In recent decades, the study of evolution has been greatly advanced by the use of DNA analysis. Formerly based on fossils, geology, modern observations and a good deal of speculation, we now find that some of our past evolutionary assumptions were incorrect. But such is the history of science; as new information and tools become available, our knowledge and our theories change.
Watching sea lions romp in the surf, one might naturally assume that they are most closely related to otters; and who hasn't thought of a walrus as they watched a manatee loll among the sea grass? In fact, as DNA studies have shown, pinnipeds (seals, sea lions and walruses) are most closely related to bears, having diverged from a common ancestor some 25 million years ago. Manatees, on the other hand, are related to elephants and cetaceans (whales and dolphins) diverged from cows and pigs about 50 million years ago.
Of course, many humans dismiss the idea of evolution altogether. For them, the story of Noah's Ark provides the only explanation they will ever need.
