Basic Evolution

[strubenuff]

This may be a misconception on my point, but I've always understood survival of the fittest to mean that the smartest, fastest, strongest, etc. version of species survives and overcomes the dumber, slower, weaker, etc. version of its species. I don't understand why there seems to be such a focus on these beneficial mutations, when simply having more sex produces the same result. There need be no correlation between positive mutations and an evolutionary outcome. For example, let's say finch x has a smaller, and therefor less useful beak, than finch y. How do we know finch x won't simply produce more offspring then finch y, and eventually replace it as the dominant type? Or, just in general, some creature less able to survive then its counterparts produces more offspring to counteract this, and eventually becomes dominant. In my mind, it doesn't follow that some slight advantage via mutation will mean that one produces more viable offspring than the other. Because that's what it comes down to, right? So long as one is able to produce viable offspring (offspring that will in turn live to propagate), one could end up on top in the evolutionary pyramid. Thoughts?

 

[Pete Harcoff]

Using your finch example, you can't ignore competition for resources. A finch with a larger beak might be more adept at getting food, thereby reducing the amount of food available for smaller beaked finches. Therefore, smaller beaked finches would have a greater chance of starvation, poor health and possibly death, and there would be a gravitation towards larger beaked finches.

 

[strubenuff]

Perhaps it was a bad exmaple. Why can't the finch with the longer beak survive with the smaller beaked finch? The finch with the smaller beak is able to get food, and the finch with the longer beak is able to obtain more (because it has a larger beak). Why must these finches with smaller beaks die or starve? Why aren't they eating all the food that a small beak can reach? Why aren't they producing just as much, or more, offspring?

 

[Ryder]

The theory of evolution posits that these little changes will give one species a better chance of reaching maturity and producing offspring, but yeah, since those changes are supposed to be so small I don't see why they'd change the population layout either. The crunch the evolutionists face is that they can't make the changes to small, or else you get this problem of why they'd shift populations at all, but they can't make the changes to big either, else you get the 'uh huh, God didn't do it but you expect us to believe that a random mutation just added a whole micro-organelle, sure...' problem. The changes have to be small enough to be plausible, but large enough to appear to have any real effect. Pointless debate really, since evolution cannot be demonstrated to exist. Sure, religion takes faith, but evolution is often presented as the scientific answers outside of faith and the theory still eludes facts and demonstration, go figure.

Good question Strubenuff!

 

[notto]

When there isn't enough food to go around, competition will drive evolution and some species will go extinct.

As far as eating different foods, that is exactly what Darwin observed on the islands he visited. Several different beaks that were good at getting different kinds of food.

If the populations can evolve to get new food sources where there is less competition, they will survive. If they do not evolve and another population out competes them for the food in their environment, they will go extinct.

 

[Pete Harcoff]

Perhaps it was a bad exmaple. Why can't the finch with the longer beak survive with the smaller beaked finch? The finch with the smaller beak is able to get food, and the finch with the longer beak is able to obtain more (because it has a larger beak). Why must these finches with smaller beaks die or starve? Why aren't they eating all the food that a small beak can reach? Why aren't they producing just as much, or more, offspring?

It all depends on the environment. If the food source is limited, then the larger beaked finch would have access to food sources out of reach compared to the smaller beaked finches. Therefore, the larger beaked finches would have a greater chance of getting a meal.

On the other hand, if the food source is plentiful enough that beak since becomes irrelevant, then there won't be a gravitation towards a specific food source.

With respect to offspring, those offspring need to eat. So if the larger beaked finches are more able to obtain food, then there is a greater chance their offspring will survive to reproduce.

 

[notto]

The theory of evolution posits that these little changes will give one species a better chance of reaching maturity and producing offspring, but yeah, since those changes are supposed to be so small I don't see why they'd change the population layout either. The crunch the evolutionists face is that they can't make the changes to small, or else you get this problem of why they'd shift populations at all, but they can't make the changes to big either, else you get the 'uh huh, God didn't do it but you expect us to believe that a random mutation just added a whole micro-organelle, sure...' problem. The changes have to be small enough to be plausible, but large enough to appear to have any real effect. Pointless debate really, since evolution cannot be demonstrated to exist. Sure, religion takes faith, but evolution is often presented as the scientific answers outside of faith and the theory still eludes facts and demonstration, go figure.

