This activity has students build, evolve, and modify paper-and-straw birds to simulate natural selection acting on random mutations and discover that: all organisms, including humans, retain evidence of their evolutionary history; form is often linked to function; mutations are random, but selection is not; and selection is dependent on many factors. In addition, they will realize that adaptations often persist in a population because they are in some way advantageous and are preserved in a population by natural selection. Also, students should see that inherited characteristics affect the likelihood of an organism’s survival and reproduction, natural selection acts on individuals and populations in a nonrandom way, organisms cannot purposely produce adaptive mutations in response to environmental influences, and species have evolved as a result of natural selection acting upon inherited traits in changing environments. This site contains a list of materials and all information needed to complete this activity.