1. 2.5 Function
Mrs. Page
ESS

2. Assessment Statements:
2.5.1 Explain the role of producers, consumers and decomposers in the ecosystem.
2.5.2 Describe photosynthesis and respiration in terms of inputs, outputs, and energy transformations
2.5.3 Describe and explain the transfer and transformation of energy as it flows through the ecosystem
2.5.4 Describe and explain the transfer and transformation of materials as the cycle within an ecosystem.

3. Transfers vs Transformations
Transfers – flows through a system, often involve changes in location
Biomass moves from producers through food chain
Water moves from a river to the ocean
Energy moves from the sun to a plant leaf
Transformations – interactions within a system and formation of new products or changes of state
Light energy is converted to chemical energy
Glucose is broken down into water and carbon dioxide

4. What is a system?
System: a collection of matter, parts, or components which work together usually to perform a specific function.
Systems often have inputs and outputs.
For dynamic systems, by definition, one or more aspects of the system change with time.
Example of a simple dynamic system: bathtub or your ‘bank’ account.

5. How is an ecosystem a system?
What are the primary parts that make up the storages in this system?
What is the flows in this system?
Why is it important to an ecosystem to have all of these parts?
What would happen if these parts were missing or broken?
What inputs & outputs do each of these components contribute to the system?

6. 2.5.1 Explain the role of producers, consumers and decomposers in the ecosystem.
Energy flows through ecosystems as organisms capture and store energy, then transfer it to organisms that eat them.
These organisms are grouped into trophic levels...
Producers
Consumers
Decomposers
Release nutrients back into the soil
Convert light energy into chemical energy
Provide food for the base of the food chain/web
Release oxygen into the atmosphere
Pass energy from one organism to another
Release nutrients back into the soil

7. Tertiary consumers
Microorganisms
and other
detritivores
Secondary
consumers
Primary consumers
Detritus
Primary producers
Heat
Key
Chemical cycling
Sun
Energy flow

8. Trophic Levels: Route of energy flow food web - pyramid of numbers
Tertiary
consumers
10 J
Secondary
consumers
100 J
food chain
Primary
consumers
1,000 J
food web
Primary
producers
10,000 J
1,000,000 J of sunlight
- pyramid of numbers

9. Where does the energy go?
Plant material
eaten by caterpillar
200 J
Figure An idealized pyramid of net production
67 J
Cellular
respiration
100 J
Feces
33 J
Growth (new biomass)

10. PRODUCERS
What organisms are capable of trapping the energy of sunlight for conversion into the chemical energy or organic food?
Plants
Algae
Some Bacteria
These organisms are collectively referred to as producers. They provide food for themselves and for virtually all other organisms.

11. Chloroplasts (containing chlorophyll) – this is needed for photosynthesis
Cell wall – made of cellulose which strengthens the cell
Cytoplasm – Chemical reactions happen here
Cell membrane – controls what comes in and out
Large vacuole – stores water, supports cell
Nucleus – controls what the cell does and stores information

12. SUNLIGHT CHLOROPHYLL WATER CARBON DIOXIDE
Four things are needed for photosynthesis:
SUNLIGHT
Specific wavelengths of light gives the plant energy
CHLOROPHYLL
The green stuff where the chemical reactions happen
WATER
Travels up from the roots
CARBON DIOXIDE
Enters the leaf through small holes on the underneath

13. ENERGY TRANSFORMATIONS

14. PHOTOSYNTHESIS

15. CELLULAR RESPIRATION
Transformation of chemical energy in food into chemical energy cells can use: ATP
These reactions proceed the same way in plants and animals. Process is called cellular respiration
Occurs in the mitochondria of plant or animal cells
Overall Reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O

18. Biogeochemical Cycles
Nutrients exist in stores of chemical elements
FOUR main reservoirs where these nutrients exist are:
1) Atmosphere – carbon (C) in carbon dioxide (CO2), nitrogen (N) in atmospheric nitrogen (N2)
2) Lithosphere - the rocks – phosphates (PO4), calcium in calcium carbonate, potassium in feldspar
3) Hydrosphere - the water (H2O) of oceans, lakes, streams and soil - nitrogen (N) in dissolved nitrate, (NO3) carbon (C) in carbonic acid (H2CO3)

19. Living Organisms and Nutrient Cycles
Living organisms are a reservoir (stores) in which carbon exists in carbohydrates (mainly cellulose) and fats, nitrogen in protein, and phosphorus in ATP

20. In studying cycling of water, carbon, nitrogen, and other chemicals, ecologists focus on four factors:
Biological importance of each chemical
Major reservoirs (stores) for each chemical
Forms in which each chemical is available or used by organisms
Key processes driving movement of each chemical through its cycle

21. The Water Cycle Water (H2O) is essential to all organisms
97% of the biosphere’s water is stored in the oceans, 2% is in glaciers and polar ice caps, and 1% is in lakes, rivers, and groundwater
Water moves by the processes of evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater (transfers)

22. The Carbon Cycle
Carbon-based organic molecules are essential to all organisms
Carbon stores include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, and the atmosphere
CO2 is taken up via photosynthesis and released via respiration
Volcanoes and the burning of fossil fuels contribute CO2 to the atmosphere

23. Carbon Cycle
1. Stores – atmosphere (as CO2), fossil fuels (oil, coal), durable organic materials (for example: cellulose).
2. Inputs – plants use CO2 in photosynthesis; animals consume plants.
3. Outputs – plants and animals release CO2 through respiration and decomposition; CO2 is released as wood and fossil fuels are burned.

25. The Nitrogen Cycle
Nitrogen is a component of amino acids, proteins, and nucleic acids
The main store of nitrogen is the atmosphere (N2) 78%
N2 is converted to NH3 via nitrogen-fixing bacteria
N2 is converted to NO3− via lightening
Organic nitrogen is decomposed to (ammonium) NH4+ by ammonification, and NH4+ is decomposed to (nitrate) NO3– by nitrifying bacteria; NH4+ and NO3– assimilated by plants
Denitrifying bacteria convert NO3– back to N2
NOTE: N2, NO, N20, and NO2 are not usable by plants (all but N2 contribute to smog.)
NO3- (nitrate) and NH4+ (ammonium) forms of nitrogen are biologically usable

26. Nitrogen Cycle: Key Points
Nitrogen is in the atmosphere as N2 (78%)
N2 is an inert gas and cannot be used by plants or animals
N2 can be converted to a usable form via
Lightening
N-fixing plants and cyanobacteria
Industrial process (energy intensive)
Nitrogen limits plant growth
Nitrogen is easily lost from biological systems

27. List Some Examples of Transformations
Carbon cycle: Organic compounds to CO2 (processes: respiration, decomposition, or fire)
Carbon cycle: CO2 to organic compounds (process: photosynthesis)
Nitrogen cycle: N2 to NO3 (atmospheric nitrogen to plant utilizable nitrate) (process: N-fixation)
Nitrogen cycle: N2 to NH3 (plant utilizable ammonia) (process: Haber-Bosch Industrial N-fixation)
Water cycle: Liquid water to water vapor (process: evaporation and evapo-transpiration)
Water cycle: Water vapor to liquid water (process: condensation)

28. HOMEWORK
Read pp 43-52
Exercises 1-5 page 52