1. Energy Flow In Ecosystems
Big Idea:
What happens to energy stored in Body tissues when one organism eats another?

2. Food Chains & Food Webs How does energy flow through ecosystems?
A 1-way stream, from primary producers to consumers
Food Chains
A series of steps in which organisms transfer energy by eating and being eaten

3. Food Chains & Food Webs Food Webs
A network of feeding relationships; shows all the feeding relationships within an ecosystem

4. Food Chains & Food Webs Food Webs – Very complicated Notebook Time:
Describe the ecosystem that is your backyard
Draw a food web of that ecosystem
Be as specific as possible
Draw a food chain from within your food web
What role do decomposers & detritivores play in food webs?

5. Food Chains & Food Webs Disturbances
In your groups, answer the following questions using the food web below:
What effect would an insecticide have on the food web?
Would this have an effect on the populations of non-insect eating animals?
What populations would increase?
What populations would decrease?
Would this change any animals eating habits? Which ones & how?

6. Trophic Levels & Ecological Pyramids
Each step in a food chain
Ecological Pyramids
Show relative amount of energy or matter contained within each trophic level in a given food chain or food web
There are 3 different types of Ecological Pyramids
Pyramids of Energy
Pyramids of Biomass
Pyramids of numbers

7. Ecological Pyramids Pyramids of Energy
Show relative amounts of energy available at each trophic level
Typically
1/10 or 10% of available energy within one trophic level is passed on to the next level
In other words:
1/10 of the solar energy captured and stored in leaves of grasses ends up stored in the tissues of cows

8. Ecological Pyramids Pyramid of Biomass & Numbers Biomass –
Total amount of living tissue within a given trophic level
Pyramid of Biomass
Illustrates the relative amount of living organic matter available at each trophic level of an ecosystem

9. Ecological Pyramids Pyramid of Biomass & Numbers Pyramid of Numbers
Shows the relative number of individual organisms at each trophic level in an ecosystem

10. Cycles of Matter How does matter move through the biosphere?
Biogeochemical cycles
Elements pass from one organism to another and among parts of the biosphere in closed loops
These loops are powered by the flow of energy.
4 Processes involved with biogeochemical cycles
Biological Processes
Any and all activities performed by living organisms
Geological Processes
Volcanic eruptions, erosion, plate tectonics
Chemical & Physical Processes
Formation of clouds, flow of running water, lightning
Human Activity
Deforestation, burning of fossil fuels, use of fertilizers

11. Water Cycle
Water moves continuously between, oceans, the atmosphere, land and the organisms in them.
Transpiration
Evaporation of water from leaves of the plants
Evaporation
Loss of water from surface of bodies of water
Condensation
When water vapor cools & becomes liquid
Precipitation
When water falls out of the atmosphere

12. Nutrient Cycles
3 main Nutrient Cycles
Carbon
Nitrogen
Phosphorus

13. Nutrient Cycles Carbon Cycle
Found in several large reservoirs in biosphere
Atmosphere = CO2
Oceans = Dissolved CO2
Land = in organisms, soil & rocks
Underground =
Coal, Petroleum & Calcium Carbonate
In Life = base of all organic molecules

14. Nutrient Cycles Nitrogen Cycle Required to build proteins, DNA, RNA
Atmospheric Nitrogen
N2 = Non-usable form for most organisms
Needs to be “fixed”
Nitrogen Fixation
Process of N2 being converted into ammonia, nitrates & nitrites by bacteria
Relatively small amounts of N2 can be fixed by Lightning
Denitrification
When N2 is released by soil bacteria who use nitrates for energy
Fertilizer
Huge human influence in adding excess Nitrates & Nitrites into aquatic ecosystems
Can cause algal blooms

15. Nutrient Cycles Phosphorus Cycle Essential for creation of DNA, RNA
Not very abundant in biosphere
Remains mostly on land in rock, soil, & sediments
As rock & sediments wear down, P is released to environment.

16. Nutrient Cycles Nutrient Limitation Limiting Nutrient In Soil In Ocean
The nutrient whose supply limits productivity
In Soil
Typically Limiting Nutrients are:
Ca, Mg, S, Fe, Mn, P, Fixed N,
In Ocean
Fixed N