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Author | Topic: What is the mechanism that prevents microevolution to become macroevolution? | |||||||||||||||||||||||||||
Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
Jar wrote:
quote: Wow, this is an easy to understand, powerful test. Biologists can find and approximately date past bottlenecks as RickJB gave an example of. A bottleneck often reduces a population down to just a few hundred or thousand individuals. Imagine how MASSIVE a bottle neck the flood is by comparison - just 4 or 14 individuals - what a massive signal to look for. It would be obvious to any biologist that a species underwent such a bottleneck. Dating would show species after species that underwent a huge bottle neck - and they would all show the approximately the same date, even if there was some noise in the dating method. Faith wrote:
quote: You’ve got to be kidding me. It’s not like we are looking for a needle in a haystack. Biologists very often find and approximately date bottlenecks based on genetic evidence. The fact that this hasn’t been found speaks volumes. I guess it goes back to the creationists who claim that God created everything with the appearance of age - now I guess creationists must also say that god miraculously changed the genomes of every living thing on the planet after the flood to wipe out the evidence of this bottleneck. How else could we explain the glaring absence of a universal bottleneck in 2,500 BCE? Claiming that the bottleneck has been misinterpreted sounds like claiming that God created the world’s tallest mountain in Kansas, and that it’s still there, but has been “misinterpreted”. Geologists can find, (and approximately date) mountains. I haven't heard any good creationist reason for the missing bottleneck.
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
philip wrote:
quote: Um, we came up with over a dozen on a recent thread. Are we going to go over them all again?
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
I found the bottleneck idea so striking that I put in the errancy wiki here:
Genesis 8:17 - Errancy Wiki Thanks jar for pointing out the "reply" button, and WK for suppling great information on the ways that a past bottleneck is clear to anyone who understands DNA. Have a fun day all- -Equinox
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
mjflorestra wrote:
quote: Argh... This has been discussed again and again, and still some miss the past discussion. There are tons of examples of mutations that add information and are beneficial. Even on this thread I earlier posted:
quote: As a recap, here is how a set of mutations can add information, again from an earlier post:
quote:
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
WK - yes, it is a little different. Sorry about that everyone, and thanks for pointing out my error.
Speciation does not appear to me to be the loss of diversity. If I have 10 alleles for a trait, and a very small sub population because isolated, and, say, it lacks 2 of the alleles, having only 8, and then mutates enough in other loci to cause speciation, then yes it has lost diversity in the original loci, but the whole overall genus has not, since all 10 alleles are still present if you count both groups. In fact, further mutation is very likely to add alleles, perhaps "re-making" some of the missing ones in the new species, or more likley, introducing new ones in both species. For example, after some time the parent population may now have 12 alleles and the new species may have 11 (say, 2 unique and 1 that matches one of the ones in the parent species.). Now even if one of the species goes extinct, the genetic diversity has increased. Looking over geologic time, it's clear that huge amounts of genetic diversity have built up, resulting in the huge genetic difference between a crow and an extremophile. We have plenty of evidence of mutations adding information, and plenty of examples of extinction resulting in lost alleles. Extinction has been the fate of nearly every species that has ever existed, yet the genetic diversity is extremely high now. For instance, the gene for "shorter wings" in the dodo is lost now, but in the same time we've gained alleles for "beautiful buttocks", "eating nylon", "fast algal growth" and more. A great example of a time period with a net loss of genetic information due to extinction would surely be the KT time, and a conversely great time for massive gains in mutational innovation would be, say, the early teriary, or the early triassic. Fun, but perhaps not relevant. Have a fun day- Equinox
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
Philip wrote:
quote: Hey, don't forget that we just talked about dozen+ beneficial mutations that we came up with without much problem. Well, one could quibble or the estimated numbers, but taking most reasonable estimates and doing the math shows that there really isn’t a problem. Take people. We have about 3 billion base pairs. That has to replicate several times for each generation (you have to make the germ line cell, it has to replicate as an embryo, up to the germ line cell for the next generation, etc). So for each generation you have to have billions of copying events. Even if your copying is 99.999999% accurate, you’ll still have 1 in a billion mistakes, and that means at least a dozen mutations per generation. I’m sure that most of them will be neutral (say, in non-coding DNA), but even if only a few are beneficial, that’s still quite a few. So how many generations do we have? For humans, we can guess a generation has been around 20 years for the past 500,000 years or so. So that’s around 20,000 generations. Before that it was probably shorter, say 10 years