2.1 Through ideas about biodiversity
The academic structure for ecology, as a new science was established by geographers. The prominence of the discipline of geography in the nineteenth century, its contributions to other sciences, and its widespread interest for the general reader are seldom appreciated today. But geography in that period was a powerful cultural force; Humboldt, Lyell, and Darwin are only the most famous of its students. Strictly speaking, however, it was an aberrant group among geographers who first attempted to describe the topography of living things.
Throughout most of the nineteenth century, as today, the most familiar school of biogeography was the study of flora and fauna. Essentially this was a matter of compiling statistical data on the distribution of species around the world and then deriving from such data a system for classifying geographic regions. The floristic geographer was bound to be interested in the adaptations of organisms to their environments, a process that Haeckel included in the territory of ecology. But this interest was limited; the controlling purpose of the dominant school was taxonomic more than ecological. To reverse this order of priorities was precisely the intention of the lesser-known, rival school, which was at first known as "physiognomic," then "physiological," and finally as "ecological" geography. This school preferred to talk about the forms of "vegetation" and their determinants rather than about the distribution of the earth's plant species.
The variety of life is an expression of geography. Geographical ranges of species vary in size from a few square metres to almost the entire globe. Geographical boundaries, beween species are determined by the local solar economy and the planetary economy; i.e. effects of climate and seasons and the effects of geomorphological events in Earth's history.
These two economies of material energy define local biogeographical systems which determine the evolution of species and the diversity of communities.
Biodiversity is now declining through the impact of human activities.  'Conservation' is the local response to preserve and enhance geographical variety amongst living things.