Evolution of complexity/information

I don't think any biologist would deny that your average E. coli was less complex than a human being. There are more cells, more organisation involved, and a far larger genome (encoding far more proteins).Equally, I don't think any biologist would see that increase in complexity as a problem, as it is all a matter of a series of steps. Its' not simply a matter of bacteria to man (as you seem to want to imply), its' a matter of bacteria-eukaryote-multicellular-complex multicellular-vertebrate-tetrapod.......all the way to human. So where's the uphill task with complexity? Which step is the problem? And here's the big stumbling block. How do you measure complexity objectively? If you tried to measure it by genome size for example we'd be about as complex as a banana. Brain size/weight ratio would probably see us neck and neck with a dolphin (at best). Its' not that simple. The best thing I can think of is to look at duplications in gene families, which tend to increase in number as you go 'up' your percieved complexity gradient. I doubt this is what you're looking for though, as this supports the step-by-step hypothesis of evolution: a protein which has one function in one organism duplicates and diversifies to provide more information and more complex function.So, what scientific way could you devise to measure complexity that does not just boil down to "look bacteria...human...WAAY more complex, right?" This is exactly what is being done at the moment. Certain steps are recognised as being important by looking at the fossil record and molecular evidence. Work is then done to determine what could have caused such events. A number of things (like origin of eukaryotic organelles as symbiotic bacteria) are relatively well established. Others (like the origin of cartilage and bone) are still fairly vague but that's no reason to start inserting the deity of your choice in all of the gaps in our knowledge - nothing suggests that there was a huge leap in complexity that could not be explained by good old fashioned descent with modification.

I'm not convinced that evolution is always accompanied by increased complexity. Often there seem to be steps "up" mount improbable followed by steps "down" before a different "up" is tried.Walking sticks getting wings, losing them, getting them again, for example. In each case the surviving organism was better fit for the selection process, yet each step cannot be an increase in complexity when vacillating with such indecision (which is also an argument against the process being designed by intelligence).Does this mean that an overall trend is necessarily "up" or that this is just an inference dictated by human {species} ego?Would a world of telepathic amoebas be more or less complex?

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

This brings to mind a question: Why are there no 2, 3, 4, or 5 celled organisms?

because things breed faster than that.

That is a good question. One thing we'd have to clear up first is whether there are or not.We'd also have to decide where the line between unicellular and multicellular organisms are. Is filimentous algae uni or multi? What is the dividing line? If it is multi then I guess there are multis of all numbers.If it isn't (perhaps because there is no differentiation?) then we would be, by definition, be making it impossible or such an "organism" to exist.There are a continuum for creatures from uni cellular to complex, differentiated multicellular and some organisms which switch back and forth across the line (slime mold). So until we get very clear on what the words mean you can't decide what is and isn't.

To expand a little on Ned's answer it is because the move from unicellular to multicellular was not a matter of adding one cell at a time. It is far more likely that the path involved increasingly greater integration of colonies of single-celled life forms.We do have a possible analogy for the specialisation of cells, too - the social insects have specialised "castes" in their colonies. Even reproduction is handled by a single queen (and a number of drones)

No, I wouldn't suggest that every tiny step is increasing complexity. A very weak definition of complexity, such as the size of genome, would be sufficient to explain an increase in the maximum complexity of all species under evolution.I'm talking about maximum complexity (no average). Because: do we have to take into account amoebes, stones, interstellar space? A world with telepathic amoebes I consider as more complex than a world with ordinary amoebes, because the greater amount of interdependencies. But we're talking about biological analytic complexity isn't it?Quote [Bruce Edmonds]: "It seems almost certain that at some time in the past there were only organisms of (presumably) small biological analytic complexity while now there are complex beings which are difficult to understand (us)."

