Hold A to open the Options menu. You can change the: • Speed • Zoom (Zoom out to see more of the graph, or zoom in to see the graph more closely) • Switch between regular view and phase space (y and t or x and y)
Made using Lotka–Volterra equations to model ecosystem dynamics. The equations used are (X - Xt-1) / Xt-1 = A - B • Yt-1, and (Y - Yt-1) / Yt-1 = C • Xt-1 - D, where: • X represents the number of prey, and Y represents the number of Predators. • Xt-1 represents the number of prey in the previous iteration, and vice versa with Yt-1. • A represents a factor that affects the natural Prey growth rate (for example, how much food is available). • B represents a factor that affects the natural Prey death rate (for example, how well the predators are at catching the prey). • C represents a factor that affects the natural Predator growth rate (for example, how well the prey nourishes the predator). • D represents a factor that affects the natural Predator death rate This is made for my school project as a presentation of a possible idea of how to use computer technology and graphics to simulate a basic ecosystem and graph the results. Basically what's happening is that you can see an oscillating up and down movement; when the predators overpopulate, the prey dies off and the predators naturally shrink back down because they have nothing to eat. When the prey overpopulates, the predators grow in response and regulate the prey. Given the right values for A, B, C, D, and the initial starting values for X and Y, you can make the ecosystem sustainable, or it may eventually go to extremes and die out. You can see that the predator population usually doesn't surpass the peak of the prey population, and when it does, the ecosystem dies out. I'm guessing this is because if you have more predator than prey, then the predators can eat all the prey and the prey cannot reproduce, so the predators all die from starvation.
