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← Lessons from fungi on markets and economics

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Zeige Revision 6 erzeugt am 11/01/2019 von Brian Greene.

  1. So I stand before you
    as an evolutionary biologist,
  2. a professor of evolutionary biology,
  3. which sounds like a rather fancy title,
    if I may say so myself.
  4. And I'm going to talk about two topics
  5. that aren't normally
    talked about together,
  6. and that's market economies and fungi.
  7. Or is it fun-GUY, or,
    as we say in Europe now, fun-GEE?
  8. There's still no consensus
    on how to say this word.
  9. So I want you to imagine a market economy

  10. that's 400 million years old,
  11. one that's so ubiquitous that it operates
    in almost every ecosystem of the world,
  12. so huge that it can connect
    millions of traders simultaneously,
  13. and so persistent
  14. that it survived mass extinctions.
  15. It's here, right now, under our feet.
  16. You just can't see it.
  17. And unlike human economies
  18. that rely on cognition to make decisions,
  19. traders in this market,
    they beg, borrow, steal, cheat,
  20. all in the absence of thought.
  21. So hidden from our eyes,

  22. plant roots are colonized by a fungus
    called arbuscule mycorrhizae.
  23. Now the fungus forms
    these complex networks underground
  24. of fine filaments
    thinner than even threads of cotton.
  25. So follow one of these fungi,
  26. and it connects multiple
    plants simultaneously.
  27. You can think of it
    as an underground subway system,
  28. where each root is a station,
  29. where resources are loaded and unloaded.
  30. And it's also very dense,
  31. so roughly the length
    of many meters, even a kilometer,
  32. in a single gram of dirt.
  33. So that's the length of 10 football fields
  34. in just a thimbleful of soil.
  35. And it's everywhere.
  36. So if you passed over a tree,
    a shrub, a vine, even a tiny weed,
  37. you passed over a mycorrhizal network.
  38. Roughly 80 percent of all plant species
  39. are associated with these
    mycorrhizal fungi.
  40. So what does a root covered in fungi

  41. have to do with our global economy?
  42. And why as an evolutionary biologist
    have I spent the last 10 years of my life
  43. learning economic jargon?
  44. Well, the first thing
    you need to understand
  45. is that trade deals
    made by plant and fungal partners
  46. are surprisingly similar
  47. to those made by us,
  48. but perhaps even more strategic.
  49. You see, plant and fungal partners,
  50. they're not exchanging stocks and bonds,
  51. they're exchanging essential resources,
  52. and for the fungus,
    that's sugars and fats.
  53. It gets all of its carbon
    directly from the plant partner.
  54. So much carbon, so every year,
    roughly five billion tons of carbon
  55. from plants go into
    this network underground.
  56. For the root, what they need
    is phosphorus and nitrogen,
  57. so by exchanging their carbon
  58. they get access to all of the nutrients
    collected by that fungal network.
  59. So to make the trade,
  60. the fungus penetrates
    into the root cell of the host
  61. and forms a tiny structure
    called an arbuscule,
  62. which is Latin for "little tree."
  63. Now, you can think of this
    as the physical stock exchange
  64. of the trade market.
  65. So up until now, it seems very harmonious.

  66. Right? I scratch your back,
    you scratch mine,
  67. both partners get what they need.
  68. But here is where we need to pause
  69. and understand the power
    of evolution and natural selection.
  70. You see, there's no room
    for amateur traders on this market.
  71. Making the right trade strategy
  72. determines who lives and who dies.
  73. Now, I use the word strategy,

  74. but of course plant and fungi,
    they don't have brains.
  75. They're making these exchanges
  76. in the absence of anything
    that we would consider as thought.
  77. But, as scientists,
    we use behavioral terms
  78. such as strategy
  79. to describe behaviors
    to certain conditions,
  80. actions and reactions
  81. that are actually programmed
    into the DNA of the organism.
  82. So I started studying
    these trade strategies

