The frequency of species extinctions is correlated to the size of human population on the Earth which is directly related to resource consumption, land-use change, and environmental degradation. Other human impacts to ecosystems include species invasions to new habitats, changes to the abundance and dominance of species in communities, modification of biogeochemical cycles , modification of hydrologic cycling, pollution, and climatic change. Major Components of Ecosystems Ecosystems are composed of a variety of abiotic and biotic components that function in an interrelated fashion. Soils are much more complex than simple sediments. They contain a mixture of weathered rock fragments, highly altered soil mineral particles, organic matter , and living organisms.
Soils provide nutrients , water, a home, and a structural growing medium for organisms.
The vegetation found growing on top of a soil is closely linked to this component of an ecosystem through nutrient cycling. The atmosphere provides organisms found within ecosystems with carbon dioxide for photosynthesis and oxygen for respiration . The processes of evaporation , transpiration , and precipitation cycle water between the atmosphere and the Earth's surface. Solar radiation is used in ecosystems to heat the atmosphere and to evaporate and transpire water into the atmosphere. Sunlight is also necessary for photosynthesis .