Thursday, 25 July 2013

Bacteria Are Winning With Evolution

Antibiotic resistance: The last resort : Nature News & Comment

Evolution is the weapon of choice for bacteria fighting the war on antibiotics.

Except, of course that there is no choice involved and bacteria are not even aware they are fighting a war. All that's happening is that an environment with antibiotics in it has given those few bacteria which have a genetic resistance to antibiotics such a massive advantage that they are quickly replacing the non-resistant form in the population. Bacterial genes are simply doing what they have done since the first self-replicating molecules arose on Earth - they are replicating themselves. The natural environment is sorting out the fittest and allowing them through the natural selection sieve into the next generation.

The above article in yesterday's Nature superbly illustrated evolution in progress. We have created the classical Darwinian model for evolution to be inevitable:
  1. Replication.
  2. Variability.
  3. Selection.
[A]ntibiotic resistance should be added to the UK government’s list of threats to national security, alongside pandemic influenza and terrorism.

Previously, before we started to use antibiotics, any chance variation in the relevant genes might have had no meaning whatsoever, and may even have disadvantaged the carrier. The environmental change we created has changed the meaning of the information carried by the genome. The amount of information hasn't changed, only it's meaning.

As Maryn McKenna points out, we are now reaching the point where bacteria are evolving resistance to one of the last drugs on the shelf. Unless we can invent antibiotics more quickly we will eventually lose this arms race and a purely natural undirected and aimless process, will have beaten everything that human science can muster against it. Such is the power and inevitability of evolution by natural selection. So far, we have not managed to exterminate a single known bacterial species. Even tuberculosis, once having looked to be on it's way out, is making a comeback having overcome our antibiotics of choice.

Of course, we have exterminated smallpox and the cattle disease rinderpest in the wild and have come close to exterminating poliomyelitis, but these are viruses not bacteria and are not touched by antibiotics. The only non-viral organism we have had any real impact on has been the Plasmodium species which cause malaria and they are now showing signs of a similar resistance to antimalarial drugs as are the mosquito vectors which transmit them to us to insecticides.

We have a very serious problem, and we need to sound an alarm.

Thomas Frieden, director of the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, USA.
Many protozoans such as bacteria have a very short generation time - as low as 10-20 minutes in favourable conditions - so they represent a speeded up version of evolution - humans are several orders of magnitude slower at about 25 years. Bacteria also have a much smaller genome so they show us much more clearly what can be produced in a few generations by environmental change and under intense selection pressure such as a new antibiotic. A multicellular organism, with its much slower generation time would be expected to evolve much more slowly but, with a larger genome, they are likely to be evolving with several gene-lines in parallel.

Bacteria sharing genetic information
Bacteria don't reproduce sexually, of course, which on first consideration might be thought to reduce the scope for evolution which sexually reproducing organisms get from frequent shuffling and mixing of the genomes from two individuals, however, bacteria do exchange genetic material in the form of plasmids by which they can pass antibiotic resistence to other bacteria and even to another species - a process known as horizontal gene transfer. This appears to give bacteria at least the same degree of 'evolvability', in other words, the ability to adapt quickly to environmental change, as does sexual reproduction in more complex organisms.

So here we have a wonderful example of evolution in progress and an illustration of how an arms race can be won not by planning and intelligent design but by a mindless, undirected, yet inexorable and inevitable process of evolution driven by natural selection which looks for all the world to an uninformed observer like an intelligent one.

Now, those few Creationists who didn't stop reading when I opened with the word 'evolution' and who have made it to this point without becoming too afraid to continue reading may still be telling themselves that an invisible magical friend who loves them above all else is directing things, the way the Discovery Institute likes to tell them, have to answer a couple of question:
  1. Why would a benevolent intelligent designer be ensuring our defense against killer bacteria is abolished by making them resistant to it, unless it is on their side and wants to make us sick and die?
  2. Why has it made it look like a natural process, which can be fully explained without the need for magic or gods, or a designer of any description?
If you think you can answer these, you are free to avail yourself of the comment section here to do so.

If you can't, you might like to explain why you still like to believe an imaginary friend is directing things for your benefit.

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20 comments :

  1. This comment has been removed by a blog administrator.

    ReplyDelete
  2. >the ultimate question that you asked was, do bacteria evolve from one life form to another? although, you stated it as a fact that they do, in the beginning. <

    I nowhere asked that question nor made that statement.

    Can I suggest you read the blog and deal with what I said in it.

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  3. This comment has been removed by a blog administrator.

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    1. >you are indicating that you believe that the adaptation observed is part of the process of an organism evolving from one life form to another<

      Nowhere did I make that claim. Please read the blog and deal with what I said in it.

      NB: Your difficulty with understanding this stuff is probably because you are insisting the well-established science of evolution should cease to be scientific and should comply with your infantile creationist parody version so it will be easier for you to attack.

      Have you been fooled by creationist pseudo-scientist frauds or are you a creationist pseudo-scientist fraud?

      Delete
    2. This comment has been removed by a blog administrator.

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    3. My blog is a available for people to read for themselves, so they can see exactly what I wrote. When will you be dealing with it instead of making up things to attack?

      Did you not understand when I explained that the science of evolution isn't going to magically change into your infantile parody version so you can attack it more easily?

      We already know your theology doesn't agree with science - that's how we know your theology is wrong, so I'm puzzled by what you're trying to demonstrate here.

      Are you maybe trying to show us how dishonest and ignorant you need to be to be a Creationist? I think we already know that too.

      Delete
    4. This comment has been removed by a blog administrator.

      Delete
    5. Once again, and for the last time, please read the blog and deal with what I said.

      Any more of your abuse of this blog to post your sanctimonious gibberish will not be tolerated.

      Even Christians are expected to behave in a civilised manner here no matter how much they feel they have the right to dump their excrement anywhere they wish.

      You have already established beyond doubt that you know nothing of the subject of evolution and are not prepared to learn anything.

      Do not abuse your privilege to post here again.

      Thank you.


      Delete
    6. This comment has been removed by a blog administrator.

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    7. This comment has been removed by a blog administrator.

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    8. This is your last warning.

      Since you have now descended into the traditional creationist abuse any further comments from you will be removed.

      Delete
    9. This comment has been removed by a blog administrator.

      Delete
    10. James Smith

      Your obnoxious preaching was removed, as I warned it would be.

      If you are unable to control your antisocial behaviour, can I suggest you produce your own blog in which you can indulge your self to your heart's content. That way you wouldn't need to parasitise other people's blogs.

      Delete
  4. This comment has been removed by a blog administrator.

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    1. Read my reply above.

      I would be grateful if, in future, you would deal with the blog in question rather than using this blog as somewhere to preach and to show off your condescending judgmental bigotry and scientific ignorance.

      Any more preaching will be removed.

      Thank you.

      Delete
  5. This comment has been removed by a blog administrator.

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    1. James Smith

      Your ignorant abuse and preaching have been removed in accordance with the several warnings I gave you and in line with the policy clearly set out above the comment box.

      Delete
    2. Since you are clearly unable to control yourself and see no reason why you should behave in a civilised manner, I have now removed all you obnoxious drivel from this blog.

      Any other comments by you will also be removed.

      Delete
  6. This comment has been removed by a blog administrator.

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    1. James

      I appreciate that you find this almost incomprehensible, but even Christians are expected to behave like civilised people here. I'm afraid the privilege to behave exactly as you wish under cover of your phoney piety, which you normally take for granted, is not extended to you in this blog.

      Delete

Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers or by known sock-puppet accounts.

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