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Author | Topic: Evolution of complexity/information | |||||||||||||||||||||||
Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
The problem, when it comes to down to it, is that
'information' in the genome is an analogy, rather than a fact. The genome does not contain the information to build an organism,it contains templates for proteins that, when formed and operating together, produce an organism. These are two very different things.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I view information to be that which an intelligent
agent obtains from data. You are assimilating a collection of data (the letters) asyou read this, and if you have been taught to read english, and have sufficient context you will obtain information from it (the meaning). In 'design' you can view the blue-print as data, and whatthe 'engineer' (say) does with that blue print is to interpret it to form an implementation. Give the same blue-print to different engineers and you cannot guarantee that the outcome will be identicle. It requires an intelligent, interpretive act. There is no 'information' in the genome, any more than thereis the 'information' within hydrogen and oxygen atoms on how to make water, or to bond with carbon to make alcohol, or ... Within living things there are a set of chemical reactions goingon, the emergent property of that system of chemical reactions is the organism. The 'information' on 'how to build an organism' doesn't exist.The organism emerges from the complex set of chemical reactions that go on. 'Information' in the genome is an unfortunate consequence ofreferences to the 'genetic code'.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Doesn't the concept of an increase in 'order' presuppose
a direction or intent for the change? The problem with extending the analogy of information inthe genome is that one starts to think of 'increasing' or 'decreasing' the information content. All that is happening in evolution is that the set of chemicalreactions available is being changed. Some changes provide the system (organism) with a benefit in its environment, some don't. Some old greek bloke once said 'things change', and that's allthat evolution is about ... change. Concepts of information or even complexity, and defintely of 'order' obfuscate the simplicity of what is going on. There are a vast array of chemical reactions, and the way theyinteract is so complex that the human brain cannot fully encompass them (according to another thread we can never understand them since we are a part of the same system ). If someone claimed that there was 'information' involved inproduction of water and carbon dioxide from the combustion of wood or coal would anyone listen?
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
The definition of information that I use isn't one that
I have made up ... it's the result of an extensive literature search in the field of information theory. There has been, typically, an poor usage of the word 'information'even within the field itself, and many have argued for a pinning down of it's meaning. The one that I use is a concensus of various researchers including Peter Checkland from the 'soft systems thinking' camp. 'Meaning' is something different. If I write: T697AOK It's just alpha numeric characters ... except that to anyone inEngland it brings vehicle license plates to mind, and for myself a particular nice CBR600 motor-cycle. The reader makes associations based upon their own context to gleaninformation from data. The same reader/observer may obtain different information from the same data when viewed at different times. In the main, older works do not differentiate between data andinformation. Perhaps it is simply misleading to use the term 'information' ifit has different meanings in different areas of study. You say there is a well-defined term 'information' that is used,could you please post (or link to) that definition, since that may be the root of my objection to it's use in reference to genomes.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
If order can be arbitrarily defined how is it a helpful
concept? I think I agree with you as far as the rest of your commentsgo. Basically my position is that the term 'information' when usedby anti-evolutionists is used in the more ethereal sense than in any mathematical sense. They then apply, to an analogy, processing which is only consistent with 'actual' information, rather than the 'sort-of' information that genomes actually appear to contain. I wonder if a creationist would use 2LOT to claim that theoceans don't exist
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Shannon's work on data signal processing is expressed
in a manner such that 'data' and 'information' are often but not always interchangeable. His work (important stuff) is all about how much can weleave out and still be able to reconstruct the original data. He calls this core 'information' or the information contentof the message. Like 'txt' is all you really need to send in order to send 'text',most people who use computers are used to all manner of abbreviated versions of words (mainly missing vowels) like 'ctrl'. With signals it's about sampling frequencies (needs to be atleast twice the fastest freq. in the signal). In effect Shannon information is about the amount of uncertaintyin a message. When Shannon says 'information' it largely means 'the minimumamount of data for message reconstruction' ... but the reconsturction is done by some intelligent agent (or an algorithm that acts in proxy of one). The information content of the word 'text' is not embodied inthe letter string ... so I suppose 'meaning' is more what information is about (although meaning implies that something has a distinct objective meaning whereas information is more subjective in nature). If you want to look at genomes again ... it's chemically complexsystems (which there may be some definitions of information or information formalism that are approriate to) that result in something. It's not strictly speaking a 'this sequence of DNA codes forblue eyes' kind of relationship ... it's 'this sequence of DNA produces proteins which then interact with other cells products in particular development modes that lead to blue pigment in the iris'. A ball doesn't roll down a hill because it has a code withinit that tells it how to ... there are numerous forces and factors interacting with the hill and the ball which lead to the ball rolling down the hill.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I see what you mean about the arbitrary selection of
a reference point .. that makes sense to me so long as, as you say, it is a relevent one and is used consistently. The problem I have with anti-evo 'information' arguments is thatthey fundamentally assume that the genomes of organism are the same as a blue-print or design spec. That is, something which tells the cell how to grow. That is the sense in which 'information' is used most oftenin this context ... a definition much closer to the one I lean towards than to the more restricted forms used for data signal processing. Anyone who deals with computers and believes that computerscan handle information should stop and think very hard about what they beleive information to be.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
But I view those differences to be an emergent property
of the extremely complex chemical interactions within cells (and between cells), rather than as any 'real' information/blue-print type construct. In a similar way that 'transportation' is an emergent propertyof a collection of wheels, cogs, chains, pedals, and frame form a bicycle, but the interaction of those components with an environment create a 'transportation' property.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I appreciate the power of understanding the way that
'emergent properties' are generated, but my objection lies in the application of the term 'information' to genomes because this is more likely to obscure such explanation than to facilitate it.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I think we do.
