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Author Topic:   Natural Limitation to Evolutionary Processes (2/14/05)
Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 144 of 299 (341065)
08-18-2006 12:44 PM


I’ve never understood why creationists try to use this “argument”.
It’s clear that mutations provide a continual new supply of variation, especially since mutation rates have been estimated based on simple copying errors. For a human genome of around 6 billion base pairs, even an extremely good copying accuracy of 99.999% would still give thousands of mutations with each birth. I’ve read estimates of the mutation rate in humans, and it is generally somewhere around 1 to 200 mutations in every birth. Wow! If most of our DNA was needed for life, this would be a terrible rate! But, most of our DNA is not essential, so many changes in it are irrelevant.
A good site for this is here: NO REDIRECT
Of course, depending on the environment, any change can be good or bad. For instance, say a mutation makes one a little taller. If you live in an environment were everyone is well fed and where women like good basketball players, this mutation could be selected for and be good. However, if you live on a small island (say, Flores . ), where food is scarce and where there are no big predators, then this will be a “bad” mutation.
So with all this variation constantly coming in, the “no variation outside of a kind” seems to make little sense. This is especially clear when we measure difference with real numbers. Using actual numerical measurements usually makes any science discussion much clearer, and biology is no exception.
So looking at the differences in the genome between animals, we can see how this all works. The genetic variation between humans of different races is less than half a percent (0.5%). I hope no one disputes the idea that mutation and selection in different environments (such as sunlight favoring dark skin) can demonstrably cause 0.5% genetic difference over time. So what about dogs? The genetic difference is around 1%. OK, could a chimp evolve into a human? Only around 3% of our DNA differs from chimps.
So if the constant introduction of mutations (which we’ve observed), coupled with environmental changes can lead to a change of 1% in 20,000 years (which I think nearly all creationists agree with), then couldn’t another 20,000 years give us another 1% change, for a total of 2% change? Using a rough number of 6 years for a dog generation (feel free to use any number between 2 and 8 if you prefer), then that’s 20,000/6 = 3,000 generations, or around (25 X 3,000=) 75,000 years for humans. At that rate, we could get from a chimp like ancestor to a human in less than 200,000 years! Of course, our evolution hasn’t been nearly as fast since our selective pressures weren’t as strong. And of course, that means that 500 million years is plenty of time for something like a roundworm to evolve into a human (roundworms and humans share only 21% of their DNA, so that’s 79% different). This is especially apparent when one takes into account the much shorter generation time as one goes back in our ancestry (for instance, roundworms certainly don’t wait 25 years to reproduce!).
When using numbers for the genetic difference like this, it seems that anyone who imagines some arbitrary “kind” boundary hasn’t tried their hand at the math. I know that there are more sophisticated ways of doing this math, but this rough back of the envelope kind of calculation shows that we have orders of magnitude of room for evolutionary change. It’s just a rough estimate.
Have a fun day-
Equinox

Replies to this message:
 Message 146 by Faith, posted 08-18-2006 1:00 PM Equinox has not replied

Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 149 of 299 (341120)
08-18-2006 3:25 PM
Reply to: Message 145 by Faith
08-18-2006 12:51 PM


Re: Considering rapid rate of mutation
quote:
Re: Considering rapid rate of mutation
Archer O wrote:
quote:
The second fallacy is your woolly use of the word 'variability.' You use it to mean two different things: anatomical variety in a single population and as a synonym for 'ability to change,' by which you mean potential for genetic mutation across generations.
Faith replied:
Actually I don't use the term mutation in my conceptualization on this very old thread at all, and I only MEAN to use the term variability as in GENETIC variability, or genetic potential, and I doubt I've confused it with anatomical variety.
No, you are still using the same term to mean two different things. Does "variability" = genetic variability (meaning the gene pool of a population, the sum total of all the alleles), or instead do you mean that "variability" = genetic potential (by which I’m not sure what you mean, but if you mean anything having to do with future generations, then you must mean something like “the possible gene pool at some point in the future”, which, due to evolution, is very large. For instance, with that definition the future "variability" or “genetic potential” of a theropod dinosaur would include everything from a penguin to a parrot.
I'm glad we are getting our meanings straight, since that is a prerequisite to any good conversation.
-Equinox

