When does a theory stop being a theory?

[Anachronous Rex]

Do tell...My experience tells me your defining the term evolution and the mechanics of science would be an accurate representation of your education, interpretation of what you gleaned from that education and would still illicit argument and debate from like minded individuals.

Verbosity isn't intimidating. Just so you know.

Well, in fairness it can be. Remember mirandansa?

 

[australopithecus]

Miranada was more infuriating than intimidating I found.

 

[Prolescum]

...and TruthIsLoquacious7's posts. Not intimidating in content, but certainly in volume. I'm confident it'll eventually reach the point where I'll have read more of his waffle than I have Isaac Asimov.

That sad, sad day will be all too soon, I fear. :cry:

 

[Laurens]

Thank-you for taking the time to demonstrate your understanding of how mutations occur in an organism. It seems to me that a contradiction is evident in your explanation. The magic I was referring to is cited in your explanation of harmful and beneficial mutations. Since I am not a scientist, but I do study it with great interest, I cannot fact check your explanation at this moment. I'll take you at your word that you believe what you have stated;

A. There are harmful mutations
B. There are more harmful mutations than beneficial ones
C. There are more ways to be a dysfunctional organism than a highly functional one
D. Harmful mutations are quickly weeded out by natural selection
E. Whereas beneficial mutations are favoured
F. The net result is a tendency for an organism to become more adapted to its environment, because beneficial mutations are passed on, whilst harmful ones are eliminated.

I was following you up until my note B when all I can say is, "really"? And C makes sense if B is correct, then I started wrinkling my brow at D and E., and later F. The magic I referred to in my original comment was, in deeper terms, natural selection. I have never personally read anything but theories about natural selection. It seems this is a magic ingredient, along with almost unlimited amounts of time that somehow chooses the right mutation at the right moment, yet how does the magic of natural selection determine between a harmful and beneficial mutation unless it can test the result of it first? This, to me, is somewhat of a contradiction. I could be convinced otherwise, but I'm sensing some slight of hand here.

Well B is true because of C. There is nothing hard to understand about the notion, if there were a mutation that made a bird incapable of flying for instance, this grounded bird would very soon be eaten by a predator, and is highly unlikely to produce any offspring. What this means is that the mutation that causes the bird to be incapable of flight does not become prevalent in the population.

Say this same species of bird is preyed upon by eagles. A mutation which causes them to be slightly more agile and manoeuvrable would provide an advantage because those with that mutation would be more likely to dodge a hungry eagle. So just as a harmful mutation is stopped from spreading because the bearer is unlikely to breed, a beneficial mutation becomes prevalent in a population because the bearer would be more likely to survive long enough to produce offspring, and those offspring would carry the advantageous trait and likely produce more offspring and so on. Even if a trait is a 1% advantage, it can still have a big effect on the species over time.

Death is how natural selection determines between a harmful and a beneficial mutation. You have a harmful mutation you're more likely to die without leaving offspring. You have a beneficial mutation you're more likely to survive long enough to produce offspring. This is really rudimentary stuff, I shouldn't really have to explain it to you, either you weren't paying attention in biology class, or your tuition was severely lacking.

Now your net result comment (my note F) uses the word "tendency" and that leads me to believe you are about to tell me the organism itself is only sometimes doing the natural selection, that is creating both harmful and beneficial mutations in some sort of biological Russian roulette. Is this not also contradictory in that it's either the organism, or the natural selection choosing the mutation to run with?

Lots of factors do the selecting. Predators, parasites, choosy females, availability of food, environmental factors etc. I don't think you quite understand how evolution works, I'd recommend reading the wikipedia article on it before we continue any further discussion.

Here it is: http://en.wikipedia.org/wiki/Evolution

 

[Anachronous Rex]

Miranada was more infuriating than intimidating I found.

Yeah, but there were times when I almost cried when I saw the scale of the post I'd be responding to... made all the more difficult because of their wording.

 

[Gnug215]

God of the gaps? Is that what you're seriously going with?

Seriously, what is a God of the gaps?

A God of the gaps is a God that conveniently lives in those "50%" of the knowledge of the Universe that we DON'T know.

Whenever we discover more, and as the percentage increases, this God is never revealed, but sits comfortably and conveniently in the reamaining, unknown part of the Universe.

For many theists, God has been pushed back all the way to before the Big Bang, where we, conveniently, sadly, cannot look.

For some other theists, God is still around, either having initiated the process of biological evolution, or actively participating in the process as we speak, tinkering. Those theists usually have to go what established science has to say about observations of nature, although some of them might argue that God's tinkering would be indistinguishable from a natural process.

