1. Warm Up 1. Why can’t a food chain have an infinite number of links?
2. Why aren’t there large numbers of big animals (top consumers) in an ecosystem?
3. Name two processes that recycle water in an ecosystem.

2. The Water Cycle Condensation Transpiration Precipitation Evaporation
Runoff
Use this slide to discuss cycle, students don’t need to write down yet

3. The Water Cycle
This slide has all the important processes. Draw a stick-figure diagram on the board for students to copy.

4. What you should know about the Water Cycle
5 main physical processes:
Evaporation (ocean/lake  water vapor)
Condensation (water vapor  clouds)
Precipitation (clouds  rain/snow)
Transpiration (the process of water vapor coming out of plant leaves)
Runoff (rivers, streams)
You need to be able to draw the water cycle as a network.

5. Think and be ready to share:
1. What are some forms of carbon found on earth or in the atmosphere?
2. Name two processes that recycle carbon in an ecosystem.

6. Why is Carbon important?
Glucose
Required for all organisms on earth
Needed to make DNA, proteins, fats, sugars
Cell membranes are composed of lipids

7. The Carbon Cycle
Draw a stick-figure example of this slide on the board. Add fossilization and skip detritus. Separate trees burning and burning of fossil fuels.

8. Photosynthesis and respiration
6CO H2O C6H12O O2
Respiration
C6H12O O CO H2O
sunlight
Carbon
dioxide
Water
Sugar
Oxygen
Carbon
dioxide
Sugar
Oxygen
Water

9. Photosynthesis and Respiration
Note how the OUTPUT of photosynthesis is the same as the INPUT of respiration
Note how the OUTPUT of respiration is the same as the INPUT of photosynthesis
Matter CYCLES back and forth between photosynthesis and respiration.

10. What happens to plants that aren’t eaten by consumers?

11. What is the role of decomposers?
Small organisms
Worms, insects
Microorganisms
Fungi, bacteria

12. Decomposers
Small organisms (worms, insects) break down waste and dead organisms into smaller parts.
Microorganisms (bacteria, fungi) digest the smaller parts into chemical forms that can be used by plants.
Ex: CO2

13. Decomposers in the Carbon Cycle
The decomposers take waste and turn it back into a form usable by the producers (CO2). The producers then release the carbon dioxide back into the atmosphere.

14. What you need to know about the Carbon Cycle
The role of…
Photosynthesis
Respiration
Decomposers
Combustion, human impact
You need to be able to draw the carbon cycle as a network. Let’s practice.

15. Nitrogen Cycle
All living organisms must have nitrogen to live (make DNA and proteins.)
Atmospheric nitrogen (N2) cannot be used as a nitrogen source by plants or animals.
Nitrogen exists in other chemical forms:
Ammonia (NH3)
Nitrites (NO2) and Nitrates (NO3)
Other molecules in waste (urine, dung, corpses)

16. Draw a network to summarize:
Plants (autotrophs) get their nitrogen from nitrites (NO2) ammonia (NH3) and nitrates (NO3) in the soil.
Animals (heterotrophs) get their nitrogen from eating plants and other animals.
Some special plants and bacteria can “FIX” atmospheric nitrogen (N2) and turn it into nitrites (NO2) ammonia (NH3) and nitrates (NO3)
Some Bacteria can produce atmospheric nitrogen (N2) from ammonia (NH3)
Animals produce waste containing molecules with nitrites (NO2) ammonia (NH3) and nitrates (NO3) (urine, corpses, feces)
Decomposers can turn the nitrogen in dead organisms into nitrites (NO2) ammonia (NH3) and nitrates (NO3)

17. The Nitrogen Cycle
Nitrites, nitrates

18. What’s important?
You must be able to explain that microscopic decomposers (bacteria, fungi) function in ecosystems to recycle carbon and nitrogen.