This message is a reply to:
 Message 145 by Faith, posted 08-18-2006 12:51 PM Faith has not replied

Replies to this message:
 Message 151 by Brad McFall, posted 08-18-2006 4:11 PM Equinox has not replied

Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 150 of 299 (341132)
08-18-2006 4:01 PM
Reply to: Message 147 by Faith
08-18-2006 1:17 PM


Re: mutation and immigration
quote:
What does "a change of 1% in 20,000 years" mean? You assume a positive change that can facilitate evolution, but all your examples are hypothetical and you give no statistics on the percentage of USEFUL mutations as compared to undesirable ones -- meaning those that NO environment is going to favor..
I’m talking about net change (see below) - notice that I used the dog example, there is a 1% difference between, say, a dog and a wolf (depending a bit on the breed, of course).
The labels “good” vs. “bad” mutations, as I mentioned, are misleading. The vast majority of mutations (over 90%) are neutral - they don’t do anything at all. For instance, say your instruction book contained pages of random gibberish - randomly changing a word of that doesn’t change the instructions.
OK, now, let’s think about the mutations that do change something. Most changes could be either “good” or “bad”, depending on the environment. Take a second to step back and look in a mirror. Consider changing any aspect of your body. Darker skin? Is that “harmful”? Well, it is if you are a female living in northern areas, and you need to get enough sunlight to provide vitamin D when pregnant. Or instead do you live in Africa, where it is a good mutation, since you need protection from too much sunlight, which can cause skin cancer? Larger nostrils? Do you live in a windy desert, where larger nostrils will allow more sand into your lungs (ouch)? Or instead do you live in a forest, where being able to pull in more air when running from a predator will help you escape?
We could look at examples like this all day - the point is that mutations aren’t usually inherently “good” or “bad” - that depends on the environment, which will either cause them to help the bearer have more kids, (hence, “selected for”) or not (“selected against”).
OK, now look at the 1% I mentioned for dogs. I meant the net total of the mutations that WERE SELECTED FOR over 20,000 years. The number of mutations selected against is completely irrelevant, since those mutations all disappeared with their unfortunate owners. See why the ratio is unimportant? If half of the mutations that have an effect are selected for, then the ration you want is 1:1, and you end up with only the "selected for" mutations. If there is only 1 helpful, "selected for" mutation in 5, then you ratio is 1:5, and you still have exactly the same number of mutations at the end of the day, since the ones that weren’t selected for are gone anyway. That's why the number of non-selected for mutations is irrelevant.
If you want to discuss extremely harmful mutations, such as those that cause an quick death or some such, that's fine. Again, they are completely irrelevant, since that animal dies, the mutation (new allele) is gone, and we are back to square 1.
In fact, “harmful” mutations are very often selected for by humans. Look at the pathetic bulldog. We have selected the mutations that slowly made his snout all smashed in, resulting in hampered breathing. Have you ever been near a sleeping pug? It sounds worse than Darth Vader! Whether a mutation is “good” (selected for) is a function of the environment as much as it is a function of the mutation.
So, the % is the net change in the genome due to the accumulation of mutations that were selected for. It took thousands of beneficial mutations to get to a poodle from a wolf - and that change is only “beneficial” if you keep the poodle out of the wolfpack.
You mentioned how mutations work. Here are some basic types of mutations and how they work:
Duplication of a stretch of DNA. This is like accidentally copying part of a book twice. Example - when making a copy of a book that has chapters 1, 2, 3,4,5,6,7,8,9,10,11, 12, you end up with a book that has chapters 1, 2, 3,4,5,6,7,3,4,5,6,7,8,9,10,11, 12
Deletion of a base pair. AATCTGTC becomes ATCTGTC
Addition of base pair AATCTGTC becomes ACATCTGTC
Transposition (like a mirror) AATCTGTC becomes CTGTCTAA
All of these can have no effect, an effect which is selected for, or an affect which is selected against.
To add information, first, take a functional gene, and make an extra copy using the duplication mutation. That won’t hurt the organism, since the second copy is simply redundant. Then use any of the other mutation methods so as to make the second copy do something new. The organism still has the original copy doing whatever it is supposed to do, but now has the added ability of whatever the new gene does (such as digesting nylon, as in a species of bacteria).
The process can also add entire chromosomes, that’s how, over time, the total number of chromosomes changes. For that, simply copy a whole chromosome twice (it happens), then the rest of the process is the same as above.
I don't understand what you mean by "a mistake which is only destructive". Do you mean that all mistakes have to be harmful? Why? Many inventions have been found by people making mistakes. In genetics, if a group of animals is living in a valley and the climate changes to make it colder, then wouldn't a genetic "mistake" which made their hair grow a little longer be helpful?
Oh, I'll be out until next week. Have a fun weekend-
Equinox
Edited by Equinox, : No reason given.

