It is commonly stated by anti-evolutionists that there are no known transitional fossils. This position is based on a misunderstanding of the nature of what represents a transitional feature. A common creationist argument is that no fossils are found with partially functional features. It is entirely plausible, however, that a complex feature with one function can adapt a wholly different function through evolution. The precursor to, for example, a wing, might originally have only been meant for gliding, trapping flying prey, and/or mating display. Nowadays, wings can still have all of these functions, but they are also used in active flight.
Although transitional fossils elucidate the evolutionary transition of one life-form to another, they only exemplify snapshots of this process. Due to the special circumstances required for preservation of living beings, only a very small percentage of all life-forms that ever have existed can be expected to be discovered. Thus, the transition itself can only be illustrated and corroborated by transitional fossils, but it will never be known in detail. However, progressing research and discovery managed to fill in several gaps and continues to do so.
