Entry 700, on 2008-02-19 at 04:39:35 (Rating 2, Religion)
I have been debating creationists for many years now and I usually hear the same old arguments over and over again. The points in favour of creationism tend to be interesting and simple little stories which are easy to remember and easy to understand but not necessarily very deep in their analysis of the truth. A favourite story I have heard a bit recently is that evolution is impossible because its like a hurricane blew through a junk yard and spontaneously assembled a 747.
They are saying that taking useless simple components and assembling them into something incredibly complex without intelligent intervention is impossible. Looking at the 747 metaphor they seem to have a good point but there are good reasons why that shouldn't be accepted.
The essential differences between the hurricane and evolution are first, that evolution occurs in many small steps in a huge number of places simultaneously; and second, that there is a selection process which allows only favourable changes to go on to the next round of random changes. So the process has a random component but its not totally random, and a million small steps can produce what would be impossible with one big step.
With evolution what happens is that an organism produces offspring which have mutations (random changes) which make it different from its parent(s). Most of the time those changes will not be beneficial and that means the offspring won't survive to reproduce. But in the unlikely (but not impossible) event that something better results from the change that individual will be more likely than others in its generation to reproduce so its new type will become more numerous. Most species exist in large numbers so this change is going on constantly in parallel millions of times simultaneously. This means that even though the chance of a beneficial change is small it will still happen given a certain amount of time.
So let's change the hurricane metaphor and present it like it should be. First, there are billions (or trillions) of junkyards with frequent hurricanes going through them. The vast majority of the time nothing useful happens but just occasionally two components might be stacked together (just through luck) to produce a better piece of junk. Only the good junk is moved into the next junkyard to have another hurricane hit it again. The process repeats in those billions of junkyards for billions of years. After a while something better and incredibly complex will result. It might not be a 747 but it will be something equally unlikely.
Changing the story around to represent what really happens in evolution shows that it is hard to ever say that evolution couldn't occur. Given the huge number of junkyards, the huge amount of time the process works on, and the process which takes the good results and discards the bad ones its impossible to see how evolution could not occur. Its really just common sense. If evolution is presented this way most creationists will have to admit they do think evolution happens. If they won't admit that I would like to know which part of the process they don't think is feasible!
So the process of species evolution isn't totally random -- but why do the guided processes only allow favorable changes to advance? I can't grasp "they just do".
Comment 2 by OJB on 2008-02-19 at 08:25:43:
If the individual has a mutation which gives it an advantage it will be more likely to survive and reproduce so that advantageous mutation will be passed to the next generation. Other individuals with harmful mutations will probably die before reproducing so that mutation will disappear. Individuals with no significant mutations will survive but not in the same numbers as those with the good mutation. Eventually the good mutation will dominate and after more time it will be complete within the species.
Comment 3 by OJB on 2008-02-19 at 08:28:10:
The reason you asked that question (I guess) is that junk in a junkyard doesn't reproduce. That's another reason its not a very good analogy (but its what the creationists use so I stuck with it). In the junk yard analogy the survival to reproduce part doesn't exist so I just used a non-specific "process".
Comment 4 by WF99 on 2008-02-19 at 10:35:26:
But what makes beneficial mutations dominant? I've always been told "that's just the way things are" and I have to wonder why.
Comment 5 by OJB on 2008-02-19 at 17:33:09:
The mutation is beneficial because it helps the organism survive better than individuals without the mutation. It might be better colouring for protection against predators, longer legs to run faster, etc. If the organism is more likely to survive it is also more likely to reproduce so the advantageous mutation is passed on to the next generation in greater numbers. After a few generations the mutation becomes more and more prevalent because its advantages are passed to more individuals. Eventually the whole species has changed to incorporate the new mutation.
Comment 6 by WF99 on 2008-02-20 at 10:15:25:
Yes, I understand that, but why do species incorporate beneficial mutations? Why are they dominant, as opposed to harmful ones?
Comment 7 by OJB on 2008-02-20 at 10:43:49:
Maybe the word dominant was confusing in this context. I didn't mean they were dominant in the genetic sense, I just meant in the more general sense, that is that they become more common than the un-mutated gene because the individuals carrying that mutation become more numerous in the population because they are more likely to survive and reproduce.
Comment 8 by WF99 on 2008-02-23 at 14:33:10:
Okay, whatever happens, why?
Comment 9 by OJB on 2008-02-23 at 19:17:36:
Why? Why what? You're asking why evolution happens, or what is the purpose of it all? I'm not sure. There is no bigger purpose. Things just happen because thats the way the physical laws work. Why the laws are the way they are, why there are laws at all, or why the universe even exists, who knows? Maybe we'll never know. Maybe those aren't even real questions.
Comment 10 by WF99 on 2008-02-24 at 08:40:10:
That's what I'm asking. Of course, there aren't answers, and they're pretty much meaningless questions, but they're still thoughts that I can't get past.
Comment 11 by OJB on 2008-02-24 at 09:08:48:
I'm not saying they are definitely meaningless and without answers or that we should ignore them. There may be answers but we don't really have any clues as to what they are right now. Of course there have been many things in the past which have seemed impossible to answer but that we understand well today, so predicting the future is always difficult.
Comment 12 by WF99 on 2008-02-24 at 12:13:37:
This seems different, for some reason. But there's really no sense in continuing this conversation when there's no answers on hand or means by which to determine them at present.
Comment 13 by OJB on 2008-02-24 at 14:07:55:
Yes, it reminds me of the famous incident where the well known science fiction writer Isaac Asimov was asked to write a 1500 word essay on life on other planets. He (allegedly) wrote "We don't know" 500 times!
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