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Survival of the fittest - what does it mean ?

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Mefiante
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« Reply #15 on: January 21, 2008, 12:31:24 PM »

New Findings Confirm Darwin's Theory: Evolution Not Random
Quote
Now, the findings of an international team of biologists demonstrate that evolution is not a random process, but rather occurs through the natural selection of successful traits.


It should be noted that the article is very, very badly titled.

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« Last Edit: January 21, 2008, 12:33:47 PM by Anacoluthon64 » Logged
bluegray
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« Reply #16 on: January 21, 2008, 14:12:07 PM »

How do one go about to read the actual study?
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Mefiante
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« Reply #17 on: January 21, 2008, 14:52:31 PM »

Here you go.

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Warm Lug
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« Reply #18 on: February 28, 2008, 22:55:39 PM »


Now other than noting that traits which become common are heritable, how were their favoribility actually measured?


From bacteria to kittens to humans:

Sickle-cell disease in humans is caused by a simple and well-understood mutation. It is inheritable in the same way that blue eyes are. This, otherwise, somewhat debilitating disease occurs more commonly in people (or their descendants) from parts of the world where malaria is or was common, but it also occurs in people of other ethnicities. This is because those with one or two alleles of the sickle cell disease are resistant to malaria since the red blood cells are not conducive to the parasites - in areas where malaria is common there is a survival value in carrying the sickle cell genes.

I see no problem with cause and effect here, and no problem with measuring the survival value that the mutation confers to the "victim". 

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ArgumentumAdHominem
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« Reply #19 on: February 29, 2008, 21:27:45 PM »

Sickle-cell disease in humans is caused by a simple and well-understood mutation.

There is another related blood disease which has a similar effect.  16% of the population of Cyprus (and lower percentages of the population of nearby Mediterranean countries) suffer from thalassaemia which was seen for centuries as a curse, having a visible presentation in the formation of facial features and causing shorter life expectancies for those afflicted.  As a result of the prevalence, all islanders carry the gene (most in the recessive form) and every Cypriot is immune to malaria.

I first heard about this story in a brilliant documentary by the geneticist Professor Robert Winston (not sure if it was "Threads of Life" or "The Human Body").  His point was that our understanding of genetics may lead us to want to "prune-out" genetic disorders like these and lose undiscovered benefits such as malaria resistance.  If we discovered genes which cause certain heritable diseases, would pruning them from the genome help us or possibly introduce a weakness to diseases discovered in the future or future mutations of current life-threatening diseases?
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scienceteacheragain
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« Reply #20 on: March 14, 2008, 13:51:48 PM »

I believe that is Cooley's Anemia  that is specific to the Mediterranean, right?
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scienceteacheragain
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« Reply #21 on: March 14, 2008, 14:25:02 PM »

Now, back to the dead horse that is the argument of survival of the fittest is a tautology.
I am not even going to go into explaining how it is not, as it is such a tired argument that has been shown to be false many times.  And, from what I have seen from Metari1, I believe he goes around to wacky creationist sites and comes back here and regurgitates what he has read with nothing novel to add.  But that is typical of many creationists I've heard, and is expected when reason is the enemy of your faith.

Jason Rosenhouse blogged (long ago now) about how to spot a bad argument, and it most certainly applies here.
If you hear someone say that a well supported theory is invalid, not because of some new evidence, but because of a basic flaw in logic, you should dismiss this argument out of hand.
How likely is it that generations of scientists have used a theory extensively and further developed the theory and produced mountains of experimental evidence for the theory, but somehow missed something very basic.  Further, it takes someone as brilliant as Metari 1 (or whoever it is that he is parroting) to point out this flaw to the stupid scientists who weren't clever enough to see it.
The tautological argument is word play.  I would say that I can't believe there is still any discussion on it, but the dishonesty of creationists have taught me that some things that should go away sometimes never do.
 
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metari1
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« Reply #22 on: March 15, 2008, 11:11:56 AM »

Now, back to the dead horse that is the argument of survival of the fittest is a tautology.
I am not even going to go into explaining how it is not, as it is such a tired argument that has been shown to be false many times. 

Please provide references as to who has showed which individual with his particular intent was false.

The tautological argument is word play.  I would say that I can't believe there is still any discussion on it, but the dishonesty of creationists have taught me that some things that should go away sometimes never do.

Other than noting a particular creature survived how was its fitness measured ?
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johanvz
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« Reply #23 on: March 15, 2008, 23:02:25 PM »

Quote from: metari1
Other than noting a particular creature survived how was its fitness measured ?

Warmlug already provided a good example of sickle cell disease causing resistance to malaria. Therefore, if you live in a malaria area sickle cell disease makes you fitter to survive.

A simpler example. A lion chases 2 bucks, the one buck is fast and gets away, the slow buck is caught. The faster buck was more fit to survive and got away.

So, to answer your question, fitness is measured in terms of the trait or ability that gives an organism the ability to overcome an adverse condition.

