What is evolution?

reply to post by txpiper


Let me show you an example of evolution at work and how really dumb things seem to get built into what might appear to be really intelligent designs.

Take the human eye. Here is a link that shows what I want you to examine.
The Normal Eye

Look at the optic nerve. A lot of eye images leave out the artery and vein that follow the optic nerve and pass into the eye. Are the blood vessels behind the retina? No. Somehow they ended up going into the eye and passing in front of the field of view. Would you design a camera and pass the internal wiring in front of the film or chip capturing the light? When I first saw that years ago I thought it was a mistake made by the biological artist. I went and asked around and sure enough the blood supply or at least a good part of it lies in front of the retina. This is hardly a designed structure. It works. Got a few weird things in there, but it works.

Millions of years is a lot of time. According to the wikipedia the rates of mutation are around 1 in 10,000 to 1 in a million base pairs per generation. That's not many, but in tens of thousands of years to millions of years it adds up.

reply to post by stereologist

Somehow they ended up going into the eye and passing in front of the field of view. Would you design a camera and pass the internal wiring in front of the film or chip capturing the light?

Complex problems require thougtful, compex designs. Look up Muller Glial cells and see it they sound like something a DNA replication error would produce in the nick of time.

Muller glial cells act as living optical fibers, transporting light through the inverted retina of vertebrates. With their funnel-shaped endfeet, Muller cells collect light at the retinal surface and guide it to the photoreceptor cells on the opposite side. Images are thus transmitted through optically distorting tissue. PNAS / May 15, 2007 / vol. 104 / no. 20 / 8287-8292



[edit on 1-6-2010 by txpiper]

reply to post by txpiper


Like many cells this cell type has some interesting properties.

Muller Glia
Notice how quite a bit of the research is done with zebra fish. There is a simple reason for that. It's a vertebrate model with very short time periods between generations. That means it is good for studying evolutionary processes.

Zebra Fish

Research with D. rerio has allowed advances in the fields of developmental biology, oncology, toxicology, reproductive studies, teratology, genetics, neurobiology, environmental sciences, stem cell and regenerative medicine, and evolutionary theory[

Its greatest advantages for use as a model system include:

* Fully-sequenced genetic code
* Well understood, easily observable and testable developmental behaviors
* Availability of well-characterized mutants.

Other advantages:

* Rapid embryonic development (progressing from eggs to larvae in under three days, although overall generation time is comparable to that of mice)

reply to post by stereologist

Like many cells this cell type has some interesting properties.

Yes it does, as shown here www.pom.cam.ac.uk...
What I would like to understand is how mutations would have resulted in such cells. How many replication errors would you suppose were involved? Would you think that the regulatory genes that control these cells evolved coincidentally along with them? This is important because even the accidental formation of cells designed to perform as fiber-optics would not be helpful unless they wind up in the right place, in the right arrangement and in the appropriate numbers.



[edit on 1-6-2010 by txpiper]

reply to post by txpiper


I think you're question may really be "How tissues end up where they ought to be?" It wouldn't be helpful to have lung tissue in the eye or liver tissue in the brain. I'm not sure about that. That's an excellent question.

This cell type gets around the problem of evolution having created what appears to be a backwards structure. I mean the retina has the photoreceptors in the wrong place, or maybe its the support for those cells is in the wrong place.

Evolution of the Mollusc Eye
Molluscs are on a different evolutionary path, being a separate phylum from chordates. The development and structure of their eye is different. If you go back and check on Muller cells you will see that they are found in vertebrates. That suggests at least that evolutionary processes have been addressing the bad design of the vertebrate eye for a long, long time. I am not suggesting that evolution is goal oriented, rather that Muller cells have been around a long time.

[atsimg]http://files.abovetopsecret.com/images/member/16f98b9db438.jpg[/atsimg]

reply to post by stereologist

I think you're question may really be "How tissues end up where they ought to be?"

No, my question is always about how an unpredictable series of random DNA replication errors produced specialized tissues, and how those screw-ups produced the control mechanisms that limit, distribute and regulate specialized cells.

Do you not think it just a tad unlikely that in a genome composed of millions, if not billions of base pairs, you have recurring mutations accidentally landing in the same gene region and accidentaly resulting in more sophisticated proteins? Do you honestly believe that this happened, generation after generation, billions of times?





[edit on 2-6-2010 by txpiper]

Originally posted by txpiper
Do you not think it just a tad unlikely that in a genome composed of millions, if not billions of base pairs, you have recurring mutations accidentally landing in the same gene region and accidentaly resulting in more sophisticated proteins? Do you honestly believe that this happened, generation after generation, billions of times?

That is what happened (in simplified version as different loci are not equally susceptible to mutations). Mutations that resulted in worse proteins happened too, however the organisms that carried them died away as they weren't as fit as the other guys (natural selection). However if we're still speaking of evolution of eyes then it wasn't really protein coding genes that changed, but instead mostly genes that control expression of protein coding genes.

