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Author Topic:   Doesn't Natural Selection lead to Specified Complexity?
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 121 of 138 (620112)
06-14-2011 7:48 AM
Reply to: Message 120 by PaulK
06-13-2011 12:30 PM


Drifting into drift.
Drift 'function':

As I have suggested before, the way I see it is that the 'process' of drift has far too many variables for us to model approriately.

It is, for example, inevitably affected by natural selection.

It is, by definition, not directly affected by environmental pressures on the population in question.

To justify excluding it from a discussion on the 'specifying'/'designing' power of natural selection I added it as an offset. I concede that this is a rather large simplification.

I consider it a distraction from the main point here.

Determinism:

So do you accept or reject 'universal determinism'? i.e. that what we see as random is actually the result of interactions too complex for us to comprehend.

Leaving us to model as best we can (with full knowledge that we are using a best fit rather than a precise model).


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 Message 120 by PaulK, posted 06-13-2011 12:30 PM PaulK has responded

Replies to this message:
 Message 122 by PaulK, posted 06-14-2011 11:44 AM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 122 of 138 (620147)
06-14-2011 11:44 AM
Reply to: Message 121 by Peter
06-14-2011 7:48 AM


Re: Drifting into drift.
quote:

As I have suggested before, the way I see it is that the 'process' of drift has far too many variables for us to model approriately.

Well, I would disagree. Too many to model as a deterministic process, perhaps, but I would question if that was appropriate even if it was possible. And that doesn't explain why you excluded the environment from your drift function, while including it in your natural selection function when, under your definition it affects both. It looks very much as if you are using a more normal definition of environment.

quote:

Determinism:

So do you accept or reject 'universal determinism'? i.e. that what we see as random is actually the result of interactions too complex for us to comprehend.


Universal determinism is irrelevant to the questions before us. If natural selection is "deterministic" solely because of universal determinism then it is deterministic only in a trivial sense which tells us nothing useful about it. Regardless of determinism the outcome of evolution is influenced by many factors which might as well be random and therefore treating them as random gives us a clearer view of natural selection, whether they are random or fully deterministic.


This message is a reply to:
 Message 121 by Peter, posted 06-14-2011 7:48 AM Peter has responded

Replies to this message:
 Message 123 by Peter, posted 06-14-2011 12:56 PM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 123 of 138 (620155)
06-14-2011 12:56 PM
Reply to: Message 122 by PaulK
06-14-2011 11:44 AM


Re: Drifting into drift.
Good. So we can draw a line under determinism and move on then.

As for environment and drift:

It is and remains my understanding that drift is about gene frequency within a population changing over time for no particular reason -- or rather not in response to a specific stimulus.

I therefore regard it as a function purely of the gene distribution from the previous time quanta.

It is affected by which genes (should I be saying alleles?) get into the gametes, and which gametes get into the next generation.

There are, quite possibly, factors which affect this, but it appears to be a random process.

Drift will affect small populations most, having the effect of reducing allele diversity (within the population).

So I now say that a reasonable way to view it is:

GeneDist[k] = NaturalSelection(Env, PopulationSize[k], GeneDist[k]) + Drift(PopulationSize[k-1],GeneDist[k-1])

Which is a little different (thanks for the thought processes being triggered) but does NOT impact my original post:

Natural Selection can produce entities that appear to have Specified Complexity.


This message is a reply to:
 Message 122 by PaulK, posted 06-14-2011 11:44 AM PaulK has responded

Replies to this message:
 Message 124 by PaulK, posted 06-14-2011 1:09 PM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 124 of 138 (620159)
06-14-2011 1:09 PM
Reply to: Message 123 by Peter
06-14-2011 12:56 PM


Re: Drifting into drift.
Unless you have changed your definition of the environment, you are still wrong to exclude it from your drift function.

And to suggest that drift is purely a function of gene distribution when you yourself add population size as a factor is self contradictory.

(You are also inconsistent in your use of the variable k. You probably meant to use k-1 in your natural selection function).


This message is a reply to:
 Message 123 by Peter, posted 06-14-2011 12:56 PM Peter has responded

Replies to this message:
 Message 125 by Peter, posted 06-21-2011 11:23 AM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 125 of 138 (620850)
06-21-2011 11:23 AM
Reply to: Message 124 by PaulK
06-14-2011 1:09 PM


Re: Drifting into drift.
No. In natural selection the pressures are on the current population therefore k not k - 1 (they obviously have an effect on subsequent population via iteration).

I already stated that I had had to rethink some aspects of my position on drift, and that rethinking was what I intended to convey.


This message is a reply to:
 Message 124 by PaulK, posted 06-14-2011 1:09 PM PaulK has responded

Replies to this message:
 Message 126 by PaulK, posted 06-21-2011 3:24 PM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 126 of 138 (620896)
06-21-2011 3:24 PM
Reply to: Message 125 by Peter
06-21-2011 11:23 AM


Re: Drifting into drift.
quote:

No. In natural selection the pressures are on the current population therefore k not k - 1 (they obviously have an effect on subsequent population via iteration).

No, k is the resultant population, which is shaped by the pressures on the previous generation, so you should use k-1, just as you do for drift.


This message is a reply to:
 Message 125 by Peter, posted 06-21-2011 11:23 AM Peter has responded

Replies to this message:
 Message 127 by Peter, posted 06-22-2011 11:10 AM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 127 of 138 (621005)
06-22-2011 11:10 AM
Reply to: Message 126 by PaulK
06-21-2011 3:24 PM


Re: Drifting into drift.
No k is the current generation, the gene distribution of which is a function of past changes and current changes due to survivability.
This message is a reply to:
 Message 126 by PaulK, posted 06-21-2011 3:24 PM PaulK has responded

Replies to this message:
 Message 128 by PaulK, posted 06-22-2011 12:41 PM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 128 of 138 (621015)
06-22-2011 12:41 PM
Reply to: Message 127 by Peter
06-22-2011 11:10 AM


Re: Drifting into drift.
quote:

No k is the current generation, the gene distribution of which is a function of past changes and current changes due to survivability.

