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Author Topic:   The Common Ancestor?
nwr
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Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 47 of 341 (583468)
09-27-2010 3:10 PM
Reply to: Message 43 by Jon
09-27-2010 12:49 PM


The most recent common ancestor
Jon writes:
But this ape also has ancestors. Why stop at the ape? Why not keep going further back?
Usually, it is the most recent common ancestor that is of interest.

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 Message 43 by Jon, posted 09-27-2010 12:49 PM Jon has replied

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 Message 53 by Jon, posted 09-27-2010 7:39 PM nwr has replied

  
nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 54 of 341 (583520)
09-27-2010 8:18 PM
Reply to: Message 53 by Jon
09-27-2010 7:39 PM


Re: The most recent common ancestor
Jon writes:
I'm trying to understand how anthropologists decide what is and is not a common ancestor.
I would guess that there is usually some uncertainty.
Hopefully, somebody with more knowledge of the field will be able to comment.

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nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 70 of 341 (583630)
09-28-2010 10:09 AM
Reply to: Message 67 by Dr Jack
09-28-2010 7:43 AM


Re: Ancestor in common; yes.
Dr Jack writes:
Are you sure about this? Could we see a proof?
While I have not fully thought it through, I'm inclined to think that Dr Adequate is correct. This would likely come from graph theory (part of combinatorics, which is a branch of mathematics). The family tree is a directed acyclic graph. Well, things get murky if eukaryotes arose from a symbiotic union of simpler organisms, but you don't have to take things back that far if your concern is with a common ancestor for humans and chimps.

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nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 151 of 341 (587012)
10-16-2010 10:16 AM
Reply to: Message 150 by frako
10-16-2010 5:47 AM


Re: Time Tree : : Timescale of Life
barbara writes:
Some people here do not agree that genes actually carry information
frako writes:
If this where true, transfering Jellyfish Genes, the ones that make them glow in the dark, to rats would not make rats glow in the dark.
No, sorry, that's a poor argument.
If I hammer a nail into a car tire, the tire will go flat. We usually don't say that it is because the nail carries information. Rather, we say that it is a cause.
Disagreements over whether genes carry information are conceptual disagreements over what we mean by "information".

Jesus was a liberal hippie

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 Message 150 by frako, posted 10-16-2010 5:47 AM frako has replied

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nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 156 of 341 (587023)
10-16-2010 11:27 AM
Reply to: Message 152 by frako
10-16-2010 10:41 AM


Re: Time Tree : : Timescale of Life
frako writes:
i dont get it, if the gen did not have any information on how the organism should look like and function, then there would be no change in the organism.
The gene works by chemistry, not by information. Whether or not we say that the gene has information does not in any way affect the chemical behavior of the gene.

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nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 158 of 341 (587025)
10-16-2010 11:34 AM
Reply to: Message 154 by frako
10-16-2010 11:07 AM


Re: Time Tree : : Timescale of Life
frako writes:
would you say a tiny hole in a cd-rom that alowes light to reflect from the mettal in the middle of the disk contains information?
When people talk about a CDrom containing information, they are talking about 0s and 1s. They are not talking about pits in the surface.
The pedantically strict view would be that the surface pits are a physical representation of the information, but they are not the information itself. Rather, the information itself is in the 0 and 1 symbols that are represented in the pits. And those 0 and 1 symbols are abstractions, which means that they exist only in Plato's heaven (for a mathematical platonist), or they are mere useful fictions (for a mathematical fictionalist).

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 Message 159 by frako, posted 10-16-2010 3:10 PM nwr has seen this message but not replied
 Message 160 by Dr Jack, posted 10-16-2010 5:00 PM nwr has replied

  
nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


Message 161 of 341 (587063)
10-16-2010 5:26 PM
Reply to: Message 160 by Dr Jack
10-16-2010 5:00 PM


Re: Information rides again
Dr Jack writes:
The only reason I can see for denying that the section of DNA that codes for a protein contains the information for that protein is the nonsense and equivocation we've had to put up with from Creo's regarding the information issue.
There's also equivocation and confusion about information in cognitive science, AI, consciousness studies.

Jesus was a liberal hippie

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 Message 162 by barbara, posted 10-17-2010 10:50 AM nwr has replied

  
nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


(1)
Message 164 of 341 (587199)
10-17-2010 4:07 PM
Reply to: Message 162 by barbara
10-17-2010 10:50 AM


Re: Information rides again
barbara writes:
The word "information" is constantly used to describe genetics by scientists so why is when a creationist (I hate that word) uses your own term is considered an idiot?
Firstly, I don't recall using "idiot" in this discussion.
Some people use "IDiot" to refer to ID proponents - note the capitalization used. While it is possible that I have used that expression in the past, I mostly try to avoid it. I take it as a kind of joke/pun with a built in insult. I am not a fan of ID arguments, but I usually prefer to omit the insults.
Getting back to the work "information" - it is both an ordinary word from our common language (derived from the verb "to inform"), and it is also a technical term. It's meaning/usage as a technical term is different, more precise, than its use as a word in ordinary language.
I don't have any problem with the ordinary use of the term in normal speech, and that includes much of the use of it in genetics. The problem is when people use it loosely, as in ordinary speech, and then try to make claims about it that are only appropriate in technical usage. This mixed use is what leads to bad arguments. And, as mentioned previously, I see that kind of faulty mixed use coming from the creationist/ID communities, and also coming from the cognitive science/consciousness studies/AI communities.
barbara writes:
Molecules based on shape and electron configuration that do what physics has assigned in terminology to explain the reaction is information.
The cogs on the gear wheels in the gear box of my car do what the automotive engineers have assigned them to do. So I guess cogs are information, too.
Normally, we think of the cogs as acting causally and mechanically. Normally, we think of information as detached from the direct causal chain, and as used for communication. So I think we unnecessarily confuse things when we use "information" for actors in direct causal chains.
If things that act in direct causal chains are information, then everything is information. And if everything is information, then the word "information" becomes useless.

Jesus was a liberal hippie

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nwr
Member
Posts: 6185
From: Geneva, Illinois
Joined: 08-08-2005
Member Rating: 3.3


(1)
Message 165 of 341 (587201)
10-17-2010 4:18 PM
Reply to: Message 163 by Wounded King
10-17-2010 3:07 PM


Re: Information rides again
Wounded King writes:
But whatever the pros and cons of a semantic debate on the nature of information theidea that there is some form of information inherent in specific sequences of DNA is certainly one that is well established in the scientific literature, in terms of Shannon entropy, Kolmogorov complexity, Fisher information, Kullback-Leibler information and probably many others.
I don't actually have a problem with that.
My view is that when "information" is used as a technical term, we should understand that we are using a mathematical model. So we should be prepared to identify the information system to which we are applying that model. And if we want to talk about ideas such as "conservation of information", then we either need to prove that such conservation is provable purely from the mathematics, or we need to be able to provide a basis for assuming that conservation as part of the particular information system being modeled.

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