For a long time, scientists have believed the human eye's ability to see in color developed hundreds of millions of years ago. The newest discovery of fossilized fish whose eyes have remained largely intact has provided the proof that this assertion is indeed a fact. Now scientists can confidently confirm the biological vision technology has been in existence for over 300 million years.
The human eye depends on pigments that absorb light. These pigments are present in cells referred to as rods and cones; these are the two main photoreceptors that send information to the brain for the human eye to see. These photoreceptors convert the electromagnetic radiation that can be seen to information the human brain can process. Rods are useful for night vision while cones help to perceive color, note details, and decipher quick changes. Working together, rods and cones provide the ability to perceive complex vision.
The creature recovered by paleontologists working for Kumamoto University in Japan is best known as "myllokunmingia". And with its discovery, It now becomes the earliest known creature to have had the ability to see in color like human beings today. In addition, it was also found with a backbone, making it the earliest known vertebrate to exist on the face of the earth. The researchers noted the creature's eye may also have had a basic camera-like ability.
The fossilized fish is 10 centimeters long. Scientists discovered it in Kansas in the Hamilton Quarry. Once a lagoon, the researchers found the quarry to be a terrific research site for the apparent explanation why the fossils discovered in this area were astonishingly well-preserved: buried under the quickly changing sediments of the lagoon, myllokunmingia was left in tact and perfectly impressioned for millions of years.
"Except for the optical system, as in the calcified lenses of trilobite and ostracod arthropods, other parts of the visual system are not usually preserved in the fossil record, because the soft tissue of the eye and the brain decay rapidly after death" lead researcher of the study Gengo Tanaka says. "The Upper Carboniferous Hamilton Formation (300 Myr) in Kansas, USA, yields exceptionally well-preserved animal fossils in an estuarine depositional setting."
The fossilized fish has eyeballs estimated to be over 300 million years. And due to the fact that they are so well preserved; they can be viewed quite clearly under an electron microscope. It has always been a challenge studying the evolution of the eye because the eye's soft tissue is usually one of the first ones to decay when one dies; this is why this discovery is such a significant step in studying the evolution of sight.
In findings published in the Journal of Nature Communications on December 23, Tanaka noted, "Rods and cones are not usually preserved because these soft tissues are more fragile."
Tanaka further said gills and pigments of the fish were also well preserved. According to the paleontologist, this discovery would help in the study of vertebrates like birds, other fossil fish and even extinct animals like dinosaurs.
