The role of chance in evolution

This animation presents a simplified simulation that illustrates the importance of chance in the evolution of a small, isolated population.

Here we observe the genetic diversity involved in a characteristic: the color of a fictional species of flower.

The selection carried out on the flower population is represented by rabbits, who eat the flowers without any particular preference for their color. This selection (a random draw) is thus done by chance and is not to the profit of a form of flower that is better adapted to its environment.

At the start, the population has 6 flowers of 6 different colors.

Each of these flowers reproduces to produce two "daughter&rdrdquo; flowers. There are thus 18 flowers.

The “daughter” flowers are the same color as their “mother” flower (in effect, we are assuming asexual reproduction).            

Then the random draw  by the rabbits makes 12 flowers disappear.

There remain only 6 flowers, which will reproduce again, etc.

The principle behind this simulation is to carry out a certain number of cycles of reproduction/random draw. We see that the greater the number of generations, the more the diversity in flower color diminishes.

Click  on the “Reproduction” button to generate two plants that are genetically identical to the “mother” plant.

Click  on “Random Draw” to have 12 out of 18 flowers, selected at random, disappear.

After each reproduction/random draw cycle, the flower population remains unchanged (6 flowers)