48 - Bioluminescence

Abstract

This chapter describes that the emission of visible light by living organisms is an unusual phenomenon, both in terms of its relative rarity and with respect to the biochemical and regulatory mechanisms involved. But where it does occur, bioluminescence is spectacular and is inferred to have functional importance—a consequence of the fact that another organism detects and responds to the light. The uses of the light are classified under three headings: defense, offense, and communication. Light is used defensively to startle or frighten, to divert predators, as a decoy, or to provide camouflage. Offensively, light is used as a lure, to attract, and convert would-be predators into prey. Communication occurs in courtship and mating displays. The single most striking aspect of bioluminescence is its wide and diverse phylogenetic distribution and independent evolutionary origin of different systems. The chapter also discusses that bioluminescence is an enzymatically catalyzed chemiluminescence, a chemical reaction that emits light. The enzymes involved are all referred to generically as luciferases because they are not conserved evolutionarily, and are, thus, structurally different in different groups of organisms.