The primary sources for this illustration are:

•  The journal Science (13 June 2003: Vol. 300. no. 5626).
• The NIH on-line taxonomy browser ( http://www.ncbi.nlm.nih.gov/Taxonomy/ )

The picture below is JPEG.  A higher quality PDF version is  here  (3 MB) .  Feel free to download the PDF and take it to a print shop (Kinkos will work) and get it printed as a large poster (it prints 24" x 48").   Please leave my name on the poster.  

Keywords:   Tree of Life, evolution, cladogram, cladistics, darwin, phylogenetic tree, phylogenetics, evolutionary tree, darwin, poster.  

Permission to copy and modify this illustration is given under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License (http://creativecommons.org/licenses/by-nc-sa/3.0/us).   To paraphrase that license:  you must keep my name Neal Olander in any derived documents you create;  you cannot sell your derivative work commercially; and any derivative copies you create must be distributed with the same CC-by-nc-sa license.