Pokémon “Smelly Smelly Mud”

  The Japanese animation “Pokémon”, which was released in 1997, has taken the world by storm and is still very popular today. The world of the cartoon is similar to reality but somewhat different. There are various creatures called Pokémon. They are based on real creatures, but they are more distinctive and have strange superpowers. Among them is a kind of Pokémon called stinky mud, which looks like a pool of soft mud, usually wriggling forward, and when it launches superpowers to attack humans, it will gather and form, becoming a person with eyes, mouth and hands” Mushrooms”, spewing out a cloud of mud.
  Recently, we can see groups of real “stinky mud” in reality, and they are waiting to greet people at the Paris Zoo.
“Smelly mud” that looks like animals and not animals

  The scientific name of the “new tenant” of the Paris Zoo is Physarum polycephalum. It is a single-celled organism. Biologists classify it as a protozoan, but until now, biologists have not understood it. Is it an animal or a fungus, because it is so strange!

Physarum polycephalum walks the maze

  The living habits of Physarum polycephalum are like mushroom fungi. They all like to grow on the back of rotting wood or wet leaves, and feed on bacteria, molds, mushrooms and fallen leaves. But it is not a mushroom. Its life can be divided into two periods, the growth period and the reproduction period. In these two periods, its shape and behavior are completely different.
  Polycephalum polycephalum behaves like animals in the growth phase, a moist cell wall-free protoplasm cluster, like a piece of orange jelly, which can move flexibly and take the initiative to eat. And when there is a shortage of food in the surrounding area, they will also send out a signal to summon the surrounding companions to gather together and transform into a large “smelly mud”, and then through collaborative search, they will catch all the surrounding food.
  Although Physarum polycephalum does not have a specially differentiated motor organ, they can slide forward 1 cm per hour. They will also use chemical substances to mark the route they have taken to remind latecomers not to take the inappropriate road again, just like the sign that we have set up “this road is nowhere”, and later Physarum polycephalum will avoid this. Way. A large “stinky mud” is composed of thousands of Physarum polycephalum. They move in all directions while looking for food. They can detect tens of square meters in a day. ?
  When the breeding season comes, they become the same. A group of Physarum polycephalum combines together to grow into immobile “mushrooms”. Some Physarum polycephalum becomes a “hyphae”-like vegetative structure, and the other part becomes a “fruiting body” reproductive structure. In the fruit body, Physarum polycephalum will combine in pairs to produce offspring spores. Slowly, the entire “mushroom” will gradually become dry and black, and finally, countless spores of different genders will squeeze the dry sporangia wall and spew out from it.
  Although Physarum polycephalum will mate nearby, they are not at risk of deformity because they have hundreds of sexes. For example, we use the three mitochondrial genes matA, matB and matC of Physarum polycephalum to determine their sex. Individuals with exactly the same three genes are considered to be of the same sex. But each of these three genes has as many as 16 variants, and the number of variant genes is different, resulting in a total of about 720 sexes. Except for the same sex, each Physarum polycephalum can mate and reproduce with individuals of any other sex, so that genetic diversity can be maintained and there is no need to worry about inbreeding.
Who will fight for the way in the maze

  Although the individual size of Polycephalum polycephalum is small, they have the momentum of being eager to eat and swear when they unite to find food. Their method of finding food is fast and efficient. Biologists quickly thought of their magical use-exploration road.
  In 2000, the Japanese biologist Toshiyuki Nakagaki was the first to let the Physarum polycephalum walk the maze. They cultivated Physarum polycephalum in the center of the maze, and put their favorite food-oats at the beginning and end of the maze, to seduce them to start walking the maze. Physarum polycephalum lived up to expectations. They quickly found the food at both ends of the maze, and they also brought us unexpected surprises. In this maze, there are 4 roads of different lengths leading to the food at both ends. All the long hairs The bubble fungus chose the shortest one in the end.

