ABSTRACT
Organisms are all to some extent sociable beings, interacting with one another to survive. Their interactions create populations and communities. Populations are loose collections of individuals belonging the same species. Red deer (Cervus elaphas) in Britain constitute a population. All of them could interbreed, should the opportunity arise. In practice, most populations, including the red deer population in Britain, exist as sets of local populations or demes. A local red deer population lives in the grounds of Lyme Park, Cheshire. Its members form a tightly linked, interbreeding group and display features typical of many populations (Box 4.1).