Johan
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metari1
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« Reply #24 on: March 16, 2008, 20:25:26 PM »

A simpler example. A lion chases 2 bucks, the one buck is fast and gets away, the slow buck is caught. The faster buck was more fit to survive and got away.

So, to answer your question, fitness is measured in terms of the trait or ability that gives an organism the ability to overcome an adverse condition.


Johan weet jy wat is die definisie van a tautologie? Ek gaan vir jou Wikipedia kwoteer.

http://en.wikipedia.org/wiki/Tautology_%28rhetoric%29
"...In colloquial terms a logical tautology can also be defined as a series of statements that comprise an argument, which statements are constructed in such a way that the truth of the proposition is guaranteed. Consequently the statement conveys no useful information regardless of its length or complexity. Thus, for a simple example, the statement "if you can't find something (that you lost), you are not looking in the right place" is tautological. It is also true, but conveys no useful information. As a physical example, to play a game of darts where the dart board was full of bullseyes, could be called a "tautological" game. You can't lose. Any argument containing a tautological statement is thus flawed logically and must be considered erroneous.

A tautological argument is not an argument; a tautological game is not a game. Mathematical equations, such as e = mc2, are not tautologies. The terms on both sides of the equation are defined elsewhere independently, and thus the equal sign does not mean "is defined by" but rather equal to, thus establishing an equivalence...."

So let me ask the question again:

"...fitness is measured in terms of the trait or ability that gives an organism the ability to overcome an adverse condition...."

Other than noting an organism had the ability to overcome an adverse condition, how was its fitness measured ?

Our observation was that an organism indeed had the ability to overcome and adverse condition, how does labeling this "fitness" tell us anything we don't already know.
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Warm Lug
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« Reply #25 on: March 16, 2008, 22:47:53 PM »

Metari1:

The reason these observations of survival of the fittest are not a tautology, is that it refers not to a single population from which the weaker individuals have been removed, but to a replicating gene pool with errors.  The conclusion is drawn that heritable traits are selected for and against. Heritable traits that confer superior benefits in survivability, will increase in the gene pool, over generations. 

How about this:
A herd of buffalo is only as fit as its weakest individual.  Because lions tend to catch the weaker individuals, the net effect of lion predation on a buffalo herd is an increase in its fitness (this is a tautology). 
Now, every time a person imbibes alcohol, a great number of neurons are killed off in his brain.  BUT! Its those weaker neurons that are killed off.  That's why we feel so clever after a couple of beers (OK, also a tautology, but have a couple of beers, Metar1, and you might see the light).

If the surviving buffalo have a heritable trait that confers upon them superior predator evasion abilities, their offspring will be fitter than those who do not have this inherited trait. The tautology becomes irrelevant, because we're examining a deeper level of interaction.  "Survival of the fittest" refers to the selection of genes that encode for this superior trait, whether it is superior by default (loss of the trait by the weaker ones) or by a fortunate set of mutations in the "fitter" ones.  It is the distinction between individuals who by some fortunate nurturing have superior but not heritable traits and those who have superior traits encoded in their genes that elevates "survival of the fittest" above a self-evident theory. The truth of the proposition is not guaranteed. Heritability and gene expression of traits have to be examined in every specific proposition.
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ArgumentumAdHominem
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« Reply #26 on: March 17, 2008, 07:22:26 AM »

Other than noting a particular creature survived how was its fitness measured ?

Some good examples were provided by Warm Lug and Johan, but natural selection goes beyond the "faster = better" examples.  We know that using the predictive power of the theory of evolution, we can describe a scenario which has not happened yet which allows us to view the potential course of a life form's development.  We can look at a herd of antelope who have been shown to develop genes to become faster or more nimble or are hard-wired to "spronk", but could easily be wiped-out by a new hypothetical disease.  We might see that these fast individuals are not going to out run the disease and that a particular sub group of the less-fit-to-survive-lion-attacks group happens to have a blood disorder which causes deformed red blood cells (inhibiting the uptake of oxygen, thus making them unable to use the full potential of their muscles, thus slower).  The virus cannot use the deformed red blood cells.  This red blood cell deformity can be the "fitness" which the group of antelope is selected on in the future, but right now it is a hindrance, a disadvantage.

If I showed you a slow antelope with the blood cell deformity and said to you that this is a fit individual which will ensure the survival of the species for the next two hundred years, you would laugh; it is clearly not fit and likely to be eaten.

The thing to take from this is that fitness is not an obvious conclusion drawn from observation.  We do not say "look at the elephant, it is big and strong and thus it was fit to survive.  It's presence is proof of its fitness", we say "look at the elephant, it was fitter than the mammoth because of these traits which natural selection acted on to ensure its survival".

