1 00:00:01,840 --> 00:00:07,880 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff, Lauren 2 00:00:07,920 --> 00:00:13,840 Speaker 1: Bolebon here. For a long time, nobody understood slime molds. 3 00:00:14,880 --> 00:00:18,000 Speaker 1: To be clear, no one really understands them now either, 4 00:00:18,320 --> 00:00:22,120 Speaker 1: But scientists now know that these pulsating piles of jelly 5 00:00:22,280 --> 00:00:25,320 Speaker 1: found on rotten logs in the forest are not fungi, 6 00:00:25,960 --> 00:00:30,600 Speaker 1: but are in fact more closely related to amieba's And 7 00:00:30,960 --> 00:00:33,920 Speaker 1: though there's nary and neuron in a slime mold's entire 8 00:00:34,000 --> 00:00:37,600 Speaker 1: gelatinous body, they seem to be able to solve relatively 9 00:00:37,680 --> 00:00:42,800 Speaker 1: complex problems. There are over nine hundred species of slime 10 00:00:42,840 --> 00:00:46,320 Speaker 1: molds living in the soils, leaf litter, and rotten logs 11 00:00:46,320 --> 00:00:50,120 Speaker 1: of this planet and other appropriately damp and humid areas 12 00:00:50,320 --> 00:00:54,360 Speaker 1: like maybe your bathroom. A Researchers have found a slime 13 00:00:54,400 --> 00:00:57,160 Speaker 1: mold cast an amber dating back at least one hundred 14 00:00:57,160 --> 00:01:01,040 Speaker 1: million years that remains entirely unchained from one you could 15 00:01:01,040 --> 00:01:05,320 Speaker 1: find today. A slime molds in general, though, have probably 16 00:01:05,360 --> 00:01:08,800 Speaker 1: been squishing their way around Earth for around a billion years. 17 00:01:09,520 --> 00:01:12,720 Speaker 1: It's possible that they're one of the first multicellular ish 18 00:01:12,800 --> 00:01:19,039 Speaker 1: organisms created by single cells joining and working together. Slime 19 00:01:19,040 --> 00:01:22,720 Speaker 1: molds are a really diverse group. They can appear in 20 00:01:22,760 --> 00:01:26,120 Speaker 1: any color except true green, a being that they lack chlorophyll. 21 00:01:27,240 --> 00:01:31,520 Speaker 1: Some called cellular slime molds live mostly as a single cell, 22 00:01:32,000 --> 00:01:35,240 Speaker 1: but may collect with others in a swarm in response 23 00:01:35,280 --> 00:01:41,720 Speaker 1: to chemical signals like food shortage or gotapprocreate now. Others, 24 00:01:41,840 --> 00:01:45,440 Speaker 1: called plasmordial slime molds, spend their entire lives as one 25 00:01:45,600 --> 00:01:50,280 Speaker 1: humongous organism enclosed in a single membrane. These are what 26 00:01:50,400 --> 00:01:54,320 Speaker 1: happen when thousands of single cells meet up and fuse together. 27 00:01:55,560 --> 00:01:58,320 Speaker 1: Either way, Once the cells of a slime mold are 28 00:01:58,400 --> 00:02:03,440 Speaker 1: in a collective, they can network and share resources. Slime 29 00:02:03,440 --> 00:02:06,480 Speaker 1: molds can form up in the shape of delicate lattices 30 00:02:06,600 --> 00:02:12,000 Speaker 1: or bulbous masses. They can remain microscopic or form collectives 31 00:02:12,160 --> 00:02:14,919 Speaker 1: ten feet long or longer now that's about three meters. 32 00:02:16,160 --> 00:02:20,239 Speaker 1: Given the motivation of, for example, finding food, those collectives 33 00:02:20,240 --> 00:02:23,880 Speaker 1: are capable of crawling like worms, towards a source of 34 00:02:24,000 --> 00:02:27,400 Speaker 1: nutrients or light, where nutrients are more likely to be. 35 00:02:28,880 --> 00:02:31,480 Speaker 1: The thing all slime molds have in common is their 36 00:02:31,480 --> 00:02:35,160 Speaker 1: life cycle, loosely resembling that of a fungus, which is 37 00:02:35,160 --> 00:02:40,560 Speaker 1: why taxonomists lump them in the fungi kingdom for so long. Basically, 38 00:02:40,760 --> 00:02:43,519 Speaker 1: when they vacuumed as much food out of their environs 39 00:02:43,520 --> 00:02:46,480 Speaker 1: as they can, they turn their bodies into clusters of 40 00:02:46,520 --> 00:02:52,040 Speaker 1: spore packets, usually on stalks and sometimes wildly colored, called sporangia. 