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.

[Dimensio]

Anyway, I have offered three references of evolutionist that said the theory was incomplete.......for starters.

I did not see those references. Nonetheless, the claim itself is of little consequence. All scientific theories are incomplete. That is why research always continues in investigating scientific explanations. Evolution is no different than any other scientific explanation in that regard.

[Dimensio]

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.

Are you suggesting that I am making a personal "stab" -- or attack -- to individuals when I point out that their claims are in error? Should I refrain from correcting individuals who make statements that are not true? Do you believe that I was attacking you personally when I explained that your claim of there being "six kinds" of evolution was false and based upon a lie by Kent Hovind?

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.

It was not intended as an insult. It was intended as an observation based upon your statement that you required the consumption of alcohol as a means of comprehending a dynamic biological system.

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".

Your assumptions regarding my behavior and motivations in no way changes the fact that evolution is not based upon "random chance", but rather is a deterministic system due to the nonrandom filter of natural selection. Your commentary regarding your perception of my attitudes do not alter the facts of biology.

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,

I am unable to parse this statement, though it appears to be predicated upon a strawman.

but the rest of us have to learn by practice, research, being aware, seeking the truth, etc.......

I have never claimed that I learned through different methods than "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.:))

If, as you admit, you have not actually studied and researched the theory of evolution, then how can you know that it is a "waste of time"? Moreover, how can you make any authoritative claims regarding the theory, including that it violates the second law of thermodynamics or that there are "six kinds" that include elements of cosmology? Please correct me if I have misunderstood you, but it would appear as though you have just acknowledged that none of the information that you provide regarding the theory of evolution can be trusted as accurate.

[taxesareforever]

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.

No its not. And that is a fact.

[taxesareforever]

Your reply is a non-sequitur.

Again, one of your favorite copouts. And please, don't ask me to explain. I believe it is self-explanatory.

[taxesareforever]

That does not explain how the find falsifies common descent.

Certainly does. Since you state that evolution is a process of mutations how do you explain an organism that hasn't changed in over a million years. You have said that same species don't generate same species. In other words, evolution. A person has to be really really gullible to believe this organism survived by itself for over a million years.

[taxesareforever]

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 then you will declare that evidence false. Happens every time.

[taxesareforever]

Evolution is a theory, and a theory is the highest status that a scientific explanation can achieve.

So if a theory is the highest status that a scientific explanation can achieve, what do scientists call a fossil? Is it a theory or is it a fact?

[Dimensio]

And then you will declare that evidence false.

If information provided is incorrect, I will explain why it is incorrect. Do you believe that false information should not be corrected?

[Dimensio]

So if a theory is the highest status that a scientific explanation can achieve, what do scientists call a fossil? Is it a theory or is it a fact?

A fossil is a fact. It is a single data point. It is not an explanation, it is a physical object.

Why would you ask if a word denoting an explanation would apply to a physical object? Physical objects themselves are not explanations.

[Dimensio]

Again, one of your favorite copouts.

It is not a cop-out to state that a reply does not address the previous statement.

[Dimensio]

No its not.

If your speculation is not unfounded, then please provide the supporting evidence that supports your speculation.

[Ethan Clive Osgoode]

How have I misstated the situation?

Natural selection is not a deterministic process.

[Ethan Clive Osgoode]

Natural selection produces a deterministic result from random input.

That is not only false, it is absurd.

[taxesareforever]

Do you believe that false information should not be corrected?

I don't think it should be declared false because it doesn't agree with what you believe.

[taxesareforever]

A fossil is a fact. It is a single data point. It is not an explanation, it is a physical object. Why would you ask if a word denoting an explanation would apply to a physical object? Physical objects themselves are not explanations.

Because a fossil cannot be proven for a fact to be as old as many say it is. Therefore, it is a guess or theory and you stated that the theory of evolution is the highest category of theory there is. Now you say a fossil is a fact. I believe you are getting theory and fact confused.

[Dimensio]

Natural selection is not a deterministic process.

Then what sort of process is it?

[Dimensio]

I don't think it should be declared false because it doesn't agree with what you believe.

When I state that an assertion is false, I provide justification for that statement. I do not declare statements to be false merely because they contradict "what I believe". If you have evidence to suggest otherwise, please present it.

[Dimensio]

Because a fossil cannot be proven for a fact to be as old as many say it is.

You are speaking of the age of fossils, not the fossils themselves. You have changed the subject of discussion.

Therefore, it is a guess or theory

Actually, when speaking of calculated ages, the correct description is "estimate", based upon established and trusted techniques.

and you stated that the theory of evolution is the highest category of theory there is.

You you have again misunderstood my previous statements. I have said that a theory is the highest category of scientific explanation that there is. I did not say that the theory of evolution is the "highest category of theory".

Now you say a fossil is a fact.

Correct.

I believe you are getting theory and fact confused.

I am not confused. Fossils, as physical objects, are data points. Physical objects may be used to derive explanations, but physical objects themselves are not explanations. As such, physical objects, including fossils, cannot be considered theories.

[Ethan Clive Osgoode]

Then what sort of process is it?

A non-deterministic one.

[Dimensio]

A non-deterministic one.

Is it a random process?