OCR Biology Ecosystems Revision Notes

• 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 within ecosystems enhances resilience.
• 5Human activities can significantly impact ecosystems.

An ecosystem is a community of living things, like plants and animals, along with their environment, such as soil and water. These living and non-living parts interact with each other in many ways, like food chains, where one organism eats another. Ecosystems can be big, like forests, or small, like a pond. They are important because they support life and help keep nature balanced.