This message is a reply to:
 Message 147 by Faith, posted 08-18-2006 1:17 PM Faith has not replied

Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 247 of 299 (341952)
08-21-2006 1:16 PM


Hi Everyone! Hi Faith!
I’m back, though of course with limited time as always.
Some of the material in my last post was ignored (around post 150 on page 10 ), I think because it happened to land on the bottom of a page, and was quickly buried behind tons of unpleasant posts on the previous thread. It contained two important concepts, in addition to answering some of your questions. One concept is that “beneficial” is a fuzzy and meaningless term. Here is the part on that:
quote:
The labels “good” vs. “bad” mutations, as I mentioned, are misleading. The vast majority of mutations (over 90%) are neutral - they don’t do anything at all. For instance, say your instruction book contained pages of random gibberish - randomly changing a word of that doesn’t change the instructions. OK, now, let’s think about the mutations that do change something. Most changes could be either “good” or “bad”, depending on the environment. Take a second to step back and look in a mirror. Consider changing any aspect of your body. Darker skin? Is that “harmful”? Well, it is if you are a female living in northern areas, and you need to get enough sunlight to provide vitamin D when pregnant. Or instead do you live in Africa, where it is a good mutation, since you need protection from too much sunlight, which can cause skin cancer? Larger nostrils? Do you live in a windy desert, where larger nostrils will allow more sand into your lungs? Or instead do you live in a forest, where being able to pull in more air when running from a predator will help you? We could look at examples like this all day - the point is that mutations aren’t usually inherently “good” or “bad” - that depends on the environment, which will either cause them to help the bearer have more kids, (hence, “selected for”) or not (“selected against”).
In fact, “harmful” mutations are very often selected for by humans. Look at the pathetic bulldog. We have selected the mutations that slowly made his snout all smashed in, resulting in hampered breathing. Have you ever been near a sleeping pug? It sounds worse than Darth Vader! Whether a mutation is “good” (selected for) is a function of the environment as much as it is a function of the mutation.
Another important concept from then was exactly how mutations increase the genetic information, by literally making whole new genes. Here is that part:
quote:
You mentioned wondering about the details of mutations. Here are some basic types of mutations and how they work:
Duplication of a stretch of DNA. This is like accidentally copying part of a book twice. Example - when making a copy of a book that has chapters 1, 2, 3,4,5,6,7,8,9,10,11, 12, you end up with a book that has chapters 1, 2, 3,4,5,6,7,3,4,5,6,7,8,9,10,11, 12
Deletion of a base pair. AATCTGTC becomes ATCTGTC
Addition of base pair AATCTGTC becomes ACATCTGTC
Transposition (like a mirror) AATCTGTC becomes CTGTCTAA
All of these can have no effect, an effect which is selected for, or an affect which is selected against.
To add information, first, take a functional gene, and make an extra copy using the duplication mutation. That won’t hurt the organism, since the second copy is simply redundant. Then use any of the other mutation methods so as to make the second copy do something new. The organism still has the original copy doing whatever it is supposed to do, but now has the added ability of whatever the new gene does (such as digesting nylon, as in a species of bacteria).
The process can also add entire chromosomes .
OK, now lets list some mutations that could be what you are looking for:
* Tails in human babies. Since creationists generally deny that humans evolved from lower primates, these tails would be “new”. As such, that mutation has certainly added something new. There have been a number of babies born with fully functional tails, including the ability to use the tail to signal emotional state (think of how a pooch does this already).