  83. when I was 19 years old
  84. and I was living in
    the tropical rainforests of Panama.
  85. Now, everybody at the time was interested
    in this incredible diversity aboveground.
  86. And it was hyperdiversity.
    These are tropical rainforests.
  87. But I was interested
    in the complexity belowground.
  88. We knew that the networks existed,
    and we knew they were important,
  89. and I'm going to say it again,
    by important I mean important,
  90. so the basis of all plant nutrition
  91. for all the diversity
    that you do see aboveground.
  92. But at the time, we didn't know
    how these networks worked.
  93. We didn't know how they functioned.
  94. Why did only certain plants
    interact with certain fungi?
  95. So fast-forward to when
    I started my own group,
  96. and we really began to play
    with this trade market.
  97. You see, we would manipulate conditions.
  98. We would create a good trading partner
    by growing a plant in the sun
  99. and a poor trading partner
    by growing it in the shade.
  100. We would then connect these
    with a fungal network.
  101. And we found that the fungi
    were consistently good
  102. at discriminating among
    good and bad trading partners.
  103. They would allocate more resources
    to the host plant giving them more carbon.
  104. Now, we would run
    the reciprocal experiments

  105. where we would inoculate a host plant
    with good and bad fungi,
  106. and they were also good at discriminating
    between these trade partners.
  107. So what you have there is the perfect
    conditions for a market to emerge.
  108. It's a simple market,
  109. but it's a market nonetheless,
  110. where the better trading partner
    is consistently favored.
  111. But is it a fair market?

  112. Now this is where you need
    to understand that, like humans,
  113. plants and fungi
    are incredibly opportunistic.
  114. There's evidence that the fungus,
    once it penetrates into the plant cell,
  115. it can actually hijack the plant's
    own nutrient uptake system.
  116. It does this by suppressing
    the plant's own ability
  117. to take up nutrients from the soil.
  118. So this creates a dependency
    of the plant on the fungus.
  119. It's a false addiction, of sorts,
  120. whereby the plant has to feed the fungus
  121. just to get access to the resources
    right around its own root.
  122. There's also evidence that the fungi are
    good at inflating the price of nutrients.
  123. They do this by extracting
    the nutrients from the soil,
  124. but then rather than
    trading them with the host,
  125. they hoard them in their network,
  126. so this makes them unavailable
    to the plant and other competing fungi.
  127. So basic economics,
  128. as resource availability goes down,
    the value goes up.
  129. The plant is forced to pay more
    for the same amount of resources.
  130. But it's not all in favor of the fungus.

  131. Plants can be extremely cunning as well.
  132. There are some orchids --
  133. and I always think orchids somehow
    seem like the most devious
  134. of the plant species in the world --
  135. and there are some orchids
  136. that just tap directly into the network
  137. and steal all their carbon.
  138. So these orchids, they don't even make
    green leaves to photosynthesize.
  139. They're just white.
  140. So rather than photosynthesizing,
  141. tap into the network,
  142. steal the carbon
  143. and give nothing in return.
  144. Now I think it's fair to say
    that these types of parasites

  145. also flourish in our human markets.
  146. So as we began to decode these strategies,
  147. we learned some lessons.
  148. And the first one was that
    there's no altruism in this system.
  149. There's no trade favors.
  150. We don't see strong evidence
  151. of the fungus helping
    dying or struggling plants
  152. unless it directly benefits
    the fungus itself.
  153. Now I'm not saying
    if this is good or bad.

  154. Unlike humans, a fungus, of course,
    cannot judge its own morality.
  155. And as a biologist,
  156. I'm not advocating for these types
    of ruthless neoliberal market dynamics
  157. enacted by the fungi.
  158. But the trade system,
  159. it provides us with a benchmark
  160. to study what an economy looks like
  161. when it's been shaped by natural selection
  162. for hundreds of millions of years
  163. in the absence of morality,
  164. when strategies are just based
  165. on the gathering and processing
    of information,
  166. uncontaminated by cognition:
  167. no jealousy, no spite,
  168. but no hope, no joy.
  169. So we've made progress

  170. in decoding the most basic
    trade principles at this point,
  171. but as scientists we always
    want to take it one step further,
  172. and we're interested in more complex
    economic dilemmas.
  173. And specifically we're interested
    in the effects of inequality.
  174. So inequality has really become
    a defining feature

