Describe the different levels of organisation from individual organisms, populations, communities, to the whole ecosystem

Explain how communities can be affected by abiotic and biotic factors, including:

a) temperature, light, water, pollutants
b) competition, predation

Describe the importance of interdependence in a community

Describe how the survival of some organisms is dependent on other species, including parasitism and mutualism

Core Practical: Investigate the relationship between organisms and their environment using field-work techniques, including quadrats and belt transects

Explain how to determine the number of organisms in a given area using raw data from field-work techniques, including quadrats and belt transects

Explain how some energy is transferred to less useful forms at each trophic level and that this affects the number of organisms at each trophic level, limits the length of a food chain and determines the shape of a pyramid of biomass in an ecosystem

Calculate the efficiency of energy transfers between trophic levels and percentage calculations of biomass

Explain the positive and negative human interactions within ecosystems and their impacts on biodiversity, including:

a) fish farming
b) introduction of non-indigenous species
c) eutrophication

Explain the benefits of maintaining local and global biodiversity, including the conservation of animal species and the impact of reforestation

Describe the biological factors affecting levels of food security, including:

a) increasing human population
b) increasing animal farming and the increased meat and fish consumption
c) the impact of new pests and pathogens
d) environmental change caused by human activity
e) sustainability issues, e.g. use of land for biofuel production and the cost of agricultural inputs

Describe how different materials cycle through the abiotic and biotic components of an ecosystem

Explain the importance of the carbon cycle, including the processes involved and the role of microorganisms as decomposers

Explain the importance of the water cycle, including the processes involved and the production of potable water in areas of drought including desalination

Explain how nitrates are made available for plant uptake, including the use of fertilisers, crop rotation and the role of bacteria in the nitrogen cycle

Evaluate the use of indicator species as evidence to assess the level of pollution, including:

a) polluted water – bloodworm, sludgeworm
b) clean water – freshwater shrimps, stonefly
c) air quality – different species of lichen, blackspot fungus on roses

Explain the effects of temperature, water content and oxygen availability on the rate of decomposition in food preservation

Explain the effects of temperature, water content and oxygen availability on the rate of decomposition in composting

Calculate rate changes in the decay of biological material