1 00:00:01,920 --> 00:00:06,520 Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey 2 00:00:06,600 --> 00:00:10,080 Speaker 1: brain Stuff Lauren boglebam here. Let's say you meet a 3 00:00:10,080 --> 00:00:12,959 Speaker 1: person on a flight from Boston to Brisbane. The two 4 00:00:12,960 --> 00:00:14,520 Speaker 1: of you are seated next to each other for a 5 00:00:14,560 --> 00:00:18,960 Speaker 1: couple dozen hours, and you talk the entire time about books, politics, 6 00:00:19,000 --> 00:00:22,400 Speaker 1: current events, religion, the weather, et cetera. You hear some 7 00:00:22,480 --> 00:00:25,160 Speaker 1: of their personal stories, observe the way they eat and drink. 8 00:00:25,480 --> 00:00:27,240 Speaker 1: You watch them play a game on their phone, and 9 00:00:27,400 --> 00:00:30,360 Speaker 1: notice that they snore when they sleep. By the time 10 00:00:30,400 --> 00:00:32,360 Speaker 1: you get to Australia, you feel you've got a pretty 11 00:00:32,400 --> 00:00:34,839 Speaker 1: good sense of who this person is. You've become friends 12 00:00:34,840 --> 00:00:38,440 Speaker 1: and exchange contact info even But then their entire family 13 00:00:38,479 --> 00:00:40,600 Speaker 1: shows up to meet them at the airport, and immediately 14 00:00:40,640 --> 00:00:43,239 Speaker 1: you learn more and some of the assumptions you made 15 00:00:43,280 --> 00:00:47,680 Speaker 1: on the plane have to be reevaluated given this new input. Later, 16 00:00:47,800 --> 00:00:49,520 Speaker 1: they invite you to a family dinner at their home, 17 00:00:49,640 --> 00:00:52,680 Speaker 1: and their story broadens again. The smell of their house, 18 00:00:52,760 --> 00:00:55,280 Speaker 1: the taste of their drinking water, the view from their porch, 19 00:00:55,320 --> 00:00:59,120 Speaker 1: and the contents of their refrigerator and bookcases speak volumes 20 00:01:00,000 --> 00:01:02,480 Speaker 1: about These details reinforce what you thought you already knew, 21 00:01:02,680 --> 00:01:05,920 Speaker 1: and some change your mind. At some point your observations 22 00:01:05,959 --> 00:01:08,840 Speaker 1: become not about the person themselves, but about the whole 23 00:01:08,880 --> 00:01:12,959 Speaker 1: system in which they live. In order to understand anything, 24 00:01:13,080 --> 00:01:16,360 Speaker 1: it's helpful to understand everything, or as much as you 25 00:01:16,400 --> 00:01:19,720 Speaker 1: possibly can. In the study of ecology, the concept of 26 00:01:19,720 --> 00:01:23,240 Speaker 1: an ecosystem acknowledges the fact that, as the nineteenth century 27 00:01:23,319 --> 00:01:26,080 Speaker 1: naturalist John Muir said, when we try to pick out 28 00:01:26,120 --> 00:01:29,000 Speaker 1: anything by itself, we find it hitched to everything else 29 00:01:29,000 --> 00:01:32,759 Speaker 1: in the universe. But it's difficult to look at everything 30 00:01:32,800 --> 00:01:35,360 Speaker 1: at once, and natural systems, of all the things we 31 00:01:35,360 --> 00:01:38,600 Speaker 1: can investigate with science, are particularly hard to nail down, 32 00:01:38,959 --> 00:01:44,000 Speaker 1: but ecologists are always trying. In five and English botanist 33 00:01:44,120 --> 00:01:48,240 Speaker 1: named Arthur Tansley, strongly influenced by Danish botanist Eugenie's Varming, 34 00:01:48,600 --> 00:01:51,720 Speaker 1: introduced the term ecosystem in a paper titled The Use 35 00:01:51,760 --> 00:01:54,760 Speaker 1: and Abuse of Vegetal Concepts and Terms that was published 36 00:01:54,760 --> 00:01:58,520 Speaker 1: in the journal Ecology. He defined an ecosystem as the 37 00:01:58,560 --> 00:02:02,520 Speaker 1: whole system included not only the organism complex, but also 38 00:02:02,600 --> 00:02:05,480 Speaker 1: the whole complex of physical factors forming what we call 39 00:02:05,640 --> 00:02:09,560 Speaker 1: the environment. What Tansley was trying to get at was 40 00:02:09,600 --> 00:02:11,720 Speaker 1: the idea that you can look at a natural system 41 00:02:11,760 --> 00:02:13,840 Speaker 1: at a bunch of different levels, and that there was 42 00:02:13,880 --> 00:02:16,760 Speaker 1: one level that