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Author Topic:   "The Edge of Evolution" by Michael Behe
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


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Message 31 of 149 (531396)
10-17-2009 2:51 PM
Reply to: Message 30 by bluegenes
10-17-2009 9:05 AM


Re: Joe Thornton (and creationist targets).
Or to put it another way, Behe is trying to use a (flawed) a posteriori estimate of how long it took some particular feature in some species to evolve --- to come to an a priori estimate of how long it should have taken some particular species to be what it is.
No, his reasoning just doesn't fit together, does it?
Edited by Dr Adequate, : No reason given.

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 Message 30 by bluegenes, posted 10-17-2009 9:05 AM bluegenes has not replied

  
Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


(1)
Message 32 of 149 (531432)
10-17-2009 6:51 PM
Reply to: Message 30 by bluegenes
10-17-2009 9:05 AM


Re: Joe Thornton (and creationist targets).
I think Wounded King made a links post on an article about it recently
Indeed, the thread was [thread=-13798]. Unfortunately the original Nature paper and commentary are only available with a subscription.
TTFN,
WK

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Colin
Junior Member (Idle past 5245 days)
Posts: 27
From: Adelaide, Australia.
Joined: 10-14-2009


Message 33 of 149 (531452)
10-18-2009 1:31 AM
Reply to: Message 25 by Modulous
10-17-2009 6:48 AM


Re: What Behe's calculations actually mean for human evolution
Hi Modulus, just a quick question, how do you put my quotes in the blue highlighted boxes? It would be easier for me to respond to people using this. Is this a feature of the site or do you just cut and paste?
Since the number of potential evolutionary paths is unknown, let me work backwards. Behe puts the probability of chloroquine resistance at 1 in 10^20. Although he he himself claims to have been very conservative, lets say he was way too pessimistic by a thousand fold, and put it at 1 in 10^17. You suggested 36 x billion for human ancestry, lets make it a trillion. The easiest way to proceed from here is to set up an "even odds" situation, (a 1 in 10 chance gets 10 trials). Not the most mathematical approach, but it is just an illustration. I will leave the unknown value of potential pathways with the "loose change" from the even odds.
Referring back to the "big if" you mention. This comparison draws again on the benchmark of chloroquine resistance. A step of similar difficulty for other species could be anything, and without the specific nature of this step. It could be an adaptation that improves the eye, or memory, or gives resistance to cancerous cells forming, anything. In using the Malaria example, Behe seems to have assumed that a step of this complexity would not be remarkable in nature, assuming evolution to be true.
This part is important. In achieving this step, although malaria had a very specific problem, it was not restricted to any specific solution. Indeed how could we, it is a real example. We can assume that any genetic stage setting, drifting, duplicating, inserting, deletions of any type, were open for use.
Getting back to the numbers, 1 in 10^17 chances with 10^12 trials, leaves 10^5 in change. In other words, if all 1 trillion creatures on the line to humans each had 100000 feasible steps to gaining an advantage of similar complexity to the step of developing chloroquine resistance, there would be even odds of such an event happening once in all of history on our branch. Note: This example does not limit the changes to those which lead to "human." Feasible steps refers to any advantage, including growing gills, wings, six legs, anything. Consider also, we are not just looking for one occurrence, we are looking for many, many steps of change.
BUT, nothing is special about our branch on the evolutionary tree! It could have just dropped off and who would care? If ours perished, another would prosper. No, this example does not discriminate on where a branch should lead, and does not assume any necessity for the human line to survive. It deals with the difficulty of a branch propagating anywhere, since each of the proposed 100000 options represent a potential "off shoot" from the branch. The existence of other species shows only that this is not a unique event, and that many "off shoots" also continue to propagate.

