Tautology and Natural Selection

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In contrast, the humble peacock carries plumage that no one would consider advantageous in the fitness equation except for the fact that peahens are attracted to it. An organism can be not-well-adapted to its environment and still win the reproductive lottery.

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But I would consider the peahens apart of the peacocks environment (am i using the term too loosely?). And if ones purpose is to reproduce, then they'd have to be a factor in the equation. So wouldn't the peacock with the flamboyent plumage be the best adapted to its environment?I'm not asking for an objective set of traits that make an organism fit. I understand that you can't say "speed" is a fit characteristic without reference to the environment. Couldn't you say that a walrus and cactus are fit because they are best engineered for reproductive success for their environments, factoring in their historical contingencies?I understand that natural selection isn't a tautology. Like I said before, you'd be denying that an organisms traits have anyting to do with reproduction. I just get into alot of these conversations with creationists, so I just wanted to see what other people think about it.

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But I would consider the peahens apart of the peacocks environment (am i using the term too loosely?). And if ones purpose is to reproduce, then they'd have to be a factor in the equation. So wouldn't the peacock with the flamboyent plumage be the best adapted to its environment?

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If you want to make the charge of tautology even more acute, sure. In terms of susceptibility to predation, however, the peacock with the biggest plumage is at a disadvantage, regardless of its popularity with peahens.Our definition of 'fitness' means 'having most reproductive success,' independent of any objective measure of environmental adaptation. If you want to make 'probability of reproductive success' part of our definition of well-adaptedness, then we're back to square one.------------------
Quien busca, halla

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If you want to make the charge of tautology even more acute, sure. In terms of susceptibility to predation, however, the peacock with the biggest plumage is at a disadvantage, regardless of its popularity with peahens.

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I'm not sure it makes it any more acute. I'm just saying that in certain environments, certain features aid in reproduction a priori. The environment would be everything in its surroundings.You defined fitness as 'having most reproductive success'. I might of missed this, but do you think "reproductive success of the fittest" would be an accurate description of Natural Selection?

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I'm sorry but there is no unique viewpoint in my post as far as I'm aware.

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ROTFLMAO!!!!!!!That is so frigging funny!!!

That's our Sy, he speaks for himself.------------------
Quien busca, halla

Hola Mr. H:Would it help for the purposes of this conversation to simply forego discussion of reproductive success as it relates to fitness? Substituting the slightly more reductionist concept of "marginal fitness", which merely describes the tendency for the frequency of a specific allele or suite of alleles to vary in a population over time based on environmental interaction without discussing the "how it increases", would seem to eliminate the tautology problem. (Damn, that was a long sentence.) In addition, it removes the emphasis on reproductive success that seems to have everybody in knots. If the allele increases, it may be caused by anything from drift and other stochastic processes to deterministic processes. Finally, it's a fairly easy one-step to get from there to discussions of mean population fitness, when you want to take it to a different level.Hope that made sense.

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I'm just saying that in certain environments, certain features aid in reproduction a priori. The environment would be everything in its surroundings.

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I agree with that.
Are not the members of the own species also part of the environment?
(And an important part as that).

I don't see how marginal fitness is a reductionist definition. I also don't see why reproductive success per se is such a hard concept to grasp by some. Ultimatley, reproduction is the method of transfer of alleles from one generation to the next and that is why reproductive success is included in discussing fitness. An allele can potentially be just dandy but if the individual carrying it is sterile...hasta la vista. Even in cases of genetic drift...the "drift" involves reproduction as the means of increase is via reproduction. If reproduction makes fitness a tautology does DNA make genetics a tautology?
As Quetzal points out, one can discuss population level measures of fitness for a particular allele(s) without discussing reproduction as this is independent of discreet reproductive events and is an aggregate fitness measure. But ultimately, since evolution and evolutionary terms are population biological in nature, reproduction is a key concept.

Hey there my hairy friend,I don't disagree with you - and I don't understand either what the problem is with the observation that the critters that have alleles that provide some kind of advantage are more likely to leave offspring. However, it looked like the discussion had completely bogged down, so I was trying to be creative in getting it going again."Reductionist" the way I meant it was to say marginal fitness takes it down to the genetic level and ignores the individual organism - a frequency of alleles in a population. Could be a plus or a minus in terms of the individual's chance to survive to reproduce. Oh well, so much for trying to get the conversation going again.

