Cause of Mutations

[bluetrinity]

I think this is essentially correct. An example using artificial selection may help.

Suppose a dog breeder wishes to take his existing stock of dalmatians to produce a dalmatian 50 inches tall instead of the normal 25. Each litter will yield dogs with a variety of height; this is where randomness comes in. The breeder selects for further reproduction only the tallest individuals in each litter. So in this example, the breeder plays the role of the environment -- the factor which decides which organisms will reproduce.

Now suppose that in the middle of this process the breeder changes his mind and now wants dalmatians with only 1/2 as many spots. Height is now a secondary concern. The breeder will take his stock of dals, who now may average 40 inches in height, and breeds them with this new goal.

This change in goal reflects what may sometimes be natural selection's moving goal posts. For a million years natural selection may favor only the quickest rabbits so they can avoid their many predators. But when rabbits are introduced to Australia where there are very few predators to threaten them, the selection pressure changes radically. Now natural selection will favor, say, the rabbits who can eat the most food at one sitting or the ones who might have the best immunity to strange Australian diseases. With no predators to flee, even the slow rabbits can make a living. Speed becomes a minor trait.

I follow your example but I believe it confuses the issue in that the breeder has a certain idea of what he wants the outcome to be, while my understanding of NS is that it merely provides the environment for survivial of the species. If you had made the breeder a completely neutral person or a lunatic, I would agree with the example. As it happens, you appear to have made him more like God.

 

[GoSeminoles!]

I follow your example but I believe it confuses the issue in that the breeder has a certain idea of what he wants the outcome to be, while my understanding of NS is that it merely provides the environment for survivial of the species. If you had the made the breeder a completely neutral person or a lunatic, I would agree with the example. As it happens, you appear to have made him more like God.

The example does not hinge on the notion that the breeder is a sentient being. As I said, the breeder only provides the condition necessary for an individual to be selected for reproduction. In this case the condition is a trait for tall. Mindless natural selection does exactly the same thing. If an environment has fast predators, then natural selection is going to favor zebras who are also fast. There are no slow, lumbering zebras. As does the breeder, natural selection defines the condition necessary for an individual to survive long enough to reproduce.

 

[bluetrinity]

The example does not hinge on the notion that the breeder is a sentient being. As I said, the breeder only provides the condition necessary for an individual to be selected for reproduction. In this case the condition is a trait for tall. Mindless natural selection does exactly the same thing. If an environment has fast predators, then natural selection is going to favor zebras who are also fast. There are no slow, lumbering zebras. As does the breeder, natural selection defines the condition necessary for an individual to survive long enough to reproduce.

Yes, but the key is that natural selection is exactly that: mindless. Your breeder is not in common understanding, unless he randomly chooses what he wants.

 

[bluetrinity]

Now that I understand that we have essentially matter, natural laws and random mutations, I suppose I understand how evolution is claimed to work. Now then, it would follow that everything that exists today would have to be the result of an iterating process in which mutations helped or hindered by the effect of natural laws coupled with the specific circumstances in the environment produce essentially all life on earth. I don't really understand yet, how life could come from mere dead matter, but maybe someone can explain that to me as well.

My question is this, however. Presumably human brains also developed as part of this long chain of iterations and natural selection called evolution. Now, what basis do I have to trust anything that I think, say or do, if, at the end of the day, all is merely the result of a process driven by chance? For example, if it is by chance that I prefer chocolate over rice pudding why wouldn't it also be by chance that I would favor love over hate? Am I even able to form any coherent thought thinking that the whole thought process is merely the result of an incredibly long chain of events driving essentially random neurological activity?

 

[GoSeminoles!]

Yes, but the key is that natural selection is exactly that: mindless.

Indeed. We know of no evidence that natural selection is somehow a sentient process.

 

[Loudmouth]

Now that I understand that we have essentially matter, natural laws and random mutations, I suppose I understand how evolution is claimed to work. Now then, it would follow that everything that exists today would have to be the result of an iterating process in which mutations helped or hindered by the effect of natural laws coupled with the specific circumstances in the environment produce essentially all life on earth.

I would say that you have matter, natural laws (quantum mechanics and thermodynamics), and the environment. Those are the real players.

My question is this, however. Presumably human brains also developed as part of this long chain of iterations and natural selection called evolution. Now, what basis do I have to trust anything that I think, say or do, if, at the end of the day, all is merely the result of a process driven by chance?

You don't have to trust anything, it is a personal choice. Personally, I trust my thoughts because they correspond to what happens in reality.

Also, natural selection is not chance, as has been said before. Selection is the opposite of random.

For example, if it is by chance that I prefer chocolate over rice pudding why wouldn't it also be by chance that I would favor love over hate?

It's not chance, it's preference. Some people do favor hate over love, pain over pleasure, or death over life. Such is the human condition.

Am I even able to form any coherent thought thinking that the whole thought process is merely the result of an incredibly long chain of events driving essentially random neurological activity?

It's not random.

Think of evolution as a game of gin rummy. You start out with a random set of cards. You also draw random cards on each turn and discard. However, due to a selection process, the cards in your hand are not a random collection otherwise the chances of laying down would be near nil. That is how evolution works. Random changes are put through a selection process which results in a non-random assortment of genes.

 

[GoSeminoles!]

Now that I understand that we have essentially matter, natural laws and random mutations, I suppose I understand how evolution is claimed to work. Now then, it would follow that everything that exists today would have to be the result of an iterating process in which mutations helped or hindered by the effect of natural laws coupled with the specific circumstances in the environment produce essentially all life on earth. I don't really understand yet, how life could come from mere dead matter, but maybe someone can explain that to me as well.