I would say that acinonyx jubatus - the cheetah - is probably a good example, it is my favourite animal and a great example of how fitness is hit-and-miss.  Unlike most animals around today which have many hundreds of thousands of years of genetic history, cheetahs were almost extinct ten thousand years ago.  There is some disagreement on the number of cheetahs who survived the climate change event (some say it was one small closely-related family, others say it was only one pregnant female) but the shallowness of their gene pool is evident today.  We very nearly lost a very "fit" (by today's standards) animal due to the catastrophic climate change event of 10 000 years ago.  How many other "fit" animals did we actually lose?  Cheetahs are very well adapted to their environment and nobody can argue that they are not fit to survive, and yet they almost didn't because they were not fit in the right way at the right time.
« Last Edit: March 17, 2008, 07:28:25 AM by ArgumentumAdHominem » Logged
Mefiante
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« Reply #27 on: March 17, 2008, 09:28:44 AM »

Well, metari1 if you insist that “survival of the fittest” is a tautology by asking silly questions, then by extension so is every other empirical observation we make about the world: Other than noting that an oven plate produces a particular variety of physical actions or reactions, how do we measure that it is hot?

So why not do a proper job and criticise all scientific epistemology?  You can also add ontology, metaphysics and language while you’re at it.  That way at least you might contribute something useful to human knowledge instead of getting to pick the bits that suit and rejecting the bits that don’t.

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bluegray
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« Reply #28 on: March 17, 2008, 16:44:20 PM »

"...fitness is measured in terms of the trait or ability that gives an organism the ability to overcome an adverse condition...."

Other than noting an organism had the ability to overcome an adverse condition, how was its fitness measured ?

Our observation was that an organism indeed had the ability to overcome and adverse condition, how does labeling this "fitness" tell us anything we don't already know.
Maybe the links in this post is relevant: Re: Myths of Origin and the Theory of Evolution

@metari1:
What do you agree with? Do you agree that traits are heritable in organisms via genes? And do you agree that one organism (collection of genes) will survive better in some environment than another organism?
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metari1
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« Reply #29 on: March 17, 2008, 19:41:30 PM »

Metari1:

The reason these observations of survival of the fittest are not a tautology, is that it refers not to a single population from which the weaker individuals have been removed, but to a replicating gene pool with errors.  The conclusion is drawn that heritable traits are selected for and against. Heritable traits that confer superior benefits in survivability, will increase in the gene pool, over generations. 

"Survival of the Fittest" is a sentence a human being uses to project some sort of intent, it is not some formally defined established theory like newton's theory of gravity or something. The term was coined by Herbert Spencer and adopted by Darwin, where did Spencer have any intent about genes if he didn't know about genes ?

Lets get back the to the Perry Marshall green light example:
"You have a green light."
1) It could mean you are holding a green light bulb.
2) Or you have a green light to drive your car.
3) You can go ahead with the project.

Three completely different meanings based on intent. Intent changed but syntax and semantics, grammar didn't change. What is your intent with "Survival of the Fittest". Do you for example know that Spencer viewed evolution as a progressive upwards process that will eventually lead to an ideal society? That was his intent with SoF, but his intent differs from Robert Sapolsky who views evolution as non-directional.

Evolution, SoF, Selection - these are the semantics. You need in order syntax, grammar, semantics to finally get to the pragmatics or intent as you signal receiver send info to me signal decoder. I am trying to decode  your intent and thus I need to ask you a few questions such as where did you get your interpretation that SoF had anything to do with genes.

For this you would need to tell me who said SoF in relation to genes, where did this person derive a theory with genes and the label SoF. SoF is just a label, not some sort of abstract authority or entity in and of itself, the label SoF can only be used to communicate your intent - what is your intent with SoF and where did you derive  your intent.

"...Survival of the Fittest ...." Who says so ?
1) Herbert Spencer - what was his intent.  Evolution towards our higher destiny which differs from Robert Sapolsky.
2) General with Phd in philosophy saying SoF to bolster the morale of his troops in the heat of battle.
3) John Wilkins - What was his intent  ?
4) Mussolini repeating over and over in his speeches SoF
5) Charles Darwin quoting Spencer.

6) Cat walking over somebody's keyboard typing out -  SoF and then pressing print and the paper flies out the window. You pick it up tomorrow a single term SoF on a blank piece of paper. You have no idea who wrote it (the cat unintentionally) thus you don't know what was the will,motive,intent or pragmatics behind the words "Survival of the Fittest".

7) Eight year old kid thinking he is a genius by saying that those that survived are the fittest and those that are the fittest survived. Notice that the term ToE , ToNS are used by eight year olds and professors in quantum physics - are they talking about the same thing ? The very fact that little children can talk about the Theory of Natural Selection with a great sense of intellectual achievement - that alone should tell us that we need to look very carefully at what exactly is the Theory of Natural Selection and Evolution. Is there any other theory in physics, math etc. where everybody can all talk together about such a theory, only with the Theory of Natural Selection is everybody from a six year old to a 60 year old physicist under the illusion that they are talking about the same thing. They all use the same label but is their intent the same.
« Last Edit: March 17, 2008, 20:01:53 PM by metari1 » Logged
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