Good question Strubenuff!

Thanks for the strawman. Would you like to discuss these issues and stick around?

Evolution has been observed. Small beneficial changes can certainly become prevalent in a population and this has been observed.

Mutation may be random, but selection isn't. It really simple logic. In a large population, there will be variation. This variation will lead to some of the population surviving better than the rest due to differences that allow them to out compete for food, mates, etc. The variations that these individuals possess, no matter how small, that gave them the advantage will be passed on to their offspring. Because they survive better, they will produce more offspring. Where is the problem with the theory?

Evolution says nothing about faith. It is sound science and can be understood and accepted by anyone regardless of their faith.

 

[Vance]

You have to think in larger pictures. Evolution happens in populations, not individuals. Those finches with more suitable beaks, even very slightly more suitable beaks, will TEND to live slightly longer and reproduce slightly more. Over a long enough period of time, the greater offspring by those with the "better" beaks will begin to increase exponentially (following the "he told two friends, and they told two friends, and so on . . ." principle). The next thing you know (after a few thousand years) every bird in the gene pool has the better beak. Voila!

So, no, the "smallness" of the change caused by the mutation really makes little difference. In fact, small changes are MUCH more likely that large changes, so it is more likely that the beneficial mutation for a small change will happen, then time and selection pressures do the rest.

 

[strubenuff]

It really simple logic. In a large population, there will be variation. This variation will lead to some of the population surviving better than the rest due to differences that allow them to out compete for food, mates, etc. The variations that these individuals possess, no matter how small, that gave them the advantage will be passed on to their offspring. Because they survive better, they will produce more offspring.

I realize I sound retarded, but I still don't see why. Take a population that is suseptible to a certain disease. It's dominant and lethal, but only shows up after they're old enough to produce. Why couldn't that population simply produce more offsping? Yes, they're going to die in larger numbers and faster than they're counterparts, but how do we know they simply won't produce more than they're counterparts? If they produce more, then the disease spreads. Though they live shorter lives, and have a harmful mutation, they're are more of them. They begin taking over the resources and the species gravitates towards being diseased.

 

[notto]

I realize I sound retarded, but I still don't see why. Take a population that is suseptible to a certain disease. It's dominant and lethal, but only shows up after they're old enough to produce. Why couldn't that population simply produce more offsping? Yes, they're going to die in larger numbers and faster than they're counterparts, but how do we know they simply won't produce more than they're counterparts? If they produce more, then the disease spreads. Though they live shorter lives, and have a harmful mutation, they're are more of them. They begin taking over the resources and the species gravitates towards being diseased.

They can't just decide to have more offspring. Something would need to happen to allow them to do this. Reproduction takes energy and energy = food.

Generally, the number of offspring, is geared toward what can survive. In the example of birds,they need to be cared for. The mother can only care for so many (and even in this case, many don't survive if the brood is too large).

 

[Arikay]

Evolutionists dont pick the size of a mutation.

Evolutionists also never say that god did not create the mutations, that is impossible to tell, just that it is possible for natural things to create mutations, and some of these mutations can be beneficial to a population of animals.

As far as a small mutation not making a difference. That is why change can sometimes take a long time to happen. A mutation that gives a population a very slight advantage, over the short term, wont show much progress for that population, but as time goes on, that small percentage becomes an increasing majority eventually ending up as a standard part of that organism.

As far as larger changes are concerned, we have observed some pretty big changes happen, for example, a frame shift mutation (I believe) added an enzyme that allowed a bacteria to consume Nylon, a man made product. This mutation gave that population of organisms a niche that none of their other cousins had, allowing them a huge food source, while their non mutated friends were fighting over the old food source.

Of course, that mutation was only beneficial when nylon was around, and most likely would have been considered a harmful mutation otherwise, as it would have created an unneeded drain on the organism.