The origin of the first life forms, abiogenesis, is still not well understood (or at all, really). See here and here for some discussion of what is known.

My question is this, however. Presumably human brains also developed as part of this long chain of iterations and natural selection called evolution. Now, what basis do I have to trust anything that I think, say or do, if, at the end of the day, all is merely the result of a process driven by chance? For example, if it is by chance that I prefer chocolate over rice pudding why wouldn't it also be by chance that I would favor love over hate? Am I even able to form any coherent thought thinking that the whole thought process is merely the result of an incredibly long chain of events driving essentially random neurological activity?

Sometimes what our brain tells us is erroneous (you've surely seen examples of optical illusions) and sometimes our thought process leads to fallacious conclusions. However, for the most part how we think is in good accord with how the world works. We could not do science otherwise. For example, we can formulate a theory of gravity and test its predictions by running an experiment. When the results repeatedly match our predictions, then we've got a good reason to believe the theory is correct. This also tells us that our thought process works. If we were a race of madmen whose thought process was totally disconnected from reality, then there would be no way we could achieve such a result.

 

[Dragar]

Now, what basis do I have to trust anything that I think, say or do... Am I even able to form any coherent thought thinking that the whole thought process is merely the result of an incredibly long chain of events driving essentially random neurological activity?

Nobody can give you good reason to trust reason. To do so would be circular.

 

[Jet Black]

I follow your example but I believe it confuses the issue in that the breeder has a certain idea of what he wants the outcome to be, while my understanding of NS is that it merely provides the environment for survivial of the species. If you had made the breeder a completely neutral person or a lunatic, I would agree with the example. As it happens, you appear to have made him more like God.

the person's preference is merely the factor which determines which class of variations will be preferentially passed onto the next generation, but the effect is identical to what happens in the natural world. In the natural world, the effects of the environment and the fact that resources are limited result in individuals with certain features breeding more than individuals with other features. those features that result in increased numbers of offspring will be more highly represented in the next generation, and so on. If the environment changes, then the features selected for and against will also change, but the effect will be the same, that certain features will result in a higher number of offspring than the average.

 

[Jet Black]

Now that I understand that we have essentially matter, natural laws and random mutations, I suppose I understand how evolution is claimed to work. Now then, it would follow that everything that exists today would have to be the result of an iterating process in which mutations helped or hindered by the effect of natural laws coupled with the specific circumstances in the environment produce essentially all life on earth.

no. It does not follow at all. The evolutionary process you have loosely described there only covers the effects of these things on existing life. it does not cover everything from cosmology to the formation of that life.

I don't really understand yet, how life could come from mere dead matter, but maybe someone can explain that to me as well.

Essentially life is a imperfectly replicating system. The origins of life will have emerged from simple imperfectly replicating chemicals, others have given links.

My question is this, however. Presumably human brains also developed as part of this long chain of iterations and natural selection called evolution. Now, what basis do I have to trust anything that I think, say or do, if, at the end of the day, all is merely the result of a process driven by chance?

dear me, it looks like you haven't been paying attention. remember that this process is also driven by the environment i.e. the interactions of the various organisms with the environment, which also includes other organisms.

For example, if it is by chance that I prefer chocolate over rice pudding why wouldn't it also be by chance that I would favor love over hate?

you probably don't prefer chocolate over rice though. remember that your body is formed as a result of billions of years of evolution, and so the genes that code for you will be the result of lots of trials and mixes of possibilities. So for example the taste sensors that tase for sugar and their effect on your brain will be part of the mix of genes that resulted in increased breeding success. Furthermore the body is also trained through life as well, so there will be cultural influences too. If you were Chinese, you might not like chocolate so much, since your diet would be very different from the outset.

Am I even able to form any coherent thought thinking that the whole thought process is merely the result of an incredibly long chain of events driving essentially random neurological activity?

but that is just it, the neurological activity isn't essentially random. it has been shaped by the environment ever since neurons first started to form. if your brain activity were truly random, you would do totally random things. you would not be able to function, you would not be able to see and build a map of the world around you, you would not be able to walk and all of those things. your brain functions as it does, because other brains that functioned in a similar way had a higher breeding success than brains that functioned in different ways.

 

[Karl - Liberal Backslider]

BlueTrinity - how about this example.

Years ago, when people started keeping fish in aquaria, the common swordtail, Xiphophorus helleri - grew to about six inches.

Now they're mostly around two or three inches. This is partially cross-breeding with genetic relatives, but there is another reason.

Fish are bred in large fish breeding farms. Livebearing fish, such as the one we're interested in here, are actually bred by putting lots of females and a few males in a large tank with lots of hiding places, and letting them get on with it.

Now, there is some natural variation in adult size of swordtails, as with any organism, and the smaller the average size, the sooner the fish reaches that size. And the sooner it starts breeding.

Consequently, in the environment in which swordtails are bred, those who mature earliest and start breeding quickest are those who have the most fry. Genes for a small adult size are passed on more than genes for a large adult size.

There's another factor as well. These fish need lots of swimming space to mature properly. Consequently, those with genes for a large adult size are less likely to make it to breeding age successfully. Again, genes for a smaller adult breeding size are selected for.

And that is why swordtails, IMO, are now smaller than they were in the 1950s. But nobody intended that outcome. The breeders were not purposely selecting for smaller fish. There was no intelligence guiding the process. But it was both predictable and whilst based on random mutations and variation, it was not a random overall outcome.