This message is a reply to:
 Message 25 by Modulous, posted 10-17-2009 6:48 AM Modulous has replied

Replies to this message:
 Message 34 by Modulous, posted 10-18-2009 3:10 AM Colin has replied
 Message 35 by Dr Adequate, posted 10-18-2009 6:48 AM Colin has replied
 Message 40 by bluegenes, posted 10-18-2009 5:59 PM Colin has replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


(1)
Message 34 of 149 (531456)
10-18-2009 3:10 AM
Reply to: Message 33 by Colin
10-18-2009 1:31 AM


Hi Modulus, just a quick question, how do you put my quotes in the blue highlighted boxes? It would be easier for me to respond to people using this. Is this a feature of the site or do you just cut and paste?
At the bottom of my post is a button labelled 'peek'. If you press that it reveals the code I used to construct my post. Alternatively, instructions can be read this. In simple terms: enclose the letters qs in square brackets and close it using /qs.
[qs]Like so[/qs]
I'm not sure what your point is with the rest of your post, unfortunately. Though I feel I should probably point out that
Feasible steps refers to any advantage, including growing gills, wings, six legs, anything.
These don't strike me as particularly feasible steps. Perhaps you were simplifying?

This message is a reply to:
 Message 33 by Colin, posted 10-18-2009 1:31 AM Colin has replied

Replies to this message:
 Message 36 by Colin, posted 10-18-2009 7:15 AM Modulous has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


(1)
Message 35 of 149 (531473)
10-18-2009 6:48 AM
Reply to: Message 33 by Colin
10-18-2009 1:31 AM


Re: What Behe's calculations actually mean for human evolution
Since the number of potential evolutionary paths is unknown, let me work backwards. Behe puts the probability of chloroquine resistance at 1 in 10^20.
You see where I proved that his reasoning was droolingly hopelessly wrong?
Edited by Dr Adequate, : No reason given.

This message is a reply to:
 Message 33 by Colin, posted 10-18-2009 1:31 AM Colin has replied

Replies to this message:
 Message 37 by Colin, posted 10-18-2009 7:27 AM Dr Adequate has replied

  
Colin
Junior Member (Idle past 5245 days)
Posts: 27
From: Adelaide, Australia.
Joined: 10-14-2009


Message 36 of 149 (531479)
10-18-2009 7:15 AM
Reply to: Message 34 by Modulous
10-18-2009 3:10 AM


These don't strike me as particularly feasible steps. Perhaps you were simplifying?
Okay, thanks.
About the feasible steps. Imagine "animal space" with some details of my own added in, and without referring directly to genes. Imagine the trillion creatures directly preceding living humans. Extended back as far as necessary until a trillion is reached. I imagine this will go back several million years, and may include some of our cousins. When we reach one trillion, we may have stopped on a small community of some primate looking things. Lets say that every one of these creatures, right up to all modern day humans, each have 10000 opportunities to pass on some mutation comparable in complexity to that needed to cause chloroquine resistance in malaria. In referring back to your query, a feasible step here means any number of possible mutation clusters that will lead to some advantage in some way. I suggest 10000, which I arrived at arbitrarily in order to produce an "even odds" example at the end. I have no idea what this number actually would be - we are talking about hypothetical biological machinery. So, if each of these trillion creatures, each had 10000 such beneficial evolutionary steps open to them, there would be even odds of just one of these steps being taken in the whole trillion creatures. (Please note: I am again using the step to chloroquine resistance as an ball park estimate of the difficulty of taking a modestly complex, beneficial evolutionary step.)
PS. Its been a long day, if this still doesn't make any sense i will come back to it.

This message is a reply to:
 Message 34 by Modulous, posted 10-18-2009 3:10 AM Modulous has replied

Replies to this message:
 Message 38 by bluegenes, posted 10-18-2009 9:21 AM Colin has replied
 Message 39 by Modulous, posted 10-18-2009 1:52 PM Colin has replied

  
Colin
Junior Member (Idle past 5245 days)
Posts: 27
From: Adelaide, Australia.
Joined: 10-14-2009


Message 37 of 149 (531483)
10-18-2009 7:27 AM
Reply to: Message 35 by Dr Adequate
10-18-2009 6:48 AM


Re: What Behe's calculations actually mean for human evolution
Hi Dr Adequate,
Ive just been rereading your posts. Have you read the first part of message 23, and does this apply to the argument you made about Behe's probability argument? If not, could you remind me.
Thanks.

