Diversification: Random Walk or Biological Determinism?

It is easy enough for us to see that biological evolution will lead eventually to biological diversification. The most dramatic suggestion of this is the trend of diversification following the Permian Extinction: Some would say, however, that there is no trend toward diversification. Instead, it’s only the mirage of a staggering drunk. Is biological diversification merely the result of the random-walk phenomenon? Or is there something meta-evolutionary about it? Does nature allow for any such determinism as this to foster some undiscovered holist principle?I take notice of the evidence of natural diversification in non-living things as well, like rocks. There are several species of quartz, you know, that have accrued over time. So maybe nature allows for deterministic diversification in all of her domains.Or maybe not? Any thoughts?(Biological Evolution please?)”FTF

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Thread moved here from the Proposed New Topics forum.

Probability is a hard science. It tells us that at the roll of a dice the same number could come up at an infinite number of throws. However I don't think that we yet have the knowledge to accurately interpret randomness occurring in the Universe, or what ancient Greeks referred to as Chaos. (apart from old physics, forces, etc).So events may be following certain RULES, but ones of which complexity may well be beyond our reach.

Steven, I'll take what you say to mean that you think there are meta-Darwinian forces at work to spread the biological news around.”FTF

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Hey hoot. Actually I think it is an emergent property of random events, arbitrary human categorizations, and the fact that any graph of distribution would show a skewed distribution, simply because you cannot have negative value.Enjoy.

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Thanks for joining in, RAZD. That's really the core question of this issue: Is diversification, in and of itself, an emergent property? If so it would seem that such an emergent property could exert pressure on a large biological system, which might be measured over the long term on planet Earth as three families of marine life per one million years (see graph in Message 1).”FTF

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I don't think if is because of a skewed distribution or arbitrary categorizations.I think the increase in diversity is a consequence of evolutionary processes operating in an adequately diverse environment.The evolutionary processes operate to 'search' the available space for phenotypes. This 'search' is very, very thorough and relentless.If the environment is diverse enough the 'search' will find more and more finally tuned things to squeeze into it.When you consider that the environment also includes all other organisms then you can see that diversity can be driven to increase.Only if the environment is sparse or undergoes huge disruption would this effect be reversed.In other words, I think increasing diversity is the usual consequence of evolutionary processes.Also, I think it will tend to curve upward as the surrounding diversity (other organisms) feeds back into the processes.

I agree with your comments.But they can be simplified: evolution is 1) opportunistic and 2) uses trial and error feedback.

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Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

Things get more complex because of trial and error trying all avenues, but not being able to be simpler than a single cell. This skews the distribution towards increased complexity with time. With only limited resources you can either have a lot of different kinds of similar one-celled life OR you can have life diversified into multicellular forms. How do you measure diversity? by arbitrary categories. If one "lumps" you get more diversity than if one "splits". In one sense all we have is one form of life: DNA life. All the rest of it is just packaging for how the DNA gets around and reproduces. So is stasis, with the difference between diversity and stasis being random situations or events that divide populations.Enjoy.

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we are limited in our ability to understand
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Rebel American Zen Deist
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Is said same diversification a consequence or an emergent property? I like Nosy's "consequence," because diversification happens after evolution occurs, if the environment is adaquently diverse. But, then again, water happens after the oxidation of hydrogen in a certain tempearure range, and it is considered by some chemists and physicists as an emergent property.”FTF

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Hi Razd,I don't think that things have become more complex. I find hard to believe that even the reactions occurring in the primordial bath or the first cells are simple and maybe will never be elucidated. What has occurred is a diversification in structures, the complexity (e.g. in reactions) has remained, but the communication between structures has changed. Evolution doesn't increase complexity.

Hey StevenFire, The chemical reactions in the first cells would likely be less complex (information) than outside due to being fewer in number (rather than all possible reactions).The diversification of structures can be seen as more complex, with different proteins being constructed and assembled.The (theoretical) combination of two prokaryotes into a single eukaryote could be seen as reducing the information of the two individuals. Same with chloroplasts in plant cells.The combination of cells into an organism structure would be similar to the combination of atoms into a molecular structure (some show chirality too), and the degree of complexity would be related to how you could describe the structure. I'd say it changes complexity, either increased or decreased (the change in hereditary traits in populations from generation to generation).This guy (Epulopiscium fishelsoni) has a pretty complex life cycle compared to other bacteria, the DNA is some 500x's the human genome, and it gives live birth to daughter cells formed inside it's cell, rather than budding.Because it is (random) increase or decrease, it is a skewed distribution - you can only go so far into the decreased direction and still have a cell\organism.Enjoy.

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Complexity is usually measured as a function of the number of elements in a system and the number of relationships between those elements. By this measure, modern cells are more complex than primitive cells. The primitive prokaryotes, no nucleus and usually only a single DNA strand, are much simpler than the later eukaryotes with their cell nucleus and many chromosomes.I understand that you would like to leave structure out of the equation, but I question whether that's really valid, and even if adhere to your preference of only considering reactions, the difference in the number of reactions and interrelationships between reactions for primitive versus modern cells is still dramatic.While evolution doesn't have to increase complexity, in practice competition puts species into an evolutionary arms race, and this generates complexity as species are forced to perform continual evolutionary one-upmanship.--Percy

and Razd,So it would be safe assuming that diversification is reaching a less complex/less chaotic/more ordered system. That is fine by me since entropy in the Universe increases but not necessarily that on Earth. Be careful when associating length of dna with complexity, most of dna is non-coding or "junk-dna".

Percy,That's probably an acceptable definition for complexity, but it reflects more on the mechanical aspects of the system. If I were to use the term "complexity" in describing a system from information theory's standpoint, I would want to address the "uncertainty" about the system. Complexity, then, becomes a measure of the system's "entropy". In Shannon's theory, "conditional entropy" S (i.e., complexity) is shown as:S = D ” I,where D is the systems "diversity" and I is the systems "average mutual information." (I'd show the equations, but it takes a little trouble”best to consult an information theory textbook or website).I offer this only as an alternative to the mechanical notion of complexity.”FTF

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