 

[Squawk]

It seems this is a magic ingredient, along with almost unlimited amounts of time that somehow chooses the right mutation at the right moment, yet how does the magic of natural selection determine between a harmful and beneficial mutation unless it can test the result of it first? This, to me, is somewhat of a contradiction. I could be convinced otherwise, but I'm sensing some slight of hand here.

No slight of hand, just a misunderstanding. A mutation is not known to be beneficial or detrimental when it occurs. Instead, that muation manifests as a slight varition in the phenotype of whatever individual it happens to be in relative to the rest of the population.

The environment does the rest, and it is only retrospectively that you can really assess if a mutation was beneficial or not. Nature certainly has no way of knowing, and a common misconception is that natural selection has some perceived direction. It doesn't.

Put it this way. Would it be beneficial for a cheetah to run slightly quicker? A faster cheetah can catch prey faster. But, it may also have a slightly higher metabolism, possibly a little more muscle mass, meaning it must catch and eat slightly more prey to survive. It could be that the slightly faster cheetah is actually at a disadvantage. Nature has no way of knowing of course (how could it, no conscience anyway), but at any given time there are cheetahs of various speeds roaming around, and those with the most efficient set of genes are more likely than the less fortunate to survive.

Note that it's not the fittest that survive, but instead that the fittest have the greatest likelyhood of survival. The fittest can still fail and die.

 

[devilsadvocate]

Just as a non-serious side note. When we are talking about the survival of the fittest, what are we actually talking about? it sees to me in the terms of evolution, we are just stating a tautology when we say "the fittest will survive", since fitness is already defined in terms of survival in the theory.

 

[Laurens]

Just as a non-serious side note. When we are talking about the survival of the fittest, what are we actually talking about? it sees to me in the terms of evolution, we are just stating a tautology when we say "the fittest will survive", since fitness is already defined in terms of survival in the theory.

Personally I'd define fitness in evolutionary terms as producing lots of grandchildren.

Its not that technical but it works with me...

Fitness does not necessarily mean big, strong, clever, fast etc. (although it can), an organism is fit if it has a lot of offspring. If being small, weak, stupid and slow cause you to have lots of offspring then you're still fit in these terms.

 

[Squawk]

Just as a non-serious side note. When we are talking about the survival of the fittest, what are we actually talking about? it sees to me in the terms of evolution, we are just stating a tautology when we say "the fittest will survive", since fitness is already defined in terms of survival in the theory.

If you want to see this addressed properly I believe Gould did a good piece on it. Basically it stems from a misunderstanding inherent in the phrase survival of the fittest, because people take it to mean that the organisms that survive were the fittest (hence the tautology).

In reality what we talk about fitness we refer to the probability of survival. A "fitter" organism is simply one with a greater probability of survival than the next organism. Nothing says it has to survive, and indeed it may not, it just happens to have greater odds of survival due to some trait or other.

we can't say the fittest survive. We can say they have a greater chance of it.

 

[Laurens]

If you want to see this addressed properly I believe Gould did a good piece on it. Basically it stems from a misunderstanding inherent in the phrase survival of the fittest, because people take it to mean that the organisms that survive were the fittest (hence the tautology).

In reality what we talk about fitness we refer to the probability of survival. A "fitter" organism is simply one with a greater probability of survival than the next organism. Nothing says it has to survive, and indeed it may not, it just happens to have greater odds of survival due to some trait or other.

we can't say the fittest survive. We can say they have a greater chance of it.

See I've always heard it defined in terms of reproductive success rather than survival, because I guess in theory you could survive well and not reproduce (although that might be unlikely).

I've heard adaptive evolution described as consisting of 4 factors:

1. Variation in reproductive success
2. Variation in a trait
3. Heritability of the trait
4. A non-zero correlation between the trait and reproductive success

In this context fitness would be a high reproductive success would it not? For which a particular trait might be a advantage thus providing the correlation.

 

[Squawk]

Heh, well, if we really want to take this one further I'd argue that success is defined as the rate at which your decendents reproduce, since you could be prolific at having children and they could all be sterile. If your kids can have kids, you're pretty much set. I don't have any real issue with those 4 points.

They key is not to define fitness as survival (or even as having kids), but rather to refer to the probability of doing so in relation to other members of your species.

 

[Laurens]

Heh, well, if we really want to take this one further I'd argue that success is defined as the rate at which your decendents reproduce, since you could be prolific at having children and they could all be sterile. If your kids can have kids, you're pretty much set. I don't have any real issue with those 4 points.

They key is not to define fitness as survival (or even as having kids), but rather to refer to the probability of doing so in relation to other members of your species.

I agree, I also think it's important, when talking to a creationist to state that fitness is not necessarily what we'd define as 'better'.

