After many semesters teaching an introductory Ecology course to non-majors, I have gotten a pretty good sense of the misconceptions that they bring to the subject. Most students receive little or no high school education in ecology: the majority of secondary school biology curricula are still predominantly organismal in their approach, with ecology and maybe sometimes evolution tacked on at the very end. Perhaps it is these whirlwind footnote lessons in ecology that fuel misconception. It might also be the never-ending stream of nature media that populates cable television channels like Animal Planet or Discovery. But it might be something else: a prevalent perception that all things are designed. Whatever the source, many of my students firmly believe that ecosystems have properties that few ecologists or evolutionary biologists would feel comfortable with endorsing.
Most of the misconceptions that students bring to my classroom fall into a category I like to call “eco-mysticism”? What is eco-mysticism? Eco-mysticism is the belief that ecosystems have been designed to achieve outcomes, that they have been fine-tuned to maintain their own balance. A number of metaphors that permeate popular culture stem from this misconception. The main idea is that components of ecosystems exist to maintain this balance: for instance, predators exist to maintain the health of their prey by exerting population control and culling weak or sick individuals. A related idea is that all species are connected and therefore essential, and that removing a single species is highly likely to disrupt the fine balance of the ecosystem. When I am feeling particular grumpy about these sorts of misconceptions, I sometimes refer to them collectively as “Lion King ecology”: scientific ideas derived from Disney romanticism. All these ideas are at least unsubstantiated if not wholly wrong. They describe a metaphoric impression of nature rather than explaining why natural phenomena exist.
Recently I got a killer dose of eco-mysticism when I asked the following question on a quiz:
Why do populations have carrying capacities?
While a good number of students answered this question with fairly grounded and logical statement such as “populations have carrying capacities because the resources they need to survive are limited”, at least as many gave the eco-mystical answer: “populations have carrying capacities to avoid over-exploiting resources and throwing the ecosystem out of balance”. I might need to re-write this question to make it more clear to students what I was looking for (something more like “what determines the carrying capacity of the population?”), but the fact that when baffled by my question so many students fell back on the eco-mystical answer is illuminating. Students really do think that ecosystems are designed to be stable, and that the good of the species, or the community, or the ecosystem is a clear outcome of all ecological processes.
Modern ecology and its sister evolutionary biology reject this naive “for-the-good-of-the-system” thinking, because it violates the blind and expedient nature of the evolutionary process as we understand it. Through the lens of modern ecology and evolution, people who hold these eco-mystical ideas are naive, romantic, and maybe even a little new-age deistic.
The ironic thing about my critique of my students’ eco-mysticism is that I might — in the end — agree with some of the conclusions that they reach. Their belief that ecosystems are designed to maintain their own balance is naive, and if asked how such a design was achieved they will only make a mess of evolutionary theory trying to produce that mystical self-balancing ecosystem. And yet the fact remains that ecosystems are remarkably resilient and persistent, often through complex mechanisms that appear from the outside to be designed to maintain homeostasis. And honestly, this property of ecosystems is really poorly explained by contemporary evolutionary theory, which seeks to explain all properties of living things using a bottom-up reductionist approach which only considers evolution at the level of individuals or even single genes. It is hard to see how individual selection alone could produce the complex set of feedback mechanisms that allow ecosystems to persist, so is every stable ecosystem a lucky coincidence? Probably not. Modern evolutionary theory needs a robust explanation of how persistent ecosystems come into being. Only once that explanatory achievement has been made will I have something to supplant my students’ eco-mysticism with.