This message is a reply to:
 Message 35 by Dr Adequate, posted 10-18-2009 6:48 AM Dr Adequate has replied

Replies to this message:
 Message 44 by Dr Adequate, posted 10-19-2009 12:25 AM Colin has replied

  
bluegenes
Member (Idle past 2477 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


(1)
Message 38 of 149 (531497)
10-18-2009 9:21 AM
Reply to: Message 36 by Colin
10-18-2009 7:15 AM


Colin writes:
In referring back to your query, a feasible step here means any number of possible mutation clusters that will lead to some advantage in some way. I suggest 10000, which I arrived at arbitrarily in order to produce an "even odds" example at the end. I have no idea what this number actually would be - we are talking about hypothetical biological machinery.
I suggest 100,000,000 (equally arbritrarily).
So, if each of these trillion creatures, each had 10000 such beneficial evolutionary steps open to them, there would be even odds of just one of these steps being taken in the whole trillion creatures.
With my figures, 10,000 "steps."
More importantly:
Colin writes:
(Please note: I am again using the step to chloroquine resistance as an ball park estimate of the difficulty of taking a modestly complex, beneficial evolutionary step.)
P. falciparum seemed to take ~10^12 individuals to achieve resistance to atovaquone, so you could have chosen that as a "ball park estimate". The monkey in the picture to the left achieved an interesting new advantage in its digestive system by a series of mutations when there had probably been not more than a billion members of its species, so we could call that a 10^8 mutation series, which you could have chosen as a ball park estimate.
Humans developed cold climate adaptions of lighter skin, straighter hair and other minor things from a population of probably not more than 100,000,000 so we could call these a 10^7 combination of adaptions. Lactose tolerance in adults seems to have arrived several times in human populations since the advent of agriculture, so it is perhaps a 10^6 advantageous mutation.
The ease or difficulty with which one particular species develops one particular adaption does not work as a measure of evolution, or of the complexity of a particular characteristic. My little monkey's advantage involved more mutations than P. falciparum did for its chloroquine resistance, so a specific "10^8" could easily be described as more "complex" than a specific "10^20".
But the monkey could have received what was really one out of 10^12 possible "10^20" mutation sequences. Who knows?
Colin, it isn't variation that limits evolution. Look at the variety we can get very quickly when we cheat natural selection and breed plants and animals. It is conservative natural selection that keeps a wild wolf from developing rapidly into lots of very different looking creatures, not lack of genetic variation.
Edited by bluegenes, : No reason given.

This message is a reply to:
 Message 36 by Colin, posted 10-18-2009 7:15 AM Colin has replied

Replies to this message:
 Message 41 by Colin, posted 10-18-2009 10:44 PM bluegenes has replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


(1)
Message 39 of 149 (531538)
10-18-2009 1:52 PM
Reply to: Message 36 by Colin
10-18-2009 7:15 AM


I suggest 10000{0}, which I arrived at arbitrarily in order to produce an "even odds" example at the end.
Yes - I realize that you picked that number and why, but I don't see what you think the point is with it. You picked a number which you think results in there being a 50% chance of the human lineage having stumbled upon a certain mutation and then 'deduce' there is only a 50% chance that human ancestors could have stumbled upon one of them.
I didn't see the point in that exercise.
Getting back to the numbers, 1 in 10^17 chances with 10^12 trials, leaves 10^5 in change. In other words, if all 1 trillion creatures on the line to humans each had 100000 feasible steps to gaining an advantage of similar complexity to the step of developing chloroquine resistance, there would be even odds of such an event happening once in all of history on our branch.
I'd like to see the maths expanded a bit there actually. I can't replicate it.
But either way as I said earlier - if our ancestors expected to come up with any decent number of long shots in the order that Behe proposes the malarial resistance was then we'd probably have failed. If our continued existence depended on it -we'd be extinct.
So as I said - Behe's equation simply confirms that this probably hasn't happened.
There is no reason to think that all possible beneficial mutation events are equally improbable, and there is no reason to think there are a small number of such possible beneficial mutations.
Take bog standard bacterial resistance to antibiotics. That is advantageous in certain contexts and can appear in a population starting from 1 within a few hours or days. Over and over and over again.

