What is an Ecosystem?
An ECOSYSTEM is all the living things (plants, animals, fungi, bacteria) in an area PLUS the non-living environment they interact with (air, water, soil, sunlight, rocks). A pond is an ecosystem. A forest is an ecosystem. Even a small puddle or your backyard is an ecosystem. The key idea: living and non-living parts INTERACT, and the system maintains itself.
How energy flows. The SUN powers most ecosystems. Plants (PRODUCERS) use sunlight to make food via photosynthesis. Animals (CONSUMERS) eat plants — or eat the animals that ate the plants. When organisms die, DECOMPOSERS (fungi, bacteria) break them down, returning nutrients to the soil for plants to use again. Energy flows ONE WAY (from sun to producers to consumers, eventually lost as heat). Nutrients CYCLE (used and reused).
In an ecosystem, energy ___ and matter ___:
Healthy ecosystems are RESILIENT — they can absorb shocks (a fire, a flood, a drought) and bounce back. Loss of biodiversity weakens them. Removing one species can cascade — for example, removing wolves from Yellowstone caused elk overpopulation, which damaged plants, which affected birds, which affected... and so on. Returning wolves restored balance. Ecosystems are interconnected webs.
Local Ecosystem
Pick a small ecosystem near you. Identify: producers (plants you see), consumers (animals/insects), decomposers (fungi or rotting wood). The non-living parts (soil, water, sunlight). What would happen if one disappeared?
Every spot on Earth is part of an ecosystem. Understanding them is the first step toward protecting them. And protecting them is essential — for biodiversity, for clean water and air, and for our own future.
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