  175. of today's economic landscape.
  176. But the challenges of inequality
  177. are not unique to the human world.
  178. I think as humans we tend to think
    that everything's unique to us,
  179. but organisms in nature
  180. must face relentless variation
    in their access to resources.
  181. How does a fungus
    that can again be meters long

  182. change its trade strategy
    when it's exposed simultaneously
  183. to a rich patch and a poor patch?
  184. And, more generally,
  185. how do organisms in nature
    use trade to their advantage
  186. when they're faced with uncertainty
  187. in terms of their access to resources?
  188. Here's where I have
    to let you in on a secret:

  189. studying trade underground
    is incredibly difficult.
  190. You can't see where or when
    important trade deals take place.
  191. So our group helped pioneer
    a method, a technology,
  192. whereby we could tag nutrients
    with nanoparticles,
  193. fluorescing nanoparticles
    called quantum dots.
  194. What the quantum dots allow us to do
  195. is actually light up the nutrients
  196. so we can visually track their movements
  197. across the fungal network
  198. and into the host root.
  199. So this allows us finally
    to see the unseen,
  200. so we can study how fungi bargain
    at a small scale with their plant hosts.
  201. So to study inequality,
  202. we exposed a fungal network
  203. to these varying concentrations
    of fluorescing phosphorus,
  204. mimicking patches
    of abundance and scarcity
  205. across this artificial landscape.
  206. We then carefully quantified fungal trade.
  207. And we found two things.
  208. The first thing we found

  209. was that inequality encouraged
    the fungus to trade more.
  210. So I can use the word "encouraged"
    or "stimulated" or "forced,"
  211. but the bottom line is
    that compared to control conditions,
  212. inequality was associated
    with higher levels of trade.
  213. This is important,
  214. because it suggests that evolving
    a trade partnership in nature
  215. can help organisms cope with
    the uncertainty of accessing resources.
  216. Second, we found that,
    exposed to inequality,

  217. the fungus would move resources
    from the rich patch of the network,
  218. actively transport them
    to the poor side of the network.
  219. Now, of course, we could see this
  220. because the patches
    were fluorescing in different colors.
  221. So at first, this result
    was incredibly puzzling.
  222. Was it to help
    the poor side of the network?
  223. No. We found that the fungus gained more
    by first moving the resources
  224. to where demand was higher.
  225. Simply by changing where
    across the network the fungus was trading,
  226. it could manipulate
    the value of those resources.
  227. Now this stimulated us to really
    dig deeper into how information is shared.

  228. It suggests a high level
    of sophistication,
  229. or at least a medium level
    of sophistication
  230. in an organism with no cognition.
  231. How is it that a fungus can sense
    market conditions across its network
  232. and then make calculations
    of where and when to trade?
  233. So we wanted to look about information
    and how it's shared across this network,
  234. how the fungus integrates cues.
  235. So to do that, what you need to do is
    dive deep in and get a higher resolution

  236. into the network itself.
  237. We began to study complex flows
    inside the hyphal network.
  238. So what you're looking at right now
    is a living fungal network
  239. with the cellular contents
    moving across it.
  240. This is happening in real time,
  241. so you can see the time stamp up there.
  242. So this is happening right now.
    This video isn't sped up.
  243. This is what is happening
    under our feet right now.
  244. And there's a couple of things
    that I want you to notice.
  245. It speeds up, it slows down,
    it switches directions.
  246. So we're working now with biophysicists

  247. to try to dissect this complexity.
  248. How is the fungus using
    these complex flow patterns
  249. to share and process information
  250. and make these trade decisions?
  251. Are fungi better at making
    trade calculations than us?
  252. Now here's where we can potentially
    borrow models from nature.

  253. We're increasingly reliant
    on computer algorithms
  254. to make us profitable trades
    in split-second time scales.
  255. But computer algorithms and fungi,
  256. they both operate in similar,
    uncognitive ways.
  257. The fungi just happens to be
    a living machine.
  258. What would happen
    if we compare and compete

  259. the trading strategies of these two?
  260. Who would win?
  261. The tiny capitalist that's been around
  262. since before and
    the fall of the dinosaurs?
  263. My money is on the fungus.

  264. Thank you.

  265. (Applause)