n an ecosystem, each organism has its' own niche, or role to play.
Consider a small puddle at the back of your home. In it, you may find all sorts of living things, from microorganisms, to insects and plants. These may depend on non-living things like water, sunlight, turbulence in the puddle, temperature, atmospheric pressure and even nutrients in the water for life. (Click here to see the five basic needs of living things)