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 "A University of Windsor computer scientist has created a virtual world that would blow Charles Darwin's mind. Evolution in the virtual world created by Robin Gras moves quickly. The university associate professor can go back in the simulation to see how new species were created. "We have the ability to make fast computations of things that take millions of years in order to happen," Gras said. "Here in our computer, we can see that in a few days." A research paper on the new computer program by the associate professor was in the Massachusetts Institute of Technology's fall academic journal Artificial Life. Gras said very few teams of scientists in the world are using computer simulations to study ecosystems; his virtual world is different than other programs because his has a higher level of complexity for individual behaviours. The computer program takes into account the environment and the internal state of the species: fear, hunger, sexual needs, curiosity and satisfaction. The virtual species use that internal state to make decisions on what action to take. They can evade predators, search for food, stay where they are, eat, reproduce, socialize and explore. The program can be used to study evolution. It could help scientists understand how new species emerge, how species survive or become extinct and the interactions between predators and prey, he said. It can look at how diseases spread. It can test theories. Gras can make two separate ecosystems and take one species from one ecosystem and put it in another. It could help scientists understand what makes an invasive species successful, he said. Gras, who will work with the university's Great Lakes Institute for Environmental Research, said biologists have expressed interest in the program. The computer program, which hasn't been named yet, doesn't have graphics or specific animals. Gras said it took him about a month to design but it will take years to perfect. He used what is called a fuzzy cognitive map to make his virtual world. There are graphs that show the artificial species – red dots to represent predators, blue for prey species. Each dot lives a specific amount of time, during which it gets to make about 70 decisions, such as hunting and mating. The virtual species breed and can create new species. They can also become extinct. The species act like ones in the real world, with one key difference: Gras can quickly zip forward and backward in his ecosystem to observe changes in behaviour and learn how and when the changes happened. For example, over many generations his predators began to scavenge. It wasn't something he'd programmed them to do. Gras is eager to see what happens next in his virtual world. "I'm very curious and surprised to see how things that really happen in the real world can emerge from these systems." Windsor Star"
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What drives evolution? How does one species become two? Where will organisms disperse and why? Theoretical questions about the way natural ecosystems function have been puzzling biologists for years. Now a University of Windsor professor of computer science is providing the solutions with a complex and unique virtual ecosystem simulation. Prof. Robin Gras, who also holds the Canadian Research Chair in Probability Heuristics and Bioinformatics, created the simulation to accurately represent the behavior of real world ecosystems. His simulation is the first to model the fact that individual behaviours can affect the evolutionary course of the entire species. To achieve this realism, Gras relies on the computational power of SHARCNET. “Because we take into account the perceptions and behaviours of every individual in a species, our data gets quite large,” says Gras. “In fact, each time we run our simulation it takes between 5 or 6 weeks of computational time. We really rely on SHARCNET’s resources.” Gras collaborated with biologists to gather the background data for the virtual simulation. Although it’s not based on any one specific living system, it was designed to model situations and problems that many real world ecosystems face, such as limited food resources, invasive species and disease. At the beginning of the simulation, two species exist: one predator, the other prey. Throughout the simulation, new species can emerge in either class. Regardless of species, each organism in the simulation has the ability to perceive and make decisions about its environment. This allows them to feel basic needs and high level desires, from hunger and reproductive drive to curiosity, fear and happiness. A mathematical concept called “Fuzzy Cognitive Map” (FCM) makes this possible. An individual organism experiences its environment, and then the FCM model transforms the data in some way to simulate the individual’s interpretation of its surroundings. This means the information perceived by the individual isn’t the exact information that comes from its environment – and the imprecision caused by individual perception makes the simulation more realistic. This model also integrates emotions and desires which, coupled with the perception of the agent, have influence on its decision of action. Then there’s virtual offspring. When two virtual organisms reproduce, their offspring’s genetic information is a combination of the parents. Because the behavioural model for the organism is encoded in the genome, both the mother’s and father’s behavior will be represented in the offspring. As in nature, chance genetic mutations are possible. So, the offspring could end up with new genetic variations that lead to totally new behaviours. They may be able to avoid predators or find food in different ways, and this could eventually result in “speciation”: a new species emerging. Gras and his team manipulate their simulated ecosystems to see if they can affect phenomenon like speciation and migration. “We try, for example, to integrate a new source of food into our system to see if it accelerates the way the species emerge or dedicate themselves to one food source or another, says Gras. By adding virtual obstacles, they can restrict the movement and breeding opportunities of a group of organisms. This models a very important biological paradigm, where a reduction in gene flow leads to more speciation events. The researchers can also integrate virtual diseases into the simulation and study how individual interactions are linked to the disease’s spread. Just like diseases, invasive species can diffuse throughout an ecosystem. In the virtual ecosystem, Gras can examine how a foreign species survives in a new environment, and how its survival impacts the native organisms. Gras uses a special program to analyze the results of all these simulations. The program itself takes several days of computation with SHARCNET resources, and gives the researchers a clear picture of what’s going on. “We can compare what we observe with real biological data, and we see the same kind of patterns, the same kind of high level behaviours as we see in nature,” says Gras. “We have the ability to observe what, at the individual level, leads to the cause of these emerging patterns—so we have the whole chain of representation.” Collaborators include Prof. Melania Cristescu, Great Lakes Institute for Environmental Research, University of Windsor. Funding is provided by the Natural Sciences and Engineering Research Council.
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