Blind Cavefish Designed to Adapt to Low Oxygen Levels
Although tetra means four, here it is a short form of Tetragonopterus, a genus name meaning "square finned" or "four-sided-wing". Tetras are popular with aquarists because some are quite colorful. The Mexican tetra is unimpressive in appearance, and has two forms. The most common lives where one would expect to see fish doing fish stuff, but the other is the blind cavefish. (We had some in our aquarium, and thought they were gentle and got along with other fish.) They exhibit changes that are erroneously claimed to be examples of evolution.
As in other cases, Darwin's disciples try to bamboozle people by saying loss of traits are examples of onward and upward evolution. Blind cavefish have shown that they are designed to adapt. For that matter, the blind and sighted varieties cannot be considered separate species, so there's nothing exhibited that can be legitimately claimed as evolution. Interestingly, blind cavefish in aquariums do just fine in well-oxygenated tanks, but the Master Engineer designed them with an adaptation that surprised scientists.
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| Blind cavefish, Wikimedia Commons / Syrio (CC BY-SA 4.0) |
A wide array of fish, amphibians, and arthropods have successfully colonized cave environments. In their cave adaptation, these creatures display complex systems of morphological, physiological, and behavioral traits that allow them to thrive in light-deficient and resource-scarce environments. One of the best-studied of these creatures is the Mexican tetra blind cavefish which is now revealing surprising and ingenious adaptive engineering that enables it to thrive in oxygen-depleted cave water.
To read the rest, go to "Oxygen-Based Adaptive Engineering in Blind Cavefish."