A-Level Biology Ecosystems Revision Notes

• 1Ecosystems consist of biotic and abiotic components.
• 2Energy flow and nutrient cycling are essential processes.
• 3Trophic levels indicate the position of organisms in food chains.
• 4Biodiversity is crucial for ecosystem stability and resilience.
• 5Human activities can significantly impact ecosystems.

An ecosystem is a place where living things, like plants and animals, interact with each other and their surroundings, like water and soil. Everything in an ecosystem works together to create a balance, where energy flows from one organism to another. For example, plants use sunlight to grow, animals eat the plants, and decomposers break down dead organisms, returning nutrients to the soil.