2.3 Transfers and transformations of energy

Question 1

Absorbtion

Answer 1

51% available from sun energy
49% absorbed by the ground

Question 2

Ecological efficiency

Answer 2

energy used for growth (biomass development) x 100
Energy supplied

Question 3

Light pathways

Answer 3

1. Light → chemical
2. Transfer of chemical from one trophic level to another
3. Conversion of visible light and UV to heat energy
4. Re-radiation of heat energy to atmosphere

Question 4

Primary productivity

Answer 4

The gain by producers in energy/biomass per unit area per unit time.
→ depends on amount of sunlight, availability of factors needed for growth, ability of producers to use energy to create organic molecules

Question 5

Gross primary productivity (GPP)

Answer 5

mass of glucose created by photosynthesis per area per time.

Question 6

Net Primary productivity (NPP)

Answer 6

gain by producers in energy/biomass after accounting for loss of energy through respiration. Represents potential energy available for next level of consumers. NPP = GPP - R.

Question 7

Secondary productivity

Answer 7

the biomass gained by heterotrophs through feeding and absorption, measured in unit mass/energy per unit area per unit time

Question 8

Gross secondary (GSP)

Answer 8

total biomass assimilated by consumers.
GSP = FOOD EATEN - FAECAL LOSS.

Question 9

Net secondary productivity

Answer 9

gain by consumers in energy/biomass after allowing for respiration. Represents amount of potential energy available for next trophic level. Aka. assimilation.
NSP = GSP - R

Question 10

Max sustainable yield

Answer 10

Rate of increase in natural capital that can be exploited without depleting original stock.

Question 11

factors affecting nutrient cycles

Answer 11

soil erosion, runoff, amount of rainfall, decomposition, plant density etc.
→ Nutrients can be stored in organic (plants and animals) or inorganic (rocks etc.) matter.
→ Macronutrients are needed in large quantities, eg. carbon, nitrogen, oxygen, hydrogen

Question 12

Carbon stores

Answer 12

trees, fossil fuels, limestone, organisms

Question 13

Carbon transfers

Answer 13

herbivores x producers, carnivores x herbivores, decomposers x dead organic matter

Question 14

Carbon transformations

Answer 14

photosynthesis (carbon dioxide turned into glucose + oxygen)
→ respiration (organic matter turned into carbon dioxide)
→ combustion (biomass is turned into carbon dioxide)
→ fossilisation (dead organic matter turned into fossil fuels via pressure and decay)

Question 15

Nitrogen stores

Answer 15

organic → organisms
Inorganic → soil, fossil fuels, bodies of water, atmosphere

Question 16

Nitrogen flows

Answer 16

herbivores x producers, carnivores x herbivores, decomposers x dead organic matter
→ plants absorbing nitrates through roots, metabolic waste products from organism (excretion)

Question 17

Nitrogen transformations

Answer 17

→ fixation of nitrogen from atmosphere by lighting and nitrifying bacteria
→ nitrifying bacteria transforms ammonium ions into nitrite → nitrate
→ denitrifying bacteria transforms nitrates back to nitrogen
→ decomposers break organic nitrogen (proteins) into ammonia
→ nitrogen from nitrates used by plants to make amino acids and protein (assimilation)

Question 18

Impact of human activity

Answer 18

combustion of fossil fuels, urbanisation, agriculture, deforestation impact both energy and matter flows

Question 18

Industrial energy flows

Answer 18

industrial revolution increased use of fossil fuels, allowing humans access to energy trapped in oil, coal etc.
→ amount of energy available to humans increased, increasing agricultural output
→ however, changes in ‘energy budget’ lead to climate change, reduction of natural capital etc
→ combustion of fossil fuels alters the way light energy interacts w/ surface of planet and atmosphere
→ increased CO2 → increasing temp → reduction in ice → less reflected sun energy → more GHG
→ pollution → increased trapping of solar radiation → more heat

Question 19

Matter cycles

Answer 19

timber harvesting interferes w/ nutrient cycling through decomposition
→ removal of trees = canopy cannot intercept rainfall and rich floor litter is washed away
→ trees often cleared to grow oil palm (for food, domestic products and biofuel), thus increasing need for fertiliser in nutrient poor rainforest soil to produce yields
→ fertilisers contain nitrates, leading to contamination of nearby bodies of water (eutrophication)
→ harvested crops are transported, along w/ sequestered nitrogen, altering storages
→ burning fossil fuels reduces storages of non-renewable energy and increases storage of carbon in atmosphere