An ecosystem is a community of plants and animals living in a specific place. Sometimes people are part of it too. The place or habitat is also a part of the ecosystem. It’s called a biotope. The Greek word “eco” means “house” or “household”. The word “system” denotes something that is interconnected. The natural science that describes ecosystems is ecology.
How large this living space is and what belongs to it is determined by the people, mostly scientists. It always depends on what you want to find out. You can call a rotting tree stump or a pond an ecosystem – but you can also call the entire forest in which the tree stump and pond are located. Or a meadow together with the stream that flows through it.
Ecosystems change over time. When plants die, they form humus on the soil on which new plants can grow. If an animal species reproduce strongly, it may not find enough food. Then there will be fewer of these animals again.
However, an ecosystem can also be disturbed from the outside. This is what happens to a stream, for example, when a factory pours dirty water into the ground. From there, poison can get into the groundwater, and from there into the stream. Animals and plants in the stream can die from the poison. Another example is lightning striking a forest, setting all the trees on fire.