Saturday , July 31 2021

500 million years of evolutionary weapons race for a better vision



A new study suggests that the half-billion-year-old “evolutionary arms race” may have been triggered by the development of the vision of deep-sea giants called “radiodonts”. The Cumbrian explosion occurred about 541 million years ago and lasted about 13-25 million years. This is the beginning of the evolutionary arms race, when almost all major groups of animals appeared. A new study now claims that it provides “critical new information” about the evolution of earlier marine animal ecosystems that emerged at the time, resulting in better predators with improved vision.

Extreme environmental form evolution weapons race

The new study has been published Development of science . The study was written by Professor John Paterson of the University of New England Paleozoic Research Center , in collaboration with University of Adelaide , Museum of South Australia and the Natural History Museum in London. Talking to Archaeological news network Professor Paterson says the study highlights how “vision” played a crucial role in the Cumbrian explosion more than half a billion years ago.

Radiodonts are named after their “radiating teeth,” and about 500 million years ago, their muscular, overlapping abdominal flanges propelled these creatures through the oceans much like modern rays and cuttlefish fly. The radiodontal head boasted a pair of large “segmented suffixes to capture the prey,” and the circular mouth was broken with rows of toothed teeth. The new study shows that some of these animals inhabited ocean layers 1,000 meters (3,280 feet) deep. And they developed “big, complex eyes” to compensate for the lack of light in this extreme deepwater environment.

Radiodont Anomalocaris, with its large, stalked eyes, is considered the leading marine predator that swam in the oceans more than 500 million years ago.  (Catherine Kenya / University of New England)

Radomont Anomalocaris with large, stalked eyes is considered to be the leading marine predator that swam in the oceans more than 500 million years ago. (Catherine Kenya / University of New England )

Better vision was an important driver of evolution

The study was mainly based on fossils recovered from the shale formation of Emu Bay on Kangaroo Island in southern Australia. The article’s co-author, Associate Professor Diego Garcia-Bellido of the University of Adelaide and the Museum of South Australia, said the Emu Bay shale is “the only place in the world to keep an eye on Cambrian radiodontal lenses.”

The study concluded that with the development of more complex visual systems, animals gained a greater understanding of the environment. According to the study, this led to an “evolutionary arms race” between predators and victims. In essence, vision became the “driving force of evolution” that forms the biodiversity and ecological interactions we see today.

Fossil Eyes: A Decade of Evolutionary Progress and Insights

The same group of researchers published two papers in the journal Nature In 2011, after exploring a pair of “one-centimeter-diameter fossilized connected eyes,” they were discovered on Kangaroo Island.

However, at that time the creature to which these eyes belonged was unclear, but now it is completely diverted and the creature is named ”. Anomalocaris’ briggs. Professor Paterson said they found much larger samples of these eyes, which have different “acute areas”.

These “acute areas” in the lens of the eye improve the amount of light entering the eye and sharpen the resolution. And that’s why researchers think ‘Anomalocaris’ briggs could be seen in very low light, at great underwater depths.

Dr. Greg Edgecombe, a researcher at the Natural History Museum and co-author of the new study, says that in a 2011 study, South Australian radiodonts had different “feeding strategies” to capture or filter their prey, as the appendices pointed out. However, it is now known that the eyes of predators on these appendages were attached to the surface of the head, “on the stems,” said Dr. Edgecombe.

'Anomalocaris' briggs eye.  Left: full fossil eye (scale bar 5 mm or 0.2 inches);  Middle: close-up of the lens (scale bar 5 mm or 0.2 inches);  Right: Reconstruction by an artist showing the

‘Anomalocaris’ briggs eye. Left: full fossil eye (scale bar 5 mm or 0.2 inches); Middle: close-up of the lens (scale bar 5 mm or 0.2 inches); Right: Reconstruction by an artist showing the “acute zone” of a magnified lens, allowing the creature to see in low light. (J. Patersons / University of New England )

Fossil footprints from a 500 million year old Cambrian explosion

The new study shows how the eyes of radiodontics grew and developed as the species evolved and grew, and how the lens of the eye formed at the edge of the eyes. In addition, it was found that the eyes of large individuals increase significantly, as is observed in many modern arthropods. And that’s the way compound eyes have grown over 500 million years, according to a study by scientists.

It should be noted that the eye fossils examined in this new study are one of the oldest ever discovered. In 2017 BBC wrote about the discovery of an extraordinary 530 million-year-old, well-preserved trilobite fossil with the “oldest open eye” seen in many modern animals, including crabs, bees and dragonflies. And it was during this “Cambrian explosion” that radiodonts appeared, and therefore their fossils reflect the “birth of a predator” on planet Earth.

Top image: the artist’s reconstruction “Anomalocaris” briggsi, a deep-water creature that started the evolutionary arms race because its improved vision made it a better predator. Source: Catherine Kenya / University of New England

Author Ashley Kovia


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