The four components of habitat are food, water, shelter and space. These things must be available in the proper arrangement to meet a species needs. Biotic elements include plants and animals. Abiotic elements include soils, water and energy sources. An ecosystem can be small, such as a pond, or very large, such as a rainforest ecosystem.
Some people consider the Earth itself to be an ecosystem.
For example, the Sonoran Desert constitutes an ecoregion. For example, deserts, forests, and grasslands are recognized as distinct biomes. Three fundamental ecological processes are water cycling, nutrient cycling and energy flow. We value biodiversity in many ways and for many reasons.