This message is a reply to:
 Message 36 by Colin, posted 10-18-2009 7:15 AM Colin has replied

Replies to this message:
 Message 43 by Colin, posted 10-19-2009 12:20 AM Modulous has replied

  
bluegenes
Member (Idle past 2477 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


(1)
Message 40 of 149 (531567)
10-18-2009 5:59 PM
Reply to: Message 33 by Colin
10-18-2009 1:31 AM


Variation and artificial selection
Colin writes:
Since the number of potential evolutionary paths is unknown, let me work backwards. Behe puts the probability of chloroquine resistance at 1 in 10^20.
It would have taken far, far less than 10^20 organisms to produce the divergence seen below. No specific targets here. If it tastes good and it looks good, it gets selected.
To brighten up the thread, here are examples of the variations that can exist in real life due to mutation. All of these descend from the first within the last few thousand years, due to artificial selection. This illustrates that it is really natural selection far more than mutation that defines the "edge of evolution", and that there is no shortage in variation when we cheat natural selection.
Brassica Oleracea
Kohlrabi
Kale
Chinese Broccoli
Cauliflower
Romanesco Broccoli
Cabbage
Brussels Sprouts
Broccoli
All this (and more) from a common ancestor in just a few thousand years; instant geological time. For more details, see:

This message is a reply to:
 Message 33 by Colin, posted 10-18-2009 1:31 AM Colin has replied

Replies to this message:
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Colin
Junior Member (Idle past 5245 days)
Posts: 27
From: Adelaide, Australia.
Joined: 10-14-2009


Message 41 of 149 (531579)
10-18-2009 10:44 PM
Reply to: Message 38 by bluegenes
10-18-2009 9:21 AM


Nuts & Bolts
P. falciparum seemed to take ~10^12 individuals to achieve resistance to atovaquone, so you could have chosen that as a "ball park estimate". The monkey in the picture to the left achieved an interesting new advantage in its digestive system by a series of mutations when there had probably been not more than a billion members of its species, so we could call that a 10^8 mutation series, which you could have chosen as a ball park estimate.
Indeed, in an exercise of playing with variables this is an equally legitimate calculation. My interest in considering different types of changes comes from a desire to consider the nuts and bolts of how mutations can actually produce new features, and what sort of gaps are in place between even the small steps. If we consider the evolution of the eye, it would be good to know what specifics are involved in making a group of skin cells distinguishably more photo sensitive than the others. And then, what further genetic changes are required to produce some sort of cavity, to gain some directional perspective from those photosensitive cells, and so on. Whether Behe's calculation is common or not, it would of course not be unique. We always expect for sure that some mutations would be less likely and others more likely. The purpose of looking for any such estimate is similar to say, the necessity to find the probability of flipping a head on a coin toss, in order to find the probability of flipping several in a row. The difference of course is that we don't have a standard "head" in this case, but many different possibilities with different probabilities. So any ball park estimate is by no means a rule, and if Behe's estimate is indeed not typical in terms of the steps available, then I would expect the argument to break down. His assertion is though, is that life is full of features requiring many such steps to be taken. Of course, we would still need to account for how many similar steps are available at the same time, just as holding several lottery tickets is different to holding just one. we don't really care which ticket wins.
With my figures, 10,000 "steps."
Indeed, we would expect steps of lower complexity to be achieved more often.
The ease or difficulty with which one particular species develops one particular adaption does not work as a measure of evolution, or of the complexity of a particular characteristic. My little monkey's advantage involved more mutations than P. falciparum did for its chloroquine resistance, so a specific "10^8" could easily be described as more "complex" than a specific "10^20".
But the monkey could have received what was really one out of 10^12 possible "10^20" mutation sequences. Who knows?
I would agree with half of this. "Complex," here i would imagine refers strongly to the probability of a specific adaptation occurring from the creatures current position. The more solutions there are, the less complex the adaptation. The less amount of changes necessary, the less complex the adaptation. So a specific 10^8 would not be more complex than a specific 10^20, but a specific 10^8 could be more complex than a more general 10^20. In this particular I do not think his calculations are off, because the resistance was not restricted to a specific mutation, but to any. what I would not agree with is the first sentence. I think the ease or difficulty of acquiring a characteristic could by definition be called the complexity. Whether it is a measure of evolution in general is another question. For that we need to consider how typical that level of complexity is, and the number of alternate paths.

