Biology-Online • View topic - Looking for answers/input.

Discussion of everything related to the Theory of Evolution.

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Note: While reading this, bear in mind that I'm not on either side of any fence; I'm interested only in answers.

'ello, all.

I'm getting bored of wandering into accidental debates/discussions with people who don't know what they're talking about and/or think very narrowly... so I figure I'll come to a specialized hub and hopefully find some more valuable interaction here.

Basically, my problem is that evolution is advertised as an answer to the evolution (obviously) of life from the earliest to the latest, as well as a theory on how a species or its features become dominant due to its role in nature (i.e. survival). While I am aware of the evidence supporting the latter, it seems to me that everything outside of that (the "this is how life got from A to B") strays from proof and goes into assumption/faith territory.

The introduction of new things ("information") is due to random mutation. Whenever I've questioned a scientist on this, they give you some line about how "life has had 4 billion years" as if 4 billion years is enough time for enough trial and error for nature to finally get it right. In actuality, 4 billion years is nowhere near enough time. Yes... I realise that "you only have to get it right once" and it's POSSIBLE, but what science is doing is claiming that it's fact that it would've eventually happened over 4 billion years which isn't true.

One example I read was something about the probability of spelling out "The Theory of Evolution" using random draws. I'll be reconstructing the math as I forgot that part. There're 23 letters using a set of both upper and lower case letters (26 + 26 = 52) plus 1 for the space (53) so the probability is 1 in 53 to an exponent of 23 using the multiplication rule.

Example: Chances of rolling 1 and 1 on a 6-sided dice are 1 in 6 with an exp of 2 or 1 in 36.

I wrote a quick PHP script to calculate this for me and it shows the probability as 1 in 4,553,496,434,179,608,714,608,509,855,011,245,654,016.

As per the example of a computer making 1 billion attempts per second (1,000,000,000,000 in large scale - I believe the example used small scale for the sake of making the numbers appear bigger), I wrote the script to calculate how many seconds this would be & convert that to years. The result was 8,663,425,483,598,950,563,840 years.

I then rewrote the script to calculate how many times the age of the earth this is (assuming 4.54 billion years according to Wiki) and the result: 192,520,566.

So through trial and error, it'd take 192 million times the age of the earth to write the sentence above - and scientists claim that 4.54 billion years is long enough for trial and error to form all life on earth randomly.

Another thing I often bring up is the evolution of the eye. According to evolution theory, features which are beneficial to an organism will increase its survival chances and so those features will become dominant. It's easy to say that "sight randomly happened and then survived" but it's not that simple. Sight had to start with a single mutation. To quote one person trying to explain the single mutation of a photosensitive cell (this is supposedly the current starting point in eye evolution theory):

"The simple light-sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator"

After questioning what possible survival advantage a single photosensitive cell itself could bring, they replied with something about stimulation of the cell releasing chemicals into the organism's system, but this mechanism would surely require more than just the photosensitive cell so we're back to the problem of the mutation requiring more than just itself to become beneficial.

My point here is that it's no longer a case of "<such a thing> is added to an organism, helps it get the upper hand, it survives, reproduces and it becomes the norm" - it instead becomes, "<such a thing> randomly mutates with no benefit from the mutation, any intrinsic systems which force out the mutation don't start or work, the organism survives, reproduces and passes on this single mutation, several mutations later a new random mutation conveniently contributes yet again to the previous mutation and this process repeats until it's finally useful and beneficial."

To summarise: it appears to me that evolution on this large scale claims to be a factual explanation when in fact, it relies a lot upon assumption and improbability.

I welcome input to help me understand better.
Mirabilis
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Hi Mirabilis,

You're not alone. The role of randomness in evolution is perhaps the most misunderstoood concept plaguing evolution's acceptance by those who are at least trying to understand, as you seem to be. The formation of any biological structure or physiological system is NOT a random process. Any attempted analogy with randomly joining letters to produce a sentence completely misses the mark. Evolution is "descent with modification", as Darwin so elequently put it. "Descent" means reproduction, and "modification" means variation. Without either of these, there is no evolution. Randomness enters the picture in the production of the variation. The mutations that cause the variations occur randomly. Nature has no particular goal in mind - there is no "getting it right", as you put it. Mutations blindly happen here and there. Most are neutral - neither good nor bad - and don't really cause much modification. Some are bad and get removed in time. Some prove to be good and are favoured, with "good" being defined as an increased probability of continuing into the future. But they are still blind. No mutation knows (or cares) where it's going.

