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So I stand before you
as an evolutionary biologist,
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a professor of evolutionary biology,
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which sounds like a rather fancy title,
if I may say so myself.
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And I'm going to talk about two topics
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that aren't normally
talked about together,
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and that's market economies and fungi.
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Or is it fun-GUY, or,
as we say in Europe now, fun-GEE?
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There's still no consensus
on how to say this word.
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So I want you to imagine a market economy
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that's 400 million years old,
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one that's so ubiquitous that it operates
in almost every ecosystem of the world,
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so huge that it can connect
millions of traders simultaneously,
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and so persistent
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that it survived mass extinctions.
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It's here, right now, under our feet.
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You just can't see it.
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And unlike human economies
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that rely on cognition to make decisions,
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traders in this market,
they beg, borrow, steal, cheat,
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all in the absence of thought.
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So hidden from our eyes,
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plant roots are colonized by a fungus
called arbuscule mycorrhizae.
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Now the fungus forms
these complex networks underground
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of fine filaments
thinner than even threads of cotton.
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So follow one of these fungi,
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and it connects multiple
plants simultaneously.
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You can think of it
as an underground subway system,
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where each root is a station,
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where resources are loaded and unloaded.
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And it's also very dense,
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so roughly the length
of many meters, even a kilometer,
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in a single gram of dirt.
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So that's the length of 10 football fields
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in just a thimbleful of soil.
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And it's everywhere.
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So if you passed over a tree,
a shrub, a vine, even a tiny weed,
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you passed over a mycorrhizal network.
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Roughly 80 percent of all plant species
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are associated with these
mycorrhizal fungi.
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So what does a root covered in fungi
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have to do with our global economy?
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And why as an evolutionary biologist
have I spent the last 10 years of my life
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learning economic jargon?
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Well, the first thing
you need to understand
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is that trade deals
made by plant and fungal partners
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are surprisingly similar
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to those made by us,
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but perhaps even more strategic.
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You see, plant and fungal partners,
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they're not exchanging stocks and bonds,
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they're exchanging essential resources,
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and for the fungus,
that's sugars and fats.
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It gets all of its carbon
directly from the plant partner.
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So much carbon, so every year,
roughly five billion tons of carbon
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from plants go into
this network underground.
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For the root, what they need
is phosphorus and nitrogen,
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so by exchanging their carbon
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they get access to all of the nutrients
collected by that fungal network.
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So to make the trade,
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the fungus penetrates
into the root cell of the host
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and forms a tiny structure
called an arbuscule,
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which is Latin for "little tree."
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Now, you can think of this
as the physical stock exchange
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of the trade market.
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So up until now, it seems very harmonious.
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Right? I scratch your back,
you scratch mine,
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both partners get what they need.
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But here is where we need to pause
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and understand the power
of evolution and natural selection.
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You see, there's no room
for amateur traders on this market.
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Making the right trade strategy
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determines who lives and who dies.
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Now, I use the word strategy,
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but of course plant and fungi,
they don't have brains.
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They're making these exchanges
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in the absence of anything
that we would consider as thought.
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But, as scientists,
we use behavioral terms
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such as strategy
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to describe behaviors
to certain conditions,
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actions and reactions
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that are actually programmed
into the DNA of the organism.
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So I started studying
these trade strategies
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when I was 19 years old
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and I was living in
the tropical rainforests of Panama.
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Now, everybody at the time was interested
in this incredible diversity aboveground.
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And it was hyperdiversity.
These are tropical rainforests.
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But I was interested
in the complexity belowground.
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We knew that the networks existed,
and we knew they were important,
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and I'm going to say it again,
by important I mean important,
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so the basis of all plant nutrition
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for all the diversity
that you do see aboveground.
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But at the time, we didn't know
how these networks worked.
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We didn't know how they functioned.
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Why did only certain plants
interact with certain fungi?
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So fast-forward to when
I started my own group,
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and we really began to play
with this trade market.
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You see, we would manipulate conditions.
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We would create a good trading partner
by growing a plant in the sun
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and a poor trading partner
by growing it in the shade.
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We would then connect these
with a fungal network.
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And we found that the fungi
were consistently good
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at discriminating among
good and bad trading partners.
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They would allocate more resources
to the host plant giving them more carbon.
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Now, we would run
the reciprocal experiments
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where we would inoculate a host plant
with good and bad fungi,
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and they were also good at discriminating
between these trade partners.
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So what you have there is the perfect
conditions for a market to emerge.
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It's a simple market,
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but it's a market nonetheless,
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where the better trading partner
is consistently favored.
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But is it a fair market?
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Now this is where you need
to understand that, like humans,
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plants and fungi
are incredibly opportunistic.
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There's evidence that the fungus,
once it penetrates into the plant cell,
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it can actually hijack the plant's
own nutrient uptake system.
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It does this by suppressing
the plant's own ability
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to take up nutrients from the soil.
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So this creates a dependency
of the plant on the fungus.
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It's a false addiction, of sorts,
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whereby the plant has to feed the fungus
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just to get access to the resources
right around its own root.
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There's also evidence that the fungi are
good at inflating the price of nutrients.
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They do this by extracting
the nutrients from the soil,
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but then rather than
trading them with the host,
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they hoard them in their network,
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so this makes them unavailable
to the plant and other competing fungi.
