Scientific discovery makes new connection to modern eyes. There have been changes in the lifestyle of vertebrate ancestors.
Researchers from the universities of Lund (Sweden) and Sussex (United Kingdom) revealed a new interpretation on the evolution of vision in vertebrates, including humans.
The new one connects to origin of the modern eyes to one ancestral singular with a single light-perceiving organ on top of the head.
The researchers propose that this distant precursor to all vertebrates had just one average eye, capable of detecting light and dark; Over millions of years, both the paired eyes and the pineal gland present in today’s brains were derived from it.
According to this study, this primitive organism lived almost 600 million years and had a lifestyle sedentary, filtering plankton from ancient seas.
As the environment and behavior evolved, it lost its original lateral eyes and began to depend on this single central eye.
The hypothesis, according to scientists, contradicts previous interpretations that imagined a more linear development of complex visual organs and suggest a more tortuous evolutionary path marked by functional losses and reacquisitions.
From this evolutionary point onward, behavioral changes — such as the transition to a more active and mobile life — would have pushed for a greater ability to form complex images, driving the reemergence of paired eyes from parts of that ancestral median eye.
This explanation, continues , helps to understand why the eyes of vertebrates are so different from those of other animals – such as insects or squids, whose visual organs originate from skin tissues on the sides of the body.
Furthermore, the pineal gland — now known for regulating circadian rhythms thanks to the production of melatonin — could be a remaining of this ancient middle eyewhich reinforces the deep connection between sensory evolution and modern biological functions.
If confirmed, this discovery adds a surprising chapter to the story of the evolution of vision and expands our understanding of how complex structures can emerge from unlikely adaptations in the ancient past.
