[MUSIC]
This is a pretty simple maze. It shouldn’t be too hard for you to solve. Of course, you’re
pretty smart. You’ve got 86 billion neurons at your disposal, you’re a member of the
most intelligent species on the planet.
But what if you were a pulsating wad of yellow goo? I’m going to let my friend Amy from
Deep Look introduce you.
[AMY VO] This is Physarum polycephalum, a slime mold.
It might look similar to the mold you find on stale bread, but it’s not a fungus. It’s
a jelly-like protist.
You can think of it like one big cell, holding millions of nuclei.
And they might not seem look like much, but slime molds are smarter than they look.
Just watch.
[JOEVO]
This slime mold can solve mazes. It does so by first exploring every path, and when it’s
found the food at either end, it retracts any paths that don’t connect the points.
Solving a maze involves remembering where you’ve been. Where does a single celled
ball of goo hold memories? Physarum does this by leaving chemical trails to mark dead ends,
so it can “remember” where it’s already explored.
When slime molds are presented with a maze that has more than one solution, they’ll
even figure out the shortest one.
No matter the shape, they’ll almost always connect distributed food sources by the shortest
path.
If that doesn’t impress you, realize that once you start adding points, mapping efficient
networks is an incredibly complex problem that humans need big computers and complex
math to solve. This living ooze is redefining what it means to be intelligent.
They’ve even been able to map the rail system of Tokyo, and the major highways of the UK.
--- Another kind of slime mold shows a different
kind of smarts. This is Dictyostelium, a cellular slime mold. Instead of a creeping blob, this
slime mold lives most of its life as single, free-living amoebae, gulping up bacteria.
But when it runs out of food, something amazing happens.
[AMY VO] One cell starts emitting a chemical. This
attracts other cells, and once they join up, those cells start emitting chemical pulses
of their own. This is called chemotaxis, and the bigger the mass gets, the stronger that
signal, until eventually there’s tens or hundreds of thousands stuck together.
These once free-living cells now cooperate like a multicellular organism, coming together
like Voltron and moving in unison. This “slug” travels farther and faster
than any single cell could on its own. It’s about to undergo a second incredible transformation.
[AMY VO[ After the slug migrates away, it flattens
itself and begins to sprout. A thin stalk grows out, lifting a fruiting body into the
air. From here, spores will be released, to be collected by passing insects and carried
to plentiful food.
What’s amazing is the cells making up the stalk die, they sacrifice themselves so other
cells can live on.
It’s not that different from what a wheat plant does. Growing, dying off, and releasing
the next generation to the wind. But a plant lives its whole life as a multicellular organism.
These amoebae are separate individuals, yet they’re acting for the benefit of others.
This is a principle called “altruism”.
It goes against what we might expect from natural selection, that every individual wants
to succeed and pass its own genes on. But altruism suggests that helping the group that
we’re genetically related to can help the entire species survive.
We see this in animals hunting together, worker bees tending to the queen, meerkats standing
guard over their dens, chimpanzees sharing food.
But these slimy species especially challenge what we think of as intelligence, because
so many of our preconceived notions don’t fit what we see.
Anthropologist Jeremy Narby writes, “We struggle over words when the slime mold solves
the maze, because our concepts don’t fit the data. It is not that nature lacks intelligence,
but that our own concepts do.”
What he means is any view of nature that puts humans in a separate category isn’t a very
good view of nature at all. And if something as simple as a slime mold can solve problems…
can come together and cooperate for the good of the group, it’s a nice reminder…
[AMY VO] That If the goo can do it, so can we.
If you want to get an up-close look at how slime molds move and how scientits are using that as inspiration
for futuref robots…. follow me over to Deep Look.
And as always, Stay Curious.