-
Welcome to Religious Forums, a friendly forum to discuss all religions in a friendly surrounding.
Your voice is missing! You will need to register to get access to the following site features:- Reply to discussions and create your own threads.
- Our modern chat room. No add-ons or extensions required, just login and start chatting!
- Access to private conversations with other members.
We hope to see you as a part of our community soon!
How did people see before the eye was fully evolved?
- Thread starter MSizer
- Start date
JMorris
Democratic Socialist
IF there were such a thing as ' eyes that evolved ' (algae slime that figured out it needed eyes) then considering the weakness of this evolved human, whose enemies can and often did approach from behind to destroy them, how come in all this time eyes in the back of the head didn't ' evolve? '
Cheers!
Cheers!
JMorris
Democratic Socialist
Some animals, usually prey animals, have their two eyes positioned on opposite sides of their heads to give the widest possible field of view. Examples include rabbits, buffaloes, and antelopes. In such animals, the eyes often move independently to increase the field of view. Even without moving their eyes, some birds have a 360-degree field of view.
Other animals, usually predatory animals, have their two eyes positioned on the front of their heads, thereby allowing for binocular vision and reducing their field of view in favour of stereopsis. Examples include eagles, cats, and snakes.
Some predator animals, particularly large ones such as sperm whales and killer whales, have their two eyes positioned on opposite sides of their heads. Other animals that are not necessarily predators, such as fruit bats and some primates also have forward facing eyes. These are usually animals that need fine depth discrimination/perception; for instance, binocular vision improves the ability to pick a chosen fruit or to find and grasp a particular branch.
Binocular vision - Wikipedia, the free encyclopedia
DadBurnett
Instigator
Interesting question ... they probably "saw" like all those creatures that live in the dark caverns deep underground, or perhaps like those in the depts of the oceans where ther is no discernable light ...
JMorris
Democratic Socialist
Runewolf1973
Materialism/Animism
ever seen the movie "The Descent"?
Ha ha! That's what I was just thinking. Good movie.
JMorris
Democratic Socialist
Ha ha! That's what I was just thinking. Good movie.
i dunno if id say "good"............ but its............ something. "extremely violent" comes to mind
enchanted_one1975
Resident Lycanthrope
Maybe we used sonar like bats and dolphins.
JMorris
Democratic Socialist
Evolution of the Eye:
If evolution occurs through gradations, the critics say, how could it have created the separate parts of the eye -- the lens, the retina, the pupil, and so forth -- since none of these structures by themselves would make vision possible? In other words, what good is five percent of an eye?
Darwin acknowledged from the start that the eye would be a difficult case for his new theory to explain. Difficult, but not impossible. Scientists have come up with scenarios through which the first eye-like structure, a light-sensitive pigmented spot on the skin, could have gone through changes and complexities to form the human eye, with its many parts and astounding abilities.
Through natural selection, different types of eyes have emerged in evolutionary history -- and the human eye isn't even the best one, from some standpoints. Because blood vessels run across the surface of the retina instead of beneath it, it's easy for the vessels to proliferate or leak and impair vision. So, the evolution theorists say, the anti-evolution argument that life was created by an "intelligent designer" doesn't hold water: If God or some other omnipotent force was responsible for the human eye, it was something of a botched design.
Biologists use the range of less complex light sensitive structures that exist in living species today to hypothesize the various evolutionary stages eyes may have gone through.
Here's how some scientists think some eyes may have evolved: The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light-sensitive patch, a deepening pit that made "vision" a little sharper. At the same time, the pit's opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.
Every change had to confer a survival advantage, no matter how slight. Eventually, the light-sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye. It could have arisen as a double-layered transparent tissue containing increasing amounts of liquid that gave it the convex curvature of the human eye.
In fact, eyes corresponding to every stage in this sequence have been found in existing living species. The existence of this range of less complex light-sensitive structures supports scientists' hypotheses about how complex eyes like ours could evolve. The first animals with anything resembling an eye lived about 550 million years ago. And, according to one scientist's calculations, only 364,000 years would have been needed for a camera-like eye to evolve from a light-sensitive patch.
Evolution: Library: Evolution of the Eye
Evolution of the eye - Wikipedia, the free encyclopedia
But that's exactly what we see (
). A light sensitive molecule is all that's needed to start the process from a light sensitive patch to a camera-like eye. Nilsson's experiment that JMorris posted is awsome in its simplicity, and astounding in its implication that an octopus or human eye came about in less than 400,000 years. Just amazing stuff. 
Last edited:
