University of Southern California
Structure of Matter: Animals
A slide show that demonstrates the development of physical structure in the animal world, moving from sponges through mammals.
Curated OER
Frozen Wood Frog
This site describes how slimy amphibians crawled and swam on the Earth 190 million years ago. They have adapted in many different ways to become the way they are today. Use this site for more information about amphibians.