I am curious where you heard evolution can not be demonstrated to exist?

The theory of evolution posits that these little changes will give one species a better chance of reaching maturity and producing offspring, but yeah, since those changes are supposed to be so small I don't see why they'd change the population layout either. The crunch the evolutionists face is that they can't make the changes to small, or else you get this problem of why they'd shift populations at all, but they can't make the changes to big either, else you get the 'uh huh, God didn't do it but you expect us to believe that a random mutation just added a whole micro-organelle, sure...' problem. The changes have to be small enough to be plausible, but large enough to appear to have any real effect. Pointless debate really, since evolution cannot be demonstrated to exist. Sure, religion takes faith, but evolution is often presented as the scientific answers outside of faith and the theory still eludes facts and demonstration, go figure.

Good question Strubenuff!

 

[Ryder]

Thanks for the strawman. Would you like to discuss these issues and stick around?

Evolution has been observed. Small beneficial changes can certainly become prevalent in a population and this has been observed.

Mutation may be random, but selection isn't. It really simple logic. In a large population, there will be variation. This variation will lead to some of the population surviving better than the rest due to differences that allow them to out compete for food, mates, etc. The variations that these individuals possess, no matter how small, that gave them the advantage will be passed on to their offspring. Because they survive better, they will produce more offspring. Where is the problem with the theory?

Evolution says nothing about faith. It is sound science and can be understood and accepted by anyone regardless of their faith.

I agree with almost everything you said, but the mechanism for evolution still isn't proved. Think about those moth populations in England, there were dark and light colored moths, during the industrial revolution the trees were blackened/darkened and the dark colored moths became dominant through natural selection (they had better camo) no problems here. Then later during environmental cleanup years the trees lightened up somewhat and the light colored moths made a comeback, again through natural selection, that's cool, no arguments here. So natural selection has been observed and proven. The problem is that evolution itself has not been observed or proven. All the genetic information for light and dark colored moths was already present in the gene pool, all we've observed is a shifting population, not any new genetic material. So while natural selection can be observed, the actual mechanism for evolution has not been observed and can only be speculated at. At no time has new genetic information coding for an advantageous trait every been seen to appear, all we've got is the 'breeding in and out' of genetic material already present, already there. So the theory, imho, remains as such perpetually, a theory, nothing more. I'll have to remember who I heard lecturing on this, I remember this but not the speakers name just now, oh well, it was a good discussion anyways.

 

[lucaspa]

Perhaps it was a bad exmaple. Why can't the finch with the longer beak survive with the smaller beaked finch? The finch with the smaller beak is able to get food, and the finch with the longer beak is able to obtain more (because it has a larger beak). Why must these finches with smaller beaks die or starve? Why aren't they eating all the food that a small beak can reach? Why aren't they producing just as much, or more, offspring?

Because finches can make more baby finches than there is food to feed all of them. So, there is a limited supply of food. The individuals with larger beaks will get that food -- supposing that larger beaks actually do that -- and there won't be enough food for the individuals with smaller beaks.

I think the problem, strubenoff, is that you are looking at human society in the last 100 years, where our technology has meant that our resources have expanded faster than our population.

This is a rare event in biology. It is the opposite of the norm. But in all other species in the wild, there is a competition for scarce resources. Either food, resistance to cold or heat, mates, resistance to disease, space, whatever. There simply isn't enough of something to go around for everyone. So the individuals with the better designs do better in the competition and leave more offspring.

 

[notto]

I agree with almost everything you said, but the mechanism for evolution still isn't proved. Think about those moth populations in England, there were dark and light colored moths, during the industrial revolution the trees were blackened/darkened and the dark colored moths became dominant through natural selection (they had better camo) no problems here. Then later during environmental cleanup years the trees lightened up somewhat and the light colored moths made a comeback, again through natural selection, that's cool, no arguments here. So natural selection has been observed and proven. The problem is that evolution itself has not been observed or proven. All the genetic information for light and dark colored moths was already present in the gene pool, all we've observed is a shifting population, not any new genetic material. So while natural selection can be observed, the actual mechanism for evolution has not been observed and can only be speculated at. At no time has new genetic information coding for an advantageous trait every been seen to appear, all we've got is the 'breeding in and out' of genetic material already present, already there. So the theory, imho, remains as such perpetually, a theory, nothing more. I'll have to remember who I heard lecturing on this, I remember this but not the speakers name just now, oh well, it was a good discussion anyways.

