An important experimental discovery has just been made that casts doubt on the traditional models of Darwinian Evolution. And instead, provides support for the existence of irreducibly complex – and by implication designed – mechanisms within Biology.
Biochemist Michael Behe does not believe that the incredibly intricate biological machinery in the cell has developed step by step, with natural selection acting on each viable mutation. Instead – he has contended that much cellular machinery is – like a mousetrap – irreducibly complex. In other words – if you take away the base or the spring or the lever or the trigger…the system fails to function as a mousetrap altogether. While the mousetrap example is hotly debated amongst Biologists – it is just a simple example. The real issue – is the incredible complex co-dependent mechanisms that we find, working away in the billions of cells that operate within our bodies.
And there is now some tantalizing experimental evidence that could just suggest that Behe has been on the right track all along.
The experiment was undertaken by the National Academy of Sciences, USA, and has focused on the proposed Darwinian process of Protein Evolution. While I’m no Biologist – I’ll explain what I know as simply as I can!
What are Proteins? They are the crucial biological machines that keep our bodies running. For example, Hemoglobin is the protein that allows oxygen to be carried thru your bloodstream. The protein is basically a precise, complex chain of many different amino acids. Proteins are constructed within cells – the protein has a distinctive 3 dimensional shape that determines its function. The instructions for assembling proteins from amino acids are found in our DNA, which lives in the nucleus of our cells.
Since Charles Darwin, it has long been proposed that the evolution of life occurs one step at a time. Zooming down to the cellular level, it is proposed that protein evolution works something like this. An event causes the protein – which is composed of many amino acids – to randomly flip one of its amino acids in its chain. Assuming the newly mutated protein is still functionally viable – natural selection ensures that the system continues creating more and more proteins like the new mutated one for a while longer. Until the next new protein mutation occurs – and so on.
John Maynard Smith, Evolutionary Biologist, describes the process using a word game.
The object of the game is to get from one meaningful word to another meaningful word while only changing one letter at a time. Remember – each intermediate step must also be a meaningful word.
For example, to get from the word “WORD” to the word “GENE” takes 4 steps –
WORD -> WORE -> GORE -> GONE -> GENE
This is the essential understanding of how protein evolution would work – one step at a time. Whenever an amino acid flips causing the intermediate to be non-meaningful (e.g. WORD -> WORQ) then natural selection ensures that that this latest protein does not continue to reproduce. This protein dies out.
This model makes sense – and it fits inside the wider cultural understanding of evolution in the West. Namely – day by day…step by step…we are getting better and better all the time.
So – what is the big deal around the latest experiments that perhaps point towards Design rather than evolution?
Behe has proposed in his book “The Edge of Evolution” that – for many functioning proteins, one could never ever arrive at its function by moving just one a step at a time toward it. Why? Because in order for the protein to survive – and maintain its meaningful status – more than one amino acid has to flip state simultaneously. In other words…two letters or more have to flip SIMULTANEOUSLY. Further, the nature of the protein is such that – were you to try to get to certain functions one step at a time – you would fail. The protein would die, it would become non-functional during the intermediate steps. UNLESS two or more specific amino acids flipped to the appropriate setting at the same time.
Behe was predicting that for the process of evolution to actually produce the complex protein mechanisms we find in life forms today – highly complex changes must happen in one evolutionary step. This is a massive problem for the theory of evolution – because science doesn’t believe the Universe is old enough to accommodate all the probabilities and random letter flipping involved. Darwin only works if we can get there one step at a time!
As you can imagine, many Darwinian Evolutionary Biologists have rejected Behe’s proposition. They choose instead to believe in a step by step approach to protein formation.
Well – this belief is now more tenuous than it used to be. The big deal this year is – Behe’s proposal of necessary highly complex mutation has been experimentally verified and documented by the Proceedings of the National Academy of Sciences, USA.
The experiment was related to how an important protein in the Malaria Parasite becomes resistant to anti-malarial drug chloroquine. They have proven experimentally that it cannot happen in a step wise fashion (WORD -> WORE -> GORE -> GONE -> GENE). Instead – for the protein to remain viable – it has to happen in a much more complex scenario (WORD -> GONE -> GENE). Two specific letters switching to a specific alterative SIMULTANEOUSLY. The Malarial Parasite does not become resistant to the drug unless this very rare and very specific complex mutation happens this precise way.
Now this is just one example where protein function requires highly complex mutation rather than stepwise mutation to arrive at a viable, new function. There are bound to be countless more. But it provides some experimental evidence that begins to support Michael Behe’s overarching thesis.
What is the overarching thesis?
The Universe is not old enough for all of life’s various proteins to evolve because more and more highly complex mutations would be required to get from one viable stage to another. The latest experimental results intensify this position – its not longer a theory, its experimental observation.
THEREFORE…maybe evolution hasn’t been the cause of these proteins after all. Rather – these irreducibly complex and co-dependent biological mechanisms are actually a small part of the work of an Intelligent Designer.