I read recently a comment on understanding genomes ... alongthe lines that given a DNA sequence one could produce the right set of amino-acids ... but reconstructing the actual protein from that would not be trivial due to working out the folds. I'm not a biochemist, but this is in line with my way of thinking. DNA is not a blue-print in an information sense ... it providesa kind of catalyst for the necessary chemical reactions that lead to living things. Evolution of dominance may be an interesting topic to discuss inanother thread (if not already there). Not sure how you would apply an Ogive curve (in Sir Francis' sense)to genomic data though.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
No problem ... unfortunately agreement is a conversation
stumper
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
The biggest problem one faces (beyond defining terms )
when considering information and complexity to biological systems is to decide what we are applying them to. Many start with the DNA .... unfortunately it is not theDNA that makes the organism so this is inapproriate. It is the collection of proteins made from the DNA that makes the organisms so information and complexity have to be considered at least at this level. Not the proteins, but the INTERACTION of a collection ofproteins. I'm still not convinced that information and complexity areuseful concepts in biology let alone evolutionary theory. Evolution is about change. That's all. Change. It focusses on the relationship between a set of phenotypictraits with an environment. That we appear to see an increase in complexity (if viewed asnumber of interacting components of some kind) is suggestive of an environmental need for such complexity to overcome the shortcomings of organism. Like 'human intelligence', much valued and praised, is onlyrequired because we are so puny as an organism. The more resilient and adaptable an organism is, the less'intelligence' it requires to survive .... that's why there are more bacteria and insects than mammals. More complex (however one considers it) doesn't mean betterif it did (even in terms of match to environment) there wouldn't be any 'simple' organisms left after 3.5 billion years.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
I appreciate your points.
All I was trying to get at (rather than dismissingthe importance of DNA) is that in relation to 'informational' effects in Evolution DNA is not the place to look (it is at too a low a level in the 'system'). It would be like looking at electron flow to understanda computer program's behaviour .... inapproriate yet essential. As one moves through the hierarchy of systems within any systemwe loose sight of some essential features which are emergent properties and only visible at a particular level ( and higher) in a hierarchy. Once we delve lower in the hierarchy the feature is no longer visible. To understand information and complexity in relation to evolutionI beleive the lowest level of the system hierarchy to look at has to be the protein interactions within the cell. Added by edit:- To elaborate a little ... if a base gets changed in aDNA sequence what happens to the organism? Sometimes nothing at all, because the base sequences are synonomous,sometimes catastrophy because we destroy essential-protein production capability, sometimes .... well all manner of effects that are only explicable by looking at what the DNA produces. This message has been edited by Peter, 11-29-2004 08:59 AM
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
DNA doesn't build organisms .... it builds proteins.
Proteins interact in various ways with other chemicalsin the environment in which they exist. Proteins don't build organisms ... they react chemicallywith other compounds, elements and proteins. Chemical interactions in vast nested, cyclic, complex systemsresult in organisms. If we wish to consider the nature of the information required toconsider how evolution may or may not lead to an increase in complexity of the organism we need to look at the complexity of the chemical intercations .... not at what happens in the DNA. Whether a base change in a DNA sequence is increase/decreaseof information at that level (or niether) is of little relevence to information 'used' or consumed by evolutionary processes. Proteins do NOT communicate DNA information, they are theend product of that layer of the cell heirarchy and deliver that product into a higher layer. All analgies to communication systems are very poor in this context.
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Peter Member (Idle past 1507 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
Perhaps it's just a semantic difference.
The protein, even in the case(s) that you mention,aren't what 'build' the organism. It is the interaction of an array of proteins. The information for 'organism' is then based upon the'information' content of the interaction rather than the proteins themselves.
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