Ecologists see distinctions that microscopists miss. Among the boldest of those distinctions, Whittaker noted, are three categories of organism: producers, consumers, and decomposers. Animals are consumers, swallowing other creatures for their sustenance. Plants are producers, gaining sustenance from sunlight and water, creating their bodily substance from nonliving materials. Bacteria and fungi are decomposers, taking their sustenance by gently dismantling other creatures, dead or alive, and putting the pieces to new use.
