What Do "Living Fossils" Mean for Evolution?

While some Darwin-critics make a big deal about so-called "living fossils," I've never discussed them much because it's never been entirely clear to me what they show, whether for or against neo-Darwinian evolution. Living fossils are of course organisms that have not changed at all over long periods of time. In some cases, such as the horseshoe crab, the coelacanth, or the ginkgo tree (pictured above), these species seem to have remained virtually the same for hundreds of millions of years....