Edexcel Biology 2105, also Additional Science 2103

Unit B2

Topic 4 — Interdependence

Understanding the principles of interdependence is the key to managing the Earth’s resources successfully and sustainably. Television and newspapers often have stories about damage to the environment, but how can we put right the damage?

This topic explores how competition and predation affect the distribution and numbers of organisms in selected environments. The impact of human activity is then considered with the opportunity for students to interpret data on living and non-living indicators. This leads to the need for responsible recycling and conservation and consideration of the effects on biodiversity.

Guidance for students

Have you ever wondered?
Why are rabbits such a pest in Australia?
Why is territory so important for animals?
If animals fight over land and mating partners, what do plants fight over?
Why is there a variety of birds in the park and not just one species?
Why did dinosaurs become extinct?
Why do deep-sea fish have cylindrical eyes and not eyeballs?
Why are all conservation initiatives not equally successful?
Why is recycling of materials encouraged?

Learning objectives

• Organisms compete with each other for resources.
• Organisms are interdependent which affects their distribution and population size.
• Extreme environments often promote unusual organisms with unusual strategies.
• Human impacts on the environment and conservation measures need management.

Glossary
You will be expected to be able to recall, explain, describe and use appropriately the following words and phrases:

adaptation extreme environment pollution sewage
aquatic global temperature population skin cancer
biodiversity interdependence predation terrestrial
competition nitrate recycling waste disposal
conservation organism reforestation  
coppicing ozone replacement planting  
environment phosphates resource  
biodegradable chloroflurocarbons CFCs greenhouse gases hydrothermal vents indicators

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:

• explore the principles of interdependence, adaptation, competition and predation and explain how these factors influence the distribution and population sizes of organisms in a given terrestrial or aquatic environment B2 4.1
• use primary and secondary data to consider how human activity, including differing economical and industrial conditions, can affect the environment and cause changes in sizes of population B2 4.2
• investigate, using primary and secondary data, the impact of human activity on the environment, including the pollution of air and of water; and the effects of air pollutants (including carbon dioxide, sulphur dioxide, carbon monoxide) and of water pollutants (including sewage, nitrates and phosphates) B2 4.3
• interpret data on environmental change B2 4.4
• explain the importance of protecting natural populations B2 4.5
• describe the special nature of some extreme environments, notably deep sea volcanic vents, the Antarctic and high altitudes B2 4.6
• interpret data to show the impact of human activity on the environment to include:
- living indicators eg lichen distribution and incidence of skin cancer
- non-living indicators eg global temperature and ozone depletion
 B2 4.7
• explore whether recycling reduces demand for resources and reduces the problem of waste disposal, including paper, plastics and metals B2 4.8
• consider conservation management techniques, including reforestation, coppicing, replacement planting and discuss how conservation can lead to greater biodiversity. B2 4.9