Using Polycephalosporium to Plan Urban Roads

  After the experimental results came out, more people were interested. Would such a simple creature choose the shortest and most efficient route? How did they do it?
  In 2010, Toshiyuki Nakagaki asked Polycephalosporium to produce a “design draft” for Tokyo Railway. The researcher made a large plate shaped like Tokyo city, and kept the Physarum polycephalum inside. Use one of the largest oats to represent the location of Tokyo Station, and 35 small oats to represent the 35 stations passed by the Tokyo Railway and place them in the corresponding locations. They also designed “roadblocks” for Polycephalosporium fungus because they don’t like light. Researchers placed small light bulbs on the mountains and rivers that represent real cities and told them to avoid these places.
  At first, Physarum polycephalum moved in all directions, slowly exploring new territories. After more than ten hours, they figured out all the positions of the food and began to optimize the route. For example, the straight road between oats became more “congested”, and some detours became “sparsely populated”. It took about 26 hours to complete a design that was highly similar to the Tokyo rail network. Moreover, this “design draft” is very flexible and changeable. If the researcher “Party A” is not satisfied, as long as the position of oatmeal is changed or the number of oatmeal is changed, the polycephalum can also “design” a new one in one day. route map.
  Polycephalum can quickly find the most suitable way in the mini “Tokyo City”. If the scope is expanded to the world, how will they expand? Professor Andy Yadamowski from the University of the West of England did an experiment.
  Andy made a small earth out of agar, and cut the surface agar into oceans, continents, and lakes based on the terrain of the earth, creating a surface of different heights. Then, the oatmeal was sprinkled on the locations of the most densely populated cities such as Seoul, Tokyo, and London, and the polycephalosporium fungus was placed in the location of Beijing.

  Physarum polycephalum took more than a week to occupy all the “cities”. They started from Beijing and first covered Seoul and Tokyo. After that, they gradually “colonized” Hong Kong, and at the same time branched out to extend to Indonesia and Australia. The main line steadily advanced from Hanoi, Vietnam to London, England. Polycephalum polycephalum once again made the same choice as humans, and their entire “colonization” path is highly overlapped with the Silk Road and some Asian highways.
  Now everyone finally believes that Physarum polycephalum can indeed find a way. The way they find is almost the same as the way we repeated surveys and repeated designs, which is labor-saving and efficient. In the process of finding a way, Physarum polycephalum will continue to leave chemical substances marking the route “passable”, so that after finding the most efficient new route, the latecomers will spontaneously identify the signs left by the “predecessors” Choose this most suitable path.
Welcome to the simulated city

  Physarum polycephalum has such an efficient expansion ability, if it has strong viability, will it eventually occupy the world? Fortunately, its survivability is not strong. It hates light and cannot live in dry places, so it can only hide in the dark, but if we build a simulated city for them, it may be of great use.
  In 2014, an Ebola epidemic broke out in Africa. As the number of patients increased and the scope of infection expanded, the American people felt more panic. So the US Department of Defense asked engineers to build models to predict the development trend of the epidemic. It took more than 7 months for engineers to build a mathematical model. This model uses a lot of data and refers to people’s behavior patterns, including population size, infection rate, healthcare system, population distribution, economic and social interaction trends, travel Behaviors and even cultural behaviors such as funeral ceremonies. It predicts that if it is not controlled, the Ebola virus will infect 1.4 million people. Doctors and scientific researchers have designed many measures to stop transmission, and it can also predict the effectiveness of these measures. Based on this, people chose the best measure recommended by the model, namely, isolating the patient and burying the body. Finally, the number of infections was controlled at around 30,000.
  This way of using big data to build models to predict various situations has been widely used. However, the model that took more than 7 months to design can only be used to predict an epidemic. Is this efficiency too low? Can we build a better model, such as a simulated city inhabited by Polycephalum?
  So how to simulate? In fact, the method is very similar to the previous experiment. Place oatmeal in the petri dish where Polycephalum polycephalum survives, place oatmeal in a place corresponding to a suitable refuge in real life, use lights to simulate the difficulties and dangers on the way, and then use the topography of the culture medium and dryness. The degree of humidity changes to simulate various factors such as the terrain and economic conditions of the real environment. Finally, using the habit of Physarum polycephalum to dislike salt, sprinkle salt that represents the virus on their settlements and observe their escape routes and destinations. In this way, based on the escape route of Physarum polycephalum when it encounters salt grains, scientists can guess the possible escape route of people when an epidemic occurs in a certain place and the next outbreak location. In this way, we can better control the migration areas of the affected people and prevent the virus from spreading further.
  The same simulation idea can also be used for the diversion of traffic accidents. By simulating the surrounding environment of the accident site, and then observing the route of Physarum polycephalum circumventing the salt grains, it will provide us with new ways to plan alternative traffic routes and divert and block vehicles. Ideas.
  Compared with the U.S. Department of Defense’s digital model for predicting the Ebola epidemic, the simulated city of Polycephalum not only takes a short time to build and is low in cost, it can be reused as long as the location of various conditions is changed. Except for the inability to obtain specific data such as the number of people affected by the disaster, the disaster avoidance route of Polycephalum is not much different from ours, and the measures we take based on this can also achieve miraculous results.
  If you have also envied the protagonist of “Pokemon”, Xiaozhi has many magical creatures, then you should also go to the nature to find all kinds of magical creatures. Maybe your first “Pokemon” will be able to predict the future Polycephalum?