Sheppard Software has an Animal Characteristics game where you sort characteristics into respective bins labeled Mammal, Reptile, Bird, Fish, and Amphibian:
http://www.sheppardsoftware.com/content/animals/kidscorner/games/animalclassgame.htm
PBS’s Dogs Around the World has an interactive where you match dog breeds to the environment they were bred for:
http://www.pbs.org/wgbh/nova/nature/dogs-around-world.html
PBS Kids has a Dog Breeding game where you try to breed Border Collies with the desired traits given:
http://pbskids.org/dragonflytv/games/game_dogbreeding.html
The UK Science Museum has a game called “Thingdom” which is a similar concept to above, but geared for 11-16 year-olds with more opportunity for experimentation:
http://www.nationalmediamuseum.org.uk/scim/educators/classroom-resources/online_games_websites/thingdom
[Disclaimer: I thought the game was very tastefully done, but parents may want to preview it in advance, just in case.]