Ecology draws on a combination of biological science, environmental science and geography. Ecologists work in and study ecosystems (whole environments and the living organisms within them). These organisms include people, animals, plants, birds and insects of every kind. An ecologist studies how these different organisms interact and what external influences might help to either maintain the balance or cause the destabilisation of the whole system. Many ecologists study one particular group or organism, eg amphibians, some work on particular types of project, eg restoring a former industrial landscape to a wildlife conservation area. Ecologists look at the impact of proposed developments such as housing, quarrying, fishing ...