bioluminescence

Bioluminescence is the production of light by an organism as the result of a chemiluminescence reaction.

It occurs in a wide variety of organisms, including marine vertebrates and invertebrates, terrestrial arthropods such as fireflies, some fungi, and microorganisms such as some bacteria and dinoflagellates. In some animals, the light is bacteriogenic, produced by symbiotic bacteria such as those from the genus Vibrio; in others, it is autogenic, produced by the animals themselves. Bioluminescence has evolved independently at least 94 times, first emerging in octocorals some 540 million years ago.