The National Science Foundation's "Tree of Life Web Project" is a collection of information about biodiversity compiled collaboratively by hundreds of experts and amateur contributors. Its goal is to contain a page with pictures, text, and other information for every species and for each group of organisms, living or extinct. Connections between Tree of Life web pages follow phylogenetic branching patterns between groups of organisms, so visitors can browse the hierarchy of life and learn about phylogeny and evolution as well as the characteristics of individual groups."

You can explore the Tree of Life Web page by visiting The Tree of Life

The Tree of Life project estimates that there could be anywhere from 5 million to 100 million species on the planet, but science has only identified about 2 million. (MSNBC.com)

This is an incredible number of organisms with many more yet to be discovered! Scientists want to study these organisms to better understand how they are alike and different as well as what makes them unique. These scientists (taxonomists) group organisms according to their characteristics and then name them. Taxonomy is the branch of biology that deals with classifying and naming organisms.

There are six major kingdoms that fall under the three domains that organisms can be grouped into. Each of these kingdoms has distinct characteristics. Classification starts with these criteria:

1. Number of Cells (Unicellular or Multicellular)
2. Type of Cells (Prokaryote or Eukaryote)
3. Method of Nutrition (Autotroph or Heterotroph)

Let's review the important vocabulary by playing the following game.