Ecology is a branch of biology concerning interactions among organisms and their biophysical environment which includes both biotic and abiotic components. Topics of interest include the biodiversity, distribution, biomass and populations of organisms as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up and the non-living components of their environment. Ecosystem processes such as primary production, pedogenesis, nutrient cycling and niche construction regulate the flux of energy and matter through an environment.