DNA replication is sufficiently imprecise, and external sources of mutation are sufficiently common, that new variation is readily produced. And if a population of some organism is large, then the number of individuals within that population each harbouring a different mutation can also be large. With random mating, lots of mixing can occur. Maybe one mutation alone doesn't have much effect, but combined with another, maybe something changes, either for good or ill (i.e. this "something" increases or decreases in frequency in the population over time). All this is happening on a time scale of generations, which for some organisms can be on the order of hours (not elephants). Mutations (or variations or modifications or whatever you want to call them), if they are to increase in frequency, must be beneficial, or at least not harmful, NOW. They don't see into the future and figure if they stick around long enough some other mutation will come along and then they can really do some serious evolving. And the means by which a mutation is helping an organism to produced more baby organisms may be a temporary thing. As long as it works now, that's all that matters. Then the environment changes and screws everything up. That mutation that used to help may now be a liability, or it may prove to be useful in some way different than before. Evolution is blind - it can't see where it's going and doesn't even have a destination.

Water tends to run downhill. That's just what it does. Evolution goes up, down, and sideways. Structures evolve not out of a need, but out of a possibility. Life is something a little bit different than water or letters randomly joined. Once it starts (that's the real mystery), it's a pretty tenacious thing. Large populations, new variations, and long periods of time combine to explore seemingly endless possibilites of existence. There is no random jostling of bits and pieces to produce something useful, but a slow, meandering journey to nowhere in particular but just to what's possible and successful.

And don't get hung up on this "proof" business. We'll leave that to the mathematicians. Proof in science outside well defined little boxes is pretty hard to come by. Probability rules.
wbla3335
Coral

Posts: 227
Joined: Thu Aug 17, 2006 7:20 am

Hey.

I may have misunderstood your post, but it sounded to me like you were saying one thing (that there's no random) and then saying another (that there's random which built up over time).

As stated in my post, I know that breeding is responsible for so much, but breeding cannot intentionally introduce something into a species which is why we have random mutation.

Back to my original point: random is random with no direction (as you said) and so an eye is a series of chance mutations which have eventually come to represent something useful. As stated in the previous post, not every mutation can be beneficial so the old argument of "it helps therefore it survives" doesn't cut it. What evolution then asks you to do is accept/assume that these millions of random mutations not only survived, but made something useful.

- and that's all my problem is: people sell evolution (on such a grand scale - not the small scale we've observed) as a proven and exact science when it isn't. It relies on you believing that the improbable happened... many many times over.

My probability example served only to demonstrate that 4.54 billion years isn't enough time for trial and error like some people believe. Some say, "life has had so much time to mutate, go wrong, mutate again, go right this time" which isn't true because as demonstrated, you'd need 192 million times the age of the earth to complete the trial and error process 100% just to spell out a simple sentence.

The purpose of the thread is to see if anyone can offer me any understanding which rules out my counter-points.
Mirabilis
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Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
~Niebuhr

mith
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Location: Nashville, TN

Hello again Mirabillis,

I'm not sure, but I think I now see the bit you are missing. Selection. You seem to accept that mutations are random, but you also seem to be suggesting that any structure is the result of a chance occurrence of different mutations together at the same time. Is this right? Evolution, though, doesn't work like that. In general, that is - I'm sure some new things do appear by the coincidental meeting of previously independent mutations, but this is not the main mechanism of evolution. Natural selection is the mechanism of evolution. The eye is not the product of an unlikely but lucky meeting of previously independent mutations (the "hopeful monster" hypothesis) but is the result of a slow cumulative construction where new things are added to what has come before.

Let's take your example of spelling out "The Theory of Evolution" to illustrate. Your suggestion is that letters are drawn at random to construct this phrase. If the first attempt doesn't work, then you repeat the same process from the beginning. Again, just jibberish. Evolution, though, begins with the same pool of letters, and the first draw produces jibberish, but somewhere in the jibberish an "r" and a "y" are found together. This "ry" happens to be a stable construct and tends to stay together as a unit. This is selection. The "ry" in some small way helps the initial jibberish to be a little less jibberish-ish. Now for the second draw, you don't start with a new bunch of letters and randomly put them together, but you take the first batch - including the "ry" - shake them up a bit, and then put the letters together for the second time. This time a "t" and an "i" form a stable construct. Take the "ry" and the "ti" and mix them with other single letters, stir this time, and do a third draw. An "o" has now joined the "ry" to make an "ory", and a "u" has joined the "ti" to make a "uti". I think you see where I'm going with this, so I won't continue. By keeping stable constructs together and adding to them over time, spelling out "The Theory of Evolution" will happen a little more quickly than you propose by independent random draws.

Does this make any sense to you? Selection is the key. Mutation is random, but the accumulation of mutations is not. Structures are built slowly over long periods of time, like a building. You can't have a window until there is a wall to put it in.

I'll stop here until I learn if I'm on the right track in addressing your question.
wbla3335
Coral

Posts: 227
Joined: Thu Aug 17, 2006 7:20 am

You seem to accept that mutations are random, but you also seem to be suggesting that any structure is the result of a chance occurrence of different mutations together at the same time. Is this right?

