Bioluminescence dates back to the Cambrian period, 540 million years ago, and may have been used for communication, courtship and camouflage among the earliest ocean creatures. A new study shows that bioluminescence in marine life dates back 540 million years, turning the clock back a staggering 300 million years on previous estimates.

“We often think of the deep sea as being light-limited, and that’s true from a sunlight perspective, but many organisms in the deep sea produce their own light through a simple chemical reaction known as bioluminescence,” said study author Andrea Quattrini, Curator of Corals. at the Smithsonian National Museum of Natural History, Live Science said in an email.

Bioluminescence (or glow in the dark) is common in marine life, including fish, coral, jellyfish, and crustaceans. On land, this phenomenon is observed in many animals, including fireflies, insects, fungi, algae, and some bacteria.

Scientists believe life evolved bioluminescence to aid in communication, courtship, hunting, and as a means of camouflage.

Finding similarities in genetic sequences between groups can provide clues about the evolutionary history of a trait or trait. Bioluminescence involves a highly inherited protein called luciferase, and the phenomenon is now thought to have evolved around 100 times. In a new study published Wednesday, April 24, in the journal Proceedings of the Royal Society B: Biological Sciences, scientists reveal the origins of this phenomenon. Bioluminescence in a group of marine invertebrates known as octocorallia or octocorallia.