41 00:02:53,240 --> 00:02:56,720 Speaker 1: These fruiting bodies disperse a fine mist of spores into 42 00:02:56,760 --> 00:03:01,400 Speaker 1: the air, which germinate wherever they fall. The single celled 43 00:03:01,480 --> 00:03:04,880 Speaker 1: organisms that spring from these spores start the slime mold 44 00:03:04,919 --> 00:03:09,440 Speaker 1: life cycle over again. For the article, this episode is 45 00:03:09,480 --> 00:03:12,799 Speaker 1: based on How Stuff Works. Spoke by email with Tanya Laddie, 46 00:03:12,840 --> 00:03:15,079 Speaker 1: who studies slime molds in the School of Life and 47 00:03:15,160 --> 00:03:20,000 Speaker 1: Environmental Sciences at the University of Sydney. She said, we 48 00:03:20,080 --> 00:03:23,920 Speaker 1: still know very little about the ecology of wild slime molds. 49 00:03:24,480 --> 00:03:27,680 Speaker 1: For example, how they interact with other organisms and what 50 00:03:27,840 --> 00:03:33,480 Speaker 1: role they play in ecosystems is still somewhat mysterious. A 51 00:03:33,560 --> 00:03:37,480 Speaker 1: Lattie studies cognition in both slide molds and insects, and 52 00:03:37,720 --> 00:03:40,440 Speaker 1: though we don't give insects much credit for their intelligence, 53 00:03:40,760 --> 00:03:44,840 Speaker 1: with slime molds, the already tricky concept of cognition gets 54 00:03:45,000 --> 00:03:50,240 Speaker 1: even weirder. Alattie said, slime molds and social insects are 55 00:03:50,280 --> 00:03:54,240 Speaker 1: both decentralized systems, where there is no leader in charge 56 00:03:54,280 --> 00:03:58,080 Speaker 1: of decision making. However, in the case of insects, each 57 00:03:58,120 --> 00:04:01,920 Speaker 1: individual operates both at the india visual level they have brains, 58 00:04:02,200 --> 00:04:05,640 Speaker 1: and at a collective level in slime molds, it's much 59 00:04:05,640 --> 00:04:11,760 Speaker 1: harder to even define what an individual is. We humans 60 00:04:11,880 --> 00:04:15,600 Speaker 1: rely on our brains for cognition, but even without a 61 00:04:15,840 --> 00:04:18,880 Speaker 1: giant brain such as ours, other animals do have the 62 00:04:18,920 --> 00:04:25,040 Speaker 1: ability to reason, learn, plan, and solve complex problems. A take, 63 00:04:25,160 --> 00:04:29,480 Speaker 1: for instance, the octopus, a cephalopod closely related to clams 64 00:04:29,560 --> 00:04:33,599 Speaker 1: and snails. It has a brain, but most of its 65 00:04:33,600 --> 00:04:39,520 Speaker 1: neurons are spread throughout its squishy body, mostly in its arms. Still, 66 00:04:39,600 --> 00:04:43,480 Speaker 1: an octopus has an undeniable intelligence. It can learn how 67 00:04:43,480 --> 00:04:46,800 Speaker 1: to open new kinds of containers to get snacks. It 68 00:04:46,839 --> 00:04:49,960 Speaker 1: can tell the difference between humans who are dressed identically, 69 00:04:50,480 --> 00:04:52,760 Speaker 1: or even make an escape from a tank, out a 70 00:04:52,839 --> 00:04:56,839 Speaker 1: drain pipe and back into the ocean. But this impressive 71 00:04:56,960 --> 00:05:01,840 Speaker 1: cognitive functioning bears no physiological relation ship to hours. The 72 00:05:01,880 --> 00:05:05,920 Speaker 1: neural processing equipment of an octopus evolved basically completely separately 73 00:05:05,920 --> 00:05:10,159 Speaker 1: from ours because our evolutionary lineages separated over four hundred 74 00:05:10,200 --> 00:05:14,480 Speaker 1: and sixty million years ago, but slime molds don't have 75 00:05:14,640 --> 00:05:20,120 Speaker 1: brains or even anything that resembles a neuron. There's a 76 00:05:20,360 --> 00:05:25,200 Speaker 1: lab friendly slime mold species named Physarum polycephalum, which means 77 00:05:25,320 --> 00:05:29,039 Speaker 1: many headed slime mold, though it's been affectionately