Posted on 09/15/2010 3:57:26 PM PDT by nickcarraway
Any culture’s religious ceremonies can seem strange to outsiders: For example, take the indigenous Zoque people of southern Mexico. To ask their gods for bountiful rains during the growing season they head to a sulfur cave where molly fish swim in the subterranean lake. They then toss in leaf bundles that contain a paste made from the mashed-up root of the Barbasco plant, which has a powerful anesthetic effect.
When the stunned fish–which the Zoque people consider a gift from underworld gods–go belly-up, people scoop them from the water and bring them home for supper. This fishy protein helps them make it through until the harvest. This ritual came to the attention of scientists studying the molly fish, who wondered how the toxic root might be affecting fish populations in the caves. So evolutionary ecologist Michael Tobler and his colleagues did a little field research.
From LiveScience:
“We learned about the ceremony, and actually attended it in 2007,” Tobler recalled. “The families each take a certain amount of the fish home. The way we had ours prepared was that they were just mixed with scrambled eggs, although I hear other families fry them. They had a funny salty taste to them, although I’m not sure if that’s because of their sulfuric environment, or something the cook messed up.”
The researchers got more than a taste of local culture, they also came up with evidence of evolution-in-action that they published in a study in Biology Letters. In lab experiments they compared molly fish from the ritual cave to others from an area upstream that had never swam in poisoned water, and found that the cave fish had a much higher tolerance for the Barbasco toxin.
Study coauthor Mark Tobler of Texas A&M University told New Scientist the results show that within the ritual cave, evolution has selected for fish that can survive the poison.
“The study indicates that the fish have adapted to the local Zoque traditions,” says Tobler, who describes the effect as “an intimate bond between nature and local culture.”
The relationship may be intimate, but the Mexican government is worried that it’s also detrimental–officials have banned the ceremony, saying it’s bad for the fish.
False premise, many of these things serve other functions independently just as we see in simple mollusks.
Perhaps that is why bacteria, as part of their stress response, induce a higher mutation rate. To increase the amount of variation.
As for the fish, over time every variation that made them resistant to the toxin would accumulate in the population.
I doubt that there is just one genetic variation responsible for this, but more likely several.
the light spot serves what other functions ??
“Study coauthor Mark Tobler of Texas A&M University told New Scientist the results show that within the ritual cave, evolution has selected for fish that can survive the poison.”
The survivors survive. Another great leap forward in science.
EXACTLY
the pigment spots
the nerve cells that has to go to the brain
EXACTLY - there are 2 “steps” right there in your drawing
edit
“nerve fibres” instead of cells(the connective tissue I first stated)
First, I don’t have a problem with evolution. However, couldn’t you have the pictures backwards? Couldn’t it be just as possible that the less developed eyes came from more developed ones? what is it that proves the stages are from less complex complex to more rather than more complex to less?
What would trigger the less developed eyes to be a trait that would be passed on to future generations? How cold losing a sense increase the chances of survival and passing on the trait of loss?
Yet pigment spots on their own serve a unique purpose and the nerve connection also serves a unique purpose, both work as independent functions (for pigment spots, just like with us, protection from UV, for nerve connection, the sense of touch).
Each one had a unique, much simpler role independent of what would become sight. One functions fine in its independent role without the other.
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Interesting. Thanks for posting that.
Of course it ends poorly for the fish, he's eaten.
The same thing that triggers a change that is more developed. A mutation.
<How cold losing a sense increase the chances of survival and passing on the trait of loss?
1. You are assuming that evolution would always be a change that increases survivability. A species could evolve in such a way that it becomes extinct or, perhaps, just not quite as survivable.
2. The loss of a sense could be paired with an increase in other senses that are more applicable to that species, or at least more useful at one point in time (see number 1 above).
3. It has presumably occurred already. See, for instance, Astyanax fasciatus.
Biologists have a penchant for making assumptions that are not demonstrable or realistically testable. Assuming cause and effect, or worse, confusing cause for effect can lead to bizarre and wholly incorrect conclusions. Could it have been that astyanax fasciatus went blind and those living in the caves survived because eyesight wasn't necessary? How could you even test that?
Just like philosophies, religions, cultures, ethnic groups, etc., have memes, so does biology. After reading Hawking's latest (and ridiculous) screed, you can see that scientism has now been provided with its own metanarrative (string theory, which, according to Hawking, should be embraced as fervently as the "fact" of anthropogenic global warming). It even includes its own eschatology. I will grant that the completion of this metanarrative was penned by a physicist and not a biologist. I just don't see the difference in what the evolutionary biologists and string theorists are providing me and what the Hindus tell me. If you can't prove it in a repeatable test, it's not science. It's philosophy. I have nothing wrong with philosophy, but call it philosophical biology or philosophical physics, not science.
Right, but the point is what would cause the mutation to be a trait that is passed on?
You are assuming that evolution would always be a change that increases survivability. A species could evolve in such a way that it becomes extinct or, perhaps, just not quite as survivable.
No, I accept the fact that both positive and negative mutations happen- evolution, however, is those traits being passed on resulting in continued change. A mutation that causes a negative change is less likely to be passed on if it risks the life, health, or breeding capability of the animal.
It has presumably occurred already. See, for instance, Astyanax fasciatus.
In the Astyanax fasciatus, they evolved away the use of sight, however, the eyes did not devolve downward to just basic pigment cells, they still have the same basic structure as similar sighted animals, only unusable (I believe in the bat cave fish, if memory serves me correctly, it is just a growth of tissue over the eye).
Maybe they should switch to this:
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