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Year 8 - Science

Pyramids of number

Biodiversity

Unit Summary

This unit examines environmental changes and their impact on species' survival and adaptation, potentially leading to extinction. It also develops skills for interpreting data and observations, evaluating errors, and using SI units and IUPAC chemical nomenclature in scientific contexts.

Lesson Summary

You will learn to create and interpret pyramids of number to show the size of a population at each trophic level.

Key Notes

  • Food chains show the feeding relationships between organisms and the flow of energy through a habitat.
  • The number of organisms at each trophic level in a food chain can be used to create a pyramid of number.
  • Pyramids of number use scaled bars to represent the number of organisms.
  • Pyramids of number have the producer at the bottom.

Vocabulary To Learn

  • trophic level: A trophic level is the position of an organism in a food chain diagram.
  • pyramid of number: A pyramid of number is a diagram which shows the total number of organisms at each trophic level in a food chain diagram.
  • herbivore: An animal that only eats plants (producers) is called a herbivore.
  • carnivore: An animal that eats other animals (consumers) is called a carnivore.
  • omnivore: An animal that eats both plants (producers) and other animals (consumers) is called an omnivore.

Common Mistakes To Avoid

  • Pupils often think that the size of organisms has to increase at each trophic level within a food chain diagram.

3 Quick Questions (With Answers)

1. Explain the scientific idea in this lesson using two key points.

Food chains show the feeding relationships between organisms and the flow of energy through a habitat. The number of organisms at each trophic level in a food chain can be used to create a pyramid of number.

2. Define this scientific word and use it in context. 'trophic level'

A trophic level is the position of an organism in a food chain diagram. Include the word in a full scientific explanation, not as a single label.

3. Correct this common scientific misunderstanding.

Mistake: Pupils often think that the size of organisms has to increase at each trophic level within a food chain diagram. Correction: The lesson addresses the misconception through exemplification. There is coverage of inverted pyramid of number to show that some producers are larger organisms that are eaten by smaller organisms.

More Lessons In This Unit

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