didn't have a name yet. For instance, 43 00:02:16,800 --> 00:02:19,560 Speaker 1: you could look at a wolverine that's a single organism, 44 00:02:19,600 --> 00:02:21,840 Speaker 1: just like the person you met on the plane, but 45 00:02:22,040 --> 00:02:24,680 Speaker 1: that wolverine doesn't live in a vacuum. It lives in 46 00:02:24,720 --> 00:02:28,040 Speaker 1: a population of other wolverines that interact and organize themselves 47 00:02:28,040 --> 00:02:31,720 Speaker 1: in specific ways. Thus, an ecologist can choose to investigate 48 00:02:31,720 --> 00:02:35,160 Speaker 1: wolverines at a population level, but that's not the only 49 00:02:35,160 --> 00:02:38,720 Speaker 1: way to study wolverines. Ecologists also talk about communities of 50 00:02:38,760 --> 00:02:42,000 Speaker 1: living things. A wolverine doesn't just interact with members of 51 00:02:42,000 --> 00:02:44,799 Speaker 1: its own species. It's an omnivore, so it eats other 52 00:02:44,840 --> 00:02:47,880 Speaker 1: animals like moose and rabbit, as well as berries, roots, 53 00:02:47,880 --> 00:02:51,320 Speaker 1: and eggs. It gets parasites, It digs burrows that affect 54 00:02:51,400 --> 00:02:55,040 Speaker 1: roots systems of plants. A wolverine influences lots of living 55 00:02:55,080 --> 00:02:58,240 Speaker 1: things in its home territory, and those living things affect 56 00:02:58,280 --> 00:03:02,800 Speaker 1: it tans. These definition of ecosystem acknowledged that there was 57 00:03:02,840 --> 00:03:05,720 Speaker 1: a level of scientific inquiry that could encompass all the 58 00:03:05,760 --> 00:03:08,800 Speaker 1: living organisms in the wolverines home. In addition, to the 59 00:03:08,800 --> 00:03:13,000 Speaker 1: stuff that's not alive. We spoke with Stephen Carpenter, a 60 00:03:13,040 --> 00:03:15,880 Speaker 1: scientist in the Center for Limnology at the University of 61 00:03:15,880 --> 00:03:20,840 Speaker 1: Wisconsin Madison. He said the ecosystem concept ecologists now use 62 00:03:20,960 --> 00:03:23,560 Speaker 1: has been refined since it was first introduced by Tansley 63 00:03:23,600 --> 00:03:27,680 Speaker 1: almost a century ago. Ecosystem science studies the interactions of 64 00:03:27,720 --> 00:03:30,919 Speaker 1: all the living and non living entities in a specified place. 65 00:03:31,560 --> 00:03:35,200 Speaker 1: This definition is consistent with modern concepts of energy, nutrient flow, 66 00:03:35,280 --> 00:03:41,680 Speaker 1: and biogeochemistry, which barely existed during Tansley's career. The allure 67 00:03:41,800 --> 00:03:44,160 Speaker 1: of the ecosystem to scientists has to do with the 68 00:03:44,280 --> 00:03:46,840 Speaker 1: system part of the word. If you look at an 69 00:03:46,840 --> 00:03:50,280 Speaker 1: ecosystem like you'd look at a computer, then an ecosystem 70 00:03:50,320 --> 00:03:53,520 Speaker 1: like a coral reef runs very similar software to that 71 00:03:53,600 --> 00:03:56,560 Speaker 1: of an arctic tundra where the wolverine lives, or to 72 00:03:56,600 --> 00:03:59,880 Speaker 1: that of a tropical forest, meaning that the same base 73 00:04:00,320 --> 00:04:05,280 Speaker 1: large scale processes can apply anywhere organic matter decomposes and 74 00:04:05,320 --> 00:04:08,120 Speaker 1: becomes nourishment for something else. In a grassland or a 75 00:04:08,120 --> 00:04:12,839 Speaker 1: mountain stream, nutrients like carbon, phosphorus, nitrogen, and sulfur get 76 00:04:12,880 --> 00:04:16,200 Speaker 1: passed around like monopoly money everywhere. It just happens a 77 00:04:16,200 --> 00:04:18,599 Speaker 1: lot faster, and there's a lot more of it in 78 00:04:18,720 --> 00:04:22,680 Speaker 1: say a tropical rainforest than in most deserts. Diseases are 79 00:04:22,720 --> 00:04:25,880 Speaker 1: carried along on water or air or by hapless organisms 80 00:04:25,880 --> 00:04:29,200 Speaker 1: in similar ways, and wherever you look, if a top 81 00:04:29,200 --> 00:04:33,120 Speaker 1: predator is removed from the ecosystem, the entire dynamic changes, 82 00:04:33,400 --> 00:04:35,560 Speaker 1: be it on a mountaintop in the Andes or in 83 00:04:35,680 --> 00:04:40,599 Speaker 1: Yellowstone National Park in Wyoming. This is to say ecosystems 84 00:04:40,640 --> 00:04:43,760 Speaker 1: are a good topic for theory, as a framework for 85 00:04:43,880 --> 00:04:48,720 Speaker 1: hanging ideas about how complex natural systems work. But while 86 00:04:48,760 --> 00:04:52,720 Speaker 1: being a theoretical idea, an ecosystem is also an actual thing. 