Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff, Lauren
Speaker 1: Bolebon here. For a long time, nobody understood slime molds.
Speaker 1: To be clear, no one really understands them now either,
Speaker 1: But scientists now know that these pulsating piles of jelly
Speaker 1: found on rotten logs in the forest are not fungi,
Speaker 1: but are in fact more closely related to amieba's And
Speaker 1: though there's nary and neuron in a slime mold's entire
Speaker 1: gelatinous body, they seem to be able to solve relatively
Speaker 1: complex problems. There are over nine hundred species of slime
Speaker 1: molds living in the soils, leaf litter, and rotten logs
Speaker 1: of this planet and other appropriately damp and humid areas
Speaker 1: like maybe your bathroom. A Researchers have found a slime
Speaker 1: mold cast an amber dating back at least one hundred
Speaker 1: million years that remains entirely unchained from one you could
Speaker 1: find today. A slime molds in general, though, have probably
Speaker 1: been squishing their way around Earth for around a billion years.
Speaker 1: It's possible that they're one of the first multicellular ish
Speaker 1: organisms created by single cells joining and working together. Slime
Speaker 1: molds are a really diverse group. They can appear in
Speaker 1: any color except true green, a being that they lack chlorophyll.
Speaker 1: Some called cellular slime molds live mostly as a single cell,
Speaker 1: but may collect with others in a swarm in response
Speaker 1: to chemical signals like food shortage or gotapprocreate now. Others,
Speaker 1: called plasmordial slime molds, spend their entire lives as one
Speaker 1: humongous organism enclosed in a single membrane. These are what
Speaker 1: happen when thousands of single cells meet up and fuse together.
Speaker 1: Either way, Once the cells of a slime mold are
Speaker 1: in a collective, they can network and share resources. Slime
Speaker 1: molds can form up in the shape of delicate lattices
Speaker 1: or bulbous masses. They can remain microscopic or form collectives
Speaker 1: ten feet long or longer now that's about three meters.
Speaker 1: Given the motivation of, for example, finding food, those collectives
Speaker 1: are capable of crawling like worms, towards a source of
Speaker 1: nutrients or light, where nutrients are more likely to be.
Speaker 1: The thing all slime molds have in common is their
Speaker 1: life cycle, loosely resembling that of a fungus, which is
Speaker 1: why taxonomists lump them in the fungi kingdom for so long. Basically,
Speaker 1: when they vacuumed as much food out of their environs
Speaker 1: as they can, they turn their bodies into clusters of
Speaker 1: spore packets, usually on stalks and sometimes wildly colored, called sporangia.
Speaker 1: These fruiting bodies disperse a fine mist of spores into
Speaker 1: the air, which germinate wherever they fall. The single celled
Speaker 1: organisms that spring from these spores start the slime mold
Speaker 1: life cycle over again. For the article, this episode is
Speaker 1: based on How Stuff Works. Spoke by email with Tanya Laddie,
Speaker 1: who studies slime molds in the School of Life and
Speaker 1: Environmental Sciences at the University of Sydney. She said, we
Speaker 1: still know very little about the ecology of wild slime molds.
Speaker 1: For example, how they interact with other organisms and what
Speaker 1: role they play in ecosystems is still somewhat mysterious. A
Speaker 1: Lattie studies cognition in both slide molds and insects, and
Speaker 1: though we don't give insects much credit for their intelligence,
Speaker 1: with slime molds, the already tricky concept of cognition gets
Speaker 1: even weirder. Alattie said, slime molds and social insects are
Speaker 1: both decentralized systems, where there is no leader in charge
Speaker 1: of decision making. However, in the case of insects, each
Speaker 1: individual operates both at the india visual level they have brains,
Speaker 1: and at a collective level in slime molds, it's much
Speaker 1: harder to even define what an individual is. We humans
Speaker 1: rely on our brains for cognition, but even without a
Speaker 1: giant brain such as ours, other animals do have the
Speaker 1: ability to reason, learn, plan, and solve complex problems. A take,
Speaker 1: for instance, the octopus, a cephalopod closely related to clams
Speaker 1: and snails. It has a brain, but most of its
Speaker 1: neurons are spread throughout its squishy body, mostly in its arms. Still,
Speaker 1: an octopus has an undeniable intelligence. It can learn how
Speaker 1: to open new kinds of containers to get snacks. It
Speaker 1: can tell the difference between humans who are dressed identically,
Speaker 1: or even make an escape from a tank, out a
Speaker 1: drain pipe and back into the ocean. But this impressive
Speaker 1: cognitive functioning bears no physiological relation ship to hours. The
Speaker 1: neural processing equipment of an octopus evolved basically completely separately
Speaker 1: from ours because our evolutionary lineages separated over four hundred
Speaker 1: and sixty million years ago, but slime molds don't have
Speaker 1: brains or even anything that resembles a neuron. There's a
Speaker 1: lab friendly slime mold species named Physarum polycephalum, which means
Speaker 1: many headed slime mold, though it's been affectionately nicknamed the
Speaker 1: blob by researchers. It's bright yellow in color and can
Speaker 1: move in gloopy filaments that look a bit like fans
Speaker 1: of coral Researchers found that it can solve mazes. When
Speaker 1: scientists place food at the end of a maze, the
Speaker 1: mold will extend tendrills down different corridors and back out
Speaker 1: of dead ends until it finds the food, all within
Speaker 1: just a few hours. So while the process of learning
Speaker 1: is completely different in a slime mold versus an octopus
Speaker 1: versus a human, in each case, the outcome can look
Speaker 1: basically the same. One type of learning slime molder capable
Speaker 1: of is habituation. You do this too. You can get
Speaker 1: used to the temperature of a cold lake after a
Speaker 1: few minutes, or to the initially unpleasant buzzing sound of
Speaker 1: a fluorescent light in a room. Your brain helps you
Speaker 1: ignore the annoying sensation of the cold or the noise,
Speaker 1: and similar to humans, the aforementioned blob can habituate to
Speaker 1: environments and chemicals that it doesn't love acidic, dusty, dry,
Speaker 1: salty places, or chemicals like caffeine or quinine if it
Speaker 1: means it's going to get rewarded for putting up with it.
Speaker 1: And not only can slime mold habituate to less than
Speaker 1: ideal circumstances if it means they'll be rewarded, they also
Speaker 1: seem to be capable of memory. The blob, for example,
Speaker 1: seems to be able to remember things. An experiment involving
Speaker 1: slime molds the intentionally habituated to salt, a known repellent,
Speaker 1: before going into a dormant period, showed that they remembered
Speaker 1: how to become habituated to living in a very salty
Speaker 1: environment after a year of lying dormant. They also seem
Speaker 1: to be able to decide which direction to travel based
Speaker 1: on food that they've encountered there before, and researchers are
Speaker 1: still exploring slime mold's capacity for and mechanisms of processing information.
Speaker 1: The hope is that by figuring out how a decentralized
Speaker 1: intelligence like a slime mold functions, maybe we can learn
Speaker 1: something from them. Today's episode is based on the article
Speaker 1: Brainless Footless slime molds are Weirdly Intelligent and Mobile on
Speaker 1: how stuffworks dot Com, written by Jesslin Shields. Brain Stuff
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