The landscape of the world has been as much shaped by the cultural history of human interventions as it has by climatic effects such as glaciers, and by geological processes of uplift, erosion and deposition. There is no vanished Eden, no singular 'natural landscape' to be found, no single ideal image of nature that can be reconstructed. The metabolic processes of living forms produce changes in their environment, and these changes modify the local regime of natural selection. The organization of whole ecological systems emerges from the multiple interactions between the metabolic processes of all the forms of life that coexist within it. All animals have a territory over which they range, from which they gather energy and materials, and over which they have an effect. Relationships between living organisms are vectored by energy and material flows, organised in trophic levels through the co-evolutionary process between living things and their physical and chemical environments. Each affects the other, so that without environment there is no organism, and without organisms there is no environment. For example, the spatial pattern of a mature forest, the density and distribution of varying sizes and species of plants emerges from the interaction of all the plants within it. Each individual tree is anatomically organised to support its three-dimensional array of leaves for its photosynthetic metabolism, and the processes of that metabolism will modify the soil and the atmosphere of its local environment - 5 the transpiration of water drawn up from the ground will modify the structure of the soil, and the water vapour and gases excreted by the leaves will modify the temperature, humidity and oxygen content of the immediate atmosphere. This in turn will affect the processes of other trees near to it, as will the shade that it casts. The effect of many individual metabolisms in action produces the environment that other species inhabit, the bacteria and fungi, the insects, birds and animals that coexist within the forest. The processes of multiple individual systems, each acting across a range of spatial and temporal scales, interact with the soil and topography, with sunlight and climate, water and atmosphere, to construct an ecological system.

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