Evolution giveth, and evolution taketh away.

So this article was brought to my attention by the super-cool Tom Houslay who tweeted it earlier this evening. The article is very short so do go and read it if you can. If you can’t be bothered, FINE, I will rip it apart summarise it later in this post.

The article is written by an organisation called the Institute for Creation Research who are a… Well I’ll just take a quote from their own website which describes exactly who they are.

For over four decades, the Institute for Creation Research has equipped believers with evidence of the Bible’s accuracy and authority through scientific research, educational programs, and media presentations, all conducted within a thoroughly biblical framework.

The article in question is criticising a paper published in the open access journal BMC Evolutionary Biology which investigates traits such as loss of sight and pigment in Mexican blind cavefish, and the advantages this may carry for this species. I’m not going to go into the paper in any detail, because that’s not what this post is about. This is about clearing up blatant misunderstandings about evolution. I’ll go through the ICR paper paragraph by paragraph, pointing out what (I think) is wrong with their arguments.

Evolution maintains that as more time passes, living things evolve to acquire better and more useful traits. As such, shouldn’t the loss of a useful trait, such as eyesight, be regarded as the opposite of evolution? Not so, say recent news reports on blind fish.

Uh, ok, first of all, evolutionary theory doesn’t maintain that things acquire “better” and “more useful traits”. Evolution is defined as any genetic change that is inherited over generations. This needn’t be particularly useful, and can involve the loss of traits, not just the invention of brand spanking new ones. Eyesight may well be deemed “useful” from our anthropomorphic view, but we are here talking about fish living in a cave in almost complete darkness. Not such a useful energy investment now, is it?

A New York University news release attributed the fishes’ loss of sight to “convergent evolution,” which makes little sense if evolution, as neo-Darwinists describe it, is supposed to generate new features and functions.

Convergent evolution is the process by which unrelated species evolve similar traits because they have had to adapt to similar environments or pressures. The most common example of this is the wing. Birds and bats both have wings. However, birds and bats are not closely related animals. Their last common ancestor did not have wings, therefore they both evolved wings independently.

For lots more examples of convergent evolution, there is a whole Wikipedia page of them (Hurrah!).

In this study, the authors note that the blind cavefish live alongside and are able to breed with a very genetically similar species of fish who are not blind. Yet, despite this gene flow and interbreeding with non-blind fish, the blind phenotype is still maintained in the cave populations. This leads the authors to conclude that there must be advantages to being a blind (as opposed to a seeing) cave fish. It is perhaps because eyes are costly things to maintain in terms of energy investment, and so it may be the case that Mexican cavefish with poor or no eyesight are able to invest that extra energy in something that is more useful to them in their environment.

So to repeat, evolution is not “supposed to generate new features and functions”.

But obtaining the fish sight system required an input of a massive quantity and quality of information. And making the fish blind merely required the loss of some of that information. How could attributing these opposite processes to “evolution” be scientifically accurate?

I don’t know what to say to this, I don’t really understand what they mean. “Making the fish blind” does not require the loss of information, it requires the reduction of energy cost associated with maintaining an essentially useless trait (DARK CAVE, remember, VERY DARK CAVE) which should be favoured by natural selection.

The study of blind cavefish can undoubtedly contribute valuable insight into the genetics of trait variations and the fishes’ potential to adapt and survive in varied environments.

Well, yeah, that’s kind of… That’s kind of adaptation, you know, natural selection, evolution…? Maybe they’re getting it…

But because evolution is supposed to make new traits or develop new and useful genetic information, mere losses and variations should not be called evolution.


Bradic, M. et al. 2012. Gene flow and population structure in the Mexican blind cavefish complex (Astyanax mexicanus). BMC Evolutionary Biology. 12: 9.

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5 thoughts on “Evolution giveth, and evolution taketh away.

  1. Neil Losin says:

    I, too, read this article with disbelief. For what it’s worth, in the following passage…

    “But obtaining the fish sight system required an input of a massive quantity and quality of information. And making the fish blind merely required the loss of some of that information. How could attributing these opposite processes to “evolution” be scientifically accurate?”

    …the ICR author is indeed way off base, but in a different way than you concluded. I’m pretty sure by “input of… information” he just means “complexity increased.” I.e. more information is required to make a fish eye than to, you know, NOT make a fish eye.

    Then, he mistakenly argues that a loss of function constitutes loss of said “information.” (This is also probably false, since the easiest way to get rid of eyes is through gene-regulatory changes, not losing ALL the genes responsible for eye-building!).

    And finally, even if some of said “information” were lost during the evolution of blindness, the ICR author (as you rightly point out) seems oblivious to the fact that, yeah, that’s still evolution.

    But of course, the people reading the ICR site aren’t looking for information that challenges their existing beliefs 🙂

    • pygmylorisreid says:

      Thank you for your comment and for clarifying that! Yes of course the ICR readers won’t take any notice of my response or that of anyone else, but I worry that this “evolution makes stuff better/builds new stuff” is a fairly commonly held belief (not just among creationists) and wanted to try to clear that point up a bit.

  2. This guy (http://www.chrismcgrath.info/Page_3.html) sued me for writing about his trashing of evolution in more than critical terms. I was in the High Court for two days defending the case and the Judgment should be released soon.

    The case will consider whether you can call people “creationists” in the UK and whether those people can sue you for defamation. So on that basis the case is quite important for UK bloggers and the media in general.

    My view is that the author is a creationist and the book he wrote makes this quite clear. His own personal views also seem to make it clear that he is a creationist. He has since tried to backtrack from this without much success.

    Perhaps you might have something to say about the science itself? I know a little but not to your standard. The author seems to know even less than me so the task wasn’t completely beyond me.

    He has now made his book available as a free download. I would be interested to read your thoughts on it.

    Great article by the way! I believe there is a creationist lecture taking place in Coventry on the 24th of March supported by Creation Ministries. Should be interesting!

  3. Frank says:

    Fine tearing!

    I’d note two things:
    1- Science Fiction is largely responsible in continuing to peddle (to interested amateurs) the ‘pinnacle of evolution’-style of misunderstanding.

    2- ‘The Very Dark Caves’ seems overwhelmingly appropriate as a reference. ( http://simonkelk.adsl24.co.uk/richardwilson/html/images/father%20ted/very%20dark%20caves.jpg )

    As said, good work. 🙂

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