Human Society is constantly solving problems like how to most efficiently move people resources energy and information problems that scientists are realizing a single-celled brainless slime mold might be able to solve better than us if you've taken a walk through the forest you may have noticed webs of a yellow substance growing across dead trees and on piles of fallen leaves moving at a glacial Pace this slime slowly consumes the microorganisms living on these decaying materials and while this brainless blob may seem incredibly primitive in its structure Its Behavior is another thing entirely this unique organism is called a slime mold and as it traverses the forest floor in search of food it makes decisions based on a complicated trade-off between the risks its hunger level and the quality of food patches it's been shown to demonstrate both learning and memory and acts in such a clever way that scientists consider it to have a unique form of primitive intelligence in fact its abilities are so great that researchers are using its foraging methods to solve real-world optimization problems such as the shortest path between cities and the most efficient Transportation Network challenges that typically require a sophisticated computer algorithm but the applications for slime molds don't stop there scientists are even using them as one of the most essential components in a computer and are actually building computer chips containing this slimy substance in a world that's rushing to implement Advanced artificial intelligence as the answer to our problems slime molds show us that some of the best Solutions might be hiding in the most primitive places what even is a slime mold and how can the simple brainless blob solve so many problems slime molds are mysterious organisms that scientists struggle to classify in the tree of life because they surprisingly share some of the characteristics present in animals plants and fungi like social animals slime molds exhibit swarm intelligence communication memory and learning however there is one important difference slime molds don't have a brain like plants slime molds have the same structural material in the cell walls of their spores and organic compound called cellulose but unlike plants which famously make their own food through photosynthesis slime molds get their nutrition from outside sources making them heterotrophs most often they mistakenly get categorized as fungi which is the kingdom that includes traditional molds like fungi slime molds are heterotrophs and reproduce by dispersing spores but unlike fungi they don't have chitin in their cell walls they engulf their food instead of digesting it externally and the primary cell type during their life cycle is diploid which contains two sets of chromosomes instead of just one as in a haploid cell the primary cell type found in fungi since they don't quite fit in any of these kingdoms slime molds are classified as protists a catch-all kingdom that only requires its members to be eukaryotes a cellular organism with an enclosed nucleus it's basically a category for everything we don't really understand there are over 800 species of slime molds that can be further classified into a few main types based on their life cycle one type is cellular slime molds when food is abundant these slime molds go it alone and exist as single-celled organisms but when food is in short supply they will aggregate into a mass and start moving as a single unit this is sort of like swarm intelligence we see in other animals like ants however these individuals aren't just working together they literally become one entity aggregation begins when a single cell becomes stressed and secretes a hormone called cyclic amp nearby cells respond by moving towards the hormone many small individuals come together to create one giant accumulation one that acts like a single unit like its own brand new organism this aggregation is called a slug which can be between two to four millimeters long and composed of up to a hundred thousand cells it moves as one unit towards attractants such as light heat and humidity looking for a suitable place to settle and once it does the reproduction process begins the slug flattens onto a surface and some cells develop into two to three millimeter stalks while cells at the top of the stocks develop into fruiting bodies that contain spores what's weird here is that these are still technically individual cells some of which have the genetic fate to turn into a stalk some with the genetic fate of turning into spores and only the ones that become spores get the opportunity to reproduce the ones faded to become stock simply die spores presented in this way are then dispersed by soil invertebrates and in the right conditions spores germinate produce amoeba and thus complete the life cycle slime molds like this are true evolutionary head scratchers almost always in an organism the multicellular stage arises from a single cell a fertilized egg this ensures that the cells of the organism are derived from a single genotype all of these cells are on the same team so to speak they all agree on the goal of passing down their shared genotype to the Next Generation in slime molds the multicellular stage is a combination of many unrelated genotypes viewing these slugs with the same lens of natural selection that we view everything else in the natural world these different cells with different genotypes that make up the slug are not on the same team in any given slug selection favors the cells that take unfair advantage of the altruistic cells so much so that the selfish types of cells should threaten the existence of any altruists and yet both types of cell continue to exist how this self-sacrificial Behavior continues in the face of conditions that should select for its elimination has baffled scientists for years the other major type of slime mold belongs to the class mixogastria these slime molds are often referred to as acellular plasmodial or true slime molds while cellular slime molds are difficult to see with the naked eye a plasmodial slime mold can stretch pretty far with some species reaching 30 square meters and despite its sometimes massive size it in fact is one single cell containing millions of nuclei and this one gigantic cell is a master shapeshifter plasmodiums travel over damp decaying material like wood and leaves in the search for food they primarily eat the bacteria that feeds on the decaying plant matter making them an important player in the decomposition process while searching for food they send out tendrils in all directions to sense the environment around them these tendrils are tube-like structures with a gel like outer membrane when this vascular Network encounters a stimulus the molecule cyclic amp is released this initiates cytoplasmic streaming this is the flow of cytoplasm inside the cell driven by the movement of the cytoskeleton the rate and frequency of the contractions changes when the tendrils encounter an attractant or a repellent when an attractant is located which is typically a food source the rate increases sending more cytoplasm into the tendril to capitalize on the nutrients and send it back throughout the body of the slime mold this causes the tendril to grow the opposite happens when a repellent like sunlight is located or nutrients dry up resulting in the tendrils retracting until they Disappear Completely in this way the slime mold moves towards