nicknamed the 78 00:05:29,080 --> 00:05:33,720 Speaker 1: blob by researchers. It's bright yellow in color and can 79 00:05:33,800 --> 00:05:37,080 Speaker 1: move in gloopy filaments that look a bit like fans 80 00:05:37,080 --> 00:05:42,920 Speaker 1: of coral Researchers found that it can solve mazes. When 81 00:05:42,960 --> 00:05:45,760 Speaker 1: scientists place food at the end of a maze, the 82 00:05:45,800 --> 00:05:49,400 Speaker 1: mold will extend tendrills down different corridors and back out 83 00:05:49,400 --> 00:05:52,440 Speaker 1: of dead ends until it finds the food, all within 84 00:05:52,680 --> 00:05:57,359 Speaker 1: just a few hours. So while the process of learning 85 00:05:57,440 --> 00:06:00,760 Speaker 1: is completely different in a slime mold versus an octopus 86 00:06:00,920 --> 00:06:04,600 Speaker 1: versus a human, in each case, the outcome can look 87 00:06:04,720 --> 00:06:09,000 Speaker 1: basically the same. One type of learning slime molder capable 88 00:06:09,040 --> 00:06:12,960 Speaker 1: of is habituation. You do this too. You can get 89 00:06:13,080 --> 00:06:15,400 Speaker 1: used to the temperature of a cold lake after a 90 00:06:15,440 --> 00:06:18,800 Speaker 1: few minutes, or to the initially unpleasant buzzing sound of 91 00:06:18,800 --> 00:06:21,919 Speaker 1: a fluorescent light in a room. Your brain helps you 92 00:06:22,000 --> 00:06:25,520 Speaker 1: ignore the annoying sensation of the cold or the noise, 93 00:06:26,800 --> 00:06:30,880 Speaker 1: and similar to humans, the aforementioned blob can habituate to 94 00:06:31,000 --> 00:06:35,719 Speaker 1: environments and chemicals that it doesn't love acidic, dusty, dry, 95 00:06:35,880 --> 00:06:40,279 Speaker 1: salty places, or chemicals like caffeine or quinine if it 96 00:06:40,480 --> 00:06:43,160 Speaker 1: means it's going to get rewarded for putting up with it. 97 00:06:44,160 --> 00:06:47,040 Speaker 1: And not only can slime mold habituate to less than 98 00:06:47,080 --> 00:06:50,560 Speaker 1: ideal circumstances if it means they'll be rewarded, they also 99 00:06:50,760 --> 00:06:55,120 Speaker 1: seem to be capable of memory. The blob, for example, 100 00:06:55,440 --> 00:06:59,080 Speaker 1: seems to be able to remember things. An experiment involving 101 00:06:59,080 --> 00:07:02,920 Speaker 1: slime molds the intentionally habituated to salt, a known repellent, 102 00:07:03,240 --> 00:07:06,760 Speaker 1: before going into a dormant period, showed that they remembered 103 00:07:06,839 --> 00:07:09,760 Speaker 1: how to become habituated to living in a very salty 104 00:07:09,840 --> 00:07:14,320 Speaker 1: environment after a year of lying dormant. They also seem 105 00:07:14,400 --> 00:07:17,239 Speaker 1: to be able to decide which direction to travel based 106 00:07:17,280 --> 00:07:21,960 Speaker 1: on food that they've encountered there before, and researchers are 107 00:07:22,040 --> 00:07:27,320 Speaker 1: still exploring slime mold's capacity for and mechanisms of processing information. 108 00:07:28,800 --> 00:07:31,920 Speaker 1: The hope is that by figuring out how a decentralized 109 00:07:31,960 --> 00:07:36,120 Speaker 1: intelligence like a slime mold functions, maybe we can learn 110 00:07:36,200 --> 00:07:43,880 Speaker 1: something from them. Today's episode is based on the article 111 00:07:44,160 --> 00:07:47,920 Speaker 1: Brainless Footless slime molds are Weirdly Intelligent and Mobile on 112 00:07:47,960 --> 00:07:51,520 Speaker 1: how stuffworks dot Com, written by Jesslin Shields. Brain Stuff 113 00:07:51,520 --> 00:07:54,200 Speaker 1: is production of iHeartRadio in partnership with how stuffworks dot 114 00:07:54,200 --> 00:07:57,400 Speaker 1: Com and as produced by Tyler Klang. Four more podcasts 115 00:07:57,440 --> 00:08:01,200 Speaker 1: my heart Radio, visit the iHeartRadio app podcasts, or wherever 116 00:08:01,240 --> 00:08:02,760 Speaker 1: you listen to your favorite shows.