I see your mistake now. You assume that natural selection is primarily about survival. It isn't. It's all about reproductive success, and the survival of individuals is only relevant insofar as it contributes to reproduction.

Therefore, the generation you need to look at is the previous generation, the parents.


This message is a reply to:
 Message 127 by Peter, posted 06-22-2011 11:10 AM Peter has responded

Replies to this message:
 Message 129 by Peter, posted 07-08-2011 9:42 AM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 129 of 138 (623133)
07-08-2011 9:42 AM
Reply to: Message 128 by PaulK
06-22-2011 12:41 PM


Re: Drifting into drift.
But the distribution of genes in the current generation is about which 'genes' survive ... isn't it?
This message is a reply to:
 Message 128 by PaulK, posted 06-22-2011 12:41 PM PaulK has responded

Replies to this message:
 Message 130 by PaulK, posted 07-08-2011 10:07 AM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 130 of 138 (623137)
07-08-2011 10:07 AM
Reply to: Message 129 by Peter
07-08-2011 9:42 AM


Re: Drifting into drift.
quote:

But the distribution of genes in the current generation is about which 'genes' survive ... isn't it?

That is very unclear. However, I think I can say that whatever it means exactly, it is wrong. For instance a living individual that is sterile due to a genetic defect is in the current population, but does not contribute genetic material to the next. If you exclude dead individuals, then a dead individual that has already bred successfully has contributed to the next generation, despite being excluded from the current one.

It is breeding that is important, not simple survival.


This message is a reply to:
 Message 129 by Peter, posted 07-08-2011 9:42 AM Peter has responded

Replies to this message:
 Message 133 by Peter, posted 06-28-2013 10:24 AM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 133 of 138 (701950)
06-28-2013 10:24 AM
Reply to: Message 130 by PaulK
07-08-2011 10:07 AM


Re: Drifting into drift.
But a sterile individual can still affect the gene distribution in the subsequent generation ... by potentially removing some individuals from contributing to the next generation.

The dead thing is irrelevant in the model I was considering since if you are dead youe are, by definition, not IN the population.


This message is a reply to:
 Message 130 by PaulK, posted 07-08-2011 10:07 AM PaulK has responded

Replies to this message:
 Message 134 by PaulK, posted 06-28-2013 10:29 AM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 134 of 138 (701953)
06-28-2013 10:29 AM
Reply to: Message 133 by Peter
06-28-2013 10:24 AM


Re: Drifting into drift.
quote:

But a sterile individual can still affect the gene distribution in the subsequent generation ... by potentially removing some individuals from contributing to the next generation.

But that would be through actions, not genes.

quote:

The dead thing is irrelevant in the model I was considering since if you are dead youe are, by definition, not IN the population.

That's why it IS a problem. You don't count them, even though they do contribute to the next generations.


This message is a reply to:
 Message 133 by Peter, posted 06-28-2013 10:24 AM Peter has responded

Replies to this message:
 Message 135 by Peter, posted 06-28-2013 10:37 AM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 135 of 138 (701956)
06-28-2013 10:37 AM
Reply to: Message 134 by PaulK
06-28-2013 10:29 AM


Re: Drifting into drift.
Isn't behaviour (i.e. action) related to genetic makeup?

The deceased are counted, since we are looking at an iteration over a number of generations.

Perhaps it is more like a filter where we have something like:

a[k] = a[k-1] + b.a[k-2] ....

But the deceased are involved as they would account for 'activity' in previous iterations.


This message is a reply to:
 Message 134 by PaulK, posted 06-28-2013 10:29 AM PaulK has responded

Replies to this message:
 Message 136 by PaulK, posted 06-28-2013 10:55 AM Peter has responded

    
PaulK
Member
Posts: 13113
Joined: 01-10-2003
Member Rating: 2.8


Message 136 of 138 (701959)
06-28-2013 10:55 AM
Reply to: Message 135 by Peter
06-28-2013 10:37 AM


Re: Drifting into drift.
quote:

Isn't behaviour (i.e. action) related to genetic makeup?

Related to, but hardly dictated by. So you're really reaching there.

quote:

The deceased are counted, since we are looking at an iteration over a number of generations.

That doesn't make sense, and seems to contradict what you just said about NOT counting them.


This message is a reply to:
 Message 135 by Peter, posted 06-28-2013 10:37 AM Peter has responded

Replies to this message:
 Message 137 by Peter, posted 07-01-2013 5:20 AM PaulK has responded

    
Peter
Member (Idle past 1452 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 137 of 138 (702082)
07-01-2013 5:20 AM
Reply to: Message 136 by PaulK
06-28-2013 10:55 AM


Re: Drifting into drift.
At any point in time, k, the genetic makeup of the population is an acculation of the results from the past .... which will include deceased individuals. So maybe I changed tack a bit there, but it's been a while since I even looked at what I was saying here.

'Behaviour' is part of my environment ....

The deceased are no longer part of the population at time k, but were at some point from k-1 .... k-n.


This message is a reply to:
 Message 136 by PaulK, posted 06-28-2013 10:55 AM PaulK has responded

Replies to this message:
 Message 138 by PaulK, posted 07-01-2013 8:03 AM Peter has not yet responded

    
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