Description of the Tree of Life Project

Each page presents information about a particular group. The beetle page, for example, shows pictures of beetles, introduces them, provides a description of the key characteristics, and so on. The start of the beetle page looks like this:

Each completed page has a number of standard elements. At the top and bottom of each page are toolbars that aid in navigation through the project, as described on the Tree of Life Help document. Below the top toolbar is the name of the group of organisms shown on the page, and pictures of representatives. Following this is a diagram showing the phylogenetic tree of the group, or, if no appropriate phylogenetic hypothesis is available, a simple listing of subgroups (that is, a classification). After the tree or classification additional information about the group is given, including an introduction, description of characteristics, discussion of phylogenetic relationships, links to other Internet sites containing information about the group, literature references, and so on.

A critically important element of each page is the tree or phylogeny. On the beetle page, the tree shown looks like this:

At the left side of the tree is the root (which is symbolized as <<==). Time in this diagram runs from left to right, with the older events being near the left hand side of the tree. This hypothesis about the relationship of the major lineages makes the following claim: Beginning from the root, the ancestral beetle lineage gave rise, on the one hand, to members of the extinct Paleozoic family Tshekardocoleidae, and on the other to the ancestor of modern beetles. This ancestor in turn split into a species that gave rise to the suborder Polyphaga (which itself further diversified, as shown on the polyphagan page, into many thousands of species), and another species that was the ancestor of the suborders Archostemata, Myxophaga, and Adephaga. This latter ancestor further differentiated into those three suborders, which further diversified into the species we see today (as illustrated on the pages for each of those suborders). (Even though it isn't shown on this diagram, these splits between the suborders probably happened in the Permian period, before the time of the dinosaurs.)

The tree on each page is linked to the trees on other pages, so that combined, the pages present current ideas about the entire evolutionary tree of living things (at least to the extent that the project is completed). Touching on the names of groups at the tip of a tree (called the "terminal taxa" of the tree, which in the example presented above represent the subgroups of beetles) will take you to the page for those terminal taxa. For example, if you touch on the terminal taxon "Adephaga" (a group of beetles including ground beetles, tiger beetles, whirligigs, etc.) on the beetle page, you would be taken to the page for Adephaga, the start of which looks like this:

Touching on the name Carabidae on this page's tree would then take you to the carabid beetle page, and so on.

The tree or classification this thus the navigational center of the page. Touching on the names at the tips of the tree takes one up the branches of the Tree of Life. To go down the branches, toward the root of the entire Tree, you can touch on the root of the tree on each page. For example, touching on the root of the beetle tree will take you down to the page for the larger group of insects that includes beetles. The connections of pages around the Coleoptera page can be summarized as in the following diagram:

The root page of the entire Tree is housed on the home computer in Tucson, Arizona. The project is distributed across various computers (web sites), so that any one computer will house only a portion of the Tree's branches. Towards the tips of the tree we envisage many hundreds of sites maintaining phylogenetic and other information concerning specific groups of organisms. And throughout, there would be links to other information on the Internet for that group.

The project has many contributors, with specialists on many groups working on the pages for the groups of their expertise. Some of these contributors are listed on the page on Participants.

We have developed tools to facilitate the building of a portion of the Tree, so that specialists on a particular group could build a page for it and link it in to the rest of the Tree of Life. Another page describes the procedures for contributing to the Tree.

The project will be continually revised, either by improvement and completion of existing pages on the Tree, or by addition of new branches to the Tree. The pages of the Tree fall into one of three categories, depending upon their status:

1. Preliminary pages, under construction. These are pages that contain only a partial or preliminary classification or phylogeny of a group, or which are in the process of completion. The pages might be without a stated author, and may contain no information other than the phylogeny. Many pages in the Tree are currently in this category.
2. Authored, completed, but non-refereed pages. Once a page is complete, it could have the "Page Under Construction" icon removed from it, and the authors' names added.
3. Authored, completed, peer-reviewed pages. Eventually a system may be established by which a page can be submitted for peer-review. If accepted, the page will be so-marked.