I've heard too many people think that evolution, or 'survival of the fittest', means survival of the most intelligent, the strongest, the biggest, the most complex etc. In reality it doesn't have to work towards anything we might deem as progression, merely that which aids survival and reproduction.

 

[The Felonius Pope]

If you're talking about science, a theory is simply an explanation that does its best to explain a given phenomenon. Your

comment implied there is a difference between a theory and a fact. In my experience axioms rarely apply to the real world

while theories are everywhere to be found. I've found that the idea of an objective fact is subjective; I like to say that

what constitutes a fact is a matter of opinion.

 

[TheOnlyThing2Fear]

Do tell...My experience tells me your defining the term evolution and the mechanics of science would be an accurate representation of your education, interpretation of what you gleaned from that education and would still illicit argument and debate from like minded individuals.

Verbosity isn't intimidating. Just so you know.

I almost pointed out that the cat must have gotten your tongue, but from your picture, it appears you are lacking one.

 

[australopithecus]

I almost pointed out that the cat must have gotten your tongue, but from your picture, it appears you are lacking one.

You can avoid continuing on topic, a topic that would only highlight your continuing ignorance on the the subject of science and how it works, by posting irrelevancies all you like. It only makes you look bad. However I would strongly recommend that you either stay on topic or find another thread to display your lack of understanding in.

 

[he_who_is_nobody]

You enter a room, a cupcake is on a table. Do you believe the cupcake was made, or do you believe the cupcake came from nothing? Ignorance is not an option.

Is this hugenex2000? That argument sounds so familiar.

To Squawk and Laurens,

I have always defined fitness as reproductive success.

 

[fightofthejellyfish]

Just as a non-serious side note. When we are talking about the survival of the fittest, what are we actually talking about? it sees to me in the terms of evolution, we are just stating a tautology when we say "the fittest will survive", since fitness is already defined in terms of survival in the theory.

The way Darwin intended it when he adopted the phrase was as fitness for the organisms environment. It is better reworded as 'survival of the best fit'. Drop a whale in the desert and it's fitness is pretty poor, it's a square peg in a round hole.

Survival and number of offspring aren't definitions of fitness, they're proxies for trying to measure it.

But as with all language meanings shift over time as words are adopted for other purposes. In more recent times population mechanics has defined fitness as differential reproductive success, but that is in a context where you're looking at the statistics of populations and not focusing the interplay of species and environment as Darwin was. If you apply a modern definition with a different context to an old phrase then "survival of the fittest" does become tautological, but it wasn't as originally intended.

 

[Squawk]

Survival and number of offspring aren't definitions of fitness, they're proxies for trying to measure it.

Whilst I can see the argument for this, I don't buy into it because it could lead to a sterile individual being the fittest organism in the population. Indeed, it could be argued that having zero sex drive increases fitness as you would be less likely to pick up an STD. From an evolutionary standpoint, which must be the focus here, this individual has to be at the bottom of the fitness ladder despite being supremely adapted to survive.

 

[fightofthejellyfish]

Survival and number of offspring aren't definitions of fitness, they're proxies for trying to measure it.

Whilst I can see the argument for this, I don't buy into it because it could lead to a sterile individual being the fittest organism in the population. Indeed, it could be argued that having zero sex drive increases fitness as you would be less likely to pick up an STD. From an evolutionary standpoint, which must be the focus here, this individual has to be at the bottom of the fitness ladder despite being supremely adapted to survive.

I wasn't intending to argue that "survival of the fittest" was true under such a definition only that it's not right applying modern definitions to it. You also have to remember that Darwin was also usually talking about "races", what we'd now think of as varieties. When viewed on any level other than trying to force a purely individualistic perspective, which is a modern approach, fecundity is as vital an attribute of an organisms fitness as speed is for cheetahs, and strength is for gorillas. Proposing a sterile individual that is a good fit for it's environment is like proposing a cheetah without legs that is a good fit for an environment of running down prey. It's a contradiction of terms. By definition such an individual is a very poor fit in it's reproductive environment.

What you've done in your example is narrow the word survival to only apply to the individual, you've made it a synonym of longevity. From any perspective other than purely individualistic, survival means reproducing. Survival of a "race" says that the individuals are reproducing. I certainly don't think Darwin ever tried to differentiate the two, in fact he went to some length to keep them linked. He could equally well have said 'reproductive success for the fittest' though that would have been a weird way to say it at the time.

Which ever way you look at it, what Darwin was saying was that the organisms we have now are the ones who are best adapted to their environment, that after all was his entire thesis. He used "survival of the fittest" as a summary of that thesis. Using the definitions of survival and fitness you are we'd have 'Long lives for those who reproduce the most' which doesn't sum it up at all, but 'reproductive success for those who best fit their environment' does.