ecology …the study of how organisms interact with each other and their environments …the study...
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Ecology
…the study of how organisms interact with each other and their
environments
…the study of ……..OUR house…..
ENERGY FLOWS
MATTER CYCLES
FACTORS INTERACT
ENERGY FLOWS
Trophic Levels• Energy moves from one
organism to another when it is eaten
• Each step in this transfer of energy is know as a trophic level
• The main trophic levels are producers, consumers, and decomposers
When energy flows as organic
matter through the trophic
levels of an ecosystem, MUCH
of it is LOST at each link in a
food chain.
Why?CLUE
When you burn energy to run a mile in gym where does that energy come from?
Transfer of Energy• When a zebra eats the grass, it does
not incorporate all of the energy the grass has into its body (much of it is not digested and used for energy to live)
Transfer of Energy• When a lion eats a zebra, it
does not keep all of the energy from the zebra in its body….
Plant material eaten by
caterpillar100 kilocalories (kcal)
50 kcalFeces
15 kcal
Growth
35 kcalCellular respiration
Does all the energy this caterpillar eats get passed to the bird who eats him?
Transfer of Energy• No organism EVER keeps all of
the energy from the organism they just ate
• Only ~10% of the energy from one trophic level is really transferred to the next – this is called the 10% law
Ecological Pyramid• An ecological pyramid shows
the relationship between organisms different trophic levels in an ecosystem
• Shows the relative amounts of energy or matter and number of organisms contained at each trophic level
Ecological Pyramid
Biomass• The total mass of the organic
matter at each trophic level is called biomass
• Biomass is just another term for potential energy – energy that has yet to be eaten and used.
Decomposers:What is a decomposer and what do they
do? What trophic level would you put them at?
– Derive their energy from the dead material left by all trophic levels
– Are often left off of most pyramids and food chain diagrams
Ecological Pyramid
• Which level has the most energy?• Which level has the most
organisms?• Which level has the least
organisms?• Which level has the least energy?
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