Science is like a giant jigsaw puzzle with many of the pieces missing. To try to piece together how organisms are related, Museum scientists use cladistics (cluh-DIS-tiks). In this system, animals that share unique features, such as a backbone, are grouped together on an evolutionary tree called a cladogram.

Pronunciation: cluh-DIS-tiks
What It Is: a system to link organisms that have similar characteristics to a common ancestor in an evolutionary tree
Significance: gives scientists a way to diagram how animals and plants have changed over time without depending on the fossil record alone

Image credits: courtesy of AMNH.