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Ecology Standards 6a. Know biodiversity is the sum total of different kinds of organisms
& is affected by alterations of habitats 6b. Know how to analyze changes in an ecosystem resulting from
changes in climate, human activity, introduction of non-native species, or changes in population size.
6c. Know how fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration & death.
6d. Know how water, carbon, & nitrogen cycle between abiotic & biotic resources and organic matter in the ecosystem & how oxygen cycles through photosynthesis & respiration.
6e. Know a vital part of an ecosystem is the stability of its producers and decomposers.
6f. Know at each link in a food web some energy is stored in newly made structures, but much energy is lost to the environment as heat, represented in an energy pyramid.
Ecosystem Structure
Passing of Energy
All Energy starts from the sun
Photosynthetic plants convert energy from the sun into food
The energy moves through the ecosystem as one organism eats another
Autotrophs = Producers
An organism that converts the sun’s energy into food
Heterotrophs = Consumers
Organisms that obtain energy by eating other organisms
Can eat plants or animals Or BOTH
Food Chains
A model of the flow of energy through organisms in a community
Flow of energy is shown by arrows
Transferred Energy
At each step in the food chain only 10% energy is passed to the organism
90% of the energy is lost in the form of HEAT
90%HEAT
90%HEAT
90%HEAT
Trophic Level
A step in the transfer of energy
Producers are the 1st trophic level
** they form the base of all food chains
Primary Consumers = Herbivores
Feed directly on producers
Make up the 2nd trophic level
Secondary Consumers = Carnivores
Eat only meat
Feed on primary
Make up the 3rd
Omnivores
Eat both producers and consumers
Scavengers
Consumer that feeds on the tissue of dead animals
Decomposers (recyclers)
Feed on wastes and dead organic matter from all trophic levels
VERY IMPORTANT Waste would pile up
without them to recycle it!
Ecological Pyramid
Shows the relationship between producers & consumers in 3 ways: Biomass Energy # of organisms
Biomass Pyramid
Biomass – mass of living organisms
There is less biomass as you move up trophic levels
Energy Pyramid & 10% Law
Only 10% of energy is passed to next level
1st trophic level is important in determining the rest of the levels
# of organism pyramid
Population of each trophic level decreases as you move up the trophic levels
Food Web
Shows the interconnected food chains in a community or ecosystem
A lot of food chains together