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So basic economics,
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as resource availability goes down,
the value goes up.
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The plant is forced to pay more
for the same amount of resources.
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But it's not all in favor of the fungus.
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Plants can be extremely cunning as well.
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There are some orchids --
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and I always think orchids somehow
seem like the most devious
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of the plant species in the world --
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and there are some orchids
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that just tap directly into the network
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and steal all their carbon.
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So these orchids, they don't even make
green leaves to photosynthesize.
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They're just white.
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So rather than photosynthesizing,
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tap into the network,
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steal the carbon
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and give nothing in return.
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Now I think it's fair to say
that these types of parasites
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also flourish in our human markets.
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So as we began to decode these strategies,
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we learned some lessons.
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And the first one was that
there's no altruism in this system.
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There's no trade favors.
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We don't see strong evidence
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of the fungus helping
dying or struggling plants
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unless it directly benefits
the fungus itself.
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Now I'm not saying
if this is good or bad.
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Unlike humans, a fungus, of course,
cannot judge its own morality.
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And as a biologist,
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I'm not advocating for these types
of ruthless neoliberal market dynamics
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enacted by the fungi.
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But the trade system,
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it provides us with a benchmark
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to study what an economy looks like
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when it's been shaped by natural selection
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for hundreds of millions of years
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in the absence of morality,
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when strategies are just based
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on the gathering and processing
of information,
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uncontaminated by cognition:
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no jealousy, no spite,
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but no hope, no joy.
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So we've made progress
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in decoding the most basic
trade principles at this point,
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but as scientists we always
want to take it one step further,
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and we're interested in more complex
economic dilemmas.
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And specifically we're interested
in the effects of inequality.
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So inequality has really become
a defining feature
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of today's economic landscape.
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But the challenges of inequality
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are not unique to the human world.
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I think as humans we tend to think
that everything's unique to us,
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but organisms in nature
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must face relentless variation
in their access to resources.
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How does a fungus
that can again be meters long
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change its trade strategy
when it's exposed simultaneously
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to a rich patch and a poor patch?
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And, more generally,
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how do organisms in nature
use trade to their advantage
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when they're faced with uncertainty
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in terms of their access to resources?
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Here's where I have
to let you in on a secret:
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studying trade underground
is incredibly difficult.
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You can't see where or when
important trade deals take place.
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So our group helped pioneer
a method, a technology,
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whereby we could tag nutrients
with nanoparticles,
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fluorescing nanoparticles
called quantum dots.
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What the quantum dots allow us to do
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is actually light up the nutrients
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so we can visually track their movements
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across the fungal network
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and into the host root.
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So this allows us finally
to see the unseen,
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so we can study how fungi bargain
at a small scale with their plant hosts.
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So to study inequality,
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we exposed a fungal network
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to these varying concentrations
of fluorescing phosphorus,
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mimicking patches
of abundance and scarcity
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across this artificial landscape.
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We then carefully quantified fungal trade.
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And we found two things.
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The first thing we found
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was that inequality encouraged
the fungus to trade more.
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So I can use the word "encouraged"
or "stimulated" or "forced,"
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but the bottom line is
that compared to control conditions,
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inequality was associated
with higher levels of trade.
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This is important,
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because it suggests that evolving
a trade partnership in nature
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can help organisms cope with
the uncertainty of accessing resources.
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Second, we found that,
exposed to inequality,
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the fungus would move resources
from the rich patch of the network,
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actively transport them
to the poor side of the network.
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Now, of course, we could see this
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because the patches
were fluorescing in different colors.
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So at first, this result
was incredibly puzzling.
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Was it to help
the poor side of the network?
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No. We found that the fungus gained more
by first moving the resources
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to where demand was higher.
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Simply by changing where
across the network the fungus was trading,
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it could manipulate
the value of those resources.
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Now this stimulated us to really
dig deeper into how information is shared.
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It suggests a high level
of sophistication,
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or at least a medium level
of sophistication
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in an organism with no cognition.
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How is it that a fungus can sense
market conditions across its network
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and then make calculations
of where and when to trade?
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So we wanted to look about information
and how it's shared across this network,
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how the fungus integrates cues.
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So to do that, what you need to do is
dive deep in and get a higher resolution
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into the network itself.
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We began to study complex flows
inside the hyphal network.
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So what you're looking at right now
is a living fungal network
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with the cellular contents
moving across it.
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This is happening in real time,
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so you can see the time stamp up there.
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So this is happening right now.
This video isn't sped up.
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This is what is happening
under our feet right now.
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And there's a couple of things
that I want you to notice.
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It speeds up, it slows down,
it switches directions.
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So we're working now with biophysicists
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to try to dissect this complexity.
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How is the fungus using
these complex flow patterns
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to share and process information
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and make these trade decisions?
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Are fungi better at making
trade calculations than us?
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Now here's where we can potentially
borrow models from nature.
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We're increasingly reliant
on computer algorithms
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to make us profitable trades
in split-second time scales.
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But computer algorithms and fungi,
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they both operate in similar,
uncognitive ways.
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The fungi just happens to be
a living machine.
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What would happen
if we compare and compete
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the trading strategies of these two?
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Who would win?
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The tiny capitalist that's been around
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since before and
the fall of the dinosaurs?
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My money is on the fungus.
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Thank you.
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(Applause)