[edit on 3-6-2010 by rhinoceros]

reply to post by rhinoceros

if we're still speaking of evolution of eyes then it wasn't really protein coding genes that changed

If you’re talking about evolution of eyes, there would be a lot more than genes just “changing” involved. New protein configurations would require new genes. This is, of course, where gene duplication supposedly becomes the champion. But even if this happens, only mutations can make the copy functional in some new role, on a completely chance basis. The whole idea is preposterous.

Originally posted by txpiper
If you’re talking about evolution of eyes, there would be a lot more than genes just “changing” involved. New protein configurations would require new genes. This is, of course, where gene duplication supposedly becomes the champion. But even if this happens, only mutations can make the copy functional in some new role, on a completely chance basis. The whole idea is preposterous.

Eyes aren't as much the result of new proteins, as they're the result of how old proteins are put together in new ways (gene expression).

Originally posted by txpiper
reply to post by stereologist

 

I think you're question may really be "How tissues end up where they ought to be?"

No, my question is always about how an unpredictable series of random DNA replication errors produced specialized tissues, and how those screw-ups produced the control mechanisms that limit, distribute and regulate specialized cells.

Do you not think it just a tad unlikely that...............................................




[edit on 2-6-2010 by txpiper]

Complete the above quote. Best answer gets a prize.

reply to post by rhinoceros

Eyes aren't as much the result of new proteins, as they're the result of how old proteins are put together in new ways (gene expression).

How exciting that the genes would accidentally express themselves in such phenomenally coincidental and cooperative ways.

I have to think that the largest and worst intellectual consequence of materialism is the inability to appreciate the impossible.

reply to post by txpiper

I have to think that the largest and worst intellectual consequence of materialism is the inability to appreciate the impossible.

What I find interesting is that every creationist lecture I have ever seen is put on by a speaker that purposely and maliciously lies about the evidence and evolution.

Fortunately, that's not you. You do resist learning biology and at times mock what happens inside of cells. What differentiates you from most creationists is that you exhibit a strong desire to learn.

There are regulatory genes that affect other genes. That's well known. This is well studied.

These are the Hox genes. You might want to take a look.
Hox gene

These genes are critical for the proper number and placement of embryonic segment structures (such as legs, antennae, and eyes).

These genes are a small. They are ancient.

Originally posted by stereologist
What I find interesting is that every creationist lecture I have ever seen is put on by a speaker that purposely and maliciously lies about the evidence and evolution.

Fortunately, that's not you. You do resist learning biology and at times mock what happens inside of cells. What differentiates you from most creationists is that you exhibit a strong desire to learn.

I disagree, again over and over this guy refers to the process as completely random accident (just look at his last post) and refuses to understand that the whole thing is far from random because of selective pressure.

[edit on 4-6-2010 by rhinoceros]

reply to post by stereologist

You do resist learning biology and at times mock what happens inside of cells.

I resist theories biology theories and ideas that do not acknowledge statistics and probabilities.

There are regulatory genes that affect other genes. That's well known. This is well studied.

Of course, but once again, the issue is how random, undirected errors could result in hyper-complex formations and processes, like what happens inside of cells.

reply to post by rhinoceros

… refuses to understand that the whole thing is far from random because of selective pressure.

I recognize buzz phrases like “selection pressure” for what they are. All selection can do is remove unfit organisms. Beyond that, it is not a causal influence. The “whole thing” is completely dependant on mutations. Fluffing up natural selection is just trying to hide from that reality.

reply to post by txpiper

I resist theories biology theories and ideas that do not acknowledge statistics and probabilities.

Your references to probabilities was wrong on many important issues. It was a flagrant misrepresentation of the issues. I gave a number of reasons and have seen no responses to the 4 reasons I provided. I explained 2 of them and left the other 2 to be reviewed and analyzed by others.

Of course, but once again, the issue is how random, undirected errors could result in hyper-complex formations and processes, like what happens inside of cells.

As I pointed out with the Hox genes there have been billions of years to get this working. These Hox genes are hundreds of millions of years old. There are not millions, but a relative handful of these regulatory genes.

All selection can do is remove unfit organisms.

Not quite correct. Fit and unfit organisms are removed, but those either in the right place or better fit survive. Even though the underlying source of change is random mutations, it is survival to reproduce that counts.

Attempting to misrepresent evolution is simply something that should be left up to creationist speakers.

reply to post by txpiper


Perhaps you should acquaint yourself with Richard Lenski and his 20 year long study that quite literally proves, verifies and witnesses evolution in action. I realize in advance that this will in no way change your opinion but it will make your arguments less rational.
rationalwiki.org...

www.newscientist.com...

rationalwiki.org...

[edit on 4-6-2010 by peter vlar]

reply to post by peter vlar

“…Richard Lenski and his 20 year long study that quite literally proves, verifies and witnesses evolution…”

I am familiar with that experiment. Nobody disputes adaptations.

reply to post by stereologist

These Hox genes are hundreds of millions of years old. There are not millions, but a relative handful of these regulatory genes.

I’m not quite sure what you are getting at here. Hox genes are like main switches that trigger thousands of other genes.

Even though the underlying source of change is random mutations, it is survival to reproduce that counts.

You are still trying to trivialize the mutation side of the process. No mutations means no change means no evolution. That is not a misrepresentation.