Population Biology

1. Introduction

A system is a group of parts that interact through one or more processes (Odum 1983). The term ecosystem was introduced and defined by Tansley (1935), who as “a fundamental organizational unit of the natural world that includes both organisms and their spatial environment.” Ecosystems have since been defined in various ways, and at different spatial and temporal scales (Golley 1993; O’Neill et al. 1986; Evans 1956). Some ecologists define ecosystems on the basis of biotic organisms, populations, or communities. For example, Hutchinson (1978) considered the ecosystem to be the environmental context in which population or community dynamics occur. Others define ecosystems in terms of their abiotic characteristics and processes (Rowe and Barnes 1994). For example, Lindeman (1942) defined ecosystems as “…the system composed of physical, chemical, and biological processes active within a space/time unit.” Read the rest of this entry »