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32 Cards in this Set

  • Front
  • Back
all the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them
the different feeding relationships in an ecosystem, which determine the route of energy flow and the pattern of chemical cycling
trophic structure/levels
autotroph; usually photosynthetic, support all other levels
primary producer
an herbivore, eats plants or other autotrophs
primary consumer
a carnivore that eats herbivores
secondary consumer
a carnivore that eats other carnivores
tertiary consumer
a consumer that derives its energy and nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms; a decomposer
the pathway along which food energy is transferred from trophic level to trophic level, beginning with producers
food chain
the interconnected feeding relationships in an ecosystem
food web
the total mass of organic matter comprising a group of organisms in a particular habitat
each tier represents the standing crop (total dry mass of all organisms) in one trophic level
biomass pyramid
-a community of organisms and their environment
every ecosystem is?
an open system - inputs and outputs of both energy and nutrients
-flows in only one direction through an ecosystem
how each chain in a food web extends from producers through all the consumers
straight line sequence
biotic components of an ecosystem
producers and consumers (including decomposers)
-recycles within an ecosystem
describe one way energy flow
-photosynthesis captures energy from the sun by autotrophs, then eaten by heterotrophs
how does most energy in an ecosystem leave?
in the form of heat
examples of primary producers in a prairie
photoautotrophs, chemoautotrophs
first level consumers in a prairie
2nd trophic level = herbivores, parasites, detritivores, decomposers
second level consumers in a prairie
3rd trophic level = carnivores, parasites, detritivores, decomposers
third level consumers in a prairie
4th trophic level - carnivores, parasites, detritivores, decomposers
fourth level consumers in a prairie
5th trophic level - top carnivores, parasites, detritivores, decomposers
straight line sequence of who eats whom
food chain
simple food chains are rare in nature
energy is lost at each step of a trophic level so....
limits the number of trophic levels
-typically only 10 % efficient
-only chemical energy stored as biomass can be used
how is energy lost at each step?
-heat, organism's activities, growth and reproduction
three different kinds of pyramids
biomass (total weight of organism)
energy (flow through a level)
numbers (total number of organisms)
why do biomass pyramids narrow sharply from primary producers to top-level carnivores?
energy transfers are inefficient!!
-shows how biomass pyramid and number pyramid are proportional to one another
number pyramids
-initial energy sour for nearly all ecosystems