Evolution of the eye (science, Article, Greek)

[painted wolf]

No a control gene didn't, but lets also not suggest that lots and lots of mutations were nessisary.
Once a mutation caused formation of an eyespot from a photosensitive patch the "dumb" control gene was telling it what to do. It didn't need to mutate allong with it.

This mutation only had to happen once, and if you know anything about critters like Planeria then you know how rapid thier generations are. Rapid generations + sexual reproduction = lots of mutations = lots of material for evolution.

wa:do

[rocketman]

Originally Posted by painted wolf

No a control gene didn't, but lets also not suggest that lots and lots of mutations were nessisary.

What do you mean by 'lots and lots'? Nilsson and Pelger reckon 350,000 mutation bearing generations are needed, and that's only for rudimentary optical geometry without a single supporting system, (not to mention a few missing optical systems such as the iris). Who could really guess just how many, many, mutations were required to get to the state we are in today where control genes have so much to work with.

Originally Posted by painted wolf

Once a mutation caused formation of an eyespot from a photosensitive patch the "dumb" control gene was telling it what to do. It didn't need to mutate allong with it.

See last answer.

Originally Posted by painted wolf

This mutation only had to happen once

Same again.

[painted wolf]

Actually they determined it took "about 2000 steps" over a period of about 400,000 generations.
Not a long time really given the rapid turn over of generations for most animals.
Evolution - A-Z - Evolution of the eye

See last answer.

bad answer. Experiments have shown that control genes can make an eye anywhere, even in places that eyes don't normally deveolp, so long as they have the parts... therefore the control gene doesn't need to change to use what it has.

What is really intresting is the "first eye" evolved only once. In the jellyfish.

wa:do

[rocketman]

Originally Posted by painted wolf

Actually they determined it took "about 2000 steps" over a period of about 400,000 generations.

And that guestimate is based on a mutation per generation.

Originally Posted by painted wolf

bad answer. Experiments have shown that control genes can make an eye anywhere, even in places that eyes don't normally deveolp, so long as they have the parts... therefore the control gene doesn't need to change to use what it has.

"So long as they have the parts..." Um, that's what I've been saying all along.

[painted wolf]

every generation has several mutations... you have quite a few yourself.
there doesn't need to be a progressive mutation each generation... just the 2000.

Given millions of individuals over the course of 400,000 generations the odds are pretty good you'll end up with an eye.

wa:do

[rocketman]

Originally Posted by painted wolf

there doesn't need to be a progressive mutation each generation... just the 2000.

Well, if you insist on getting technical, that model was an incredibly simplified one. All it really did was to assume lens geometry changes in pre-set increments. If we actually got serious and started looking at all of the elements that had to be established for optical senses to work we'd be here for a while. I'm highly doubtful that the 40 or so seperate but necessary optical subsystems and post processing could have came about together or mostly together.

But each to their own.

[painted wolf]

if all of these parts are "necessary" for an eye to work, then why don't all eyes have them?

Why should an intelligent designer make an inferior eye? Sadly the most advanced eye on the planet belongs to a shrimp.

wa:do

[methylatedghosts]

Originally Posted by painted wolf

What is really intresting is the "first eye" evolved only once. In the jellyfish.

wa:do

So someone obviously cut out an eye from the jellyfish, drilled a couple holes in our heads and plonked the eye right in there! That's why our eyes have eye-jelly!!!!

There! Problem solved!

[Zeno]

Direct link to the video in Jay's first post:

YouTube - The Human Eye is NOT Irreductibly Complex

[rocketman]

Originally Posted by Zeno

Direct link to the video in Jay's first post:

The video is very good but incorrectly named. It reviews estimated lens development and little else. The eye is not a lens anymore than a car is a hubcap.