Posts Tagged ‘gross’

  • Explain the role of producers, consumers and decomposers in the ecosystem.
Producer: can make their own food, as they use sunlight to make food and are called  the basis of every ecosystem which helps the rest of the species through input of energy and new biomass. This all happens through photosynthesis which is the process when the producer uses the sun for energy.
Consumer: feed on other organisms, they do not contain photosynthesis pigments so they cannot make their own food. They have to get energy, minerals and nutrients by eating other organisms. This makes the heterotrophs. Herbivores feed on autotrophs, carnivores on other heterotrophs and omnivores on both.
Decomposer: get their food from the breakdown of a dead organism matter. They break down tissue and release nutrients for absorption by other producers. Decomposers also improve the nutrient capacity in the soil by breaking down the organic material.
  • Describe photosynthesis and respiration in terms of inputs, outputs and energy transformations.
Photosynthesis: needs carbon dioxide, water, chlorofyll and certain visible wave lengths of light to produce organic matter and oxygen.
  • inputs: sunlight as energy resource, carbon dioxide and water
  • processes: chlorofyll traps sunlight; energy is used to split water molecules; hydrogen from water is combined with carbon dioxide to produce glucose.
  • outputs: glucose used as an energy source for the plant and as a building block for other organic molecules; oxygen is released to the atmosphere through stomata.
  • transformations: light energy is transformed to store chemical energy.
Respiration: needs organic matter and oxygen to produce carbon dioxide and water.
  • inputs: glucose and oxygen
  • processes: oxidation processes inside cells
  • outputs: release of energy for work and heat
  • transformations: stored chemical energy to kinetic energy and heat
  • Describe and explain the transfer and transformation of energy as it flows through an ecosystem.
Not all solar radiation ends up being stored as biomass. Losses include_
  • reflection from leaves
  • light not hitting chloroplasts
  • light of the wrong wavelengths (not absorbed by chloroplast pigments)
  • transmission of light through the leaf
  • inefficiency of photosynthesis
In this diagram we can see the energy flow through an ecosystem.
  • Describe and explain transfer and transformation of materials such as they cycle within an ecosystem.
The Carbon Cycle:
The Hydrological cycle:

The nitrogen cycle:
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  • Define the terms gross productivity, net productivity, primary productivity, and secondary productivity.
*Productivity is production per unit time.
Primary productivity is the gain by producers (autotrophs) in energy or biomass per unit area per unit time. It is when solar energy is converted, it depends on the amount of sunlight the ability of the producers to use energy to synthesize organic compounds and the availability of other things needed for growth, like minerals and nutrients.
Primary production is highest were conditions for growth are optimal, where there are high levels of insolation, good water supply, warm temperatures and high nutrient levels.
You can then divide primary productivity into gross and net profits.
*GROSS is the income
*NET is the incomes minus costs
Secondary productivity depends on the amount of food there is and the efficiency of the consumers turning this into new biomass. Unlike the primary productivity net productivity involves feeding or absorption.
Gross productivity (GP): The total gain in energy or biomass per unit area per unit time.
Net productivity (NP): The gain of energy or biomass per unit area per unit time remaining after allowing for respiratory losses. It is the energy left for the next trophic level to consume.
  • Define the terms and calculate the values of both gross primary productivity and net primary productivity from given data.
Gross primary productivity (GPP): is gained through photosynthesis in primary producers.
Net primary productivity (NPP): is the gain by prodicers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses. (Available for consumers in ecosystem)
Productivity calculation:
Primary productivity:

where R = energy used in respiration
NPP = GPP – R
  • Define the terms and calculate the values of both gross secondary productivity and net secondary productivity from given data.
Gross secondary productivity(GSP): is gained through absorption in consumers.
Net secondary productivity(NSP): The gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses.
Secondary productivity:
NSP = GSP – R
GSP = food eaten – faecal loss
where R = respiratory loss