Evolutionary History and Relationships
Evidence of Common Ancestry and Diversity
Dinosaurs to Birds Phylogenetic Tree
There is debate in the scientific community between the paleontologists that think birds are direct
descendants of dinosaurs while others think that birds and dinosaurs evolved separately from a
common ancestor. For those who think that birds are dinosaurs, their argument is as follows.
Birds are thought to evolve from coelurosaurs, members of the same group as Velociraptor and
Tyrannosaurus. Some of the similarities between birds and dinosaurs are the large eye openings;
hollow, thin bones; and an S-shaped curved neck.
The diagram below shows a possible phylogenetic tree that traces the evolution of theropods (the
class of dinosaurs that may have evolved into birds) into Aves (the class of modern day birds).
Compare the bones of each skeleton and determine 2 similarities and 2 differences between each.
Fill out the graphic organizer on the next page.
1
Evolutionary History and Relationships
Evidence of Common Ancestry and Diversity
Dinosaurs to Birds Graphic Organizer
Coelophysis to Archaeopteryx
Similarities
Differences
Archaeopteryx to Mononykus
Similarities
Differences
Mononykus to Iberomesornis
Similarities
Differences
2
Evolutionary History and Relationships
Evidence of Common Ancestry and Diversity
Dinosaurs to Birds Graphic Organizer, continued
Iberomesornis to Ichthyornis
Similarities
Differences
Ichthyornis to Aves
Similarities
Differences
3