http://www.glencoe.com/sites/common_assets/science/virtual_labs/LS06/LS06.html

or

https://phet.colorado.edu/en/simulation/natural-selection

or

http://www.sciencechannel.com/games-and-interactives/charles-darwin-game/

or

http://sciencenetlinks.com/esheets/nowhere-to-hide/