Just click on Start to see the simulation of the peppered moth. Once it's going, try making the environment darker (more soot) and watch how the proportion of dark moths (represented by the small circles) increases. Now make the environment less sooty (simulating the great post-industrial-revolution cleanup) and notice the resurgence of the light moths.
Darwin is an open-source Java framework for solving problems using evolutionary computation.
The Peppered Moth Example is a biological example of an evolutionary computation and utilizes a sex-based
evolutionary mechanism.
The peppered moth illustrates a very fast adaptation to differing environmental
conditions, and was noted and observed during before, during and after the
early part of the industrial revolution in Britain.
The genome of the peppered moth is diploid, i.e. it uses "normal" sexual reproduction.
The "carbonaria" (dark-wing-making) allele is dominant but to start, the likelihood
of any particular gene having the carbonaria allele is only 25%.
The allele which gives rise to the lighter color is called the "typica"
allele.
The control population generally maintains roughly the original 25% proportion of carbonaria
alleles and the computation parameters allow the experimental population (where you can
control the sootiness) to occasionally find a mate from the control population.
This simulates the rest of the world, as far as the moth populations are concerned.
However, there is a further mechanism in play here: approximately once every one hundred
gene copies results in an error - and the other allele is used.
This tends to ensure (insure if you're in the US) that no allele ever dies out completely.
If you want to try different formulas for mate choice and fitness of wing color in soot densities
you may go to the options tab.
For more information on the (natural) Peppered Moth see Wikipedia.
If you don't see a grey box titled "Darwin Visualization Applet: Peppered Moth Evolution",
and a "start" button in the lower left-hand corner, then something didn't work right
in your browser.
You need to have the Java HotSpot client (at least version 1.5.10) installed as a plugin in your browser
(if you don't have it the browser should offer to get it for you).
If your browser asks you if you'd like to install it, you should say yes - it won't
do your system any harm. Running applets is perfectly safe!
If you are running Internet Explorer, you will have to click space or return before
the applet activates.
Running Mozilla browsers (Firefox, etc.) should be straightforward.
Of course, it could be simply that you have "Java" turned off in your browser options.
In IE, it's under Tools/Internet Options/Advanced and the checkbox is called "Java (Sun)".
In Mozilla/Firefox, it's under Tools/Options/Content and the checkbox is called "Enable Java".
If you open the "Java Console" in your browser (tools menu for IE) you can see some extra information
particularly when you stop the simulation.
Last Update: 2007/03/01 By: Robin Hillyard