7.5.3 Natural Selection and Evolution
Life on Earth has been around for over 3 billion years. (Who knows how long it has existed elsewhere in the universe?) Starting from the smallest unicellular bacteria billions of years ago, life has adapted and evolved into wondrous forms of unimaginable beauty and diversity. Looking at the existing species of the world is only a glimpse to the 99% of extinct creatures that have once inhabited this Earth, from the dinosaurs to our ancient primate relative, Ida.

How does life change and adapt over time, to eventually create new creatures and new classes of animals? In natural selection, mankind chooses traits it desires (domesticated fox). Through natural selection, the fittest survive and beneficial mutations are passed on to the offspring (ancient horses).

Check out more information at:

http://www.wellcometreeoflife.org./interactive/
http://www.pbs.org/wgbh/evolution/library/03/4/l_034_02.html

Games and Simulations:
Evolution Lab
http://biologyinmotion.com/evol/index.html
Evolution Quiz
http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel/environment/evolutionact.shtml
Guess the Embryo
http://www.pbs.org/wgbh/nova/beta/evolution/guess-embryo.html