for the range of 5 Mya to 0.4 Mya, giving another 460,000 generations. I’m going to drop to an estimate of 5 years for the time from 30Mya to 5 Mya (primates), so that gives another 5,000,000 generations. Now maybe the genome was smaller? Any biologists specializing in mammal genomes have input? I’m guessing the generation length is just 2 years for the time from 100 to 30 Mya, giving 35,000,000 generations. Now let’s add those up. I get about 40,000,000 generations. If you have an average population over all that time of, say, 2 million individuals, then that’s 2 million times 40 million, or 80 trillion (80,000,000,000,000) births. Based on my guess of a dozen mutations per birth, thats 100,000,000,000,000 mutations. Sure, only a few percent or less are beneficial, but one tenth of 1% is still 100 billion, and still a huge, huge number. Plus, don’t forget that these mutations need not be sequential. You can evolve features in parallel, getting a mutation here or there when they occur. For instance, in changing a land mammal into a whale, the nostril can be moving up the head, while the teeth are changing, while the legs are shortening, while the hair is thinning, while the tail is strengthening, etc. These can all happen concurrently. So even with people there seems to be plenty of room in the math. Try wiggling my numbers around, try a shorter or longer generation, or a different copying accuracy (though we have hard data on that), or whatever, just for the fun of it. And that was only going from mammals to humans. Going from worms to, well, worms can allow for 5 times as much time. Oh, and try doing this for insects, or shrimp, or something with a short generation time. There you have several generations a year, and can start back in the Paleozoic. Plus, your number of individuals in each generation can easily number in the billions. Wow, putting those numbers in easily gives numbers a million times as high. But we, as humans, aren’t used to dealing with numbers like this. That’s why we think at first “wow, how could that many good mutations accumulate?”. But when doing the math, we see that it’s easy. Have a fun day-Equinox Edited by Equinox, : added concurrant mutation paragraph
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
Faith wrote:
quote: Um, you still have your mutation blinders on. Speciation could occur without any loss of alleles. Simply have enough mutations so as to prevent interbreeding. These mutations could all be made by first copying genes, then only adding functions in the copies, thus the entire original genome is still there. Why ignore this possibility?
quote: Yes. That’s left out because it’s a fantasy. Speciation is a poor place to look for a “loss of genetic information”. Why? Because it only works if you put your creationist blinders on and look only at the little split off group that speciates, and then completely look away before accumulated mutations add more genetic information in the form of new alleles that weren’t in either starting population. You need the blinders because if you look at both populations, the loss is little if any. Many, if not most speciation events happen with one small group leaving a big group. The big group hasn’t lost any genetic information, since it’s big. The little group has, but again, if you look at both groups, no loss. Then, both groups ADD genetic information through mutation, resulting in an overall increase in genetic information. Now that I’ve posted it twice, do you understand how one mutation can make an extra copy of a stretch of DNA, then later mutations can change that new stretch, resulting in new alleles without the loss of the one they came from? Looking at the speciation process and claiming that speciation causes a loss (and not a gain) of genetic information seems difficult to me. A better place to argue for the loss of genetic information is clearly the extinction of a species. No one argues that they happen, and that they happen a lot. After all, over 99% of the species that have ever lived are extinct. And when a species goes extinct, ALL of the genetic information that made them different from surviving species is gone.
quote: The hours of the day are dark EXCEPT for those during the day. The only sources of light during human prehistory were candles and fires (again EXCEPT daytime, which is against my starting assumptions, so we can discuss it later). So without much light, eyes clearly don’t have a lot of use. All sensing processes work to sense something that’s there often, and so eye’s clearly can’t have evolved (nor been divinely designed) for sensing light. I can’t understand how biologists and scientists try to maintain that eyes function for sensing light. The whole “theory” of mega-eyesight is obviously just a fable made up by evil atheists.
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
Philip wrote:
quote: You’re welcome! : ) Yes, the total number is “mind boggling”, but that’s consistent with them being “occasional”. After all, something that is “occasional” for millions of years easily adds up to “mind boggling” numbers - especially when population and WK’s point about “boggling” are considered. to WK- I focused my rough estimate calcs on the simple mutations only because I don’t have data on the frequency of the larger replication type mutations. Of course, they happen too. For instance, breech births are only “occasional”. I’ve witnessed births, I know the details of dozens of births from family and friends, and I’ve never directly see or talked about an actual breech birth. However, over the past few thousand years, with a human population in the millions that whole time, I’m sure there has been a truly mind boggling number of breech births.