Mutations and variation can be observed in any population. You seem to be looking for a large mutation to produce wings or something. This is not the way that evolution is theorized to happen.

All of the mechanisms used to describe evolution (including new genetic material and chromosome doubling, especially in plants) has been observed.

 

[lucaspa]

Think about those moth populations in England, there were dark and light colored moths, during the industrial revolution the trees were blackened/darkened and the dark colored moths became dominant through natural selection (they had better camo) no problems here. Then later during environmental cleanup years the trees lightened up somewhat and the light colored moths made a comeback, again through natural selection, that's cool, no arguments here. So natural selection has been observed and proven. The problem is that evolution itself has not been observed or proven. All the genetic information for light and dark colored moths was already present in the gene pool, all we've observed is a shifting population, not any new genetic material.

That's not true, either. For instance, here is an example of scrambling a gene by an insertion mutation. The result is an activity to degrade nylon, never seen before:
1. Birth of a unique enzyme from an alternative reading frame of the pre-existed, internally repetitious coding sequence", Ohno, S, Proc. Natl Acad. Sci. USA 81:2421-2425, 1984. Frame shift mutation yielded random formation of new protein, was active enzyme nylon linear oligomer hydrolase (degrades nylon) http://www.nmsr.org/nylon.htm

There are many other examples if you are interested.

So while natural selection can be observed, the actual mechanism for evolution has not been observed and can only be speculated at.

You are shifting for different things. Natural selection does work on variations in the population.

Those variations have two sources:
1. Recombination by sexual meiosis. This is actually the major source of variation in sexually reproducing populations.
2. Mutation. I suggest doing a PubMed search on "mutation, beneficial, new, trait" and see what comes up. I submit that you will be surprised at the number of new mutations that have been observed.

 

[Arikay]

Points at the Nylon bugs and asks, would this be evidence?

Afterall, the mutation added "information", giving the bacteria a new enzyme that didn't have before, allowing them to eat a substance that did not exist 100 years ago.

I agree with almost everything you said, but the mechanism for evolution still isn't proved. Think about those moth populations in England, there were dark and light colored moths, during the industrial revolution the trees were blackened/darkened and the dark colored moths became dominant through natural selection (they had better camo) no problems here. Then later during environmental cleanup years the trees lightened up somewhat and the light colored moths made a comeback, again through natural selection, that's cool, no arguments here. So natural selection has been observed and proven. The problem is that evolution itself has not been observed or proven. All the genetic information for light and dark colored moths was already present in the gene pool, all we've observed is a shifting population, not any new genetic material. So while natural selection can be observed, the actual mechanism for evolution has not been observed and can only be speculated at. At no time has new genetic information coding for an advantageous trait every been seen to appear, all we've got is the 'breeding in and out' of genetic material already present, already there. So the theory, imho, remains as such perpetually, a theory, nothing more. I'll have to remember who I heard lecturing on this, I remember this but not the speakers name just now, oh well, it was a good discussion anyways.

 

[strubenuff]

I think the problem, strubenoff, is that you are looking at human society in the last 100 years, where our technology has meant that our resources have expanded faster than our population.

This is a rare event in biology. It is the opposite of the norm. But in all other species in the wild, there is a competition for scarce resources. Either food, resistance to cold or heat, mates, resistance to disease, space, whatever. There simply isn't enough of something to go around for everyone. So the individuals with the better designs do better in the competition and leave more offspring.

