From New Scientist: Why Darwin was wrong about the tree of life
Growing evidence is showing Darwin's idea of life as a growing, branching tree is too simple by spades, mostly because of RNA and DNA research. This article goes into detail about endosymbiosis and the development of eukaryotic cells, horizontal gene transfer, viable hybrids, and DNA implantation by viruses. There's even the discussion of the possibility that animals with distinct and completely different larvae and adult stages could be the descendants of two very different species. Very interesting.