The evolution of the eye has been an important subject of study as a distinctive example of a homologous organ found in a wide variety of species.
The development of the eye is considered monophyletic by many experts. So, all modern eyes -along with all their diversity- have taken their origin from a proto-review that is thought to have evolved about 540 million years ago. The vast majority of the process took several million years, caused by the “arms race” in the first hunter. Prey animals and rival predators have been similarly forced to rapidly develop their ability to survive. In this way, multiple eye types and subtypes that help with the vision task have developed in parallel.
The eyes in various animals have shown adaptation to the need. For example, birds of Prey have a visual capacity that is much sharper than humans; such as birds that hunt in daylight can see ultraviolet light. For example, different eye forms in vertebrates and molluscs are often presented as examples of parallel evolution. Intermediate and functional stages exist in nature, if the vertebrate / mollusc eye is decayed. This condition is also a demonstration of many types and characteristics of the eye structure. In the monophyletic model, these varieties are less common for non-vertebrate species, such as the arthropod (compound) eye, but there are fewer intermediate stages to decipher, as it is simpler to start with these eyes. Our sense of sight, perhaps the most important of our five senses, evolved in about 365,000 generations from a simple eye spot to the complex organ we now have.
Our eye collects a large amount of information, ranging from colors and shapes to sensing the level of light, depth and movement. And how did we get such a vision? Many scientists believe that the evolution of our camera-like Eyes follows the process below.
We also recommend that you watch this TED-Ed animation about the evolution of the eye. For Turkish subtitles, you can choose from the Properties button in the control bar.
Both the blind spot and the retinal rupture problem are the results of the evolutionary process of the mammalian eye. For all species, this is not the case: the eye has evolved at least 40 times independently of each other in the process of animal evolution, and the eye structures differ greatly between taxa. The eyes of cephalopods (cuttlefish, octopus) are very similar to those of vertebrates, but the retinal layers are correctly arranged so that “photoreceptors are in front, nerves and veins are in the back”, and they do not have blind spots. This multiple evolutionary origin of the eye is a classic example of convergent evolution.