New specifications
Continuing specifications
GCSE Science AUnit 6 (Science 2)
Science 2 is half of Biology 1, half of Chemistry 1 and half of Physics 1, as follows:
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Biology
B1.4 Interdependence and adaptation
Overview
Organisms are well adapted to survive in their normal environment. Population size depends on a variety of factors including competition, predation, disease and human influences. Changes in the environment may affect the distribution and behaviour of organisms.
Candidates should use their skills, knowledge and understanding to:
- suggest how organisms are adapted to the conditions in which they live
- Examination questions will use examples that are unfamiliar to candidates.
- observe the adaptations, eg body shape, of a range of organisms from different habitats
- develop an understanding of the ways in which adaptations enable organisms to survive
- suggest the factors for which organisms are competing in a given habitat
- Factors are limited to light, water, space and nutrients in plants; food, mates and territory in animals.
- evaluate data concerned with the effect of environmental changes on the distribution and behaviour of living organisms.
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B1.5 Energy and biomass in food chains
Overview
By observing the numbers and sizes of the organisms in food chains we can find out what happens to energy and biomass as it passes along the food chain.
Candidates should use their skills, knowledge and understanding to:
- interpret pyramids of biomass and construct them from appropriate information.
- An understanding of pyramids of number is not required.
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B1.6 Waste materials from plants and animals
Overview
Many trees shed their leaves each year and most animals produce droppings at least once a day. All plants and animals eventually die. Microorganisms play an important part in decomposing this material so that it can be used again by plants. The same material is recycled over and over again and can lead to stable communities.
Candidates should use their skills, knowledge and understanding to:
- evaluate the necessity and effectiveness of schemes for recycling organic kitchen or garden waste.
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B1.7 Genetic variation and its control
Overview
There are not only differences between different species of plants and animals but also between individuals of the same species. These differences are due partly to the information in the cells they have inherited from their parents and partly to the different environments in which the individuals live and grow. Asexual reproduction can be used to produce individuals that are genetically identical to their parent. Scientists can now add, remove or change genes to produce the plants and animals they want.
Candidates should use their skills, knowledge and understanding to:
- interpret information about cloning techniques and genetic engineering techniques
- Candidates will be given data to work from.
- make informed judgements about the economic, social and ethical issues concerning cloning and genetic engineering, including genetically modified (GM) crops.
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Overview
Particular genes or accidental changes in the genes of plants or animals may give them characteristics which enable them to survive better. Over time this may result in entirely new species. There are different theories of evolution. Darwin's theory is the most widely accepted.
Candidates should use their skills, knowledge and understanding to:
- interpret evidence relating to evolutionary theory
- Candidates will be given data to work from.
- suggest reasons why Darwin's theory of natural selection was only gradually accepted
- identify the differences between Darwin's theory of evolution and conflicting theories, such as that of Lamarck
- suggest reasons for the different theories.
- Scientists may produce different hypotheses to explain similar observations. It is only when these hypotheses are investigated that data will support or refute hypotheses.
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Chemistry
C1.5 Other useful substances from crude oil
Overview
Fractions from the distillation of crude oil can be broken down (cracked) to make smaller molecules including unsaturated hydrocarbons such as ethene. Unsaturated hydrocarbons can be used to make polymers and ethene can be used to make ethanol. Ethanol can also be made by fermentation.
Candidates should use their skills, knowledge and understanding to:
- evaluate the social and economic advantages and disadvantages of using products from crude oil as fuels or as raw materials for plastics and other chemicals
- Candidates should be aware that crude oil is used to produce fuels and chemicals, and that it is a limited resource.
- Candidates should be able to evaluate information about the ways in which crude oil and its products are used. Although candidates will probably know the names of some common polymers, these are not required knowledge, unless they are included in the subject content for this section.
- evaluate the social, economic and environmental impacts of the uses, disposal and recycling of polymers
- evaluate the advantages and disadvantages of making ethanol from renewable and non-renewable sources.
- Candidates should be able to compare the environmental impact of producing ethanol from renewable and non-renewable sources.
