• Unit 3-Ecosystems

    Key Points:
    • Ecosystems have biotic and abiotic components.
    • Photosynthesis, resperation and productivity are key concepts in understanding ecology.
    • A biome is a collection of ecosystems with similar climatic conditions.
    • The location of a biome depends on climare and limiting factors.
    • The most importnat climatic factors determing biome distribution are precipitation and temperature.
    • Trophic (feeding) levels, food chains, food webs and pyramids of number, biomass and productivity help us in understanding how ecosystems function.
    • Populations of organisms interact in different ways.
    • Different biotic and abiotic factors influence population size.
    • Species show different characteristics with respect to ecological niche they fill.
    • Energy flows through ecosystems and most is lost to the system as heat.
    • Humans manipulate ecosystems to get the grreatest productivity from them.
    Key words:
    biome solar radiation insolation
    climate precipitation leaching
    latitude altitude respiration
    photosynthesis productivity gross primary productivity (GPP)
    net primary productivity (NPP) gross secondary productivity (GSP) net secondary productivity (NSP)
    autotroph heterotroph species
    population ecological niche ecosystem
    biotic factors abiotic factors food chain
    food web trophic level producer
    consumer herbivore carnivore
    top carnivore decomposer detritivore
    pyramid of numbers pyramid of biomass pyramid of productivity
    bioaccumulation biomagnification intraspecies competition
    interspecies competition predation predator
    prey herbivory parasitism
    mutualism energy flow diagram biogeochemical cycles
    energy budget energy subsidy

Last Modified on March 24, 2011