University of California
Ucmp: Hot Blooded or Cold Blooded?
An easy-to-understand explanation of what it means to either hot- or cold-blooded.
Palomar Community College District
Palomar College: Class
In the animal kingdom, there are seven living classes in the phylum Vertebrata. The Palomar College shares detailed information on each of these classes. Includes examples and photos as well as a follow-up quiz.
Biology 4 kids
Biology4 Kids: Bird Anatomy Beautiful Birds
Next to fish, birds are the most abundant vertebrates around. Take a look at the physical traits of birds and how well they adapt to their environments.