Energy Flow, Food Webs and Food Chains

This lesson on Energy Flow, Food Webs and Food Chains is designed for KS4 Science students enrolled in the CIE Cambridge IGCSE Biology 0610 (2023-25) course. This is the third lesson in the ‘Topic: 19 Organisms and Their Environment’ topic.

The lesson recaps previous learning from other linked topics to ensure students have a strong foundation before diving into the material. It also includes concise and easy-to-understand information and a variety of quick assessment for learning tasks to help students solidify their understanding of the topic. Just glance through the PowerPoint presentation and you are ready to go!

This resource also includes past paper questions on drawing pyramids of numbers and biomass alongside a mark scheme to further deepen students’ understanding. These questions can be printed on one sheet of A4 (using ‘two pages one sheet’ on your printing settings). These can be used during the lesson, as homework or revision.

Objectives

• State that the Sun is the principal source of energy input to biological systems
• Describe the flow of energy through living organisms, including light energy from the Sun and chemical energy in organisms, and its eventual transfer to the environment
• Describe a food chain as showing the transfer of energy from one organism to the next, beginning with a producer
• Construct and interpret simple food chains
• Describe a food web as a network of interconnected food chains and interpret food webs
• Describe a producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
• Describe a consumer as an organism that gets its energy by feeding on other organisms
  State that consumers may be classed as primary, secondary, tertiary and quaternary according to their position in a food chain
• Describe a herbivore as an animal that gets its energy by eating plants
• Describe a carnivore as an animal that gets its energy by eating other animals
• Describe a decomposer as an organism that gets its energy from dead or waste organic material
• Use food chains and food webs to describe the impact humans have through overharvesting of food species and through introducing foreign species to a habitat
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