Globio
Glossopedia: Species
A species is defined as a single kind of animal, plant or creature. Examples of different species are given and how the many species that exist relate to biodiversity. Scientific naming conventions are introduced.
The Franklin Institute
The Franklin Institute: Living Things Families
What do centipedes and crabs have in common? What's so special about a backbone? Check this site out from The Franklin Institute if you are interested in biology and classification.
Biology 4 kids
Biology4 Kids: The Top Four Kingdoms
Read about the four most familiar kingdoms: fungi, plant, animal, and protist.
Other
Panhandle Area Educational Consortium: The Six Kingdoms of Life [Pdf]
Scientists look at the evolutionary history of organisms to divide them into kingdoms. For awhile, there has been 5 kingdoms, but many scientist are now using 6 kingdoms.
National Institute of Educational Technologies and Teacher Training (Spain)
Ministerio De Educacion: La Clasificacion De Los Organismo
This unit will describe the five kingdoms and their main characteristics. It includes 20 interactive activities.
Other
The Domains and Kingdoms of Life
This site is a description of the history behind the 5 Kingdom system suggested by Robert Whittaker. An extensive list of resources is included.