From blue-green algae to the bald eagle, there are over a million known species on our planet Earth. This amazing array of life, or biodiversity, is everywhere you look—it’s even in places you can’t see, like deep underground.

Wherever they’re found, all living things are related because they all share a common ancestor. To show how species are related, scientists create diagrams called cladograms. Like a family tree, a cladogram shows close and distant relatives. Scientists call the family tree for all species on Earth the "Tree of Life."