A very complex ecosystem consists of variety of biotic and abiotic components. Biotic components include a variety of plants and animals. Abiotic componets include soil, water, air. temperature, light, rain etc. A very complex ecosystem consists of many kinds of these components in a area. An example of such ecosystem on land is a forest. A tropical rain forest consists of very high rainfall annually, average temperature is high, soil is poor in nutrients and large biodiversity.