Analyse energy and biomass evidence across food webs, including productivity calculations, ecological efficiency, pollutant transfer and HL resource-management decisions.
Figure:Example of a lake ecosystem
Figure 1 shows an example of a lake ecosystem.
Rooting flowering plants: producers
Birds: secondary and tertiary consumer eg kingfisher
Floating plants: producers eg lilies, water fern
Frog: secondary consumer
State the source of energy for this ecosystem.
Identify one way in which energy may leave this ecosystem.
Draw a food chain from the ecosystem in Figure 1 consisting of four trophic levels.
Compare and contrast the pathways of energy through the atmosphere and the pathways of energy through an ecosystem.
Outline the transfers and transformations of matter as it enters and flows through the first trophic level of a food chain.
Describe how the emissions from the combustion of fossil fuels may impact the productivity of terrestrial ecosystems.
Figure:Example of a lake ecosystem
Figure 1 shows an example of a lake ecosystem.
Rooting flowering plants: producers
Birds: secondary and tertiary consumer eg kingfisher
Floating plants: producers eg lilies, water fern
Frog: secondary consumer
State the source of energy for this ecosystem.
Outline the transfers and transformations of matter as it enters and flows through the first trophic level of a food chain.
Outline the transfers and transformations of energy as it enters and flows through the first trophic level of a food chain.
Describe the role of primary producers in ecosystems.
Figure:Coastal seawater temperature near a nuclear power station
Figure 5 shows a range of coastal seawater temperatures at different distances from a nuclear power station. Nuclear power stations may be responsible for localized thermal pollution of coastal waters. Thermal pollution is caused by warmer water being released into a colder body of water.
Thermal pollution lowers the dissolved oxygen content of water.
Suggest the effect of this on a named transformation process.
Figure:Example of a lake ecosystem
Figure 1 shows an example of a lake ecosystem.
Rooting flowering plants: producers
Birds: secondary and tertiary consumer eg kingfisher
Floating plants: producers eg lilies, water fern
Frog: secondary consumer
Identify one way in which energy may leave this ecosystem.
The diagram shows gross and net productivity at different trophic levels in the Silver Springs, Florida, ecosystem.
Describe how the second law of thermodynamics operates in relation to the transfer of energy within the Silver Springs ecosystem.
Figure:Energy flow through an ecosystem
Figure 7 shows the energy flow in an ecosystem. The width of the arrows is proportional to the quantity of energy transferred.
With reference to Figure 7,
State the group of organisms at C that feed on dead plants, animals and feces.
Figure A simplified food web in a kelp forest ecosystem
Figure Kelp forest ecosystems with and without the presence of sea otters
The arrows indicate the flow of carbon between the atmosphere and the carbon stored in kelp.
State the trophic level of sea urchins in the kelp forest ecosystem shown in Figure.
Explain the ways in which energy is lost as it moves through an ecosystem.
Define the terms gross primary productivity (GPP) and net primary productivity (NPP). Explain, with reference to two contrasting biomes, why one biome will be more productive than the other.
Figure:Simplified food web for Mindo cloud forest
Outline one impact that a reduction in the Mindo harlequin toad population may have on the food web in Figure 10(b).
Describe how biomass data from a named biome could be collected.
Explain why pyramids of numbers, biomass and productivity may vary in shape for different food chains.
Outline two advantages and two disadvantages of using DDT.
Figure:Dead albatross chick with plastic garbage in stomach
- Figure: Albatross and plastic impacts: larger plastic pieces are taken in by fish, sea birds and animals, which may die of starvation.
- One study estimates around 1 million sea birds, including albatrosses, and 100000 animals are killed by ingestion of plastic or entanglement in plastic fishing nets.
- About half of all albatross species are endangered or critically endangered on the Red List.
Explain why albatross chicks may starve if they eat plastic.
Describe how the emissions from the combustion of fossil fuels may impact the productivity of terrestrial ecosystems.
Figure:Copperbelt land use in 1972
Figure:Copperbelt land use in 2000
Figures: Copperbelt land-use change in 1972 and 2000: land use changed from 1972 to 2000: agriculture/scattered dwellings/mixed vegetation increased from 40% to 59%; woodlands decreased from 56% to 32%; plantations increased from 0% to 4%.
- Figure: Mining in Zambia and Copperbelt impacts: 84% of Zambia export income comes from mining, although there are efforts to increase income from agriculture and manufacturing.
- Most mining occurs in the Copperbelt and Northwestern Provinces; Zambia is a major producer of copper and cobalt.
- Historic mining in Copperbelt Province has left 21 waste rock dumps, 9 slag heaps and 45 tailing dams with toxic metal concentrations.
- The Kafue River supplies local communities; young Tilapia are unable to survive near mining areas in the Kafue River.
- Mining activity in Copperbelt Province has supported an increase in local population.
- Figure: Fact file on Zambia: Zambia has approximately 14.64 million people and an annual population growth rate of 2.8%.
- Indigenous forest covers approximately 491348 km²; wood fuel contributes about 80% of domestic energy consumption.
- Zambia has abundant wildlife, forests, water resources and mineral deposits.
Identify four factors that would affect the primary productivity of forest plantations in the Copperbelt Province.
Suggest a series of procedures that could be used to estimate the net productivity of an insect population in .
The diagram shows gross and net productivity at different trophic levels in the Silver Springs, Florida, ecosystem.
Define net primary productivity.
To what extent are the concepts of net productivity and natural income useful in managing the sustainable harvesting of named resources from natural ecosystems?
Identify two reasons why a human vegetarian diet is considered to be more energy efficient than a diet containing meat.
Figure 1: A sample food chain from a marine ecosystem to show the concentration of persistent organic pollutants (POPs) and the energy within each trophic level
Calculate, as a percentage, the efficiency of energy transfer between zooplankton and herring.
Figure:Energy flow through an ecosystem
Figure 7 shows the energy flow in an ecosystem. The width of the arrows is proportional to the quantity of energy transferred.
Explain how entropy is increased by each energy transformation that takes place in the food chain.