Not long ago, anthropologist Berhane Asfaw reported the discovery of a 4.2 million-year-old humanoid fossil in northeastern Ethiopia that “helps fill in the gaps of how human ancestors made the giant leap from one species to another” (MSNBC, internet edition, April 12, 2007). In 2006, a research team led by biologist Neil H. Shubin discovered in the Canadian Arctic the fossils of a 375 million-year-old amphibious fish they call the “missing link” between aquatic and terrestrial life forms. Elsewhere, biologist Mark Sidall has spent a good part of his adult life painstakingly reconstructing the evolution of the leech (The New York Times, internet edition, February 7, 2006). Thanks to technological advances like DNA sequencing, and the great lengths to which he has gone to collect farflung specimens around the globe, Sidall has traced the modern-day leech to its “ur-form”—a worm, millions of years ago, that began feeding off the surfaces of fish and crustaceans. Finally, in the latest of a spate of research findings recently published, a team of scientists led by microbiologist Abderrazak El Albani reported discovering fossils that may have been the earliest multicellular life on earth, dating back 2.1 billion years, when the earth experienced what is known as the “Great oxidation event” (MSNBC, internet edition, July 2, 2010).