Individuals There are four identifiable subdivisions of scale which populations, ecologists investigate communities and i considering the response of individuals to their ecosystems environments 11) Examining the response of populations of a single species to the environment, and considering processes such as abundance and fluctuations (ii) The composition and structure of communities(the populations occurring in a defined area); (iv )the processes occurring within ecosystems(the combination of a community and the abiotic components of the environment) such as energy flow, food webs and the cycling of nutrientsIndividuals, populations, communities and ecosystems There are four identifiable subdivisions of scale which ecologists investigate; (i) considering the response of individuals to their environments; (ii) Examining the response of populations of a single species to the environment,and considering processes such as abundance and fluctuations; (iii) The composition and structure of communities (the populations occurring in a defined area); (iv)the processes occurring within ecosystems (the combination of a community and the abiotic components of the environment), such as energy flow, food webs and the cycling of nutrients