Analysis and Results

Genetic characteristics and natural selection

Numerical characteristics: agility, bigness, speed, fertility

We saw that with time there is a natural selection between the creatures, and consequently their characteristics evolve: all numerical genes converge on a certain value, and the percentile distribution of values decreases.

From an evolutional point of view, creatures tend to develop their speed (faster creatures can reach more quickly food, even if it is more distant) and become at the same time bigger, to eat more food each time. Because of faster creatures have a greater survival ability, the speed-graph clearly increases.

On the contrary, the bigness-graph shows a relevant decrease at the beginning of the simulation. This is caused by the fact that bigger creatures are slower (as it can be seen in the equation: speed= agility/bigness) and so are disadvantaged. However, bigness values do not drop under a certain level, because bigger creatures can eat more food in the chunks.

Fertility generally increase with time, even if it represent the minimum number of ticks that there must be between two consecutive reproductions. This is explained by the fact that creatures with a greater value of fertility need less food to reproduce themselves, because this is inversely proportional to the gene itself.

Mendelian characteristics: temperature resistance

We divided the territory into 8 classes of climatic frequency e we studied how many creatures were in each class, drawing the graphs for each temperature phenotype (c, l, N). Each bracket is coloured with 8 different shades from red (hot climate) to blue (cold climate).

It has been observed that creatures with c phenotype, that are fitted for hot climate, usually placed in hotter chunk; on the contrary creatures with l phenotype placed in cooler ones. The others (N, n) lived in intermediate zones. Figure shows the climate map of the territory and the disposition of coloured creatures coherently with their phenotype.

The division of creatures based on temperature can be considered a sort of allopatric speci- ation, because, even if in theory able to reproduce themselves, a creature with c phenotype and a creature with l phenotype cannot meet each other, because living in temperature-conflicting zones.

Control-genes: Hardy-Weinberg principle and Genetic Drift

A different discussion mast be done with the two genes that have a control function with no phonotypical effects.

The numerical gene numcontrol has not a univocal behaviour (always increasing, decreasing or constant), but varies in each simulation.

Moreover there is no reduction of the percentile distribution as in other numerical genes. Considering the Mendelian gene mndlcontrol, it can be observed that its distribution in the territory is homogeneous on temperature varying, for both the two phenotypes, A dominant and a recessive, as in Figure. We also controlled if it respected the Hardy-Weinberg principle. The condition for this equilibrium are: no mutations, casual reproduction, a big population, no gene flow and absence of natural selection with that gene. We saw that this character does not respect this equilibrium, because of the small population (only 150 creatures in the world) and the unstable trend due to the random food consumption in some of the areas at certain ticks. We can say that this character is subjected to a genetic drift.

Territory distribution of creatures considering the food

As we did for temperature, we divided the territory into 8 classes of foodmax quantity in each chunk. We represent the graph with the number of creatures for each class over time. We coloured the brackets with 8 different shades: darker ones has less food, lighter ones has more.

The graph in Figure 11 shows that creatures are generally in lighter brackets. Figure shows the distribution of creatures on the territory in a certain tick.

Demographic trend

Birth and death cycle

The population graph follows a sinusoidal trend with a creatures increase of about 100 organisms. There is a mechanism of auto-regulation that effects when there are less creatures than that world can sustain, causing many reproductions between creatures and an increase of population number. But, at this point, there are much more creatures than food availability, and we can observe a demographic fall. Then the cycle restarts.