Fossils help us to understand how life forms are related.
 

It is not easy to tell exactly how these four animals are related. However, by comparing features of these fossils and living organisms we can get a clearer picture.

Deinonychus © 1995 B. Cunningham; Archaeopteryx by Dave Smith, © UCMP; Grey Crowned Crane (Balearica regulorum) and Bald Eagle (Haliaeetus leucocephalus) by Gerald and Buff Corsi, © 2003 and 2004, respectively, California Academy of Sciences.