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C1.6 Plant oils and their uses
Overview
Many plants produce useful oils that can be converted into consumer products including processed foods. Emulsions can be made and have a number of uses. Vegetable oils can be hardened to make margarine. Biodiesel fuel can be produced from vegetable oils.
Candidates should use their skills, knowledge and understanding to:
- evaluate the effects of using vegetable oils in foods and the impacts on diet and health
- Knowledge is limited to the high-energy content of vegetable oils, the possible health benefits of unsaturated fats compared with saturated fats, and the effects of cooking foods in oil. Information may be provided in examinations for candidates to evaluate.
- evaluate the use, benefits, drawbacks and risks of emulsifiers in foods.
- Candidates do not need to recall the names of specific additives. Further information will be provided in questions for evaluation and comparison.
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C1.7 Changes in the Earth and its atmosphere
Overview
The Earth and its atmosphere provide everything we need. The Earth has a layered structure. The surface of the Earth and its atmosphere have changed since the Earth was formed and are still changing. The atmosphere has been much the same for the last 200 million years and provides the conditions needed for life on Earth. Recently human activities have resulted in further changes in the atmosphere. There is more than one theory about how life was formed.
Candidates should use their skills, knowledge and understanding to:
- recognise that the Earth's crust, the atmosphere and the oceans are the only source of minerals and other resources that humans need
- explain why Wegener's theory of crustal movement (continental drift) was not generally accepted for many years
- Candidates should have studied accounts of Wegener's work. Knowledge is limited to the theories relating to mountain building and continental drift
- Candidates should know that scientists once thought that the features of the Earth's surface were the result of the shrinking of the crust as the Earth cooled down following its formation.
- explain why scientists cannot accurately predict when earthquakes and volcanic eruptions will occur
- Candidates may be given information which they will be expected to interpret.
- explain and evaluate theories of the changes that have occurred and are occurring in the Earth's atmosphere
- Candidates should be able to compare and evaluate different theories when given suitable information.
- explain and evaluate the effects of human activities on the atmosphere
- Knowledge of the effects of human activities is limited to those in the subject content.
- describe why we do not know how life was first formed.
- HT only
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Physics
P1.4 Methods we use to generate electricity
Overview
Various energy sources can be used to generate the electricity we need. We must carefully consider the advantages and disadvantages of using each energy source before deciding which energy source(s) it would be best to use in any particular situation. Electricity is distributed via the National Grid.
Candidates should use their skills, knowledge and understanding to:
- evaluate different methods of generating electricity
- Candidates should be able to evaluate different methods of generating electricity given data including start-up times, costs of electricity generation and the total cost of generating electricity when factors such as building and decommissioning are taken into account. The reliability of different methods should also be understood.
- Knowledge of the actual values of start-up times and why they are different is not needed, but the implications of such differences are important.
- evaluate ways of matching supply with demand, either by increasing supply or decreasing demand
- Candidates should be aware of the fact that, of the fossil fuel power stations, gas-fired have the shortest start-up time. They should also be aware of the advantages of pumped storage systems in order to meet peak demand, and as a means of storing energy for later use.
- compare the advantages and disadvantages of overhead power lines and underground cables.
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P1.5 The use of waves for communication and to provide evidence that the universe is expanding
Overview
Electromagnetic radiations travel as waves and move energy from one place to another. They can all travel through a vacuum and do so at the same speed. The waves cover a continuous range of wavelengths called the electromagnetic spectrum.
Sound waves and some mechanical waves are longitudinal, and cannot travel through a vacuum. Current evidence suggests that the universe is expanding and that matter and space expanded violently and rapidly from a very small initial 'point', ie the universe began with a 'big bang'.
Candidates should use their skills, knowledge and understanding to:
- compare the use of different types of waves for communication
- Knowledge and understanding of waves used for communication is limited to sound, light, microwaves, radio waves and infrared waves.
- evaluate the possible risks involving the use of mobile phones
- consider the limitations of the model that scientists use to explain how the universe began and why the universe continues to expand.
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