Myth of the Missing Link

News reports have buzzed about about the discovery of a 47-million-year old, cat-sized fossil dubbed Ida, whose amazingly detailed and well-preserved remains have shocked and delighted scientists around the world. The news has been heralded by many in the media as the long-sought "missing link" in the chain of humans' ancestry and primate evolution.

Though the term "missing link" has currency with the public and pundits (not to mention creationists), to professionals and paleontologists, it is a myth.

The fact is that there is no such thing as "the missing link" between different stages of evolution. Many, many transitional fossils have been discovered, for example showing bone and lung development from one species to another. Of course, any given fossil (including the much-celebrated Ida) is simply one example caught in time, one snapshot of the transition process, not a missing piece that completes the chain.

Picture fossils like visual images of a horse race, and scientists as people trying to understand what happened between the start and end of the race.

Because fossilization is relatively rare, the record is incomplete, and scientists do not have a continuous film or video documenting every single step of the finish. But they do have a series of dozens or hundreds of individual photographs of the final stretch taken at differen times, giving a very complete picture of the transition between the start and finish of the race.

There is not one identifiable missing photograph or "missing link" in the process, and the transition will never show an exact halfway point between two anatomically different forms. Ida may be one of the most important links in the transitional fossil record, but she is not "the missing link."

Benjamin Radford is LiveScience's Bad Science columnist.