NOVA Online (see text links below)
The Missing Link  

Evolution in Action Go to Evolution in Action

Flash required

Evolution in Action
by Rick Groleau

It's sometimes convenient, when trying to make sense of evolution, to think of changes within a species as having a purpose, as though mother nature has some intended goal that she sets out to achieve. "The bacteria want to survive," someone might reason when thinking about the declining effect of antibiotics, "and so they evolve into resistant strains." Of course, there is no purpose in evolution, just random mutations within DNA, most of which are detrimental to the survivability of an organism, some of which are beneficial. Because the beneficial changes can help the organism to survive, these changes are the ones that tend to carry on in subsequent generations.

This interactive feature shows how random mutations can lead to species-wide change. The "world" presented in this feature is abstract—colored creatures placed within a colored environment. In a sense, these creatures are alive. They are born, they produce offspring (some with mutations), and they die off.

To help see the connection between the virtual world of this feature and the real world, try imagining that the colors represent specific characteristics. For instance, a shift in background color might signal a change in temperature, while each creature's color might indicate how well or how poorly that individual copes with a given temperature. Or imagine that a change in background color represents a slight change in the shape of a certain flower's blossom, while the creatures' colors denote birds with differently shaped beaks, which may or may not be more effective at retrieving the flower's nectar.

So how will your creatures evolve as their environment changes? See for yourself.

Flash is a plug-in that allows for increased interactivity. If you can see the animated boxes at left, the plugin is already installed. If you do not see the boxes, you can install the Flash plugin.

Rick Groleau is managing editor of NOVA Online.

Printer-Friendly Format   Feedback

A Brief History of Life | Diva of the Devonian
Confessions of a Preparator | Evolution in Action
Resources | Transcript | Teacher's Guide | Site Map | The Missing Link Home

Search | Site Map | Previously Featured | Schedule | Feedback | Teachers | Shop
Join Us/E-Mail | About NOVA | Editor's Picks | Watch NOVAs Online | To Print
PBS Online | NOVA Online | WGBH

© | Updated February 2002
Shop Teachers Feedback Schedule Previously Featured Site Map Search NOVA Home Site Map The Missing Link Home The Missing Link Home