This message is a reply to:
 Message 38 by bluegenes, posted 10-18-2009 9:21 AM bluegenes has replied

Replies to this message:
 Message 81 by bluegenes, posted 10-23-2009 3:04 AM Colin has replied

  
Colin
Junior Member (Idle past 5245 days)
Posts: 27
From: Adelaide, Australia.
Joined: 10-14-2009


Message 42 of 149 (531580)
10-18-2009 11:02 PM
Reply to: Message 40 by bluegenes
10-18-2009 5:59 PM


Re: Variation and artificial selection
Thanks, this certainly makes the page look a lot nicer!
Artificial selection would indeed help things along, in fact we could even say that is what we do any process of experimentation. However, mutations still need to do their job before a selection can be made. Unless, we are talking about variation not due to mutation. Personally I am undecided about how far this idea can go. We know that children will be different to both their parents without any mutations taking place, perhaps even more beautiful or smarter. I remember seeing what i swear were brussel sprouts attached to the bottom of a cabbage. It had never struck me before, but they are just like little cabbages. I would have no problem in believing that a cabbage plant could evolve into a brussel sprout plant just through a process of an inbuilt variation of parameters. I could even believe this and other examples happened due to Darwinian evolution.

This message is a reply to:
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Colin
Junior Member (Idle past 5245 days)
Posts: 27
From: Adelaide, Australia.
Joined: 10-14-2009


Message 43 of 149 (531587)
10-19-2009 12:20 AM
Reply to: Message 39 by Modulous
10-18-2009 1:52 PM


Explanation of Calculations
Yes - I realize that you picked that number and why, but I don't see what you think the point is with it. You picked a number which you think results in there being a 50% chance of the human lineage having stumbled upon a certain mutation and then 'deduce' there is only a 50% chance that human ancestors could have stumbled upon one of them.
I didn't see the point in that exercise.
The even odds scenario doesn't produce 50/50 chance, its more like 40/60. (ie if each ticket in a lottery gives a 1 in 100 chance of winning, you have slightly less than 60% chance of having at least 1 winning ticket) Like i said its not the most mathematical of approaches. The program i was using for the calculations couldn't handle the precision of calculations using (10^19) - 1 (basically a heap of 9's). There are obviously many out there that will but i would have had to download them. The point of the exercise is to take calculations involving
1. The probability of common evolutionary steps (highly debated in these posts).
2. Number of typically available beneficial mutations.
3. Population size
Probability - Typical/average probability of a SPECIFIC beneficial mutation (such as photosensitive cells) developing by any means available (ie ANY available method of developing photosensitive cells).
Number of typically available beneficial mutations - The number of available beneficial mutations available to "choose" from. For example, along with photosensitive cells might go, a specific drug resistance, the ability to hear notes of higher pitch, skin pigmentation, and so on.
Population - The total number of all creatures along an evolutionary branch. (for example, all humans and some of our cousins and ancestors)
I propose that this would give an idea of the number of creatures required to produce a beneficial step of a certain complexity.
By varying some parameters and compensating with others, different hypotheticals can be considered.
I propose that to set up an even odds situation, ie a slightly less than 60% chance of at least one of these beneficial mutations happening,
Then (1/probability) = Available beneficial mutations x accumulated population.
With (1/probability), i mean for example, 1 in 100 chance becomes the number 100.
The point of this equation is to get the number of creatures required to produce even odds of a beneficial mutation happening once.
In the example i used, i proposed a more pessimistic version of Behe's calculation for probability, and made it 1 in 10^17 instead of 1 in 10^20. I proposed one trillion creatures beginning from modern man and working backwards to some point (wherever a trillion is reached). Which left 100000 potential beneficial mutations for each creature, in order to produce a 60% chance of one of these mutations happening at least once. Note: of course this allows for it happening more than once, but the probability quickly decreases as we assume more "winners."
In more direct words, my point was to show that many such mutations were unlikely, but I would "assume" necessary to vary a species in any significant way.
Lastly, i must point out that these parameters can be varied, as bluegenes has already taken the liberty of doing. You may disagree with the typical number of availiable beneficial mutations within reach, or with Behe's measurements of probability.
There is no reason to think that all possible beneficial mutation events are equally improbable, and there is no reason to think there are a small number of such possible beneficial mutations.
I agree with you on this. But it is a matter of simplification to try to find a figure for which we could say "approximately x number of mutations of similar complexity would be needed for the type of evolution we see around us."
Edited by Colin, : error

