Oolon Colluphid

Just to pick on one bit...
Proportionally, this is true. But a tiny proportion of one hell of a lot is still a significant number... and there are one hell of a lot of cell divisions going on in gamete-formation, even in a small population. I can find numbers if anyone’s interested, but iirc, for comparison, each human has about 20 new mutations in their body cells.
Rubbish. There are plenty of examples of beneficial mutations. And anyway, whether a mutation is positive, negative or (most likely) neutral depends entirely on the environment it finds itself in -- positive / negative in respect of what?
Nonsense. For one thing, mutations are in effect plentiful, even if if not per individual, then per generation across a whole population. And for another, they are cumulatively selected, and evolution builds on what has been successful before. And, of course, we have millions of years to play with.

So there.

DT

Kimpatsu

DT, he's just using the Argument from Personal Incredulity.
It's not compelling, either.

EggplantTrent

Thanks for all the responses guys (and girls). Thank you also for the links you sent me. It's very interesting reading. Everything in this forum is so damn interesting, and everyone in here is so far ahead of me in all the subjects that I find myself unable to contribute to most, if not all discussions. I'll read all the info though, and read more, and hopefully I can get at least knowledgable enough to know what I'm talking about.

Incidentally, the guy hasn't responded back about the subject. But I have the distinct feeling he's going to say "God is the engine for evolution." And then I'll ask him to demonstrate it and he'll say "God is a presupposition". It drives me nuts.

EggplantTrent

Arthwollipot

Dawkins presents it in The Blind Watchmaker.

At a risk of repeating myself (I've posted quite a long article in other threads and other forums) the problem is this:

In a human eye the photoreceptors (the cells that convert light energy to electrochemical energy) are in backwards. The light has to pass through a whole lot of rubbish on the surface of the retina before it is ever picked up by the banks of photoreceptors at the very back. The light has to pass through virtually the entire cell before it falls on the photoreceptor.

Then the nerve comes out the front of the cell (closest to the surface of the retina), and travels across the retina, over the top of all of the other photoreceptors until it reaches the blind spot - known as the fovea - and dives through the retina to join the optic nerve (which incidentally has to travel through the entire brain to get to the visual cortex at the very back).

Now the clincher: The octopus eye is almost identical to our own, except that the photocells are the right way around. Photoreceptors closest to the surface of the retina, where the light falls, and the nerve goes straight out the back to join the optic nerve. No mucking about over the top of any other photoreceptors.

I suggest that this is evidence against Intelligent Design, as it implies that any purported Designer must be an absolute idiot.

KC

This, and the rest of the passage is just so much pre-packaged creationist bullshit. There is so much wrong with it that a detailed rebuttal would take far more time than it is worth.

Suffice it to say, anyone who DOES know a bit about mutations will tell you that the entire passage shows complete ignorance, not only of genetics and evolutionary biology, but apparently physics as well.

KC

Godot

Just to play devil's advocate here, but what pray tell, is the advantage conferred by colour blindness?
But then again, I can see that the intention was to demonstrate that a small change does not invalidate the function of the optical unit.
But then again, anyone care to elaborate on a potential rationale for colour blindness (silly arguments encouraged)?

Wounded King

Red/green colour blindness could be advantageous in populations with a large proportion of red headed women and high incidence of violence from men towards women. The inability of the male to distinguish between the red of the females hair and the green of vegetation allows the female to hide more easily. Assuming that the attacker causing a women to be killed or to miscarry is most likely to be her mate, for no other reason than that this seems the only way this would make sense, then obviously a gene for red/green colour blindness would be advantageous as those with full colour sight would kill off their unborn offspring.

I would like to appologise for the hugely misogynistic character of this hypothetical scenario. I myself find the whole concept quite disturbing, but it does make a twisted sort of sense, given the many assumptions.

This should not be confused with the tendency to beat red headed step children so often reffered to colloquially.

RufusAtticus

Actually its on the order of 200-600 point mutations per generation.

Oolon Colluphid

Thanks Rufus. My memory nearly made me say 200 rather than 20, but I didn’t quite believe it myself!

It’s hardly surprising though, given the number of cell divisions from a single egg to a human body... would anyone with these stats at their fingertips care to remind me of the number (I hesitate to remember such things again )? We could get a ballpark figure for the mutation rate: it'll be small, but like I said earlier, not insignificant!

Cheers, DT

Godot

I'd only expect this one from a scot.