Eyes

[Believer112]

I'm not sure how many species of animals are on this planet but why did evolution decide to put eyes on these animals?

I personally believe that God gave us eyes to see the wonders of His creative genius.

[Hunterpoet]

Excellent question and an equally excellent answer.

[nebula]

I know what the answer will be, though.

Evolution didn't "decide."

It all began with some primitive organism being born with a mutation that became the primitive nervous system. Then a descendant was born with a mutation that sensed light. Then another descendant developed a mutation that enabled the organism to see shapes. Etc., etc., etc.

And all animals today are descendants from the population that mutated fully developed eyes.

[Hunterpoet]

OK...so now I will ask the next question

did hearing, smell, touch( pressure, pain, hot and cold) and proprioception evolve along with sight or independently before or after????

[nebula]

I think the answer is:

"Evolution doesn't work that way...."

[other one]

I don't know what they are teaching now, but when I was in high school and college about 40 years ago they taught us that sight and smell came first and as they developed and got more complex the others evolved along with them.

I haven't looked at textbooks in a long time, and since I really don't buy into evolution I have not kept up with it.

[nebula]

For multi-celled, it probably started with a patch of epithelial cells becoming light sensitive.

Epithelial tissue became nervous tissue?

That's a good jump.

[nebula]

The first 'eyes' would have been eye spots on single-celled organisms.

How do "eye spots" function on a single-celled organism without the eye spot being a nerve cell of sorts?

[Matthitjah]

Hmmm? LOL

I wonder how the first primative eye decided to see things upside down and then flip them in the first primative brain? LOL

[Hunterpoet]

I'm not sure how many species of animals are on this planet but why did evolution decide to put eyes on these animals?

I personally believe that God gave us eyes to see the wonders of His creative genius.

The short answer is that eyes are advantageous and you can get eyes through mutation and natural selection.

If you can see when a predator comes your way, for example, you have a better chance of not becoming someone else's dinner. The most primitive eye on probably was only able to detect the presence of light and possibly the wavelength/color - jellyfish for example can only do pretty much that. They use that information to decide whether or not to become docile or energetic as different light has a profound impact on their enviornment.

It all began with some primitive organism being born with a mutation that became the primitive nervous system. Then a descendant was born with a mutation that sensed light. Then another descendant developed a mutation that enabled the organism to see shapes. Etc., etc., etc.

And all animals today are descendants from the population that mutated fully developed eyes.

Actually the eye evolved independently multiple times; not all eyes are decedent from some ancestral eye. The first 'eyes' would have been eye spots on single-celled organisms. For multi-celled, it probably started with a patch of epithelial cells becoming light sensitive. From what I remember it is fairly easy to do genetically. Then the patch of light sensitive cells started to indent forming a depression which allowed for more accurate discernment of where the light was coming from and so on.

OK...so now I will ask the next question

did hearing, smell, touch( pressure, pain, hot and cold) and proprioception evolve along with sight or independently before or after????

I don't know the time-line, but I don't see how they are dependent on each other. They probably evolved independently of each other, and I wouldn't be surprised if they evolved in the same time period - actually I know with our sense of smell and sight, it is evolving all the time (at least in recent past evolutionary wise). So there's probably a ton of overlap on the time scales.

I was not suggesting that these different functions were dependent on one another...however...they are all dependent on the

CNS. An example question would be...what good is eyesight if you cannot tell up from down or what position your body is in relation to up and down? How would you know which way to run from a predator if you have no sense of position?

I would be very interested to hear about the latest evolutionary advances in smell and eyesight.

And then of course....after we exhaust these issue, there is the whole biological sonar function that some aquatic animals posses, along with eyesight and smell.....