2.5 Function


Assessment 2.5.1: Explain the role of producers, consumers and decomposers in the ecosystem*

àRole of producers: basis of ecosystems, supporting them through constant input of energy and new biomass

àRole of consumers: obtain energy, minerals and nutrients from other organisms

àRole of decomposers: breakdown the dead organic matter, release nutrients that are ready for the re-absorption by producers


Assessment 2.5.2: Describe photosynthesis and respiration in terms of inputs, outputs and energy transformations.

Photosynthesis: the process by which green plants convert light energy from the sun into useable chemical energy stored in organic matter.
-Inputs-sunlight, carbon dioxide and water
-Processes- Chlorophyll traps sunlight; the energy is used the split water molecules; hydrogen from water is combined with carbon dioxide to produce glucose
-Outputs- Glucose (organic matter) and oxygen
-Transformation- light energy to stored chemical energy
external image photosynthesis3.gif



àRespiration: the process of releasing energy from glucose and other organic molecules inside all living cells.
-Input-Glucose and oxygen
-Process-Oxidation process inside cells
-Outputs- release of energy for work and heat
-Transformation- stored chemical energy to kinetic energy and heat


Assessment 2.5.3: Describe and explain the transfer and transformation of energy as it flows through an ecosystem.

Solar radiation incident on the ecosystem
  • Loss of radiation through reflection and absorption
  • Conversion of light to chemical energy
  • loss of chemical energy from one trophic level to another
  • Efficiencies of transfer
  • overall conversion of light to heat energy by an ecosystem
  • Re-radiation of heat energy to the atmosphere

Assessment 2.5.4:Describe and explain the transfer and transformation of materials as they cycle within an ecosystem.

Carbon Cycle
external image carboncycle_sm.jpg
Nitrogen Cycle
external image nitrogencycle_sm.jpg
Water Cycle
external image Watercycle.GIF

http://sciencebitz.com/?page_id=35 (More info)


Assessment 2.5.5 & 6 & 7

Primary productivity: the gain by producers in energy or biomass per unit area per unit time

Secondary productivity: the biomass gained by heterotrophic organisms, through feeding and absorption, measure in units of mass or energy per unit area per unit time
Gross productivity: the total gain in energy or biomass per unit area per unit time
Net productivity: the gain in energy or biomass per unit area per unit time remaining after allowing for respiratory losses
Net primary productivity: the gain by producers in energy or biomass per unit area per unit time remaining after allowing for respiratory loss. This is potentially available to consumers in an ecosystem
Gross primary productivity: the gain through photosynthesis in primary producers
Gross secondary productivity- the gain through absorption in consumers
Net secondary productivity- the gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses
-NPP=GPP-R, R= respiratory loss
-NSP= GSP-R
-GSP=Food eaten-Fecal loss

http://sciencebitz.com/?page_id=204( Background knowledge)


http://sciencebitz.com/?page_id=238 (More info)