Talk:Mexican tetra

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[edit] Opponents of evolution

Apart from the fact that "argument" against evolution doesn't actually make sense, who cares about every little criticsm the Flat Earthers have about scientific explanations of biology? On a zoological entry all that matters is science, not religion.

Neale Monks 20:06, 6 April 2006 (UTC)

I'd say its important to keep some form of this, as the fish is an excellent example of evolution. I'm rewriting it though, to give what I hope is a more balanced view. In particular, the bit about it being evidence of god's creation deteriorating since "the fall" is a tiny minority view, and completely in unacknowledged contradiction to the rest. the section is also entirely unsourced. Loxlie 04:05, 13 February 2007 (UTC)

I'd say that by including 'creatism' concepts in here, you give them validity. Also, the tiny minority view is just that: a tiny minority view and doesn't deserve balance. This also opens the door to include creationist concepts in other articles which would be a disaster. In short, I agree with the flat earth comment - no room for whacky religious commentary. [Jared Spice] 12 September 2007.

I've removed this statement: "Another argument, though representing a minor and controversial subset within creationists, maintains that such 'degeneration' is a product of a "fallen, cursed creation"[4]." I read thier source material and there is no support for this comment, ie not sourced. [Jared Spice] 12 September 2007. —Preceding unsigned comment added by Jspice9000 (talk • contribs) 20:18, 12 September 2007 (UTC)

'Others see such 'degeneration' as an abnormal disability.[4]' Again, removed due to lack of source material. Reference linked to http://www.onesmallspeck.com/chapter%204%20variation.html doesn't say anything about abnormal disability and in fact suggests that blind fish are not genetically different from other fish and can interbreed with 'sighted' fish which would lead the reader to believe that A. Mexicanus isn't a seperate species. [[[User:Jspice9000|Jspice9000]] 20:29, 12 September 2007 (UTC)Jspice9000]

[edit] Why is blindness advantage

The text sugests it is an advantage because that way the fish can use the energy devoted to the development of the eye in feeding, breading, etc..

It seems to me that the real reason is because the lack of that sensitive and soft tissue with no use, is an advantage in a dark cave were the eyes could be hurt and infect. (Sorry for the english)

That is a perfectly valid suggestion, and well worth adding to the text. The only criticism I might make is that many deep sea fish have no eyes, but they do not bump into things. Your English is fine! Please go ahead and make any changes! We all make mistakes here, and other people fix them for us. Cheers, Neale Neale Monks 23:39, 7 November 2006 (UTC)

I hope I've adressed this issue in my edit - there's currently no single definitive answer as to the advantage of losing the use of eyes. In fact there's several. But the fact that there's more than one contender shouldn't be interpreted to mean there's no reason why they shouldn't - quite the contrary. On the issue of bumping into things: 1. like many aquarists who have kept such fish, I can verify they are perfectly good (shoaling) swimmers, and studies show they compensate by using other, heightened senses. 2. still, fish living in caves inevitably face more potential bumps than creatures living in the open ocean - however deep - where there is almost literally nothing to bump into. Loxlie 04:05, 13 February 2007 (UTC)

[edit] Unverified claims?

"Modern genetics has made clear that the lack of use does not, in itself, necessitate a feature's disappearance[1] - as seen in humans with useless evolutionary retentions such as wisdom teeth and the appendix." Does no one consider that we may still be in the process of loosing our wisdom teeth and appendix? It takes thousands of generations for needless features to disappear. Do we know that it's been thousands of generations since we needed them? I want this sentence removed. Altonbr 23:57, 12 September 2007 (UTC)

I would agree but would also like to also delete the first half of the following sentence: "In this context, the positive genetic benefits for the 'degeneration' have to be considered," or at the very least reworded.

What do you think about the following sentence: "Among creationists the cave tetra is seen as evidence against evolution. One argument claims that this is an instance of "devolution" -- showing an evolutionary trend of decreasing complexity -- and that this is inconsistent with the main tenet of evolutionary theory, as it implies a loss of 'information'." How do we know there is a loss of information or that the DNA is less complex? Is there any proof of this? Until this fish's DNA has been thoroughly mapped, we don't know that it is in fact less complex than a sighted fish or it's closest related species. I realize that the flawed understanding of evolutionary theory is pointed out later in the article, perhaps an extra comment here would be useful. Jspice9000 15:33, 13 September 2007 (UTC)jspice9000

I'm finishing my masters in the Jeffery lab, one of the groups that does the majority of research on these fish. The lab has produced several papers showing that there is a change of gene expression patterns in early development. In laymans terms, the gene that governs the lateral structures of the head (including the eye primordia) has a smaller region of expression, while the midline gene is overexpressed. Couple this with the observed large increase of taste buds, and we believe it provides evidence that the selective drive for more taste buds provided the bulk of the evolutionary pressure, rather than energy conservation and injury prevention. The age of these populations is, in evolutionary time, quite young and therefore we think it would take something a bit more advantageous than minor energy conservation or injury prevention. Additionally, not all caves are poor in nutrients, so energy conservation is of variable necessity. http://www.nature.com/nature/journal/v431/n7010/abs/nature02864.html This approach- that it is not eyes lost but rather tastebuds gained at the expense of eyes- may also help answer the question of "more or less complex." It is merely different.70.22.104.69 (talk) 01:28, 20 April 2008 (UTC)