For centuries, the mesmerizing glow of bioluminescent creatures has captivated scientists and artists alike. This otherworldly light, produced by living organisms, has long been thought to have evolved multiple times throughout animal history.
However, recent research published in the journal Proceedings of the Royal Society B paints a different picture.
The study, led by scientists from the Smithsonian, suggests that bioluminescence in a group of marine invertebrates called octocorals may have a single origin, dating back to the Cambrian era.
This discovery pushes back the previously known timeline for the evolution of bioluminescence by a staggering 300 million years.
The first evidence of bioluminescence in animals was previously found in fossils from the Devonian period, around 359 million years ago.
The new finding, based on genetic analysis of octocorals, suggests that bioluminescence may have emerged much earlier, around 540 million years ago.
Unveiling the Secrets of a Glowing Past (Photo : DAVID GRAY/AFP via Getty Images)
The study's authors used a technique called phylogenomics to trace the evolutionary history of bioluminescence in octocorals. This approach involves analyzing the genomes of different species to identify genes associated with bioluminescence.
By comparing the presence and absence of these genes across different lineages, the researchers were able to reconstruct the evolutionary timeline of bioluminescence.
The findings suggest that bioluminescence likely originated in a single ancestor of all octocorals. This ancestor then diversified into the many different species of octocorals seen today, some of which retain the ability to produce light.
One lingering mystery is the exact purpose that bioluminescence serves in octocorals. They typically only glow when bumped or otherwise disturbed, suggesting a role in defense or communication.
Some scientists believe bioluminescence may help startle predators or attract other creatures, while others posit it might be used for mating or navigation.
Further research is needed to understand the exact mechanisms by which bioluminescence evolved and how it has diversified across different animal lineages.
However, this new study sheds light on the deep evolutionary history of bioluminescence and its potential role in the adaptation of marine animals to the deep sea environment.
A Deep Sea Mystery: The Purpose of Bioluminescence in Octocorals
Octocorals, also known as soft corals or sea pens, are a diverse group of marine invertebrates found in all oceans from the surface to the deepest trenches. They come in a wide variety of shapes and sizes, and many species are bioluminescent.
The exact function of bioluminescence in octocorals is a bit of a mystery. Unlike some bioluminescent fish that use light to attract prey, octocorals typically only emit light when disturbed. This suggests that their bioluminescence may play a role in defense or communication.
One theory is that bioluminescence may startle predators or attract other creatures that can help defend the octocoral. For example, some bioluminescent octocorals are known to live in symbiosis with stinging jellyfish.
When the octocoral is disturbed, it may emit light to attract the jellyfish, which can then ward off predators.
Another possibility is that bioluminescence is used for communication between octocorals. For example, some species may use light to signal to each other about danger or to attract mates.
Further research is needed to determine the exact function of bioluminescence in octocorals. However, this new study suggests that this ancient trait may have played a key role in the evolutionary success of these fascinating deep-sea creatures.