No, I was looking at everything. It just appears to me to be sexually driven. If you have a mutation: good, bad, or neutral, so look as you reproduce that will be passed on. Maybe a negative mutation makes you more attractive to the opposite sex. I'm struggling with the concept of "good" mutations overriding "bad" ones. Why being the most "fit" should be about anything other than "producing the most offspring". It seems to me that the current population could have acquired numerous neutral, positive, and negative mutations. They are simply the sum of those who produced most, which isn't necessarily the sum of those who had positive mutations.

*I would ask that those of you trying to help me out of my ignorance try to keep on topic. There are plenty of other threads debating the mechanisms of evolution, and those interested in discussing them (or how new information is added, etc.) should post there.

 

[notto]

Mutations are only determined to be 'good' or 'bad' by the environment the population is in. If the population has plenty of food and few predators, evolution will not likely take place. It is when the population is struggling to survive due to lack of food or heavy predation that even the slightest variation that provides even the slightest advantage will be important. It is hard to produce if you are starving or being eaten. It is when there is competition to survive that the types of variations you discuss become important and will be the drivers for evolution and cause the trait to become dominant in the population.

A good example of this in the human population may be the trait that causes sickle cell anemia. In a normal environment, it is a 'bad' variation, but in a population that is affeted by malaria, sickle cell anemia provides some protection against the disease. I should therefor be no surprise that sickle cell anemia is more prevalent in a population that has been exposed to malaria.

This will most likely be the same way that a 'cure' for AIDS will be found. There is already research going on to look at large populations exposed to AIDS and to look for variations that make individuals less suseptive to the virus that causes AIDS. If an individual in a population being killed by AIDS is immune, their offspring may also be immune and survive better. Over time, this immunity will become more prevalent in the population.

 

[lucaspa]

No, I was looking at everything. It just appears to me to be sexually driven. If you have a mutation: good, bad, or neutral, so look as you reproduce that will be passed on. Maybe a negative mutation makes you more attractive to the opposite sex. I'm struggling with the concept of "good" mutations overriding "bad" ones. Why being the most "fit" should be about anything other than "producing the most offspring".

OK. The first problem is that "mutations" shouldn't be considered just as "mutation". What is important is the change in the morphology, physiology, or otherwise of the organism. That is, the design that results from the mutation.

It seems to me that the current population could have acquired numerous neutral, positive, and negative mutations.

Well, the current population does have a huge number of neutral mutations. Most single nucleotide substitutions have no effect on the amino acids in the proteins. That is because in many of the 3 base codons the third position is "silent". That is, the amino acid is coded by the first 2 positions and the 3rd can be any of the 4.

Now, some slightly negative mutations can be "fixed" by genetic drift. This is chance. By fixed we mean that every member of the population has the allele of the gene. But you really need a small population to get fixation by genetic drift.

At any given time with a large population, there will be alleles with a negative selection coefficient because they have not yet been totally eliminated. It takes time to eliminate. Besides, if the environment changes what once used to be beneficial alleles are now detrimental alleles, and it takes time to eliminate them. The time depends on just how detrimental. I can give you the equations if you are interested.

They are simply the sum of those who produced most, which isn't necessarily the sum of those who had positive mutations.

For the designs in organisms, yes it is. It is the number who had offspring survive to reproduce in the next generation.

Below is Darwin's summary of natural selection:

"If, during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organization, and I think this cannot be disputed; if there be, owing to the high geometric powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each beings welfare, in the same way as so many variations have occured useful to man. But if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will will tend to produce offspring similarly characterized. This principle of preservation, I have called, for the sake of brevity, Natural Selection." [Origin, p 127 6th ed.]

 

[ForeRunner]

Well, you can actually demonstrate how an advantage would affect a population. I am too lazy to do the math right now but I will propose a fictional scenerio.

Let's say you have a population of small mammals living in some temperate region. The average length of the fur on them is, 8cm with a Standard Deviation of, say, 2cm. The little guys remain generally unchanged until an ice age sets in (selective pressure). Using the emperical rule and some math you can show that even a small survival advantage (ex: .01% per cm of fur) affect a population in a not all too many generations. A large scale event, like an ice age, could have even greater effects.