So same as what we did with Schelling's model, let's make this model a little bit more sophisticated. So let's see if we can raise the level of fidelity and move it a little bit closer to a little bit more realistic assumptions. So here we can see our extended version of a Sugarscape and you can see they're much more bells and whistles here. A lot of different sliders that allow us to introduce additional features to make our model always more realistic [inaudible] Weaver program that on an older version of NetLogo 4.0.5. You're welcome to check it out online and download it and play with it yourself. Well, what's the first additional characteristic we want to explore? Well, of course it's sex. Ella Fitzgerald says that the birds do it and the bees do it and even educated fleas, do it, so let's do it. Let's do the most natural thing, let's do sex on Sugarscape. So, wait. How do we do it? So it works like this. Well, first of all we have two different genders here, women and men. You might say in our setup and then if your level of sugar that you have right now is at least as high as your initial endowment, that means if you didn't party at all off and you are responsible and you still have at least as much sugar or more and you meet a neighbor of the opposite sex, then, well, there might be several. So you go by random order of your neighbors of the opposite sex just like in every good neighborhood bar, just kidding. Then you see if the neighbor also has the same condition, has enough sugar, then comes the hard part of life. You deplete your sugar by half both of you because there is not only the fun, children are really expensive. With that, that's the endowment of your children, there has to be an empty patch as well around and on this empty patch then a child will be placed with both of your half sugar and endowment. This child inherits a combination of the genetic characteristics, vision, and metabolism from both of the parents. So that's how it works. Let's see what's the effect then in our society. So we do here, we do the setup and then we keep on going. Maybe we can go a little bit faster and we can see first of all what our agents, wow, they explode. The number of agents really goes up, they are already in a 100 ticks, and then, well, then it seems to level out a bit. It seems to level out and stay, no, the level of agents actually then goes down. Wow, interesting. So we were almost 1,300 agents. So 1,200 and something and then we'll go down to 800 agents and then it picks up again, up again to, yeah 1,300, 1300 and something, and it does not stay there. It goes down again. We see vision again increases, it started at 3.5. Like the average you can also see vision between one and six, so 3.5 was the average and here we're already up at five. Metabolism also we said metabolism between one and four. So you started here 2.5 average and then went down, metabolisms is already optimized. We have a metabolism of one so everybody has a perfect metabolism. Good genes that these offspring inherit be at 400 timestamp. So no original parent is left over, maximum age is 100. Yeah, the vision stills seems to evolve and we still have these fluctuations maybe accelerate a little bit to see these fluctuations. Do they seem to level out over time? If you go fast and faster, this interface won't update anymore, but you can see by these sliders that the data is still accumulated, the data that we simulate and it goes. No, it doesn't really become more narrow, it fluctuate between 1,300 and 800, that's our fluctuation. Evolution keeps on pushing, our vision goes up and it seems also importance if we are maximizing before timing out, we're maximizing our vision here we go all the way up to six. Six is the maximum vision that we gave our agents and, where we are at, we evolve it all the way our society having an optimally society in terms of their vision and the metabolism it still keeps on fluctuating. Interesting, where do these fluctuations come from? What do you think? Why does it fluctuate up and down? Mine it's a predator-prey dynamic Lotka-Volterra these are the two researchers who basically work that out. These visions you often see that in predator-prey systems and ecological systems for example, it's basically it goes up when you produce a lot of children and then you deplete the resources. It's the dependency on the resources because you basically have overpopulation. You have too many people now. So we overpopulate the earth, our artificial earth here and with that, resources become scarce and therefore the population cannot keep up with. That's the average here in between where we fluctuate around. This is where the fluctuations are introduced by the fluctuating environment because the sugar has to grow back and if there's too many it's not enough to sustain the overpopulation, population gets reduced. Then, if there's too little there's a time lag and then it catches up. We can also see if we now, so now we maximized our vision and we maximize our metabolism right now, here the fluctuations become a little less pronounced because we have optimal society. But we can still see there's this fluctuation going up and down because the environment still needs time to grow back, our sugar patches still need time to grow back.
