Edexcel Biology 2105, also Science 2101, Additional Science 2103

Unit B1 a

Topic 1 — Environment

Environmental issues have become more important in people’s lives and feature regularly in the media, even affecting local and national elections. This topic looks at human impact on the environment and how it can be measured. Ways in which plants and animals can be improved in order to feed the world are at the forefront of modern agriculture and students will consider the energetics of food production. As usual, new food production techniques raise new ethical, social and environmental questions.
Organisms are classified according to how closely they are related and students will learn to appreciate that ‘rules’ change as new evidence emerges. It is a competitive world, all organisms compete for resources and only those that are best adapted will survive in a changing environment; specific adaptations of organisms to extreme environments will be investigated.
There is an opportunity to study populations using computer models and also to use secondary data to explore how human activity affects populations and the environment. Students will also discuss the evidence for natural selection, examining how Darwin’s ideas were received by his contemporaries and comparing this with how current scientific theory is received by today’s scientific community.

Guidance for students

Have you ever wondered?
How can the Sun’s energy support all life on Earth?
Why don’t food chains go on forever?
Which grows more quickly – grass or cow?
How do different organisms make different changes to solve the same environmental problem?
Does the number of foxes control the number of rabbits or does the number of rabbits control the number of foxes?
Is evolution still taking place?
What would happen to the human race if we were all the same?
How does natural selection ‘know’ how to create a new species?
Why are so many people worried about GM technology?
Why did a cartoon of Charles Darwin drawn as an ape appear in a national newspaper when he proposed his theory of evolution?
Learning objectives
• Animals and plants depend on each other.
• All organisms are adapted to their environment.
• There is often competition between organisms for resources.
• Natural selection is a long process over many generations.
Glossary
You will be expected to be able to recall, explain, describe and use appropriately the following words and phrases:

adaptation	environment	interdependence	prey
biomass	evolution	intra-species	quantitatively
breeding	extinct	natural selection	reproduction
characteristic	food chain	organic	species
classification	fossil	organism	mutation
competition	genetic engineering	population
ecosystem	genetically modified	predator

Information for teachers
ICT is an integral part of the way science works, and students should be given opportunities to experience and explore its use. It is expected that ICT will be used where it enhances the learning and teaching of science and helps to make scientific concepts easier to understand.
Some of the learning outcomes have been written deliberately in order to promote discussion and expression of opinion. Where contentious, unresolved or other scientific issues are discussed, it is expected that students will be exposed to the facts, evidence and opinions from all sides of the argument.
Learning outcomes
Learning outcomes, words or statements in bold indicate that this content is designated for Higher tier students only.
Students will be assessed on their ability to:

• interpret food chains quantitatively using pyramids of biomass and consider why this is more accurate than a pyramid of numbers	B1 a1.1
• describe how organisms in an ecosystem compete with each other for resources	B1 a.1.2
• explain why it is more cost effective, in terms of energy, to produce a field of wheat rather than a field of beef cows	B1 a 1.3
• explain population data in terms of predator-prey interdependence and intra-species competition	B1 a 1.4
• use secondary data to explain how human activity can affect the environment, especially changes in population size and in economic and industrial conditions	B1 a 1.5
• demonstrate an understanding of how computer models can be used to study populations, and show an awareness of the advantages and disadvantages of these models compared with real data	B1 a 1.6
• demonstrate an understanding of the principles of natural selection, to include: - how individuals within a species can have characteristics that promote more successful reproduction (survival of the fittest) - how, over generations, the effects of natural selection result in changes within species and the formation of new species from genetic variants or mutants that are better adapted to their environment - how species that are less well-adapted to a changing environment can become extinct	B1 a 1.7
• explain how fossils provide evidence for evolution	B1 a 1.8
• explain, compare and contrast selective breeding and genetic engineering in terms of changing the characteristics of a species	B1 a 1.9
• discuss why Charles Darwin experienced difficulty in getting his theory of evolution through natural selection accepted by the scientific community in the 19th century	B1a1.10
• explain the principles of classifying organisms and the difficulties encountered in attempting to do so, as illustrated by the five kingdoms, the use of phylum, class, order, family, genus, species and the main characteristics of the five vertebrate groups	B1a1.11
• discuss the ethics and principles of organic farming and explain why organic products are more expensive than non-organic produce	B1a1.12
• demonstrate an understanding of how crop plants can be genetically modified and the reasons for doing so and the ethical concerns this raises	B1a1.13