quote: OK, are you saying that beneficial mutations don’t happen? If so, then what about the baker’s dozen or so we already discussed? Or, are you saying that they do happen, but don’t cause speciation? How could they not? Or, are you saying that do happen, and they do lead to speciation, but that they don’t give rise to “higher” animals? If so, what do you mean by “higher”? If you mean "more complex", then why should some of the new varieties not be more complex? (after all, some will be less complex and some more complex). I’m afraid that after that, your post unravels, as WK pointed out. Edited by Equinox, : No reason given. Edited by Equinox, : typo
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
Faith wrote:
quote: I have to support faith on this one. I saw some of those other threads, and I too was unsatisfied with what could have been a relatively straightforward, systematic explanation. I think this is something we do a poor job at as a scientific community. We (meaning all people who understand science) generally do a poor job of communicating how things work to the general population. I saw it again in spades last week when I heard person after person say things like "they are so evil for saying Pluto isn't a planet - it's in our atmosphere like the other planets after all..." or some such. We can do a better job. As a science educator myself, I have to say that we aren't doing very well, and we even have someone here who has outright asked for a simple explanation. I have very limited time, but I tried to help a little with my post about 4 different kinds of mutations. Faith, was that post understandable? Edited by Equinox, : No reason given.
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
First-
Faith, I have yet to respond to your response to my post last week. I’ll do so, I’m just too busy now. I’m taking a short break to jump in here to supply some numbers that have been sorely lacking. OK, let’s look over the evidence (and please correct me if I miss important evidence or list some evidence incorrectly.) 1. The allele in question has only been found in 33 people in the world, despite a lot of scientific attention. 2. All 33 are direct descendants of a person who lived in the 18th century (call him Apo). 3. The allele is different from an allele generally present in the human population by a single amino acid change. 4. Both hetero and homozygous individuals appear to be healthy, and no disadvantage to the allele can be found. 5. Mendelian genetics and general probability apply. 6. The allele is dominant. Now, which explains these better? Test #1 - why are all 33 descended from Apo, and none found in, say, Chicago? If it was a mutation in Apo, then no one but his descendants should have it. That checks. If it was present in Adam (required by Faith), then somehow, despite being harmless, it must have been selected against to go from a frequency of at least 0.25 %, to a present day frequency of 33 in 6E9. The odds of a human having it are approximated by 33/6E9, and so the odds of all of them being in the same town of 1000 people is (the odds of a person being in that town vs the rest of the world)^(number of people with the allele)= (1000/6E9)^33= 2E-224 = 0.000(200 zeros)2 Now that’s unlikely. OK, next test of the explanations (#2). If it were a mutation, it would HAVE TO BE clearly and simply related to present genes. If it were an existing allele, it could be very different. In fact, it should be very different, since the odds of that long a nucleotide matching perfectly are very low. It’s as if you picked two pages from different parts of an encyclopedia, and the middle paragraph was exactly word for word identical, except for one word, which was changed from, say, “herd” to “hard”. Clearly the mutation hypothesis is much more likely for this point, since it predicts the similarity, while the Adam hypothesis must explain away this otherwise very unlikely word for word matchup. (unless we want to postulate a God that specifically tries to trick people so he can send them to hell and watch them burn). If we had the nucleotide sequences, I could calculate the odds they would match up so perfectly, assuming no relation. Test number 3. Does this gene increase or decrease over time? Humans have been eating artery-clogging meat for a long, long time. Even if reproduction happens prior to death, a longer post-reproduction life is selected for because one can help raise the kids and grandkids.So the mutation explanation says that the allele has been selected for the few generations since it has arisen, and that coupled with population growth explains how we went from 1 to 33. I’ve explained before why we know that it was just 1 back at Apo- the numbers otherwise are extremely unlikely. So the mutation explanation explains the data. The adam explanation somehow must have this gene being strongly selected against to go from at least a 0.25% frequency, to near zero (1 in 700000000 in 1750 or so), then for some reason must have the whole process reverse, where now it increases in frequency. I haven’t heard any explanation of this back and forth gene frequency from the adam explanation. In fact, if things continue to degenerate after the fall, then the frequency of this good gene should only have gone down since Apo, so it should only have a couple people at most, or not exist at all. I’m sure more comparisons can be made, and we can discuss those as well. Based on 1, 2 and 3 above, it really doesn’t look like “two explanations that work equally well”. Oh, not that it’s important, but an Aa + aa mating has a 50/50 chance of producing an aa with each child. Thus the aa aa aa aa aa aafamily mentioned has a 1 in 2^6 or 1/48 = 2% chance of happening. Yes, it’s possible, in fact, it’s thousands of billions of billions of billions of billions of billions of billions (.....) of times more likely than getting all 33 in just that one town. But in reality, these kinds of numbers show how unlikely either thing is. Take care- -Equinox
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Equinox Member (Idle past 5142 days) Posts: 329 From: Michigan Joined: |
quote: Um, I specifically DIDN'T call it a mutation in my post just to be nice. I called it an allele, even though the difference is just 1 generation.
