Vertebrate zoology collections

Vertebrate Zoology collections at the Smithsonian's National Museum of Natural History

"Sometimes individuals with particular trait variations survive and reproduce better than individuals with other variations. Owls hunting in an area with light soil, for example, are more likely to catch dark-colored mice than light-colored mice. Soon, mice with dark coats will disappear from the light soil."

Source: http://newsdesk.si.edu/photos/nmnh_since_darwin.htm