Best proofs of evolution

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Re: Best proofs of evolution

Postby tomandlu » Tue Apr 16, 2013 5:33 pm UTC

Trebla wrote:Just looking at dates Origin of Species was published in 1859 and Mendel's findings were published in 1865, so even if natural selection were instantly universally adopted (which it wasn't, it was disputed into the 20th century within the scientific community), basic genetics were understood around the same time.


I've always been puzzled by this. I know that Darwin acknowledged and was worried by the question of why life didn't just approach increasing homogeneity (in a correspondence with a vicar iirc who raised the issue), but why was it an issue. The mechanism may have been beyond them, but wouldn't simple observation have shown that it didn't work that way? That inheritance seemed to be divided up into discrete components rather than just chucking everything into a blender?
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Re: Best proofs of evolution

Postby Trebla » Tue Apr 16, 2013 5:55 pm UTC

tomandlu wrote:I've always been puzzled by this. I know that Darwin acknowledged and was worried by the question of why life didn't just approach increasing homogeneity (in a correspondence with a vicar iirc who raised the issue), but why was it an issue. The mechanism may have been beyond them, but wouldn't simple observation have shown that it didn't work that way? That inheritance seemed to be divided up into discrete components rather than just chucking everything into a blender?


In hindsight, yes, but those observations didn't really exist (or hadn't been recorded) at the time. It was a revolutionary discovery that if you crossed a tall pea plant with a short one you would get either a tall one OR a short one and not one somewhere in between. Remember, people still believed in spontaneous generation of new life forms until VERY recently... wikipedia notes "The first experimental evidence against spontaneous generation came in 1668." Emphasis mine. It wasn't until 1668 that people started to actually look into "Where do maggots come from?" instead of just assuming they appeared out of thin air.

Thinking about this with modern understanding is a trap that's easy to fall into.

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Re: Best proofs of evolution

Postby tomandlu » Tue Apr 16, 2013 6:34 pm UTC

Trebla wrote:Thinking about this with modern understanding is a trap that's easy to fall into.


Indeed - but it's also worth remembering that the gap between 1668 and Darwin is significant. There was an explosion of interest in natural history in the 19th century, with the clergy, ironically enough, being an important source of observation and insight. The odd thing about the alternatives (lamarkism, etc) is that they seem to require everything that Darwinism did, but with an added, and frequently bizarre, ingredient ('striving' in the case of Lamarkism - how the hell does a microbe 'strive' and what does it 'strive' for?). I take your point, but, also, duh...
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Re: Best proofs of evolution

Postby LaserGuy » Tue Apr 16, 2013 9:27 pm UTC

Trebla wrote:Just looking at dates Origin of Species was published in 1859 and Mendel's findings were published in 1865, so even if natural selection were instantly universally adopted (which it wasn't, it was disputed into the 20th century within the scientific community), basic genetics were understood around the same time.


Mendel's work was not widely known or discussed until it was rediscovered in the early 1900s.

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Re: Best proofs of evolution

Postby tomandlu » Wed Apr 17, 2013 6:16 am UTC

LaserGuy wrote:
Trebla wrote:Just looking at dates Origin of Species was published in 1859 and Mendel's findings were published in 1865, so even if natural selection were instantly universally adopted (which it wasn't, it was disputed into the 20th century within the scientific community), basic genetics were understood around the same time.


Mendel's work was not widely known or discussed until it was rediscovered in the early 1900s.


Been doing some reading around this. I knew that Mendel had read Darwin, and I had stupidly assumed the reverse, which doesn't appear to be the case. Further reading suggests that Darwin did notice that not all inheritance was homogeneous (e.g. sex), but the assumption was that the majority was (thus the need for Lamarkism, etc. to counteract the tendency). I'm still trying to work out whether Mendel made the connection, and, if so, why he wasn't able to promote it.

All seems very odd/unlucky, but c'est la vie.
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Re: Best proofs of evolution

Postby ahammel » Wed Apr 17, 2013 7:00 pm UTC

tomandlu wrote:Been doing some reading around this. I knew that Mendel had read Darwin, and I had stupidly assumed the reverse, which doesn't appear to be the case.
There is an urban legend that Darwin had in his possession an unread copy of Mendel's pea flower paper. There is also an apparently true story that he owned a signed, unread copy of Das Kapital, but that's beside the point.

I'm still trying to work out whether Mendel made the connection, and, if so, why he wasn't able to promote it.
He himself got promoted.