This message is a reply to:
 Message 39 by Modulous, posted 10-18-2009 1:52 PM Modulous has replied

Replies to this message:
 Message 45 by Modulous, posted 10-19-2009 1:31 AM Colin has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


(1)
Message 44 of 149 (531588)
10-19-2009 12:25 AM
Reply to: Message 37 by Colin
10-18-2009 7:27 AM


Re: What Behe's calculations actually mean for human evolution
Ive just been rereading your posts. Have you read the first part of message 23, and does this apply to the argument you made about Behe's probability argument? If not, could you remind me.
I did read it. I didn't follow it: I didn't quite see what point you were trying to make. But then you finished it up by saying: "Will have to do some research and come back to this."
So I was waiting for you to do that. It seems unnecessary for me (and unfair on you) for me to start asking you what you're getting at when you're still trying to figure that out yourself.
So far as we've got, Behe's point seems simply asinine. He's trying to calculate the probability of an evolutionary event by taking the number of times it's happened and dividing by the population size --- but this ignores the existence of natural selection. It's almost as though I were to argue that the fact of my being born is very unlikely because in all my life I've only been born once. Well of course I have. That's how it works.
Edited by Dr Adequate, : No reason given.

This message is a reply to:
 Message 37 by Colin, posted 10-18-2009 7:27 AM Colin has replied

Replies to this message:
 Message 47 by Colin, posted 10-19-2009 3:27 AM Dr Adequate has replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


(1)
Message 45 of 149 (531593)
10-19-2009 1:31 AM
Reply to: Message 43 by Colin
10-19-2009 12:20 AM


Re: Explanation of Calculations
In more direct words, my point was to show that many such mutations were unlikely, but I would "assume" necessary to vary a species in any significant way.
Lastly, i must point out that these parameters can be varied, as bluegenes has already taken the liberty of doing. You may disagree with the typical number of availiable beneficial mutations within reach, or with Behe's measurements of probability.
But your assumptions already say that many such mutations are unlikely. So it is hardly surprising that your conclusion is the same. It's circular, that's why I don't see the point in it. As I said - you picked numbers that would give a certain result and then pointed at the result as if it meant something interesting. I could have done the same exercise and made it appear as if evolution towards 'improvement' was inevitable. It would have meant nothing, though.
I agree with you on this. But it is a matter of simplification to try to find a figure for which we could say "approximately x number of mutations of similar complexity would be needed for the type of evolution we see around us."
Right - I appreciate this. It is an over simplification, indeed. But you've provided no compelling reason to think that any mutations of 'similar complexity' are needed at all for the type of evolution we see around us.

This message is a reply to:
 Message 43 by Colin, posted 10-19-2009 12:20 AM Colin has replied

Replies to this message:
 Message 46 by Colin, posted 10-19-2009 3:00 AM Modulous has replied

  
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