*Other atavisms, such as mutations which make hind legs in whales. Since creationists generally don’t believe whales evolved from land-lubbers, being able to clamber onto land is a new and beneficial feature.
*The “beautiful buttocks” mutation in sheep. I’ll look up the information on this one. I think this happened in the 80’s - a mutation in a sheep caused more muscular legs & buttocks. If this had been a wild sheep living near a mountain, a better ability to climb the mountain is clearly a benefit. As it was, this was a domestic sheep, and the farmer was overjoyed to be able to get more meat from this sheep, and the mutation was recognized a great thing. The farmer bred the sheep so as to preserve and sell this mutation. I wanted to do web searches on this, but I’m on my lunch break at work, and doing searches on (“beautiful buttocks” & sheep) would undoubtedly trigger some porn alarm!!
*Antibiotic resistance - I don’t understand how this isn’t a beneficial mutation that adds information.
*Sickle-cell: I understand not liking this one since it has a downside as well, but it still stands
*The wisdom teeth one mentioned earlier
*The ability to digest nylon in one strain of bacteria. This is also clearly a very beneficial mutation, and more, it has been studied to show which gene mutated and how it did so. I don’t understand how this isn’t a beneficial mutation that adds information.
*The ability of the monkyflower to metabolize copper compounds
OK, so that’s around a half dozen, even if one doesn’t like one or two of them.
Let’s look at the numbers again. The vast majority of mutations are expected to be neutral. This is because the vast majority of our DNA does nothing. It is like have a million volume encyclopedia, where only a few thousand volumes have real information, while the rest have gibberish or repeated sections, like if a volume had this:
quote:
and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and and
For hundred of pages. We also have a lot of copies of working genes, but the copies are non-functional due to mutations. These are called “pseudo genes”, and there is a great article on them in this month’s Scientific American. So mutations in any of that non functioning DNA doesn’t help or harm anyone- and, as Crash nicely pointed out, some mutations will change the DNA of a functioning gene but not the protein it makes due to the redundancy of the genetic code.
We’ve discussed how there are lots of harmful mutations. Yep - we should expect that, since a change to a working gene that we need is likely to be a change that isn’t as good. And as I mentioned before, the number of mutations selected against (the harmful mutations) is completely irrelevant, since those mutations all disappeared with their unfortunate owners.
If half of the mutations that have an effect are selected for, then the ration you want is 1:1, and you end up with only the "selected for" mutations. If there is only 1 helpful, "selected for" mutation in 5, then you ratio is 1:5, and you still have exactly the same number of mutations at the end of the day, since the ones that weren’t selected for are gone anyway. That's why the number of non-selected for mutations is irrelevant. See why the number of harmful mutations is unimportant?
Accumulating millions of good mutations is quite easy, since the bad ones are selected against and removed anyway, and we’ve had literally billions of years to accumulate the good ones that remain. Since we’ve seen at least the half dozen good ones mentioned above in just the past few decades, then just doing the math adds up to quite a few in a billion years - and that’s ignoring the fact that the half dozen I’ve listed is undoubtedly a tiny fraction of the ones that have occurred, since we don’t watch all births of all animals for any change - how could we?
Take care everyone-
Equinox
Edited by Equinox, : Added crash sentence (forgot it the first time).

