Fish stocks can be conserved in various ways. Which method of conservation ensures that mainly large fish are caught?

21.1.1 State how modern technology has resulted in increased food production in terms of: – agricultural machinery to use larger areas of land and improve efficiency – chemical fertilisers to improve yields – insecticides to improve quality and yield – herbicides to reduce competition with weeds – selective breeding to improve production by crop plants and livestock, e.g. cattle, fish and poultry

21.1.2 Describe the negative impacts to an ecosystem of large-scale monocultures of crop plants

21.1.3 Describe the negative impacts to an ecosystem of intensive livestock production

21.1.4 Discuss the advantages and disadvantages of genetically modifying crops, such as soya, maize and rice

21.1.5 Discuss the social, environmental and economic implications of providing sufficient food for an increasing human global population

21.1.6 Discuss the problems which contribute to famine including unequal distribution of food, drought and flooding, increasing population and poverty

21.4.1 Define a sustainable resource as one which is produced as rapidly as it is removed from the environment so that it does not run out

21.4.10 Explain that sustainable development requires:

21.4.11 management of conflicting demands

21.4.12 planning and co-operation at local, national and international levels

21.4.13 Explain the risks to a species if the population size drops, reducing variation (knowledge of genetic drift is not required)

21.4.14 Explain reasons for conservation programmes, to include: – reducing extinction – protecting vulnerable environments – maintaining ecosystem functions, limited to nutrient cycling and resource provision, e.g. food, drugs, fuel and genes

21.4.2 Explain the need to conserve non-renewable resources, limited to fossil fuels

21.4.3 State that some resources can be maintained, limited to forests and fish stocks

21.4.4 State that products can be reused or recycled, limited to paper, glass, plastic and metal

21.4.5 Outline how sewage is treated to make the water that it contains safe to return to the environment or for human use

21.4.6 Explain why organisms become endangered or extinct, limited to climate change, habitat destruction, hunting, pollution and introduced species

21.4.7 Describe how endangered species can be conserved, limited to monitoring and protecting species and habitats, education, captive breeding programmes and seed banks

21.4.8 Define the term sustainable development as development providing for the needs of an increasing human population without harming the environment

21.4.9 Explain how forests and fish stocks can be sustained using education, legal quotas and restocking