You seem to have misunderstood me here. I'm not under the impression that the mutations had to happen simultaneously. Hell, if they did, I'd be on board with this theory already. My problem is that they DON'T happen simultaneously and so during the stages between introduction and being useful (even on a tiny scale) the "rule" of selection doesn't apply.

To clarify my understanding of natural selection: as I see it, it is where a new feature (which has to be introduced randomly; a species can't decide that it wants to improve upon a previous mutation) which is immediately beneficial increases the organism's chance of survival. On a small scale, examples typically involve pigment (such as the peppered moth) which is one thing, is observed and I take no issue with. My problem is with systems which rely on other things to become useful as their survival is less down to them being better suited for it and left more to chance.

The model/example you wrote up was interesting, but I think is an oversimplification - and if not that, expects an assumption which returns to my initial point.

If we were to create a hypothetical species of simple organisms with no eyes, we can say that each time one of the organisms reproduce, there's a chance of mutation. In the event that one of these mutations is the beginning of an eye later in the sequence, it's not a simple case of that mutation just waiting around for the next few. That organism has to survive (with no immediate benefit), reproduce to pass down the mutation, that reproduction (or maybe multiples) then has to survive and so it goes on, passing down the first mutation while waiting for the next chance addition to the sequence, also under threat of deletion (mutation deleting the mutation) and maybe even the presense of multiple other harmful mutations... and so it goes on until the evolution is complete.

Do you see my problem? I can't accept this as a "fact" because so much is down to chance - and the "it seems to have happened" is no proof of the means.
Mirabilis
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Ok, let's try this again. Is the problem you're having this: how does one mutation that happens now, but will contribute to something useful a million years from now, know whether it should stick around or not? (Don't freak out biologists, I'm just trying to find out what the question is in language the poster seems comfortable with.)
wbla3335
Coral

Posts: 227
Joined: Thu Aug 17, 2006 7:20 am

I understand how it could stick around. My problem is just that it's not so black and white as "it's introduced and stays until needed" when there're factors against it (survival, negative mutation, etc).

Another thing which perplexes me (which I've never read about before, but will do so now) is reproduction itself. How did organisms mutate in such a way that they were sexually compatible - and while doing so, how did they reproduce? I imagine a complex organism is too complex for division and an organism which makes use of division wouldn't be complex enough to house all the makings of reproductive systems. If there was some extremely simplified version, how would it have evolved into the complex version we have today without there being a period of being unable to breed?

Is this something you'd be able to help me on?
Mirabilis
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Joined: Wed Mar 11, 2009 10:14 pm

Well, nothing is guaranteed in evolution. But for something to stick around, it has to be of some help NOW to reproductive success of the individual possessing it, otherwise it will disappear over time. Even beneficial mutations can easily disappear for a variety of reasons. Not every member of a species contributes its genes to the next generation. Often, only a small proportiion do. Those few, on average, have some slight advantage that the others don't. Because they have offspring, the reasons for their success are passed on to future generations. Whatever advantage they had increases in the population. But not everything succeeds. Most species that have ever existed went extinct long ago. They may have been well adapted to their environments, but maybe the environments changed faster than they could adapt. Most individual organisms of any or all species that have ever existed never contributed a single gene to future generations (although their relatives may have). Most life that has ever existed has not contributed genetically to the life that currently exists on our planet. You, though, are the product of those who did succeed. All individuals of any and all species alive today are the products of the success stories. Success, biologically speaking, is reproductive success. The vast majority of life, though, has failed. The "struggle for existence" and "survival of the fittest" are not just catchy phrases. Whatever does survive has earned the right to exist.

The origin of sex is a hotly debated issue. Lots of ideas out there but even less evidence in support of any of them than there is for evolution, so maybe we shouldn't go there just yet.

I'm in Europe and will be signing off for the day. Supper's ready.
wbla3335
Coral

Posts: 227
Joined: Thu Aug 17, 2006 7:20 am

My Input:
You must remember that as an organism gets more complex the reproduction of themselves is slower, for example when the ancestors of humans were single or simple multicellular organisms we could reproduce millions of times faster than we can now so natural selection occured much faster than it does now.
Also, on the eye point: although a single photosensitive cell is a minute advantage(and i dont know who came up with the idea that it could help them to evade predators... it couldn't) such as maybe allowing the organism to detect their depth in water, this advantage may not be extremely advantageous so that it survives dramatically better than the others but this slight advantage may increase its survival by 0.1%, this is all that is needed because over thousands of years it will make a huge difference.

*sorry if any of these points have already been raised as i do not have time to read through all the replies.
A wise man once said to me:
"Build a man a fire, and he'll be warm for a day. Set a man on fire, and he'll be warm for the rest of his life."

Only the fittest chickens cross the road.

futurezoologist
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