When organisms produce their own light, it is called bioluminescence. This phenomenon, which is very widespread in nature, especially among marine animals, but also among fireflies and glow worms, appears in corals much earlier than we thought, 540 million years ago.
This is a real ancient movement of bioluminescence: the ability of organisms to illuminate from within, producing their own light, or hosting bacteria that do so, thanks to a series of chemical reactions, appeared in tiny coral reefs 540 million ago. Years ago. This is what the study conducted by researchers from the Natural History Museum found sMethsonian Institution In Washington who have just pushed back the date of the appearance of this phenomenon by 200 thousand years.
Bioluminescence is particularly widespread in the oceans; 70% of marine animals produce their own lights (not to be confused with bioluminescence, which only reflects light). But what puzzles scientists is why there are so many different ways to radiate, shine, and light up from within?
From lure to attract prey to defense technique
There are more than 1,500 species of bioluminescent fish, which produce light to hunt and find their prey or partners, but also to communicate and even to camouflage themselves. This is the case of the Hawaiian squid, which lights up thanks to luminous bacteria that live in one of its organs, in order to camouflage itself on the surface in the moonlight by erasing its shadow. Most bioluminescent marine animals live at great depths, making them difficult to study.
One of the most famous is the angler fish, whose female is equipped with a bioluminescent bait responsible for attracting surrounding prey towards her. Other animals close to jellyfish e.g mnemiopsis, absolutely dazzling; The latter has a type of photophores inside its body, transparent and gelatinous, which refracts light and produces a rainbow of light to repel predators.
There is also the world's smallest shark – barely 15cm long – Sagree the fire-bearer Which lives up to its name. Its bioluminescent organs are located all around its reproductive organs, allowing males and females to be seen from a very long distance, and attract each other to the light of their reproductive organs. Who says it's better?
They first appeared 540 million years ago
On dry land, bioluminescence is also present. We know glow worms or fireflies that emit light thanks to oxidation in their abdomen, a chemical reaction that goes back to the famous Latin word luciferin. The devil Which gives light. There are a thousand other ways to shine.
Such is the long and winding history of bioluminescence that researchers at the Washington Museum have traced using a phylogenetic tree that shows that bioluminescence appeared independently and differently more than 94 times in evolution, and the first time there was 540 million years ago in a small group of organisms. Soft corals of very diverse shapes, octoporals (because they have eight tentacles around their mouths). Coral reefs still exist on Earth, especially in the tropical range.
As for whether it is this bioluminescence that ensures their exceptional longevity, and especially for how long given the threats affecting coral reefs, that is another story that science is trying to shed light on.
