"We all know Charles Darwin as the founder of the theory of evolution. Less known is that 125 years ago, he was the first to show the importance of burrowing earthworms. He himself thought of this as a nice, but not very important subject. Researchers of the Netherlands Institute of Ecology (NIOO-KNAW) now provide proof of the contrary. Burrowing organisms are not only real “ecosystem engineers”, but the digging has also played a crucial role in the evolution of the modern animal forms. In the December issue of the scientific magazine TREE they put it this way: ‘Darwin would have been amazed!’"...more there

Here is the full paper in PDF Bioturbation: a fresh look at Darwin’s last idea