An ecological “community” is the sum of all of the populations (i.e. all of the groupings of each species) living in an ecosystem. When you stand in the middle of an ecosystem you can see many of its species and can even appreciate their interactions and interconnections. There are, however, many organisms that evade casual observation and many kinds of important interactions that pass unnoticed.
The ecosystems here in Western Pennsylvania in which Deborah and I have spent most of our time have ecological communities that are somewhere in the middle of the worldwide continuum of complexity. They are not the bare bones systems of desert islands like we have seen in the Galapagos, nor are they the dense, almost incomprehensible species rich riots of tropical rain forests or coral reefs. Here there is almost but not quite too much to see in a given community, but there is also the luxury of finding new species or recognizing new interconnections whenever you return to a place or whenever you start to look at it in a slightly new way.
A wonderful T. S. Eliot quote comes to mind: “We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time.”
But what exactly is this thing we call a “community?”
Back in the early decades of the Twentieth Century there was a lively debate among scientists who were working in the brand new scientific discipline that they called “ecology.” One group led by Frederick Clements described plant communities (associations of plant species occurring together) as distinct and identifiable entities. Clements felt that each species contributed to the community in certain ways and every other species relied on and depended upon the other species in the community. There was a meshing, a synthesis, events full of emergent properties out of which the community became more than the sum of its parts. Clements extended these ideas to then describe how communities change over time (the process of “ecological succession”), and he described the patterns and the steps and the stages of these changes and maintained that ALL plant communities changed in this linear way and that ultimately ALL plant communities developed into stable, “climax” communities.
Clements first relied on a simile when he described his plant communities: these communities were “like” an organism. But, as my first ecology professor back at the University of Texas put it (and he had known Clements personally), he then began to describe a plant communities as actually being organisms! The level of integration and interaction in a community was likened to the homeostatic events that enable the trillions of individual cells in each one of us to function as a distinct, singular being.
Now many felt that Clements had gone too far. They felt that his “community as an organism” hypothesis strayed away from science and plunged headlong into mysticism and theology. Henry Gleason was one of the most vocal opponents of Clements’ “community as an organism” idea. Gleason described plant communities as associations made up of independently striving species. He stressed that no two plant communities were exactly the same. Gleason’s ideas at first prevailed, but there is something compelling and attractive, something emotionally appealing to Clements’ more holistic framework, and his ideas regularly resurface in the developing theories of ecology.
Are we living parts of some greater organism? Are all the populations of plants and animals and bacteria and fungi around us functioning as tissues and organs in this great beast of the Earth’s biosphere? If this is science we should be able to come up with some predictions for the outcomes of a set of experiments that should occur of the hypothesis is accurate, and if these predictions don’t occur, we should reject the hypothesis. Scientific speculations are always falsifiable, after all, and many good ideas end up in the trash can of our laboratories.
If this isn’t science, though, then we don’t really have to check the ideas beyond their emotional feels and fits. Does it “feel” right to think of the Earth’s biosphere as an integrated organism? Does that idea (or “belief”) improve your quality of life? Does it make you less anxious or more confident of your place and purpose? If so, then it is quite possibly a start of a philosophy or even a theology.
It is really important, though, to recognize if we are talking about science or about theology, and it is really easy to let the lines blur between them. I agree with Alice Dreger (“Galileo’s Middle Finger”) that science is not just “another way of knowing” that is comparable with any other theological or philosophical system. Science is a system not of belief (as Adam Gopnik recently asserted in a book review in the “New Yorker”) but of challenges. Science is a system that harnesses the inherent creativity of the human mind and demands slow, hard work to show that a good idea or explanation is truly possible or supportable (note that I don’t use the word “true.” Truth is too high a bar for science to attain. Truth implies an end point, and science always keeps the possibility alive that if just a little bit more information is gathered, just a slightly different perspective is developed, a scientific explanation could be completely upended).
Science has frequently been perverted by authoritarianism and autocratic declarations, it has been frequently hijacked by strong personalities and clever arguments, and it has been corrupted by dishonest researchers, but it is a system that eventually self-corrects and throws out these short cuts and partial ideas. Science’s history is one of many small steps forward, and occasional wild lurches both backwards and sideways.
So, is an ecological community a living organism or is it “like” a living organism? The line between the two ideas is very thin and very tortuously curved. I find myself jumping back and forth like the twins on the old Certs commercials: “it’s a candy! “It’s a breath mint!” “It’s an organism!” “It’s a complex, homeostatic system with a wide range of emergent properties!”
Science almost always needs more words that will fit on a bumper sticker!