Fish "missing link" found

[CabVet]

Wonky-Eyed Fish Link: DNews Nuggets : Discovery News

From the article:

There are about 600 species of flatfish, many of which are caught and eaten by humans. Scientists know why these fish have two eyes on one side of their faces. As free-swimming larvae, these fish have eyes on both sides of their heads. But as adults, they lie on the seafloor. By shifting one eye up and over their body's midline, flatfish avoid pointing one eye down toward the sediment.

But how this arrangement emerged has caused debate among scientists, since no living fishes show any intermediate form. At one point, flatfishes were among the examples some critics used to attack gradual evolution and natural selection that occurs over many generations, in favor of dramatic changes that could occur within a single generation, Friedman said.

"What this fossil does is it provides a clear example of precisely that intermediate morphology," Friedman told LiveScience.

 

[Elendur]

Cool ever since I was young I've been wondering over that strange movement of the eyes. Thanks for the additional information

 

[AV1611VET]

You guys who believe in missing links ... do you have names for these animals made up ahead of time; or, as I suspect, are they called 'transitional' and named after they're found?

 

[CaliforniaSun]

You guys who believe in missing links ... do you have names for these animals made up ahead of time; or, as I suspect, are they called 'transitional' and named after they're found?

You really have no idea what you're talking about, do you?!

 

[AV1611VET]

You really have no idea what you're talking about, do you?!

Nope ... should I?

 

[Elendur]

Nope ... should I?

Yes. You should.

 

[CabVet]

You guys who believe in missing links ... do you have names for these animals made up ahead of time; or, as I suspect, are they called 'transitional' and named after they're found?

we don't "believe" in missing links, we accept that the fossil record is not perfect, big difference. They are named after they are found, and nobody knows what they look like. Based on the morphology of fossils before and after the transition, we "guess" more or less what the transition should look like, but nobody knows how exactly it looks like until we find a fossil.

FYI, this one was named Heteronectes. Here is a photo:

Flatfish have both eyes on the same side of the head. Their ancestors have one eye on each side. The fossil has one eye on the side and the other on top of the head.

 

[AV1611VET]

Yes. You should.

That door swings both ways, doesn't it?

 

[Elendur]

That door swings both ways, doesn't it?

Yup, it does.

 

[AV1611VET]

we don't "believe" in missing links, we accept that the fossil record is not perfect, big difference. They are named after they are found, and nobody knows what they look like. Based on the morphology of fossils before and after the transition, we "guess" more or less what the fossil should look like, but nobody knows how exactly it would look like.

Who said anything about 'looks like'?

And for the record, did you get the point I was making?

Even Watson couldn't hold all the information, if you had atom-2-adam daisy-chained.

 

[AV1611VET]

Yup, it does.

Then I'll reiterate:

Nope ... should I?

 

[CabVet]

Who said anything about 'looks like'?

And for the record, did you get the point I was making?

Even Watson couldn't hold all the information, if you had atom-2-adam daisy-chained.

Yep, totally missed the point. And I'm still missing it.

 

[AV1611VET]

And I'm still missing it.

Well ... Heaven knows ... you guys are the experts on missing links; not I.

 

[Elendur]

Then I'll reiterate:

Nope ... should I?

And I'll repeat:
Yes. You should.

 

[CabVet]

Well ... Heaven knows ... you guys are the experts on missing links; not I.

Well, that one is not missing anymore, that is all I can say.

 

[AV1611VET]

Well, that one is not missing anymore, that is all I can say.

Do you think it would help if they put their pictures on the back of peanut butter jars?

 

[CabVet]

Do you think it would help if they put their pictures on the back of peanut butter jars?

Probably not, but having better science teachers and encouraging higher education probably would help.

 

[rush1169]

Just a drive-by observation, not to imply my endorsement or non-endorsement of biological evolution, but this made me beg a question (to follow):

as these fish mature, one eye migrates over the top of the fish's head, coming to rest above the other eye. . . .The left eye of this single specimen. . . .has migrated toward the top of the skull, but not all the way over

Wouldn't it more likely be a defect in the DNA that resulted in a signal for the eye to stop prematurely? Alternatively, wouldn't it be more likely that the signal for the eye to move never properly fired, but as the fish grew, the left eye wasn't 'anchored' and simply ended up where it did?

 

[CabVet]

Wouldn't it more likely be a defect in the DNA that resulted in a signal for the eye to stop prematurely? Alternatively, wouldn't it be more likely that the signal for the eye to move never properly fired, but as the fish grew, the left eye wasn't 'anchored' and simply ended up where it did?

Regardless of the precise genetic mechanism controlling the position of the eye, it does provide evidence for evolution simply because it has intermediate morphology and because it is from a period when the transition happened.

But to more accurately answer your question, the genetic mechanisms behind metamorphosis on these fish are not well understood as it still costs a lot of money to sequence an entire genome in multiple individuals, but costs are going down, so we might be able to answer questions like that in just a few years (that is if computer power progresses a lot too).

Also, whether it is a "defect" or not is very relative. Every mutation can be seen as a "defect" in DNA replication, their consequences can be useful or not, depending on that specific organism's environment. For example, check this:

http://en.wikipedia.org/wiki/Nylon-eating_bacteria

A recent mutation (or defect) in this bacteria's DNA has allowed it to eat sub-products of nylon manufacturing. If that mutation had happened 100 years ago, the mutants would simply have starved to death since there was no nylon back then.

 

[rush1169]

Regardless of the precise genetic mechanism controlling the position of the eye, it does provide evidence for evolution simply because it has intermediate morphology and because it is from a period when the transition happened.

But to more accurately answer your question, the genetic mechanisms behind metamorphosis on these fish are not well understood as it still costs a lot of money to sequence an entire genome in multiple individuals, but costs are going down, so we might be able to answer questions like that in just a few years (that is if computer power progresses a lot too).

Also, whether it is a "defect" or not is very relative. Every mutation can be seen as a "defect" in DNA replication, their consequences can be useful or not, depending on that specific organism's environment.

Oh, so you're saying that it doesn't matter why it's eye was is in the wrong place, the fact that it is weighs more heavily in favor of it being a transitional creature than any other possibility, including a birth defect, because of it's relative position in the strata?

Sorry for the dumb questions - I'm still learning.