87 00:04:53,360 --> 00:04:57,920 Speaker 1: It's just a thing without clear boundaries. According to Eugene 88 00:04:57,960 --> 00:05:02,080 Speaker 1: Odom's Fundamentals of Ecology, first wished in three you know 89 00:05:02,200 --> 00:05:05,360 Speaker 1: you've identified the edge of an ecosystem when more material 90 00:05:05,440 --> 00:05:09,120 Speaker 1: and energy is cycling within the boundary than crossing over it. 91 00:05:09,880 --> 00:05:13,159 Speaker 1: So a riffle and a stream cannot be an ecosystem 92 00:05:13,200 --> 00:05:16,040 Speaker 1: because all those certain types of fish and aquatic invertebrates 93 00:05:16,279 --> 00:05:19,080 Speaker 1: like to live in a fast, shallow section of a stream. 94 00:05:19,160 --> 00:05:22,120 Speaker 1: Abundant material is flowing into and out of the riffle 95 00:05:22,240 --> 00:05:24,960 Speaker 1: all the time. Some might stay in it for a while, 96 00:05:25,200 --> 00:05:27,600 Speaker 1: but most of it leaves pretty soon after it arrives. 97 00:05:28,080 --> 00:05:31,240 Speaker 1: Even the sediment and rocks don't stay forever. When they move, 98 00:05:31,520 --> 00:05:34,520 Speaker 1: it's mostly not inside the riffle, but into or out 99 00:05:34,560 --> 00:05:39,479 Speaker 1: of it. On the other hand, watersheds are classic ecosystem boundaries, 100 00:05:39,720 --> 00:05:43,080 Speaker 1: but they're extremely tricky as well. The river itself is 101 00:05:43,080 --> 00:05:46,400 Speaker 1: an ecosystem because although a lot of material and energy 102 00:05:46,480 --> 00:05:49,159 Speaker 1: passes in and out of it all the time, leaves 103 00:05:49,160 --> 00:05:52,480 Speaker 1: and soil and dead animals fall in. Terrestrial animals use 104 00:05:52,560 --> 00:05:55,159 Speaker 1: the river as a grocery store, et cetera. A lot 105 00:05:55,160 --> 00:05:58,560 Speaker 1: of cycling within it too, So although the river in 106 00:05:58,600 --> 00:06:01,480 Speaker 1: itself can be considered an eaty system, it's difficult to 107 00:06:01,560 --> 00:06:03,839 Speaker 1: view the river and the dry land around it is 108 00:06:03,880 --> 00:06:07,640 Speaker 1: truly separate, since material and energy are being exchanged across 109 00:06:07,680 --> 00:06:11,160 Speaker 1: the literally fluid boundary all the time in both directions. 110 00:06:11,680 --> 00:06:15,000 Speaker 1: Rivers flood after all, and deposit nutrient rich sediment on 111 00:06:15,080 --> 00:06:20,919 Speaker 1: the land. Ecosystems then are not static. We also spoke 112 00:06:20,960 --> 00:06:23,919 Speaker 1: with Kathleen Weathers, and ecologist at the Carey Institute of 113 00:06:23,960 --> 00:06:28,520 Speaker 1: Ecosystem Studies. She said the a biotic and biotic are 114 00:06:28,600 --> 00:06:32,120 Speaker 1: essential parts of the ecosystem, and they have boundaries, albeit 115 00:06:32,240 --> 00:06:36,200 Speaker 1: human defined boundaries. And not only do ecosystems have structure 116 00:06:36,240 --> 00:06:39,760 Speaker 1: and function, but these are controlled by many factors and 117 00:06:39,960 --> 00:06:48,560 Speaker 1: that ecosystems change throughout time. Today's episode was written by 118 00:06:48,600 --> 00:06:51,480 Speaker 1: Jescelin Shields and produced by Tyler Claying. Brain Stuff is 119 00:06:51,480 --> 00:06:53,560 Speaker 1: a production of I Heart Radio's How Stuff Works. For 120 00:06:53,640 --> 00:06:55,400 Speaker 1: more in this and lots of other topics, visit our 121 00:06:55,440 --> 00:06:58,000 Speaker 1: home planet, how stuff Works dot com and for more 122 00:06:58,040 --> 00:07:00,560 Speaker 1: podcast in my heart Radio because thy heart radio, app, 123 00:07:00,680 --> 00:07:03,279 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows. 124 00:07:14,360 --> 00:07:14,400 Speaker 1: H