While looking at data to use for this section, I stumbled upon a couple of samples where the tree of life was visualized. The tree of life contains a complete (or partial) taxonomy of all the living organisms in the world, from the smallest bacteria to apes and humans. The following image nicely shows what such a visualization could look like (from http://www.botany.wisc.edu/):
While this data is well-suited for visualizing in a tree, finding data in a form that can be visualized like this is a bit more difficult. Eventually, I found the Integrated Taxonomic Information System (ITIS), which provides much of the raw data for the Encyclopedia of Life (http://www.eol.org). While the Encyclopedia of Life provides a nice view on this data, it doesn't allow you to download trees or associated data. Luckily though, ITIS provides access to the raw data, and also allows you to download complete...