In the Bowels of Carnivorous Plants, a Tiny Model of the World

Author: admin

11 Aug

For insight into fabulously complex ecological dynamics, Harvard University biologist Aaron Ellison peers into the cupped leaves of carnivorous pitcher plants.

At the bottom of each slippery-sided leaf is a pool of water into which unlucky insects fall and drown. The bugs sustain not only the plant, but an intricate food web of bacteria, plankton and invertebrates. Each pool is small enough to fit in a shot glass, and big enough to model the world.

“Each leaf is its own individual lake, its own individual ecosystem. Suddenly, in a bog I can walk to from my office, I’ve got 50,000 lakes to do experiments on. This is an opportunity to understand how a complete, functioning natural ecosystem works,” said Ellison.

Understanding how ecosystems work is an important but challenging task for scientists. Though patterns can be described — nutrient levels shift, an animal population grows, another shrinks — it can be hard to know what’s coincidental and what’s linked.

If researchers can run experiments on an ecosystem, measuring exactly what goes in and out, tweaking different aspects and seeing what happens, then they can better decipher its underlying rules. That’s the idea behind artificial ecosystems, all the way up to the infamous Biosphere II.

However, it’s not easy to replicate nature, and it’s even tougher to run these experiments in the wild. Many experiments are unethical: you can’t take a lion from its home simply to study the effects of top-predator removal. Other experiments are impractical. It’s hard to account for every variable in a rain forest.

Ecologists have had some success studying islands and lakes, which are fairly self-contained, and extrapolating those findings to the rest of the natural world. But not everyone is fortunate enough to have an island or lake to study. Next >>