Evolution in action? African fish could be providing rare example of forming two separate species

Cornell University ^ | 01 June 2006 | Sara Ball

[PatrickHenry]

Avoiding quicksand along the banks of the Ivindo River in Gabon, Cornell neurobiologists armed with oscilloscopes search for shapes and patterns of electricity created by fish in the water.

They know from their previous research that the various groups of local electric fish have different DNA, different communication patterns and won't mate with each other. However, they now have found a case where two types of electric signals come from fish that have the same DNA.

The researchers' conclusion: The fish appear to be on the verge of forming two separate species.

"We think we are seeing evolution in action," said Matt Arnegard, a neurobiology postdoctoral researcher in the laboratory of Carl Hopkins, Cornell professor of neurobiology and behavior, who has been recording electric fish in Gabon since the 1970s.

The research, published in the June issue of the Journal of Experimental Biology, describes how some of these fish violate an otherwise regular pattern of mating behavior, and so could be living examples of a species of fish diverging into separate species.

Although these fish look alike and have the same DNA genetic makeup, they have very different electrical signals and will only mate with fish that produce the same signals. Cornell researchers believe that these different electrical signals are the fishes' first step in diverging into separate species.

The electric fish -- known as mormyrids -- emit weak electric fields from a batterylike organ in their tails to sense their surroundings and communicate with other fish. Each species of mormyrid gives off a single characteristic electric impulse resulting in the flash of signals, indicating, for example, aggression, courtship and fear. While the fish may be able to understand other species' impulses, said Arnegard, "They seem to only choose to mate with other fish having the same signature waveform as their own."

Except for some, Arnegard has discovered.

When he joined Hopkins' lab, the team was about to publish descriptions of two separate species. But when Arnegard decided to take a genetic look at these particular fish, he couldn't find any differences in their DNA sequences.

"These fish have different signals and different appearances, so we were surprised to find no detectable variation in the genetic markers we studied," Arnegard said.

Because all of the 20 or so species of mormyrid have distinct electric signals, Arnegard believes the different impulses of the fish he studies might be their first step in diverging into different species.

"This might be a snapshot of evolution," Arnegard said.

Understanding how animals become different species, a process known as speciation, is a major concern in understanding evolution. Arnegard's fish may allow researchers to test if a specific type of speciation is possible.

One common type of speciation is geographically dependent. Animals diverge into separate species because they become physically isolated from each other. Eventually, genes within each group mutate so that the groups can no longer be considered to be of the same species.

Another type of speciation, which many scientists have found harder to imagine, involves animals that live in the same geographic location but, for some reason, begin to mate selectively and form distinct groups and, ultimately, separate species. This so-called sympatric speciation is more controversial because there have been few accepted examples of it to date.

"Many scientists claim it's not feasible," Arnegard said. "But it could be a detection problem because speciation occurs over so many generations." These Gabon fishes' impulses, however, can change very quickly in comparison. So Arnegard suspects that the different shapes of the electric impulses from these mormyrids might be a first step in sympatric speciation.

One the other hand, the fish could be a single species. "This could be just a polymorphism, like eye color in humans, that violates the fishes' general evolutionary pattern but doesn't give rise to separate species," said Arnegard, who will return to Gabon in June to conduct further tests, funded by the National Geographic Society.

[tgambill]

ping

[Dimensio]

He is fighting for dear life and you will notice that it is personal battle to maintain a protected belief and fulfill a very definite agenda.

What, exactly, is my "agenda"? You seem to know more about my motives than I do.

This also incorporates the old saying that denotes a very personal interest..."He Doth Protest too much"

What, exactly, do you mean by this?

lolol....:)) the process of evolution is NOT RANDOM......even though it incorporates a RANDOM EVENT?

Correct. Mutations create random variants of offspring from a parent generation of an organism, however the process of natural selection, which acts as a filter upon the variants, is nonrandom, producing a deterministic result.

I need a few shots to actually understand this.

