Article Summary: The Evolution Of Eye Furn

Grace McNamara
GEL 03
Professor
March 23, 2017

It was thought that fish made the transition from water to land about 385 million years ago as result of the evolution that allowed them to form legs (four legged tetrapod). However, in the following peer review article, a group biologists and paleontologists examine the origin and hypothesis that even before the shift from fins to limbs occurred that allowed these animals to live on land, they needed an reason/incentive to leave the water in the first place before they could evolve and adapt their bodies to the conditions of living on land. During the transition from water to land, the fish showed significant changes in the anatomy of their body; shift from fish to tetrapods (four legged animals),
as well as exhibiting substantial changes in their vision. They noticed that this passage allowed the animal to see from long distance on a clear day, whereas before they could only see over short distances in heavy fog.
Since larger sockets are parallel with larger eyes, the increase of almost threefold in eye socket in these ancient animals indicate an increase in almost threefold in total eye size. It was estimated that the eye socket and eye size took almost 12 million to triple in size. In those 12 years, the orbit of the eye grew from around 13 millimeter to nearly 36 millimeters. The increase in eye size has little benefit on performance for animals in water, which is why it’s hypothesized that the increase in eye socket and overall eye size evolved when the ancient fish began making their way onto land and to the change in environment. With the larger eyes and pupils almost tripling, it allowed these animals to see greater distances. This evolved their vision from an underwater to an aerial viewing. The article also mentions that these ancient lobe-finned fish most likely hunted in a similar behavior to crocodiles, by creeping slightly above the water to eye their prey on the edge of the water. It was predicted that the evolution of the increase in eye size was result of early tetrapods looking above the water and
shifting from an aquatic hunting style to land hunting.
This is important since findings in fossils are crucial because they help in understanding the history of the world.
They provide physical evidence of different species of animals and plants that sustained life in the past. Besides recording how long life has existed on Earth, they also assist in understanding and classifying modern animals and plants to those of the past to analyze the effects of evolution on the organisms related to each other. In this case, the fossils revealed a clearer explanation on how ancient lobe-finned fish transitioned from water to land when before it was thought that limbs were the first sign. This new information is significant since it gives people a better understanding of the incentive and motive for the transition and what led to the evolution of limbs and transition to
land.