in which each element is available or used by organisms, major reservoirs for each chemical, key processes driving movement of each chemical through its cycle
decomp rates
rapid decomposition means low soil nutrient levels, decomp increases with temperature
biomagnification
the concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely disbursed.