I do not believe that the consumption of alcohol will improve upon your apparently deficient ability to comprehend dynamic systems.

Naturally, he will respond with a clever retort that will say words to the effect; that its hard for me to understand any concept or words to the effect. Watch......his response.

If I am using words or concepts that you are unable to comprehend, then please ask me to clarify any such words or concepts. Have you considered that perhaps your confusion lies in a lack of education on the subject?

[Dimensio]

What you really mean is "give me your data and I will say it is false." Happens everytime.

If false data is given, I will explain it as such. I will not call it false merely because you have presented it, however. Your speculation is unfounded.

[Dimensio]

That's the same as saying if you mix milk with oil all you have is milk.

Your statement is in no way analagous to the concept of natural selection producing a deterministic result even though one of the input parameters is random. Your reply is a non-sequitur.

[Dimensio]

To begin with creation is not a "mechanism" since creation is the result of a Divine Being.

The involvement of a "Divine Being" in the process does not make "creation" any less a proposed mechanism for the emergence of the first life forms.

Since when is any being considered a mechanism?

I am referring to the event, not any "beings" who may have been, in whole or in part, responsible for the event.

Following your lead what is the result of this "mechanism"?

Under the creation account that I have heard from most creationists, the result of "creation" is the existence of everything, however with respect to the current discussion as a means of comparison to abiogenesis the result is the emergence of the first life forms.

[Dimensio]

Let me see. Extinct millions of years ago and now it turns up as a living fossil. Wonder whose houses it was visiting in those millions of years. Millions of years and it's still the same today as it was then. Don't ask me to prove it. I wasn't there.

That does not explain how the find falsifies common descent. Why do you believe that the theory of evolution predicts that should a find should never have occured?

[Ethan Clive Osgoode]

Mutations create random variants of offspring from a parent generation of an organism, however the process of natural selection, which acts as a filter upon the variants, is nonrandom, producing a deterministic result.

That is false.

[Dimensio]

That is false.

How have I misstated the situation?

[tgambill]

"If false data is given, I will explain it as such. I will not call it false merely because you have presented it, however. Your speculation is unfounded."

****lolol...:)) You don't even see it. This is too funny. I'm actually starting to enjoy this. Not only do we, or I get to cite references and show your weaknesses concerning the ToE but it does help build my understanding of the matter to be better able to spread the truth. For this I thank you and am glad that you are so persistent to hold on to your assertions with extreme zeal. Bravo.

In your own quote, you proved his point exactly as the last word....;)) "however. Your speculation is unfounded",
exactly the point. Now, you will come back to declare that the reason you wrote this retort was because it says exactly the point you were making, that the post was false. We can do this all day long. Hey, you should of worked for the clinton Admin....big bucks for being a spin doctor.

Okay back to the thread. This is good.

[RunningWolf]

evo extreme zeal tight-locked circle placemarker

[Dimensio]

Not only do we, or I get to cite references and show your weaknesses concerning the ToE but it does help build my understanding of the matter to be better able to spread the trut.

You have demonstrated no "weaknesses" with the theory of evolution that I have not addressed, and you have not responded to my rebuttals of your claims regarding alleged weaknesses. You have provided exactly two references in the course of this discussion. Only one of those references claimed to explain "weaknesses" in the theory. I addressed the alleged weaknesses presented in the resource, and explained how they are not actually a weakness for the theory of evolution.

You claim that this discussion has helped to "build your understanding". Does this now mean that you understand that the Big Bang, planetary and stellar formation and abiogenesis are not a part of the theory of evolution? You have not made mention of acknowledging that you were incorrect on those points.

In your own quote, you proved his point exactly as the last word....;)) "however. Your speculation is unfounded",

How, exactly, have I proved this point? Please be specific.

Now, you will come back to declare that the reason you wrote this retort was because it says exactly the point you were making, that the post was false.

Actually, I am unable to discern the meaning of a number of your statements, and as such cannot give a declaration of truth value.

