A-LevelBiology

A-Level Biology Ecosystems Revision Notes

Master A-Level Biology Ecosystems using simple revision notes, key facts and practice questions — all generated by AI for your exam.

Ecosystems are complex networks of living organisms and their physical environment, interacting as a system. They include both biotic (living) and abiotic (non-living) components, which together support life and contribute to biodiversity.

Key Concepts

  • 1Ecosystems consist of biotic and abiotic components.
  • 2Energy flows through ecosystems via food chains and food webs.
  • 3Nutrient cycling is essential for ecosystem sustainability.
  • 4Biodiversity is crucial for ecosystem resilience and stability.
  • 5Human activities can significantly impact ecosystems and their functions.

Simple Explanation

An ecosystem is a community of living things, like plants and animals, interacting with each other and their environment, such as soil and water. Energy from the sun powers these interactions, allowing organisms to grow and thrive. Nutrients are recycled within the ecosystem, which helps maintain balance. However, human actions can disrupt these natural systems.

Memory Trick

Remember 'B.E.N.E.F.I.T' for Ecosystems: Biotic, Energy flow, Nutrient cycling, Ecosystem stability, Functionality, Interactions, and Threats.

Flashcards

Question1 / 5

What are the two main components of an ecosystem?

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Exam Questions

Describe and explain the role of decomposers in an ecosystem. [6 marks]

6 marks
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Discuss their function in nutrient cycling, examples of decomposers, and their importance for ecosystem health.

Explain how energy flow and nutrient cycling are interconnected in ecosystems. [4 marks]

4 marks
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Illustrate the relationship between energy flow through food chains and the recycling of nutrients.

What is meant by biodiversity and why is it important? [2 marks]

2 marks
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Define biodiversity and mention its role in ecosystem stability and resilience.

Practice Quiz

Question 1 of 5Score: 0

What is the term for the variety of life in an ecosystem?

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