Hi Q,
Sorry...my question to you was to why you regarded the definition as reductionist...my lack of comprehension regarding fitness was general i.e. why fitness is a concept that people like Symansu cannot understand no matter how dumbed down we try to make the explanation.A change in allele frequencies over time is what one observes. The mechanism by which alleles are passed on (with the exception of horizontal transfer) is via reproduction (sexual or asexual)...chance has a lot to do with which alleles are passed on but selection can change allele frequencies dramatically.cheers,
M

I don't actually think that 'survival of the fittest' as
a phrase is tautological unless you assume that the fittest
are the one's that survive -- rather than just treat the phrase
as a summary of an observation.Does that make any sense at all or do I need to lay off the
coffee???

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I don't actually think that 'survival of the fittest' as
a phrase is tautological unless you assume that the fittest
are the one's that survive -- rather than just treat the phrase
as a summary of an observation

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I'm not trying to be a dick here, I actually do know alot about evolutionary biology.But how can you define fitness without reference to reproductive success? If I say that a thick coat for a dog is fit in a cold environment, do I have to explain why? For instance, should I say it's fit because it increases reproductive success? So the phrase would read "Reproductive success of the organisms better equipped for reproductive sucess." Or is that not necessary?Or should fitness be purely decided from an engineering perspective of a problem. For example: Our goal is reproductive success, this organism lives in this environment, what can we do to help it out.If we can equate some purpose to life (not some ultimate purpose), then wouldn't some things follow a priori that would help it out. For example, a hammers purpose is to pound in nails, so if we modify a the hammer so it does this action with greater efficiency, how do we describe what we did to it? We made the hammer more efficient because we made the head heavier. Why does that make it better? Because it can pound in nails easier. So we have "Easier pounding of the nails by the hammer that can pound in nails the easiest." Can anything that acutates somethings purpose or makes it more efficient be stated as a tautology? Could the beauty of life be that it's autotelic? But is there a non trivial way to dichotomize things as purposeful or unpurposeful?Any thoughts?JustinC

Which, of course, is why I prefer talking in terms of populations or communities rather than organisms. The only "purpose" for a given population in a particular habitat (or a given community in a particular ecosystem), is to persist. It really doesn't matter whether or not one or any number of its members lives or dies, as long as the population continues. In a hypothetically pure equilibrium situation, the number of individuals that bite the dust or emigrate is precisely balanced by the number of individuals that are born or immigrate. From the population's standpoint, it really doesn't matter HOW that occurs. Reproduction is what individuals do - persistence is what populations do. Obviously the actual dynamics in a wild population are significantly more complex, with a myriad of stochastic and deterministic factors which will effect it. However, speaking of purpose beyond persistence at equilibrium is waaaay too anthropomorphic for me.I'd damn Spencer to the outermost hells for the miserable "survival of the fittest" phrase he invented - if I believed in hells, that is. As it is, I just think that conceptualization has done more to skew people's understanding of natural selection than anything else I can imagine. Shows you shouldn't use soundbites if you want to understand something.Hey, everyone has a pet peeve...

Fitness isn't defined in terms of reproductive success
(at least not in the weltenshaung that presents the
phrase 'survival of the fittest').Fitness is about the ability to survive -- if you are better
able to survive yu are more fit.So 'survival of the fittest' comes down to 'those that survive best
reproduce most'.I don't see any tautology there, only an abservation.Re;Purpose.One cannot use the word 'purpose' unless there is an intelligent
intent behind a function/feature. That's what purpose means.Biological systems (of any order) do NOT have purpose (unless
you are a creationist/believer), they have functions and features
which contribute to their survival.Survival facilitates reproductive success.

I think in the dog example you should look at it as the dogs with the thicker coats have a higher chance of surviving to reproduce and therefore have a higher fitness. It does not mean that some animals that do not have thick coats won't survive and reproduce but the frequency is likely to be lower given that they have a higher chance of death prior to reaching a reproductive age...over time, thicker coats may become fixed in the population as less and less "thin coat" animals survive...occasionally a thin coat individual may be born due to mutation in the thick coat population but will not likely spread the trait far if the environment remains stable...this is an extremely simplistic example but the relative fitness of a thick coat of fur in a cold environment is higher than a thin coat.I don't see a need to postulate a purpose other than what Quetzal said...a population survives when members of the population reproduce...if some members with a trait(s) reproduce at a higher frequency, that trait may become very common or fixed in the population. If members of the population reproduce at low frequency or not at all, the population ceases to exist...all the while, the environment is fluctuating and selecting for or against traits that become common or rare respectively...no higher purpose.