We can do this all day long.

If you are referring to my correction of common creationist falsehoods while creationists continue making them, then you are correct.

Hey, you should of worked for the clinton Admin....big bucks for being a spin doctor.

Please cite a specific example where I have "spun" anything.

[apackof2]

The theory of evolution is not an attempt to discredit the Bible,

Well I never inferred that is was.
And you say,

"If the theory of evolution contradicts Biblical claims"

If?

Do you think it does or does not?

And if it does, than what conclusive prove is there that the claims of evolution are correct making the Biblical claims incorrect?

[Dimensio]

Do you think it does or does not?

I do not analyze Biblical claims until they are presented to me. I have heard individuals tell me that Biblical claims contradict the theory of evolution. I have also heard from individuals who state that the Bible does not contradict the theory of evolution. As I do not rely upon the Bible as a source of information regarding the theory of evolution, I can only take the claims of contradiction or non-contradiction at the word of those who make the statements. When an individual claims that there is no contradiction, then there is no reason to request clarification or validation of the claim, however when an individual does claim a contradiction and then states that the contradiction suggests that the theory of evolution is false, I will request evidence for the claim.

And if it does, than what conclusive prove is there that the claims of evolution are correct making the Biblical claims incorrect?

Scientific theories are subject to evidentiary support; they can be validated to varying degrees of confidence -- with some confidence required for the explanation to be labelled a theory in the first place -- however scientific theories can never be "conclusively proven".

Evolution has been validated by multiple independent lines of evidence; most notably, both the fossil record and remnants in the DNA of extant species have created independent lines of evidence suggesting the same conclusions regarding common descent.

[tgambill]

This also incorporates the old saying that denotes a very personal interest..."He Doth Protest too much"

"What, exactly, do you mean by this?"

***** Sure, I mean that your posts are actually very thought provoking. You answer with Extreme zeal, using complex, almost philosophical methods of argument to retort each....and.....every.......post....word for word or even sentence by sentence for very poster that has a contrary view point like clock work.....In every case, you somehow work the response around to either be incorrect, false, wrong, and followed in some cases with a cleverly written "stab" to the poster......in order to create frustration or result in a "aggressively written retort' that could get the mods' attention. Very good technique.....that is he doth protest too much. If you didn't have an signficant agenda you would not hold on so tightly. You are holding on very, very tightly.

---

"I do not believe that the consumption of alcohol will improve upon your apparently deficient ability to comprehend dynamic systems."

***** You don't understand, the consumption of alcohol is the only way someone can understand the double talk and round de round verbage that you use to refute each and every response that is contrary to your agenda. Opppps, he will write back..."what Agenda" and i will write back a well, constructed and fully developed response....that covers the exponential retort....:)) in the form of "DUH"! :))

"your apparently deficient ability to comprehend dynamic systems"

***** I'm right again, you used that clever little method of sliding in a cleverly written insult, that might escape the observation of the mod. You are so predictable it's almost getting boring now, it was endearing, but in another way, a simplistic mind disquised by using superflorous words and typical Evolutionist retorts. If I didn't know better, I would swear that Evolutionist had a correspondence course on "How to talk to Creationist and Those Who Believe in ID".

My prediction:

"Naturally, he will respond with a clever retort that will say words to the effect; that its hard for me to understand any concept or words to the effect. Watch......his response."

Your predictable response before the above post:

"If I am using words or concepts that you are unable to comprehend, then please ask me to clarify any such words or concepts. Have you considered that perhaps your confusion lies in a lack of education on the subject?"

*****Now, I realize that in your evolutionary tree, a higher developed monkey and that your family was born with this knowledge as a result of natural selection from the dumb ones that existed before, but the rest of us have to learn by practice, research, being aware, seeking the truth, etc.......I will admit that my education lacks in the complete theory of evolution as I suffer from a condition I developed in my early years. It's called "WAFOT Syndrome".....After reading about Evolution and from the effects, the symdrome developed. Oh, WAFOT...it's called. What a "Blankyity blank" waste of Time" Syndrome.:))

Got to go, however, I will be back to you very soon....

