How long and how did the human eye develop?

Question

The human eye is amazing, it can let you see in colour and in amazing detail that we have yet to match with our cameras.
How did it come about though, it would have taken ages through evolution? Also, why would we have needed an eye to start with, couldn't our other senses just get stronger.

This is my thought, what is yours?

Our eyes were developing and were very weak. Therefore, we used a form of supersonic location and then as our eye got stronger our hearing weaken. As a bat doesn't need good eyes it hasn't developed?

Answer 1

Your view of eye development is wrong. Ancient humans were not blind. They had eyes already, inherited from the common primate ancestor we share with chimpanzees.

Eyes developed just like any other complex organ. Slowly, over many generations in incremental steps. Our eyes are not the only light sensing organ found among animals. By looking at other animals, we see many different types of eyes and we can put together a progression of more and more complex visual structures, each one built upon what evolved earlier. The link below has a nice video that explains it so I wont go into the details.

Instead, I want to point out some of the common but mistaken views of evolution by natural selection. Natural selection didn't make eyes because we needed them. Light sensing organs developed and were kept when they provided an advantage over their competition. The very first organisms that could detect light and respond to it would have an advantage over their competitors. For example, if photosynthetic bacterium could detect light and swim towards it, they would have an advantage over bacteria that swam randomly because they could not sense light.

A flat worm that could get some directional information would have an advantage over a competitor that had no directional imaging capability. Like the punchline to an old joke, if you're being chased by a lion, you don't have to out run the lion, you just have to be slightly faster than others to have an advantage over slower, more easily caught lion food.

And where did you get the idea that primates had echo location abilities? We have the ability to determine the rough direction of a sound source but nothing like sonar. Bats are mammals and they went down another path of variation where sensing sound gave an advantage in their situation. Eyes don't work so well in the dark. It doesn't have to be a perfect, working sonar right away, but an incremental difference (such as increased sensitivity or increased range of frequencies to hear insects better) provides a slight advantage over the competition.

Creationists are quick to jump to conclusions based on ignorance. Their entire argument is a celebration of ignorance. "It's too complex. I can't figure out how it happened so it must be magic." Of course we didn't go from nothing and jump directly to the eyes we have now. We did it in many tiny incremental stages. These intermediate stages are still around in different animal species.

Answer 2

You could say that the human eye has taken at least half a billion years to develop, but then, that development actually took place in our ancestors before they became human. The evolution of the eye has been traced back more than 500 million years to light-sensitive brain cells in tiny wormlike creatures ancestral to most modern animals that didn't even have most of the organs we do now.

That mostly answers the second question too: since the granddaddy-worm didn't have the kind of sensory organs we do, it couldn't compensate for its lack of vision with, say, hearing. In fact ears didn't start to evolve properly until our ancestors got out of water. At that point eyes were already way ahead in terms of usefulness.

Bats on the other hand have lost most of their vision rather than just neglecting to develop it. If you look at fruit bats, you can see that bats that still use their eyes a lot have good vision, while echolocating ones don't.

Answer 3

It took millions of years, starting with a very primitive light sensitive cell which then eventually developed into an eye. Like everything in evolution it took a very very very long time. It's not that we 'needed' eyes as such, but once having developed the ability to see, it certainly became a huge advantage for the organisms that did have this ability.

Answer 4

Uh, eyes didn't develop in humans, but in very distant ancestors of humans.

Eyes have developed independently dozens of times (for instance, an octopus has eyes; they are not in our phylum -- the most basic division among animals).

Those ancestors of our who had not yet left the water had eyes.

It turns out that it takes a surprisingly few steps to develop a full-fledged eye.

It's not so much that we NEEDED eyes, but that, critters who had sight more successfully survived and reproduced than critters of the same ancestry who didn't.

I suggest you actually learn about evolution, as you don't seem to get it.

It's really interesting, and well worth the effort.

Answer 5

Complex eyes have developed from primitive eyes. There is nothing special about the human eye. It cannot see small things from a great distance, and it cannot see well in the dark and it cannot see ultra violet and it cannot see well under water. Raptors, cats and fish, to name just three, have more efficient eyes than we have.

Answer 6

Eyes started off as cells that were sensitive to light, like you get on earthworms, Then you get a lot of cells in a sort of receptor pit, then the pit closes partially to focus light in a very basic way, like a pinhole camera. Then the whole area gets mobile, light sensitive cells specialise to colour as well as light and dark, a lid closes over to protect the delicate lens that now seals up the aperture to prevent dirt coating the light sensitive cells. Not necessarily in that exact order, but you get the idea,

Answer 7

Lasik has a wager of damaging bacause of human errors etc. learn bionic lenses, they're pronounced to be tremendous, planned to be released as early as 2017. i replaced into questioning approximately getting those as quickly as my eyes supply up coming up. solid success :)

Answer 8

Evolution is utterly unable to explain the origin of the eye, which is a marvel of engineering.

The 'light sensitive cell' argument simply doesn't wash, and is certainly not supported by any evidence. It is a just-so story, and a feeble one at that.

The eye was created along with the rest of us.

Charles Darwin himself realized that it seemed incredible that evolutionary processes had to explain human vision. He said:

'To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.'1

Yet, later on in the same chapter of his book, he explained how he believed it evolved anyway and that the ‘absurdity’ was illusory. Had Darwin had the knowledge about the eye and its associated systems that man has today (which is a great deal more than what it was in his time), he may have given up his naturalistic theory on the origin of living things.

One fascinating discovery in the study of modern ophthalmology (eye science) is that, aside from what Darwin was able to observe, there are three almost imperceptibly tiny eye movements. These three, referred to as ‘tremors, drifts and saccades’, are caused by minute contractions in the six muscles attached to the outside of each of your eyes. Every fraction of a second they very slightly shift the position of your eyeball, automatically, without conscious effort on your part, making sight as you know it possible.

Tremors — the tiniest and probably the most intriguing of these movements, continuously and rapidly wobble your eyeball about its center in a circular fashion. They cause the cornea and retina (front and back) of your eyes to move in circles with incredibly minute diameters of approximately 1/1000 (.001) of a millimeter, or .00004 inch.

This size is about 70 times smaller than the thickness of a piece of paper. Carefully look at a piece of paper, edge on, then try to imagine 70 circles of the same diameter (OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO) touching and placed in a row straight across the thickness of the paper. If you can do that, you will have a feel for the minuscule nature of the tremors along with some appreciation for the Creator who has demonstrated His capacity for designing such a thing.
http://www.creationontheweb.com/content/view/932/