khan acadamy

Today I worked on biology in khan academy. I learned about evolution and natural selection. I learned about how evolution is not how we just keep on changing, like if a horse wants to get apple's in a tall tree it doesn't just grow a long neck after thousand's of years and the turns into a giraffe. It evolves by small changes in the species. lets say there is 3 butterflies. The first one has green wings, the second one has yellow wings, and the last one has brown wings. The one with the brown wings will live and not get eaten because it's camouflaged. then it will mate and there babys will be brown and so on. so then we have a bunch of brown butterflies flying around that are camouflaged and can't be seen by birds and things.