or away from the source of the stimulus eventually configuring itself into the most optimized pathway watching this optimization process occur scientists realized these slime molds are capable of solving some complex problems displaying a remarkable form of intelligence and intelligence that operates without a brain when scientists first brought visarum polycephalum to the lab it was simply to study the way it moves no one thought that it was capable of making choices never mind choices that seemed well thought out that is until the year 2000 when researchers in Japan put visarum polycephalum to the test in the form of a maze they chopped up a single specimen and Scattered its pieces throughout a plastic maze they then put two food sources at either end of the maze there were four possible routes the plasmodium could take to get from the start and end points first the plasmodial pieces spread and reconnected to form a single organism that filled the entire maze after four hours the parts of the plasmodium that occupied dead ends shrank the remaining part of the plasmodium was then weighing its options comparing all the possible connections after another four hours it selected the shortest path between the food sources and recently scientists realized that the way slime mold achieves this is even more complex than they thought as it crawls through the maze it leaves behind a trail of slime researchers realized that the slime mold will avoid this slime Trail meaning it avoids places it's already traveled giving it a kind of externalized spatial memory since then scientists have been discovering new applications for ficerum polycephalum one of the most common is determining the optimized route between multiple locations this is known as a combinatorial optimization problem where there are many solutions but finding the best in this case the shortest path gets more and more difficult as more locations are added this type of problem often comes up in the fields of AI software engineering and Applied Mathematics and using a living organism to solve such a problem could offer some interesting insight a popular example of this is a study published in 2010 where researchers tested the efficiency of phy serum to recreate a real-world infrastructure Network the Tokyo rail system they hypothesized that the sly mold would have been fine-tuned through evolutionary selection and therefore would be capable of making the same complex trade-offs between cost transport efficiency and robustness as a man-made transport Network and that's exactly what they found on a flat template of the Tokyo region they placed food on the 36 surrounding cities connected by the rail system and let visarum grow freely from the centralized Tokyo location at first the slime mold spread out evenly over the food sources but soon it began to optimize its pattern leaving only the most efficient network of interconnected nutrient transport tubes they discovered that visarum created a map nearly identical to the real rail system with about the same cost efficiency and robustness in other words the single-celled brainless slime mold didn't reach for its food sources randomly becoming satisfied as soon as it had any food it instead behaved like a team of human Engineers editing altering and optimizing the network creating the most efficient Network possible and this is far from the only optimization problem slime molds have been able to solve the traveling salesman problem is a classic problem in mathematics where a hypothetical salesman needs to visit all the cities on a map just once before returning to his origin City the question is which order should he visit the cities to make the shortest trip possible this seemingly simple problem has a lot of real world implications a package delivery company might want to plan the shortest route between stops to save time and fuel a school district might want to plan the most efficient bus route to take children to and from school this is a problem that's surprisingly difficult to solve and for every city or every node that gets added it gets exponentially more complicated when there are just four cities there are three possible solutions when there are eight cities there are 2 520 possible solutions thus it takes traditional computers exponentially more time to solve as they go through each solution one by one but researchers discovered that slime mold can solve the problem in linear time no matter how many cities get added because it can process information concurrently while the activity of slime molds can help us find new solutions to common problems the experimental process using actual slime molds is time consuming so scientists are instead developing algorithms that model their behavior in order to test a number of different scenarios more quickly the researchers of the traveling salesman experiment created amoeba tsp an algorithm inspired by the plasmodium by incorporating the real-life constraints and behavior of ficerum polycephalum amoeba TSB found high quality solutions that also increased linearly with the number of nodes and now scientists are exploring the possibility of using slime molds as a physical Computing medium in a 2018 study researchers created a slime mold computer chip which is made of a network of slime mold tubes coated with a conductive substance it reacts to real-world optimization problems just like a slime mold does and the conductor transmit the information quickly the physerum chip solves a wide range of computation tasks including optimization on graphs computational geometry and even robot control the dawn of these biological computers shows us that while artificial intelligence may be prom missing primitive intelligence crafted by millions of years of evolution may also become a powerful tool in our toolbox for slime molds complex decision making doesn't require a brain but for us it unfortunately does having a big brain means that we're pretty good at solving problems but we're also pretty good at getting frustrated getting anxious and giving up it's all too easy to deem something too difficult even though we know we're fully capable and that's why we humans are lucky we have brilliant brilliant.org is the best way to learn math and computer science interactively it's helped me learn how to solve problems that I would have thought were way too difficult for me because brilliant takes you through lessons step by step and doesn't impede your progress if you get stuck instead they give you in-depth explanations to help guide you to the right answer it's easy to learn in this low pressure environment and most importantly it's easy to learn by doing the interactivity of these courses makes learning feel more like a game than like a class the computer science course has been particularly valuable to me this is a topic that I've always felt out of my depth in but Brilliance courses take you step by step through things like algorithms data structures and programming there's even a section on parallelism which is the very way slime molds are able to be so quick with some of their decision making it's the strategy of solving problems Faster by doing multiple things at the same time and it's a concept that's hugely important in computer science so to learn how to think more like a slime mold and to try everything brilliant has to offer free for a full 30 days visit brilliant.org real 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