Overview

EvoDots lets you explore the mechanism of adaptive evolution.

The program will create a population of dots. You will be a predator. As the dots move around the screen, you will try to eat them as fast as you can by clicking on them. After you have eaten some of the dots, the survivors will reproduce.

The population may or may not evolve, depending on the properties of the dots. EvoDots will draw histograms showing the number of dots of each type in the population. By comparing the current population to the starting population, you can see whether the population is evolving.

Click this link for a tutorial for EvoDots in PDF.

If you like EvoDots, you might like Simbio’s Darwinian Snails even more. It’s also available in an earlier version with a PDF workbook.

1) Two Explorations

EvoDots has two tabs, which let you explore different aspects of the mechanism of evolution.

The Darwin’s Theory tab opens automatically when you launch EvoDots. This tab lets explore the fundamentals of Charles Darwin’s theory of evolution by natural selection.

The Mutation’s Role tab lets you explore the role of mutation in evolution.

2) Changing properties

You can change the properties of the dots by clicking the check boxes.

For example, in the Darwin’s Theory tab, clicking on the Variable check box will turn this property on or off. If the Variable property is turned on, then when you create a new population the dots in it will be variable.

3) The properites

The properties you can alter are as follows:

In the Darwin’s Theory window the form of the dots can be variable or not and heritable or not:

• Variable: If this property is turned on, then the dots in a new population are variable.

• Heritable: If this property is turned on, then when a dot reproduces by dividing in two, its distinctive traits are inherited by both of its offspring. If the Heritable property is turned off, then when a dot reproduces by dividing in two, the distinctive traits of each of the offspring are determined at random.

In the Mutation’s Role window, the form of the dots is variable and heritable:

• With mutation or without. If the with mutation property is turned on, then when a dot reproduces by dividing in two, one or the other of its offspring may be different than the parent.

In both windows, the survival of the dots can be:

• Selective or not. If this property is turned on, then you kill dots by clicking directly on them. If the Selective property is turned off, then a randomly chosen dot is killed when you click anywhere in the box where the dots move around.

4) Running

Run the EvoDots simulation as follows:

Click on the New Population button to create a new population of dots. EvoDots automatically plots a graph showing the distribution of traits in the population.

Click on the Start button to start the dots running around on the screen. Click on the dots to kill them.

Click on the Stop button to stop the dots running around on the screen. EvoDots automatically plots a graph showing the distribution of traits in the population.

Click on the Reproduce button to make each dot reproduce by dividing in two. EvoDots automatically plots a graph showing the distribution of traits in the population.

You can change the properties of the dots any time.

You can create a new population of dots any time.

5) Options

By default, the dots you create vary in the speed at which they run around the screen. The dots also vary in color, with slower dots having cooler colors and faster dots having warmer colors.

If you click on Options next to the box of dots, you can choose to have the dots vary in other ways:

• Selecting Speed will return to the default setting, in which the dots vary in speed (and color).

• Selecting Size will make the dots vary in size. The dots also vary in color, with larger dots having warmer colors and smaller dots having cooler colors.

• Selecting Visibility will make the dots vary in color in a way that affects their visibility against the background—which can be either dark or light.

6) Learning goals

The point of EvoDots is to explore. Try different combinations of properties for the dots. Figure out when the population of dots evolves, and when it does not.

For example, in the Darwin’s Theory window:

• Will the population evolve if the traits of the dots are variable but not heritable?

• Will the population evolve if the traits of the dots are variable and heritable, but survival is not selective?

• What is different about the way the population evolves when survival is selective versus when it is not?

In the Mutation’s Role window:

• What is different about the way the population evolves with and without mutation?

• What is the best strategy for quickly evolving a population of dots optimally suited for survival? Is it better to start with a large population or a small population? Is it better to kill a lot of the dots every generation or just a few? Why?

• When survival is not selective, how often does a new mutation become common in the population?

Good luck, and have fun!

License

I make no warranties or guarantees about the quality of EvoDots or the accuracy of the simulations it runs. Please have fun with it.

EvoDots is free to use. Please share the link. You may not copy, repost, reuse, or sell EvoDots.

If you use EvoDots, or if you have comments or suggestions, please let me know with an email to herronjc at uw.edu.

Made with PixiJS, Chart.js, and flexdashboard. Thanks to the individuals and communities who created these tools!

EvoDots 2.0 © 2022 by Jon C. Herron — All Rights Reserved