Monday, December 1, 2014

Creationists and the Problem of Mutation

So... we've got this quote from Young Earth Creationist Chris Callesen:

"The thing that debunks evolution in simple terms is math.  Being that the number of possible code combinations to even form one molecule of DNA is the numeral 4, with a THOUSAND zeros behind it. Given that margin for error, and coupled with the fact that there are 1000 DESTRUCTIVE mutations in a row before a supposed "beneficial mutation" (oxymoron) the numbers defy this backward logic that every complex and beautiful creature developed slowly over millions of years until these random mutations "accidentally" got it right. Its absolutely profoundly stupid when you do the math."

Well... no.

Sorry, but your reasoning is faulty on many levels.  Your understanding of basic probability is faulty, but even worse is your understanding of how mutations work in combination with natural selection to drive evolution.  The fact that you think "beneficial mutation" is an oxymoron makes that clear enough.

So, a quick refresher on just that subject.

Your average species sees several dozen mutations appear in each generation.  The overwhelming majority of these mutations are perfectly neutral.  That is, they neither help the individual creature that possesses them, nor harms the creature.  They just are.  When and if that creature reproduces, there's a chance the mutation will be carried to the next generation, but since the mutation provides no benefit, its just as likely that it won't.

I'll give you a for instance:  I have webbed toes.

My webbed toes are from a mutation that causes the individual toes to not separate from one another.  Each of my toes is still there, they have individual bones and muscle and toenails, but the toes themselves are not separated past the first "knuckle" of each individual toe.  It gives my feet the appearance of being short and stubby.  My mother's toes are the same way, as were her mother's toes.  We're not sure how far back they go, to be honest, but I do know that none of my children have webbed toes, so its possible that the mutation stopped at me.  However, its just as possible that my grandchildren or great-grandchildren could get them.

The point being, they are a neutral mutation, and as such are just sort of there.

Interestingly enough, a neutral mutation has every chance of becoming a beneficial or harmful mutation, depending on changes the creature's circumstances and environment undergo.  For example, if I was suddenly left to fend for myself in an environment that required I have normal toes (just go with it), I'd be in trouble, and so would any of my descendants that inherited my mutation.

After neutral mutations, the most common form of mutation are, in fact, the harmful ones.  These are the ones that are bad for you.  A harmful mutation will do all kinds of nasty stuff, like cause a baby to be born with acephaly (a lack of most of its brain) or non-functional organs, or be unable to process a certain needed enzyme, and so on.  Most harmful mutations either prevent or make it very, very difficult for the creature to reproduce, and they do this usually by simply killing the creature that possesses them.

Now, I can hear the Creationists out there screaming "AHA!  SO YOU ADMIT MUTATION CAN'T CAUSE EVOLUTION AND THAT EVOLUTION IS A LIE!"

Shut up, sit down, and listen.  That's not what I said.

What I said was harmful mutations kill the creature that posseses them, usually before they can reproduce.  What that means is that the harmful mutations are almost always weeded out of the population almost as fast as they are introduced.  They are very rarely passed on to the next generation of creature because of this.

Which leaves us beneficial mutations.

A beneficial mutation is any mutation that gives an individual creature a leg up when it comes to survival and reproduction.  And because they grant advantages to the creatures that possess them, they invariably get passes on to the next generation of creature.  Since the mutations that are being passed on are advantageous, they accumulate and spread throughout the population of the species.

And when enough changes accumulate, you end up with a new species.

So, Mr. Callesen, that's how mutations work with natural selection.  Next time, I'd advise you to keep your trap shut about things you don't understand, lest you look even more like an idiot than you already do.

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