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And there is no condition to revert in this case. The bacteria were just let to reproduce for 20 years.

resedit wrote:

[snip]
Anyway - G Ledyards definition is not a definition that defines evolution in a way that any mutation is evolution, it's a real definition of evolution that actually has logic and reasoning behind it.

This is a common tactic used by creationists. A scientific paper will be in the form of:
A) here is a problem,
B) here is my solution to that problem,
C) here is my data in support of that solution.
but the creationists will quote part A and say: "Look, even Professor So-and-so says that this is a problem."

Unless and until you back that Ledyards supposed definition with a source I refuse to debate with someone--probably being quoted out of context--by proxy.

Chickenhawk wrote:

And there is no condition to revert in this case. The bacteria were just let to reproduce for 20 years.

There has to be conditions for them to be able to survive and reproduce.

Chickenhawk wrote:

Farmerkev wrote:

Chickenhawk wrote:

And there is no condition to revert in this case. The bacteria were just let to reproduce for 20 years.

There has to be conditions for them to be able to survive and reproduce.

I'm not sure if killing the bacteria would serve as any kind of experimental control.

I just thought that obviously conditions have to exist and even if they try to make them identical environments, 20 years is a long time and lots of minor things might have happened that possibly triggered mutation.

Farmerkev wrote:

Chickenhawk wrote:

Farmerkev wrote:

There has to be conditions for them to be able to survive and reproduce.

I'm not sure if killing the bacteria would serve as any kind of experimental control.

I just thought that obviously conditions have to exist and even if they try to make them identical environments, 20 years is a long time and lots of minor things might have happened that possibly triggered mutation.

Mutations happen constantly at a regular rate, particularly in bacteria.

In this case, it wasn't due to a negative selective pressure, but instead it happened that a chemical already in the petri dishes could be metabolized, some bacteria figured out how, and were slightly stronger as a result (because they had more food-- they could still use the same old food).

resedit wrote:

An example - in Florida, Corn Snakes that are Anery are increasing in the wild. You use to find maybe one a summer, now if you hunt you find several a week. The reason is roads. Roads are black, so the anery gene (sometimes referred to as black albino - lacks all red and most yellow) is advantageous - while sunning themselves on the roads, the anery corns are less visible to predators than their colorful siblings. While the gene did pop up from a random mutation, it is not evolution - take away the roads, and the gene would be deselected rather than new genes being selected.

And entirely new metabolic pathway is basis for labeling a new species, this is a little different than pigment expression. And this was only with 20 years time. Imagine millions or billions of years (oh wait...) in a more diverse environment.

The roads are make anery an advantage - roads warm up during the day, so in the early evening, the roads attract rodents and lizards to feed upon, and the snakes after feeding sit on the road and soak up the heat to digest their meal. The typical yellow and orange corns are more visible to predators like owls and hawks that similarly watch the roads for prey, the anery corns are less likely to be seen on the roads. This is why they occurrences of the recessive gene are increasing and why it would not surprise me if a mutation resulting in a dominant or codominant anery was able to survive in the gene pool.

But it's a shift in the common genotype, not evolution. They are still corn snakes and still are properly classified as corn snakes.

Last edited by resedit (2008-06-26 3:22 am)

Farmerkev wrote:

Chickenhawk wrote:

Farmerkev wrote:

There has to be conditions for them to be able to survive and reproduce.

I'm not sure if killing the bacteria would serve as any kind of experimental control.

I just thought that obviously conditions have to exist and even if they try to make them identical environments, 20 years is a long time and lots of minor things might have happened that possibly triggered mutation.

I reckon they were smart enough to allow for that.

res wrote:

But it's a shift in the common genotype, not evolution. They are still corn snakes and still are properly classified as corn snakes.

You're still thinking short-term. It'll take quite a long time for the corn snakes to turn into...cucumber snakes or whatever because of the generations involved.  The reason bacteria was used in the experiment was that enough generations can occur within the lifetime of the researchers that they could see a change.

So what does the article in the OP say?

In the meantime, the experiment stands as proof that evolution does not always lead to the best possible outcome. Instead, a chance event can sometimes open evolutionary doors for one population that remain forever closed to other populations with different histories.

Lenski's experiment is also yet another poke in the eye for anti-evolutionists, notes Jerry Coyne, an evolutionary biologist at the University of Chicago. "The thing I like most is it says you can get these complex traits evolving by a combination of unlikely events," he says. "That's just what creationists say can't happen."

resedit wrote:

He's twisting what creationists are saying just as much as some creationists twist what evolutionists are saying.

What about the concept of irreducible complexity (and how this experiment runs counter to it) do you not understand?

BTW: how's it going finding the source of that concept that you claim that Ledyards wrote of? You claim you read it in a book--so which book or paper was that? To aid in your recollection, here is his complete journals publication list and here is a list of the most widely held books by or about Ledyards in libraries.

resedit wrote:

D'Eyncourt wrote:

resedit wrote:

He's twisting what creationists are saying just as much as some creationists twist what evolutionists are saying.

What about the concept of irreducible complexity (and how this experiment runs counter to it) do you not understand?

The part where the only claims creationists make have to do with the complexity of genuinely complex systems, such as the eye. No creationist I know of has made a claim that something of this minor magnitude could not happen. In fact - I highly doubt this is the first time it has happened in the lab.
[snip]

Which just shows that you use the concept of irreducible complexity without even understanding what it is. You might consider Michael Behe's own definition:

By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. (p. 39)

Nothing about limiting the definition to "genuinely complex systems." Of course reframing the question into one of semantics ("We believe in micro-evolution but not in macro-evolution" without ever defining the distinction--because there is none) is a common tactic of creationists which leads people off on irrelevant tangents while failing to stay on topic.

btw - from the article, it doesn't even state what mutation was involved - so we don't even know if this is a case of irreducible complexity by your definition.

It probably is at least two mutations since it can only be reproduced from gen 20K or later, but that does not indicate anything complex going on. The first mutation required could be neutral or beneficial in another respect w/o the second mutation, in which case this wouldn't fit anyones definition of irreducible complexity.

Last edited by resedit (2008-06-26 4:01 pm)