quote: First, the article says that everyone found has been heterozygous. A heterozygous person mating with someone who doesn't even have one copy will make only half of the kids with even one copy. Plus, with all this attention, I'm sure they've searched hard. The article even says they did genetic tests on every single person in the whole town. Sure, some bastard or something could have sneaked out in 1820, but I'd also guess that they've checked known lines, since they identified Apo. Wouldn't you think so too?
quote: The other way around is extremely hard. For Apo to be a mutant, we are requiring 1 mutation. To eliminate it, you either have to have literally billions of mutations, all in the 1 nucleotide location, or you have to have a few mutations at very specific times (like mutate all of Adam's sons, and stop there). Both are extremely unlikely. It's like this - if I propose that 1 person out of the world's population will win the lotto, that's likely. But if I propose that Jim Jones will win the lotto on April 28th, 1964, that's unlikely. You are saying that either this mutation went one way and not the other at least hundreds of millions of times, or you are proposing that the mutation went from good to bad in very specifically times, chosen by Faith. Since the mutation can happen either way, why do you suppose going from good to bad is so much more likely than the other way? We impose no such illogical and baseless asymmetry.
quote: The article mentions that no humans are known (as expected since people don't usually marry their sisters), but that they've inserted the gene into mice, making them homozygous, and the mice are not just healthy, but better than the heterozygous mice. The human and mouse chemistry in these areas is nearly identical.
quote: We can be reasonably confident. If in the last generation, then it would probably show up in this generation, since that's where we got our genes. The key here is statistical sampling. I don't know how many have been tested for this, but it's a lot of people. First, as crash pointed out, autopsies have been done on literally millions of Americans. A simple genetic test would show it, and it's even easier than that. A simple protein test would probably show it too, since it makes a heart protein, and heart disease is a huge focus in medicine. Plus, there have been over a dozen high profile papers on this. A find of another population would make a Drs career - of course they are looking. Sure, it's quite possible that someone somewhere could be hiding it, but from basic statistics, if you take a large sample, then if something is hiding out there there is a certain probability it will happen to be in the sample. Thus our current situation doesn't prove that no one has it, but it does show that if it is out there at all, it is very rare.
[quote]More likely killed by a mutation, or mutations in several individuals over time. Since there is nothing about it to select for it or against it, I would suppose it could have been lost to the majority of human posterity through a severe population reduction at some point, that severely reduced its frequency simply at random.
[quote]
Do you hear how silly that sounds? It will be selected for, since heart disease does kill parents (a friend of mine died of heart disease at 39), plus, as we've said, grandparents are relevant, though less relevant than parents. And yes that is in the literature, it's discussed and proven often. The gene will be selected for, and increase, and so killing it off will be like trying to put out a wildfire on a windy day. Plus, you still have to explain why mutations that kill it are so much more likely than ones that make it.
quote:Of course it's silly. That's my point. The same kind of calcuations show how unlikely it is that somehow this has been hiding in the human population since Adam, and Apo is the only one left in the 18th century who still had that allele, which then and only then grew to 33 people today. [quote]Sorry, you lost me in all this. I thought we were talking about a very short segment, a mere amino acid, which is why a mutation was considered to be such a likely explanation. I don't grasp what it is you are talking about having to match so perfectly.
[quote]
the GENE or the ALLELE is of regular length. The CHANGED PART OF THAT ALLELE is short.
quote: OK, now the degeneration isn't uniform, but is rather a function of how Christian someone is? Or how nice they are? It sounds awfully larmarkian at best to claim that someone can change the genes of themselves or their kids by reading the Bible. If anyone gave that even a shred of credibility, then wouldn't preachers be claiming that as a way to increase their flocks?
quote: OK, I think both of these are significant changes in view that we need to remember. From now on the degeneration after the fall is not like the slowing down of an unplugged fan, but is rather something that goes up and down depending on your religion. If you are a good Christian, your genes are magically fixed or perhaps just preserved better. Muslim mutations happen all the time, but not as fast as those rapidly mutating Satanists! The genetic degeneration can go up or down depending on how it fits the creationists needs at the time. I know quite a few Christians who would be offended at seeing their religions used like that. Also, Faith no longer apparently cares if this clearly beneficial allele is a mutation.
quote: The probabilistic and actually tested points on this one are solid from every angle. What more could you want? Have a fun weekend, I'll be back probably monday.- -Equinox Edited by Equinox, : No reason given.
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