  Until the last decade, some seventy years after the introduction of the term “ecosystem” and forty years after a veritable explosion of ecosystem studies, it was less than clear what important new insights this disciplinary move produced. The trouble was that, at this level of analysis, very few general claims could be sustained. Those that could—for instance, that Sun is ultimately the source of all energy in biological systems or that primary producers have to contain chlorophyll or some other such molecule—were usually trivial and well-known long before the initiation of systematic large-scale ecosystem studies in the 1960s. Usually ecosystem studies produced detailed analyses of nutritional or climatic requirements of particular communities. But the details of nutritional requirements were either so general as to be almost irrelevant, or so specific that they were rarely transportable from one ecosystem to another. Almost all of what is known about climatic requirements of vegetation types (and other communities) was known to biogeographers long before the invention of ecosystem studies. The carbon and nitrogen cycles had also been worked out long before the advent of ecosystem studies as an organized discipline.