An ecosystem is everything together in one area. That includes both the living and non-living things that all share a place as their home. It’s the plants, animals, and organisms as well as the dirt, water, and air.
Each of those elements has its own part to play in the ecosystem. That unique special part is called its niche.
A pond is one example of an ecosystem. It has water, sunlight, temperature, air pressure, bugs, frogs, fish, algae, etc.
An ecosystem is threatened anytime something new is introduced into it. An ecosystem lives in a delicate balance, with everything playing their part. Any new player throws everything out of balance, which can cause a lot of damage. This can happen with biotic and abiotic factors. Temperature changes could kill plants, which would drive away animals. A new invasive insect species could eat all of a type of plant, which would remove the food for a bug, for example, which would mean that the animals that ate those bugs would have to leave, etc.
These changes in ecosystems happen in other ways as well, such as by natural disaster and often by humans coming in and destroying or changing a habitat. Humans need to be aware of the delicate balance of ecosystems, because we rely on them for our food, water, fuel, and air.