Bioluminescence, the eerie, beautiful phenomenon that makes living things glow, is much older than previously thought, according to a team of researchers who recently studied the ability of octocorals.
Despite their name, octocorals are not closely related to corals. You are a Group of marine invertebrates that live and shine in the earth’s oceans. However, according to a study, octocorals have been lighting up the seas for at least 540 million years published today in the Proceedings of the Royal Society B.
“Some animals that could detect light evolved in the Cambrian. Therefore, our research suggests the possibility that interactions with light between octocorals and other species occurred at a time when the animals were rapidly diversifying and occupying new niches,” said Andrea Quattrini, a zoologist at the Smithsonian Institution and the study’s senior author , in an email to Gizmodo. “We now know that bioluminescence is a crucial form of communication for many animals in the family tree of life, and particularly for those found in the deep sea.”
Bioluminescence in octocorals happens thanks to an enzyme called luciferase, which catalyzes a reaction that produces light. This is a different process than bioluminescence in animals like fireflies, Quattrini said, which use magnesium and ATP to turn the flickering on and off. Last year, another team of researchers discovered this Biofluorescence is much more common in mammals than previously thought – although biofluorescence occurs under an external light source and is not to be confused with bioluminescence, in which reactions within the living thing itself cause it to glow.
Bioluminescence has evolved independently at least 94 times. according to a 2020 study. The oldest known example was generally believed to be a type of small crustacean called ostracods.
To determine when bioluminescence arose in octocorals, the group relied on one Evolutionary tree of animals made by a separate team that included Quattrini in 2022. They then placed two octocoral fossils on the tree to find out when the animals’ lineages diverged and mapped the bioluminescent species still living on the tree. Finally, they analyzed the tree using ancestral state reconstruction, a method that allowed them to determine the approximate time in deep time when the animals’ common ancestor lived. They arrived and produced about 540 million years ago, just before the Cambrian explosion all sorts of crazy life forms.
To determine when bioluminescence arose, researchers will have to rely on statistics for now. But “perhaps one day,” Quattrini said, “the methods of ancient DNA techniques will be so advanced that we can detect DNA, like that of luciferase, in really ancient fossils.”
The The oldest DNA found so far is around 1 million years old and came from mammoth remains on Wrangel Island, where the animals survived until around 4,000 years ago. The oldest luminous octocorals were much, much older, but at least we now have a new era of superlatives for such a remarkable feature of Earth’s inhabitants.
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