How Do Ecosystems Work?

notice that they snore when they sleep. By the time you get to Australia, you feel you've got a pretty good sense of who this person is. You've become friends and exchange contact info even But then their entire family shows up to meet them at the airport, and immediately you learn more and some of the assumptions you made on the plane have to be reevaluated given this new input. Later, they invite you to a family dinner at their home,

and their story broadens again. The smell of their house, the taste of their drinking water, the view from their porch, and the contents of their refrigerator and bookcases speak volumes about These details reinforce what you thought you already knew, and some change your mind. At some point your observations become not about the person themselves, but about the whole system in which they live. In order to understand anything, it's helpful to understand everything, or as much as you

possibly can. In the study of ecology, the concept of an ecosystem acknowledges the fact that, as the nineteenth century naturalist John Muir said, when we try to pick out anything by itself, we find it hitched to everything else in the universe. But it's difficult to look at everything at once, and natural systems, of all the things we can investigate with science, are particularly hard to nail down,

but ecologists are always trying. In five and English botanist named Arthur Tansley, strongly influenced by Danish botanist Eugenie's Varming, introduced the term ecosystem in a paper titled The Use and Abuse of Vegetal Concepts and Terms that was published in the journal Ecology. He defined an ecosystem as the whole system included not only the organism complex, but also the whole complex of physical factors forming what we call

the environment. What Tansley was trying to get at was the idea that you can look at a natural system at a bunch of different levels, and that there was one level that didn't have a name yet. For instance, you could look at a wolverine that's a single organism, just like the person you met on the plane, but that wolverine doesn't live in a vacuum. It lives in a population of other wolverines that interact and organize themselves

in specific ways. Thus, an ecologist can choose to investigate wolverines at a population level, but that's not the only way to study wolverines. Ecologists also talk about communities of living things. A wolverine doesn't just interact with members of its own species. It's an omnivore, so it eats other animals like moose and rabbit, as well as berries, roots, and eggs. It gets parasites, It digs burrows that affect

roots systems of plants. A wolverine influences lots of living things in its home territory, and those living things affect it tans. These definition of ecosystem acknowledged that there was a level of scientific inquiry that could encompass all the living organisms in the wolverines home. In addition, to the stuff that's not alive. We spoke with Stephen Carpenter, a scientist in the Center for Limnology at the University of

Wisconsin Madison. He said the ecosystem concept ecologists now use has been refined since it was first introduced by Tansley almost a century ago. Ecosystem science studies the interactions of all the living and non living entities in a specified place. This definition is consistent with modern concepts of energy, nutrient flow, and biogeochemistry, which barely existed during Tansley's career. The allure of the ecosystem to scientists has to do with the

system part of the word. If you look at an ecosystem like you'd look at a computer, then an ecosystem like a coral reef runs very similar software to that of an arctic tundra where the wolverine lives, or to that of a tropical forest, meaning that the same base large scale processes can apply anywhere organic matter decomposes and becomes nourishment for something else. In a grassland or a mountain stream, nutrients like carbon, phosphorus, nitrogen, and sulfur get

passed around like monopoly money everywhere. It just happens a lot faster, and there's a lot more of it in say a tropical rainforest than in most deserts. Diseases are carried along on water or air or by hapless organisms in similar ways, and wherever you look, if a top predator is removed from the ecosystem, the entire dynamic changes, be it on a mountaintop in the Andes or in Yellowstone National Park in Wyoming. This is to say ecosystems are a good topic for theory, as a framework for

hanging ideas about how complex natural systems work. But while being a theoretical idea, an ecosystem is also an actual thing. It's just a thing without clear boundaries. According to Eugene Odom's Fundamentals of Ecology, first wished in three you know you've identified the edge of an ecosystem when more material and energy is cycling within the boundary than crossing over it.

So a riffle and a stream cannot be an ecosystem because all those certain types of fish and aquatic invertebrates like to live in a fast, shallow section of a stream. Abundant material is flowing into and out of the riffle all the time. Some might stay in it for a while, but most of it leaves pretty soon after it arrives. Even the sediment and rocks don't stay forever. When they move, it's mostly not inside the riffle, but into or out

of it. On the other hand, watersheds are classic ecosystem boundaries, but they're extremely tricky as well. The river itself is an ecosystem because although a lot of material and energy passes in and out of it all the time, leaves and soil and dead animals fall in. Terrestrial animals use

the river as a grocery store, et cetera. A lot of cycling within it too, So although the river in itself can be considered an eaty system, it's difficult to view the river and the dry land around it is truly separate, since material and energy are being exchanged across the literally fluid boundary all the time in both directions. Rivers flood after all, and deposit nutrient rich sediment on

the land. Ecosystems then are not static. We also spoke with Kathleen Weathers, and ecologist at the Carey Institute of Ecosystem Studies. She said the a biotic and biotic are essential parts of the ecosystem, and they have boundaries, albeit human defined boundaries. And not only do ecosystems have structure and function, but these are controlled by many factors and that ecosystems change throughout time. Today's episode was written by

Jescelin Shields and produced by Tyler Claying. Brain Stuff is a production of I Heart Radio's How Stuff Works. For more in this and lots of other topics, visit our home planet, how stuff Works dot com and for more podcast in my heart Radio because thy heart radio, app, Apple Podcasts, or wherever you listen to your favorite shows. H