A while back, Rich Lenski did a nice post summarizing and commenting on a classic evolutionary experiment: Luria and Delbrück 1943. This is the famous “fluctuation test” experiment showing that mutations in E. coli occur at random with respect to their fitness effects, rather than being caused by selection pressures. The experiment was based on simple but subtle reasoning, was very elegant, and the results were both clear and profound. It provided the basis for a massive body of research, including the cracking of the genetic code. It was also ahead of its time, in that evolutionary biologists at the time were mostly uninterested in microbes, so that the paper’s immediate influence was much greater in molecular biology. And it had a big personal effect on Rich himself. Rich calls it “for me, the single greatest experiment in the history of biology.”
So, here’s the question: what’s the single greatest experiment in the history of ecology?
I ask this question mostly for fun. “Greatest” is too broad, multifaceted, vague, and subjective a concept to expect that we’ll all agree on an answer. But questions like this are a fun way to force us to think about what really matters in science, and force us to step outside the inevitably-narrow boxes of our own personal interests and subfields. And I’m hopeful that students in particular will find the answers to be interesting entry points into the history of ecology.
Just to keep things semi-focused, I am going to ask that you pick a single experiment. Not a series of related experiments*, or an entire line of research like the Hubbard Brook Ecosystem Study, or all the work of an individual, team, or facility. And by “experiment” I mean a planned manipulation. “Natural experiments” like Brooks & Dodson 1965, comparative studies, theoretical studies, etc. don’t count (merely because they’re different than manipulative experiments; again, I’m just trying to keep things semi-focused here). The experiment need not be well-designed according to modern standards. It’s up to you to decide if, say, an unreplicated experiment can still be the greatest ecology experiment ever. And it doesn’t have to be a field experiment. Microcosms, mesocosms, etc. are fair game.
Some obvious candidates, just off the top of my head:
- Gause’s laboratory microcosm experiment with Paramecium spp., testing the competitive exclusion principle. I’m tempted to stump for that one, and I don’t think that’s just because I happen to work in the same system as Gause. Elegantly simple and direct, with a clear result. Addressing one of the most important “core” ideas in ecology. Way ahead of its time–indeed so far ahead that some ecologists still don’t think the time for Gause’s methods has come.
- Connell’s transplant experiment showing how competition affects the distribution of species in the rocky intertidal
- Paine’s Pisaster removal experiment, leading to the concept of keystone predation
- Park Grass, the longest-running ecology experiment in history. Tempted as I am to stump for Gause, I’d probably go for Park Grass.
- One of the whole-lake nutrient enrichment experiments at the Experimental Lakes Area
I’ll note in passing that, great as all of the above are, I don’t think any of them are as great as Luria and Delbrück 1943. I don’t think any of the above experiments are serious candidates for the title of greatest experiment in all of biology, as Rich suggests Luria and Delbrück 1943 is. It’s interesting to consider whether that says something about ecology or ecologists**. Ecologists aren’t great experimentalists? (unlikely!) Ecology isn’t as conceptually central or foundational for biology as are evolutionary biology and genetics? (probably something to that) No single experiment can ever greatly advance ecology? (maybe, but if not, why not?) Or maybe it just illustrates that ecology is a young-ish field (and especially young in terms of its use of experimentation)? So that the greatest ecological experiment is yet to come?
*I admit that the line between “related experiments” and “one big experiment with several treatments” can be unclear, especially when considering work from earlier decades. For instance, is Huffaker’s famous work on mite metapopulation dynamics a series of several experiments, or one big experiment with several treatments?
**Or maybe it just says something about me.