Welcome to the Selection and Mutation Series

This is a work in progress and updates will be made frequently.

The models in this section are part of a series on selection and mutation. Each model highlights a specific feature of reproduction, selection, and mutation. The following list gives a short description of each of the models. For more in depth information see the page for each model.

Introductory Model - Rabbits and Grass
This model explores a simple ecosystem made up of rabbits and grass. The rabbits wander around randomly, and the grass grows randomly. When a rabbit bumps into some grass, it eats the grass and gains energy. If the rabbit gains enough energy, it reproduces. If it doesn't gain enough energy, it dies.

Asexual - No Selection
This model deals with the question, What would happen to the population if all the rabbits were not identical? Imagine that the rabbits differed in one genetically determined trait, and that the distribution of that trait was random over a given range. What would happen to the distribution of that trait in the rabbit population over time?

Asexual - Selection
In this model, there is a gene that determines a trait that may influence a rabbit’s fitness. This gene, the metabogene, determines a rabbit’s rate of ‘metabolism’. In this simulation, ‘metabolism’ is a measure of how fast a rabbit moves and uses ‘energy’. The metabogene has a numerical value between 20 and 100. Each rabbit begins the simulation with a randomly given metabogene value.The metabogene also determines a rabbit’s color. Color is strictly cosmetic. It does not determine fitness.

Asexual - No Selection and Mutation
In this model (as in asexual no selection model) the genetically determined trait is color. Each rabbit begins the simulation with a randomly given color that is determined by a colorgene. The colorgene has a numerical value between 20 and 100. The color of the rabbit does not affect its fitness in this environment. That is, the color is cosmetic.

Sexual - No Selection
What happens to the population of rabbits over time? What would be the population dynamics if the rabbits reproduced sexually? Imagine that the rabbits differed in one genetically determined trait, and that the distribution of that trait was random over a given range. What would happen to the distribution of that trait in the rabbit population over time?

Sexual - Selection
This model is identical to the asexual selection model, except here the turtles reproduce sexually. Again observe what happens to the distribution of the metabogene in the population of successive generations.

Sexual - No Selection and Mutation
In this model (as in Sexual No Selection model) the genetically determined trait is color. Each rabbit begins the simulation with a randomly given color that is determined by a colorgene. The colorgene has a numerical value between 20 and 100. The color of the rabbit does not affect its fitness in this environment.

Sexual - Selection and Mutation
Every time two rabbits reproduce there is a chance (based on the "mutation-rate" slider that the offspring will have a random mutation in the colorgene and thereby have a different metabolic rate than their parents.