The morphology of the starfish's eyes together with their optical quality (image quality) are close to the first eye that evolved in evolution
Research has shown for the first time that starfish use primitive eyes located at the tips of their arms to navigate their way around. The researchers, led by Dr. Anders Garm from the Department of Marine Biology at the University of Copenhagen in Denmark, showed that the eyes of starfish create images and may be an essential step in the evolution of the eye.
The researchers removed eyed and eyeless starfish from their food-rich natural environment in the coral reefs and placed them on the sandy bottom a meter away, in the area where they were supposed to starve. They monitored the starfish's behavior from a bottom view and found that while starfish whose eyes were not damaged moved forward toward the reef, starfish without eyes moved randomly.
Dr. Garm explains: "The results show that the nervous system of starfish must produce visual information, which contradicts the underestimation of the ability found in the peripheral nervous system and to some extent also in the central nervous system of the skin strands."
The analysis of the morphology of the light receptors in the eyes of the starfish allowed the researchers to strengthen their hypothesis that the eyes of the starfish are in an intermediate position between two known large groups of light receptors.
Adds Dr. Garm: "From an evolutionary point of view this is interesting because the morphology of the starfish eyes together with their optical quality (image quality) are close to the first eye that developed in evolution when the theory says that image creation appeared first and led to this important stage in the evolution of the eye - navigation to the past Preferred environment associated with large permanent objects (in this case - the reef).
Most species of starfish contain a compound eye at the end of each arm, which, except for the lack of true optics, resembles the eyes of arthropods. Although the fact has been known for two decades, no example of sight-oriented behavior has yet been documented.
Comments
Today the concept of "deep homology" is gaining more and more momentum as an explanation for phenomena that lie between homology and convergence.
in one sentence:
The common ancestor did not have an eye in the sense accepted today, but he did have a genetic network or a very very primitive eye (at the level of a single cell/pair of cells), which had the potential to create a more complex eye. This potential was realized in different ways in different families. So that actually at the base of the eyes there is a strong common denominator at the level of the molecular mechanisms - hence the homology. The convergence comes because in practice, due to the necessity of physical reality, there are some rules for building an effective eye/camera - but there may be a multitude of variations to realize the same principles.
http://www.allmanlab.caltech.edu/biCNS158/PDFs/Shubin2009.pdf
For those
According to the theory of evolution, the eye evolved about 40 times separately. Only if you calculate at the molecular level it could not develop not even once. The smallest eye in nature is actually an eyespot, and this eyespot contains about 200 different proteins. Even if we can reduce it to even 10 proteins, it's still too much. What's more, an eye requires planning just as a camera/watch organically reproduces requires planning.
Asaf
Ask your questions in the Orange Portal evolution forum. There is a chance that you will find a number of people there who will be happy to give you an explicit explanation of convergent evolution.
Visual sensors have developed many times in separate evolutionary paths, since the advantages of the sense of sight are so important for the survival of the species. Apparently the eyes of insects, of terrestrial animals that are not insects, of molluscs, and other groups of life developed in completely different evolutionary paths. The eyes of insects are in a certain sense more sophisticated compared to the eyes of terrestrial animals that are not insects, this is to achieve a wider field of vision (while the focus of insect eyes is probably worse compared to the above because focus in insects does not have a high survival value).
safkan, do eyes form in convergent evolution?
It sounds strange that such a complicated organ can develop at the same time. Where is it listed?
The sense of sight is a convergent evolution, i.e. it was created again and again, therefore the whole discussion about a missing link and the whole thing is absurd on its face.
Any strategy of great value that is achieved even in primitive evolution develops as convergent evolution (=evolution that develops repeatedly from zero). For example: organs of movement, organs of hearing, heat sensors, light sensors, smell sensors.