Evolution

Classic in devolution: Burrowing snakes have poor eyesight, challenging theory

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The theory was that snakes evolved from extreme burrowers. But that’s not what this team found:

The ancestor of all living snakes probably had substantially better vision than present-day burrowing snakes, according to new research.

An international team of scientists — led by the Natural History Museum and the University of Plymouth — carried out the first detailed analysis of gene sequence data for any species of the so-called “blindsnakes” (Scolecophidia), a group of small-eyed burrowers.

They found that seven of the 12 genes associated with bright-light vision in most snakes and lizards species are not present in scolecophidians.

This, they say, demonstrates extensive vision gene loss over tens of millions of years of evolutionary history, similar to that which has also been observed in burrowing mammals with reduced vision.

It also challenges the hypothesis that all snakes living across the world today evolved from extreme burrowers, because the vision genes lost in scolecophidians are present in most other living snakes. The researchers say it would be extremely unlikely for such genetic deficiencies to have been reversed through evolution.

University of Plymouth, “Burrowing snakes have far worse eyesight than their ancestors” at ScienceDaily (December 9, 2021)

In short, the Darwinian assumption that something as complex as eyesight could just somehow evolve turns out to be “extremely unlikely”? They’re going to need to eventually read Michael Behe’s Darwin Devolves.

The paper is open access.

3 Replies to “Classic in devolution: Burrowing snakes have poor eyesight, challenging theory

  1. 1
    PaV says:

    Another day–another “bad day” for Darwinism.

  2. 2
    bornagain77 says:

    As to: “The researchers say it would be extremely unlikely for such genetic deficiencies to have been reversed through evolution.”

    A few related note,

    Dollo’s law and the death and resurrection of genes
    Abstract: Dollo’s law, the concept that evolution is not substantively reversible, implies that the degradation of genetic information is sufficiently fast that genes or developmental pathways released from selective pressure will rapidly become nonfunctional. Using empirical data to assess the rate of loss of coding information in genes for proteins with varying degrees of tolerance to mutational change, we show that, in fact, there is a significant probability over evolutionary time scales of 0.5-6 million years for successful reactivation of silenced genes or “lost” developmental programs. Conversely, the reactivation of long (>10 million years)-unexpressed genes and dormant developmental pathways is not possible unless function is maintained by other selective constraints;
    https://www.pnas.org/content/91/25/12283

    Dollo’s law and the death and resurrection of genes:
    Excerpt: “As the history of animal life was traced in the fossil record during the 19th century, it was observed that once an anatomical feature was lost in the course of evolution it never staged a return. This observation became canonized as Dollo’s law, after its propounder, and is taken as a general statement that evolution is irreversible.”
    – ibid

    If evolution is unpredictable and irreversible, … – June 13, 2015
    Excerpt: Using simulations of an evolving protein, they show that the genetic mutations that are accepted by evolution are typically dependent on mutations that came before, and the mutations that are accepted become increasingly difficult to reverse as time goes on.
    https://uncommondescent.com/evolution/if-evolution-is-unpredictable-and-irreversible/

    No Positive Selection, No Darwin: A New Non-Darwinian Mechanism for the Origin of Adaptive Phenotypes – November 2011
    Excerpt: Hughes now proposes a model he refers to as the plasticity-relaxation-mutation (PRM) model. PRM suggests that adaptive phenotypes arise as follows: (1) there exists a phenotypically plastic trait (i.e., one that changes with the environment, such as sweating in the summer heat); (2) the environment becomes constant, such that the trait assumes only one of its states for a lengthened period of time; and (3) during that time, deleterious mutations accumulate in the unused state of the trait, such that its genetic basis is subsequently lost.
    ,,, But if most adaptations result from the loss of genetic specifications, how did the traits initially arise? One letter (Chevin & Beckerman 2011) of response to Hughes noted that the PRM “does not explain why the ancestral state should be phenotypically plastic, or why this plasticity should be adaptive in the first place.”
    https://evolutionnews.org/2011/11/no_positive_selection_no_darwi/

    A. L. Hughes’s New Non-Darwinian Mechanism of Adaption Was Discovered and Published in Detail by an ID Geneticist 25 Years Ago – Wolf-Ekkehard Lönnig – December 2011
    Excerpt: The original species had a greater genetic potential to adapt to all possible environments. In the course of time this broad capacity for adaptation has been steadily reduced in the respective habitats by the accumulation of slightly deleterious alleles (as well as total losses of genetic functions redundant for a habitat), with the exception, of course, of that part which was necessary for coping with a species’ particular environment….By mutative reduction of the genetic potential, modifications became “heritable”. — As strange as it may at first sound, however, this has nothing to do with the inheritance of acquired characteristics. For the characteristics were not acquired evolutionarily, but existed from the very beginning due to the greater adaptability. In many species only the genetic functions necessary for coping with the corresponding environment have been preserved from this adaptability potential. The “remainder” has been lost by mutations (accumulation of slightly disadvantageous alleles) — in the formation of secondary species.
    https://evolutionnews.org/2011/12/a_l_hughess_new/

  3. 3
    martin_r says:

    as UD commented

    In short, the Darwinian assumption that something as complex as eyesight could just somehow evolve turns out to be “extremely unlikely”?

    if someone thinks, that this is a rare case, let me add another one,

    from PNAS.ORG (Darwinian mainstream website), look what a Darwinian scientist wrote !!!!!

    … These results illustrate exactly why arthropod compound eye evolution has remained controversial, because one of two seemingly very unlikely evolutionary histories must be true. Either compound eyes with detailed similarities evolved multiple times in different arthropod groups or
    compound eyes have been lost in a seemingly inordinate number of arthropod lineages

    https://www.pnas.org/content/pnas/99/3/1426.full.pdf

    Obviously, there is something very wrong with the theory of evolution …

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