Would you care to hear about one piece of evidence for evolution?

Question

Genetics:

Here is an analogy:
Take a document and make 2 photocopies. Then take those two copies to separate machines and copy them 1000 times, each time feeding the new copy into the machine. Little imperfections will begin appear on each of the two isolated sets that will be "passed on" to future copies. Now make two copies of each final page and repeat the 1000 copies of each of those. If you take your 4 final sheets and mix them up, it would be easy to re-group the two pairs that came from the same parent document, based on a comparison of accumulated changes.

This is what is done with DNA. Simply due to imperfections in copying, changes accumulate in untranscribed regions of DNA molecules. I'm talking about DNA that is not used to code for any protein - so this measure of relatedness is not due to a structure-function relationship, and these changes have zero effect on the organism.

This piece of evidence is often termed the "molecular clock"

questions:

Had you heard this explained before?

Did it make sense?

Tom, the mechanism is very similar. The mutations that don't change the amino acid are perfect for my point. They have no effect, but contain information about relatedness. They are passed on when the DNA is replicated.

btw, ribosomes have nothing to do with DNA replication; they are used to translate mRNA into protein.

dendronbat,
I thought an analogy might be useful for some people who start to glaze over when you give them real details. It may have worked better for people like aussie, who haven't seen any of the science.

aussie,
i guess you didn't get it. please try and read it a little more slowly. if you investigate this a little, you will find the science behind it. if you have real questions about how it works, i'd love to hear them. sadly, it looks like your approach is just to get angry and avoid the information that you don't want to hear. oh well...

Answer 1

Oh dear sweet Jesus, Mary, Joseph and his amazing technicolor dreamcoat! Did you read Quella Bella's answer?

Please, please, PLEASE God, if you are real, teach your followers about nature.

Answer 2

Why care? There is the great potential for harm. Take the Dover (Pennsylvania) Area School District. Two Creationist members of the School Board, through surreptitious means, got their church to buy Creationist text books as an "anonymous" donor. They convinced three apathetic board members to approve its introduction into the classroom. The result was that all the science teachers retired. When the parents sued, the School District fought and lost (despite the Creationist board members lying under oath and only missing perjury charges by technicalities). The small school system had to pay extensive court costs. Take Texas. A state board approves textbooks every ten years. A single vote is often the difference between science and religious indoctrination, and for a state that populous, its textbook selection impacts the whole United States. With California's budget crisis, there won't be new textbook orders for several years, so Texas has even more power. I don't care what they think. I have no interest in convincing those who chose ignorance. I do care that they would try to impose their ignorance on others.

Answer 3

First, let me say that this analogy while understandable and easy to follow, it is also a woefully inadequate comparison. Photocopiers do not have error trapping proofreading mechanisms such as are resident in DNA, and the introns you refer to are not presently understood by science, so to postulate that they have "zero effect on the organism" is a stretch to say the least.

Secondly, the method by which a photocopier propagates error is not comparable since the mechanism is entirely different. The drum which picks up the toner has been magnetized in an exceedingly rough fashion that under a microscope can be shown to be only approximate. DNA, however, is copied molecule for molecule with an accuracy rate of fewer than one mistake per 1,000,000 nucleotides. The few mistakes that do creep through either end up coding correctly anyway since there is more than one way of coding for most aminos, or else they are caught and corrected by the proofreading mechanism of the rhibosome.

Tom

Answer 4

Remember that analogies are by definition inexact. So creationists like cthemagi, Aussie, maguyver, etc. will be able to debate you on the weakness of your analogy.

Better to combine an analogy then with the data on how this relates to evolution. For example,the evolution of trichromatic vision in humans and closely related African primates.
Reptiles have four genes coding for different opsins. Humans and other mammals have only 2 of these genes which still code for opsins. We have the other two genes in fossilized form--stop codes have been introduced in these genes. When mammals became nocturnal in the Cretaceous there was no pressure from natural selection to prevent transcription errors in the nucleobases (which would act as stop codes) of genes coding for opsins of short wave light reception. As some mammals became diurnal, and further dependent on finding ripe fruits, there was selective pressure to re-evolve vision sensitive to the red end of the spectrum. In humans and other African primates related by common ancestry for the last 22 million years there is a third gene which allows for trichromatic vision. It is a near duplicate of the gene coding for the MWS opsin. It lies right next to it on the chromosome. Only three out of the 269 nucleotide sequences in this gene have been modified, enough so that it codes for a SWS opsin. Gene duplication, three nucleobase transcription errors and viola, you have the evolution of trichromatic vision.

With real examples of how evolution works on a molecular level, you can teach better science than with such inaccurate analogies as photocopying.

Answer 5

I played a computer game called SimLife and it was what finally got me to understand the mechanism for evolution. Basically, it has a planet that you populate with creatures. There are environmental conditions that they have to deal with and they have to deal with each other as well. They also can reproduce and there is also a very simple gene sharing part of the game going on. If you let it run long enough you will find that the creatures you placed have adapted to the surroundings. If you change the surroundings you will find that many generations later, the new life forms will adapt to the new surroundings (provided the change did not kill them off).

Answer 6

Yes I have heard and read about the molecular clock, there's a news article about how the male human DNA of today's homosapien is 80,000 years younger than the female human DNA, but you might get a little heat from the religious people from this forum.

I'll try to find the article.

Answer 7

The lengths some people will go to to try to explain a "theory !"

All you have done in your exercise is show how characteristics , similar to those in family groups , are passed down . SO WHAT !

We already know that ! .....

Evolutionary nonsense about life structures emerging & evolving by random chance is itself unscientific & implausible except to those who refuse to recognise or acknowledge the presence of a supreme being !

Talk about clutching at straws !

Answer 8

I've heard a variety of explanations for it. What is more impressive is that in addition to comparing genes, the anatomic relationships established by comparing living and fossil creatures had come up with essentially the same results.

Answer 9

& these changes; mutations, are occuring randomly as with the copy machine? I don't think so, the genetic build is gradually tweaking itself(evolving) although chance does play a role.

Answer 10

If you said what I think you said, that DNA can be effected and changed in time, by outside forces or just duplication, then I tend to call that Adaptation.
I wouldn't hold that up to prove Evolution.
Just to me, means that things that live on the Earth can Adapt.
But, what do I know, but that is what I think.
Ditto............

Answer 11

I've heard it before, and it's a great explanation, but it simply reinforces the creation account.

Adam and Eve were the original, perfect documents, and each succeeding copy (generation, or person) was more and more imperfect.

Great point, but it doesn't prove evolution.