Greek word for household – oikos – and applied it to the natural world. All the earth’s organisms belonged together like a family occupying a dwelling; and like the members of a household they could conflict with, or assist, one another. Organic and inorganic nature made a ‘system of active forces’, he wrote in Generelle Morphologie, using Humboldt’s exact words. Haeckel took Humboldt’s idea of nature as a unified whole made up of complex interrelationships and gave it a name. Ecology, Haeckel said, was the ‘science of the relationships of an organism with its environment’.5
