As organisms diversified on planet Earth, some branches of the tree of life became exceptionally diverse, others far less so. Still others went extinct. Why evolution favored certain groups over others is a long-standing question in evolutionary science. As organisms diversified on planet Earth, some branches of the tree of life became exceptionally diverse, others far less so. Still others went extinct. Why evolution favored certain groups over others is a long-standing question in evolutionary science. Plants & Animals Evolution Phys.org – latest science and technology news stories