[tgambill]

You have been spinning like a weaver, I'm afraid since you were able to start grade school. You have built a safe haven in this world of denial. You have built a fortress of which you are your own prisoner. However, it is beneficial to the rest, in that we know the truth, and can quit the posting and move on with little or no distrubance of conscious since we know the truth.......

he says...."Exactly what truth are you speaking of"....:))

Anyway, I have offered three references of evolutionist that said the theory was incomplete.......for starters. Also, many more references that you chose to ignore. This is what you have to deal with.


"Actually, I am unable to discern the meaning of a number of your statements, and as such cannot give a declaration of truth value."

**** Exactly my point.....from start to finish. You inability to discern is based on denial and being unable to answer.

"

[tgambill]

wow...so tight locked it squeaks while walking......even with the shuffle steps......

[tgambill]

"however scientific theories can never be "conclusively proven".

Evolution has been validated by multiple independent lines of evidence; most notably, both the fossil record and remnants in the DNA of extant species have created independent lines of evidence suggesting the same conclusions regarding common descent."

***** So, now you are declaring that the theory of Evolution is not a theory any longer. You better tell the rest of the world, they still believe it's a theory. You better straighten them out. You have disappointed me.

---

"Evolution has been validated by multiple independent lines of evidence; most notably, both the fossil record and remnants in the DNA of extant species have created independent lines of evidence suggesting the same conclusions regarding common descent."

****last time I heard, when something is validated, there is no evidence "suggesting" the same conclusions, the evidence concludes and has demonstrated beyond a shadow of a doubt validation has occurred. Now, you will give some more double talk, a personal attack and cite references you obtained from Evol-School, but this is unforgiveable and demonstrative of your lack of credibility.


Seriously, you erred big time....Evolution has never been validated by the way or it would have made big news. It's only been "validated" because Evolutionist are in a hurry to spread the lies.

[tgambill]

I love his answers......I swear, he must be a computer retort program, in that he/she loves the phrase..."Your reply is a non-sequitur". It's that thar "non-cuter" word agan. I do declar, he be one of them non-quiters who uses "non-cuter" type words.....:)) lolol....

At this point, its starting to become fun and very predictable.

On a serious note, you are correct, the double talk he uses here was written in a double talk fashion meant to deceive. It is in fact false. Now, he will respond to this post..."In what way is it false"...blah blah blah....

your response, is the best one so far and to the point.

[Religion Moderator]

Discuss the issues all you want but do NOT make it personal.

[Dimensio]

So, now you are declaring that the theory of Evolution is not a theory any longer.

You have misunderstood my statements. I did not claim that evolution is not a theory any longer. Evolution is a theory, and a theory is the highest status that a scientific explanation can achieve.

last time I heard, when something is validated, there is no evidence "suggesting" the same conclusions, the evidence concludes and has demonstrated beyond a shadow of a doubt validation has occurred.

Then you are apparently unaware of how scientific claims are validated. There is no "shadow of a doubt" standard in science.

Now, you will give some more double talk, a personal attack and cite references you obtained from Evol-School, but this is unforgiveable and demonstrative of your lack of credibility.

I am employing no "double talk", and it is not my intention to make personal attacks. When I cite references, it is to show that my statements have a credible backing. I do not see why providing evidence to support my claims is "unforgivable", nor do I see how providing evidenciary support for a claim shows a lack of credibility.

Seriously, you erred big time....Evolution has never been validated by the way or it would have made big news. It's only been "validated" because Evolutionist are in a hurry to spread the lies.

You are simply incorrect. Numerous lines of evidence have "validated" the theory of evolution amongst the community of biologists. Your error apparently lies in your misconception that scientific validation means establishing a claim beyond "a shadow of a doubt". You are mistaken, thus your conclusions are incorrect.