Right. In fact most of the time if not all the time it is accompanied by decrease in complexity. But this is only a "gut" feeling enhanced by the law of entropy.If anyone can show an example of where an organim gained an ability without losing genetic information or losing another ability, I'd appreciate it. Well, if you choose to infer that a human is no more complex than a cup of primordial soup, then this is an inference dictated by the maddening powers of evolution.This message has been edited by Hangdawg13, 07-13-2004 12:26 PM

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But this is only a "gut" feeling enhanced by the law of entropy.

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Why should a law governing the transfer of energy have anything to do with complexity in biological organisms? We are talking about the laws of Thermo(heat)dynamics(movement), not the laws of complexity. Also, within the laws of thermodynamics it is possible for entropy to increase if energy is input into the system. In our case, the sun provides more than enough energy to supply and increase in entropy among all organisms.

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If anyone can show an example of where an organim gained an ability without losing genetic information or losing another ability, I'd appreciate it.

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The nylon bug is quite famous for such an example. This bacteria, through evoltution, developed an enzyme that breaks downt waste products from nylon manufacturing. It is able to live on synthetic, man made materials alone. Go here: http://www.nmsr.org/nylon.htm. Also, other scientists have also been able to duplicate this event, however they have yet to find the mutation that lead to nylong digestion in their bacteria. I can give you more info if you want (I am guessing that you don't, ignorance is bliss).

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Well, if you choose to infer that a human is no more complex than a cup of primordial soup, then this is an inference dictated by the maddening powers of evolution.

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You have yet to give us an objective measure of complexity that would allow us to differentiate between primordial soup and humans. Care to try? What unit is complexity measured in?

How about webbed feet?It's a small step I know, but as I said before - its' all a matter of small steps (by the way, which small step from bacteria to man did you have a problem with?).Here's how it goes:What's the main difference between a duck's foot and a chicken's foot? That's right, the webbing! At a certain stage in embryo development, both the chick and the duck have webbed feet but the expression of a protein called BMP in the chick instructs the cells in between the digits to die - so when it hatches there is no webbing.Ducks produce the same BMP, in the same place but retain the webbing because the cells in between the digits gain the ability to express another protein called Gremlin, which inhibits BMP function. To me this is a gain of information (the cells have been told "don't die"), and the duck sure as hell hasn't lost any ability, so where's the problem?Similar examples of cells gaining the ability to express proteins have also gone a long way to explaining the formation of the forebrain, the evolution of tetrapod digits, and the polarity of limbs.

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"Anything that is true of E. coli must be true of elephants, except more so." -Jacques Monod

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Ducks produce the same BMP, in the same place but retain the webbing because the cells in between the digits gain the ability to express another protein called Gremlin, which inhibits BMP function. To me this is a gain of information (the cells have been told "don't die"), and the duck sure as hell hasn't lost any ability, so where's the problem?

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Within creationist logic this is actually a loss. The cells between the toes have lost the ability to go through programmed cell death (apoptosis). If we went from the duck to the chicken, this would also be a loss since the cells have lost the ability to prevent apoptosis. Too bad I can't be a creationist, I could always be right by ignoring simple common sense and logic.

I actually think the argument is creationist-proof.If they had lost apoptosis, they would simply not have the binding sites for BMP.In this case, they've actually gained an enzyme that blocks BMP. I'm fairly sure it's going to be impossible to substantiate the claim that this represents a loss.Good try, though. You really hit the creationist impression dead-on.

The "law of entropy", as you put it, actually mandates that evolution must occur.

I could see your heart wasn't in it though Besides, as crashfrog pointed out there hasn't been any loss of ability: the cells still have their cell death machinary fully intact, they've just gained the ability to ignore the death signal. This is true but only if chickens evolved from an aquatic bird, which I don't think is the case.

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"Anything that is true of E. coli must be true of elephants, except more so." -Jacques Monod

I've already made reference to the nylon bug. I've read the article about it. My point about it was that the nylon bug changed, but did not increase in complexity or information. It only had a change in the information (DNA code) already present.