From the New Scientist article:
The tree-of-life concept was absolutely central to Darwin’s thinking, equal in importance to natural selection...Without it the theory of evolution would never have happened.
http://www.newscientist.com/article/mg20126921.600-why-darwin-was-wrong-about-the-tree-of-life.html
January 2009 issue of New Scientist:Snoogums, you didn't even read it did you? I know it hurts your widdle head snoogums but science *evolves* just as species do.