Mendel's natural history hobby passed by the wayside when he was elevated to the position of abbot.
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Re: Best proofs of evolution

Postby Technical Ben » Thu Apr 18, 2013 1:40 pm UTC

gmalivuk wrote:Oversimplistically, a theory includes a big huge conjunction of statements, S1 && S2 && S3 && . . ., which in turn make certain predictions. If one of those predictions turns out to be contrary to observed reality, we conclude that the conjunction as a whole is false, !(S1 && S2 && S3 && . . .). Which only means that at least one of the individual statements is false. So we don't throw out the theory wholesale, because large parts of it are very, very good at predicting and explaining reality. We instead need to find out where exactly the flaw is, knowing all along that, with as much evidence as something like evolution or Newtonian gravity has going for it, it'll turn out to be a pretty tiny flaw indeed, at least at normal human scales.

And this is all I was asking clarification on. Others seem insistent that I am against all of the theories, observations and predictions of evolution. When I have only asked about the parts I do not see providing good prediction.
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Re: Best proofs of evolution

Postby tomandlu » Thu Apr 18, 2013 2:20 pm UTC

Technical Ben wrote:And this is all I was asking clarification on. Others seem insistent that I am against all of the theories, observations and predictions of evolution. When I have only asked about the parts I do not see providing good prediction.


What bits of evolution do you see as not providing a good prediction which has been observed? (which, you should note, is a different thing from "which bits of theory X do not agree with observation").

I have to say, you're going to need to provide some pretty good evidence from this point on that you are not a troll/shill...
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Re: Best proofs of evolution

Postby Izawwlgood » Thu Apr 18, 2013 2:36 pm UTC

If you really want to start over and have us believe that you aren't being an obtuse troll, I strongly suggest concisely stating what you feel 'does not provide a good prediction', why you feel it doesn't, and then *ACTUALLY READING* what people are writing when they explain it to you.

And more to the point, being able to say "I do not understand x, and thus, will educate myself on x or accept what you are telling me about x", rather than continually insisting that your lack of understanding of x indicates a failure of the theory. Because so far, every 'contention' you've raised has been nothing but a gap in your understanding, a gap you've insisted on maintaining.
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Re: Best proofs of evolution

Postby PolakoVoador » Thu Apr 18, 2013 4:42 pm UTC

Technical Ben wrote:
gmalivuk wrote:Oversimplistically, a theory includes a big huge conjunction of statements, S1 && S2 && S3 && . . ., which in turn make certain predictions. If one of those predictions turns out to be contrary to observed reality, we conclude that the conjunction as a whole is false, !(S1 && S2 && S3 && . . .). Which only means that at least one of the individual statements is false. So we don't throw out the theory wholesale, because large parts of it are very, very good at predicting and explaining reality. We instead need to find out where exactly the flaw is, knowing all along that, with as much evidence as something like evolution or Newtonian gravity has going for it, it'll turn out to be a pretty tiny flaw indeed, at least at normal human scales.

And this is all I was asking clarification on. Others seem insistent that I am against all of the theories, observations and predictions of evolution. When I have only asked about the parts I do not see providing good prediction.

Gmalivuk's paragraph you just quoted is a somewhat simple explanation on how a scientific theory works, and stating that IF some flaw was found with theories like Evolution or Newtonian Gravity, said flaw would likely be a very tiny one.
I can't see how this is the clarification you were asking for, since he gave no new info on Evolution, and, as others pointed out, you blatantly refuse to clarify what the hell are "the parts I do not see providing good prediction"

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Re: Best proofs of evolution

Postby gmalivuk » Thu Apr 18, 2013 7:25 pm UTC

Technical Ben wrote:And this is all I was asking clarification on. Others seem insistent that I am against all of the theories, observations and predictions of evolution. When I have only asked about the parts I do not see providing good prediction.
I told you once that you were done in this thread. Your best option is to heed that instruction.

However, if your next post here is a clear and concise list of those parts you do not see providing good prediction, and if that list does not include a number of things that people have already explained to you previously, then I'll let you continue posting here.

If your next post is not that, then I'll temporarily remove your forum-wide posting ability entirely.

Choose wisely.
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Re: Best proofs of evolution

Postby tomandlu » Fri Apr 19, 2013 9:08 am UTC

The tension is killing me...
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Re: Best proofs of evolution

Postby Technical Ben » Sun May 12, 2013 9:17 pm UTC

Some questions raised in the other thread, thought it best to post them here.

Izawwlgood wrote:Are you asking what % of mutations are deleterious/neutral/beneficial?

To some extent yes. While the answer "evolution is possible" or "we observe life exists, so evolution must be probable" are somewhat given to me. But those statements don't verify themselves. Being shown the figures would help me have confidence in such claims.

