Chapter 26
Animal Evolution & Diversity

Chapter Resources

Tiktaalik roseae

The on-line "home" of this transitional fossil.

Dr. Neil Shubin talks about the discovery of Tiktaalik

The Rise of Mammals
(National Geographic)

The First Primates




Q: How have animals descended from earlier forms through the process of evolution?

Think about it - The origins of the first animals are shrouded in mystery. Since Darwin, paleontologists have known, based on fossil evidence, that many modern multicellular phyla first appeared during a geologically brief period called the "Cambrian Explosion" between 530 and 515 million years ago. How could so many kinds of animals evolve so quickly?

Key Questions Include:

When did the first animals evolve?
What does the cladogram of invertebrates illustrate?
What are the most ancient chordates?
What can we learn by studying the cladogram of chordates?
What characteristics do all primates share?
What are the major evolutionary groups of primates?
WHat adaptations enabled later hominine species to walk upright?
What is the current scientific thinking about the genus

SciLinks: Classifying Animals
SciLinks: Human Evolution

Fossil Quest

To Josh and Pedro, it sounded like a great summer trip: fossil hunting. They would be outside, and the trip would look good on college applications. But where should they go? Both boys were interested in looking for fossils, but where could they go? Were there any good sites in the United States?

Click Here for the complete Chapter Mystery

New Fossils update the Human Family Tree (NPR)