Replies to this message:
 Message 262 by Wounded King, posted 08-21-2006 6:29 PM Equinox has replied
 Message 269 by Faith, posted 08-22-2006 12:03 AM Equinox has not replied

Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 259 of 299 (342096)
08-21-2006 5:25 PM
Reply to: Message 255 by Faith
08-21-2006 4:38 PM


Re: beneficial
Faith wrote:
quote:
I'm aware of the long list of genetic diseases, and the oddness of being given only two strange contenders for beneficial mutations
Um, that math is a little off. I mentioned about a half dozen, Crash mentioned one, and Modulous linked to a page with 6 others, which had specific gene locations mentioned. That comes to around a baker's dozen, not "two strange contenders". I can understand seeing sickle cell as "strange", even though it is quite good not to die of malaria, but don't you love the beautiful buttocks, if nothing else?
Faith wrote:
quote:
they are these mistakes called mutations, which alter some "normal" pattern of protein-making functions of genes, and it's hard for me to think of these as anything but a bad thing.
What do you mean by "normal"? If a copying error works better than a non-error, then is "normal" a bad thing by comparison? I guess if you are going to say that any mistake is bad, then you have to assert that the original creation is absolutely perfect, which seems impossible to defend based on how animals and plants are put together (anyone who knows animal anatomy knows how stupid a lot of the body plans are). Why do you suppose that any change has to be bad? Look at your own body - is it perfect for every conceivable environment? It can't be - if it's really furry, then a "less hair" mutation would certainly be good for a hot area, and vice versa. Did you read my last post?
quote:
Some of them seem to be simply normal potentials that are already in the population left over from the original gene pool, rather than mutations, but I don't know what criterion could be applied to tell the difference.
Often those are easy to tell - such as many of the examples modulous linked to, where the genes themselves are descibed.
quote:
But once the conversation has gotten to the level of asking what a mutation really is, I think it has to end because I can't follow if it gets too technical and the fact that we operate from completely different basic assumptions just adds to the difficulty.
As I descibed above, the different basic assumptions need not always prevent discussion, since they can often be tested openly.
I also described in detail what a mutation is in the DNA. So is it really an understanding issue? If it still is, then you have to give up your assertion that started this thread, since otherwise you claiming something and then when shown how it is false, saying "it's still true, regardless of evidence or logic".
Take care-
-Equinox

This message is a reply to:
 Message 255 by Faith, posted 08-21-2006 4:38 PM Faith has not replied

Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 261 of 299 (342118)
08-21-2006 6:21 PM
Reply to: Message 260 by Parasomnium
08-21-2006 6:07 PM


Re: Working against evolution? I'm afraid not.
P wrote:
quote:
Now tell me where I've gone wrong.
well, I can at least tell you the canned creationist responses. That response is that either: 1 the ark contained a greyhound,the 50K year thing is obviously wrong since the world is only 6K years old. Or 2. all the genes that do the things you described were not mutations, but were in the genome of the dog on the ark, and were only "concentrated" by breeders.
Now, I do have problems with both answers. 1, simply denies tons of evidence and logic and then relies on a myth. 2 may be testable. Since genes mix all over, this would imply that all the genes that do that are in most dogs today. If so, then creationists could provide evidence for thier story by simply finding them, and perhaps using genetic engineering to take those genes and make a greyhound from a poodle. Of course, their response to that is probably that the genes are gone now, or some such.
It's interesting that some YECs believe in such hyper evolution, from a wolf like dog ancestor "kind" into everything from a kit fox to a greyhound to a great dane in just 6000 years, while in the same breath denying that 20,000 years is enough time to do the same thing. Or denying that 4,000,000,000 years is enough to go from single cells to us.
*Sigh*
-Equinox

This message is a reply to:
 Message 260 by Parasomnium, posted 08-21-2006 6:07 PM Parasomnium has not replied

Equinox
Member (Idle past 5251 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 263 of 299 (342129)
08-21-2006 6:42 PM
Reply to: Message 262 by Wounded King
08-21-2006 6:29 PM


Re: Those beautiful buttocks
I thank the king for finding my beautiful buttocks and showing them to everyone. Now we can all enjoy inspecting the beautiful buttocks in very close detail. Ahhh.....

This message is a reply to:
 Message 262 by Wounded King, posted 08-21-2006 6:29 PM Wounded King has not replied

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