Bringing Homologies into Focus

Abstract

Anyone who has skimmed a high school biology textbook will be familiar with the iconic examples of homology that seem inseparable from any explanation of the term: the limb structure of four-legged animals, the human tailbone and the more elaborate tail of monkeys, and the remarkable similarities among the embryological development of fish, birds, and humans. These same examples make their way from edition to edition, along with the classic illustration of an analogous structure: the wings of butterflies, birds, and bats. But is that really all there is to say about homologies and analogies? Several articles in this issue discuss these concepts more deeply in the context of eye evolution (Gregory 2008; Oakley and Pankey 2008; Piatigorsky 2008). Homologies and analogies, it seems, are not a black and white issue - especially when it comes to vision.