[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.
Our world is so wonderful