Bolder-dash writes:
So let's do imagine we are in that pre-Cambrian era and noticed some creatures with light sensitive patches some where on their body. We might remark, well, that sure is odd, you don't see that very often, and even more fascinating, it really seems to help those creatures navigate better than those without that little patch.
Ok.
And then if we waited another very long time (or as Dr. A wants to suggest we only have to wait less than 40 years...
That's not what he said. But let's ignore that for now.
we would see those same creatures now, all with the light patches, and even more fortunately some of them have gotten a little depression in their bodies, EXACTLY where that little light patch happens to be, and amazingly enough that little depression (I mean little depression in animals bodies happen mutationallly all the time I guess right) ALSO happens to provide a small little concave surface which helps focus the light every so slightly more, such that now those with the depression are even better at navigating than those without the depression.
The depression could be all over their bodies, as long as the light sensitive cells are inside one, it doesn't matter, it's not as simple as having one mutation determine there is a depression somewhere on the body. It's far more likely that it results in something like a "bumpy surface".
Mutations are much more fortunate now in this scenario than we first thought.
Why?
But don't worry, there will be more of these fortunate little depressions. And then after than a cornea will pop up. And some time after that, rods will pop up, and then cones, and then a retinal nerve, and then of course an iris and then a pupil..or will it be a pupil first, and then an iris?
Kinda like that, yes.
But of course we are just getting started, because two of them will certainly be better than one. And if they are perfectly symmetrical, so much the better. I wish we could also get a tear duct. Whoa, viola! You got it. Would you like an eyelid? great. It will help if that eyelid is extremely rapid, so rapid that it can move at the speed of a blink. And you know what, its not just one form of liquid we get to luck into our tear ducts, its two!! Bonus time.
Yes, so far so good.
We could of course go on and on with these fortunate beneficial mutations which are so rare, but let's return to the present for now.
Evidence that they are rare, or anything other than simply "fortunate" as you claim?
Or how about microwave sensitive patches.
How would this improve your survival?
I could sure use a night sensitive patch on my forearm, for those times when I get up in the middle of the night and trip on my slippers. That would be an advantage.
But not to your survival. that's all that matters.
How about these random mutations for new tear ducts? Corneas anyone? Because supposedly they just pop up spontaneously every once in a while in some mutants, but we just never noticed-at least they did in the pre-Cambrian-oh, how times have changed.
I don't think anyone will say that complete tearducts will pop up all at once. Well, maybe you would.
I sure do miss those days of spontaneous rods and cones. Especially if they happen to happen in a place I could really use them. I mean, I get spontaneous rods all the time, but not always in the backs of my eye.
Evolution doesn't happen to individuals either. You would know this if you had read a biology book or two.
But heck, if a lizard can change FOUR fundamental parts of its body in 40 years, if I just lived to be 60, and have a few kids, and they have kids, who knows, they might just end up with 6 retinas instead of two, plus that night patch we so desperately could use.
We don;t need a night patch desperately, it would add absolutely nothing to our succes at survival. And I don;t think there's enough pressure for any other thing you mentioned here, not to mention that no one said
every individual would be born with these mutrations. The ones that don;t have them simply get replaced by those who have.