Study Guides

Unit Summary

This unit explores the interdependence of organisms in ecosystems, including food webs and insect-pollinated crops. It examines how organisms interact with their environment and the impact of toxic materials. It also highlights the importance of biodiversity and preserving genetic material.

Lesson Summary

You will learn to describe how toxic materials can accumulate and affect organisms in a food chain.

Key Notes

• Some toxic substances are persistent (they stay in the environment and do not break down).
• If consumed, persistent toxic substances can be passed up the food chain.
• The bioaccumulation of toxic substances can cause damage to organisms, particularly top predators.
• The use of pesticides in farming can cause bioaccumulation.

Vocabulary To Learn

• toxic: A toxic substance is one which is poisonous to organisms.
• bioaccumulation: An increase in the concentration of a chemical within an organism is called bioaccumulation.
• pesticide: Pesticides are chemicals that are used to control pests (organisms that compete with humans for food supplies).

Common Mistakes To Avoid

• Pupils do often not understand that pesticides can build up within a food chain.

3 Quick Questions (With Answers)

More Lessons In This Unit

• Adaptations of predators and prey Study Guide
• Ecosystems and habitats Study Guide
• Food chains Study Guide
• Food webs Study Guide
• Pollination and human food security Study Guide
• Predator-prey relationships Study Guide
• The importance of biodiversity Study Guide
• Using chemicals in farming Study Guide