Spoiler:
Technical Ben wrote:So that I can confidently say "If I have a live fruit fly generation today, it's ancestors must have had a mutation in the previous generation to allow it to survive", and not any other possible mechanism (such as other chemical biological factors, feedback systems or learned responses)?
Yes, you can say 'all organisms alive today are so because their ancestors had something that allowed them to survive'. I'm not sure how this fits in with our discussion though.

What tells me that something had to be a mutation? What if it was geographic migration? If I had generations A, B, C, etc, I could erroneously assign C to be the ancestor of A. How would I prevent that error and what should I look for?

Basically, as I brought up in the other thread, I accept 1 person winning the lottery is not only possible, it's probable. I accept that it's probable one person will win each round. But sadly, it's not truthful to state every lottery has a winner. We may argue, "there are many lotteries and many players". However, life has one more obstacle to overcome. Not only must there be a winner each round, the subsequent winners must be drawn from the ancestors of only the previous winners.

So I can accept, and am happy to consider many observations of steps and changes in animals. It's a definite fact of life that they change and adapt to the environment. I'm not sure we can state that such a range of mutations has the probability of stretching indefinitely. Until we can say where it's limits are, I cannot say that the observations of life are within those limits or not.
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Re: Best proofs of evolution

Postby jules.LT » Sun May 12, 2013 10:28 pm UTC

Technical Ben wrote:"evolution is possible" or "we observe life exists, so evolution must be probable" are somewhat given to me. But those statements don't verify themselves.
Yes they do.
Technical Ben wrote:What tells me that something had to be a mutation?
There is no other known mechanism for variation to arise?
Technical Ben wrote:I'm not sure we can state that such a range of mutations has the probability of stretching indefinitely. Until we can say where it's limits are, I cannot say that the observations of life are within those limits or not.
The only limit is survivability.


But I'm not entirely sure your post satisfies gmal's requirements above...
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Re: Best proofs of evolution

Postby Izawwlgood » Sun May 12, 2013 11:54 pm UTC

Technical Ben wrote:To some extent yes. While the answer "evolution is possible" or "we observe life exists, so evolution must be probable" are somewhat given to me. But those statements don't verify themselves. Being shown the figures would help me have confidence in such claims.
I don't know the frequency of mutations that are deleterious/neutral/beneficial, and I wager any answer would require explaining some biochemistry to you. I, however, don't see it as particularly pertinent a point; mutations happen, we know this, and we know this is how evolution occurs. If you want to play a game of math and try and argue something, you'll need to bring it up yourself, because frankly, your level of confidence in the fact that it happens is more or less entirely irrelevant to the discussion. We know that most mutations are deleterious. If you want to know how much 'most' means, go learn some biochemistry and figure it out!
Technical Ben wrote:What tells me that something had to be a mutation? What if it was geographic migration? If I had generations A, B, C, etc, I could erroneously assign C to be the ancestor of A. How would I prevent that error and what should I look for?
The first part of your question is the same conversation we had pages ago; are you asking if you can tell the difference between a replication error, radiation error, or toxic compound mutagenesis? The answer is you can't, unless you look at something like frequency of other mutations in the same region of DNA.
To the second part of your question; 'geographic migration' doesn't cause mutations.
To the third part of your question, you could prevent the error by being an ecologist and having the knowledge that would reduce the chances of making that error. A layman, like yourself, may look at a beetle and say 'oh, the thing has a shell casing that's red and a horn, so, obviously it's the same as this other thing that's red and has a horn', while a Coleopterist (I dunno if that's what you call 'someone who studies beetles, seems legit though) would say "Obviously these are two different species, because these two horns look nothing alike, and look at the difference in ratios of the blahblahblah."
EDIT: Cars. I should have gone with cars for the analogy: Someone who doesn't really know much about cars might look at a '94 and a '98 models and say "yeah, that's a Porche" while someone who knows about Porches can look at the two and spot the differences. Do you understand?
I'm saying this to you because, again, a lot of your uncertainty here seems to stem from assuming that because YOU don't understand something, that no one does.

Technical Ben wrote:I'm not sure we can state that such a range of mutations has the probability of stretching indefinitely. Until we can say where it's limits are, I cannot say that the observations of life are within those limits or not.
Well, I daresay again, you might need to learn more about the field before you can point to where obvious limitations are. You might find it unacceptable that an eye could evolve from a not eye, but it makes pretty good sense to some people who can point to 'eye like', 'kind of an eye', 'protoeye' and 'pretty much an eye' in extant species or evidence in development for eye formation in stages. I didn't understand evolution very well until I took a class on Evolutionary Biology and Developmental Biology. You're an engineer right? I don't understand how flying buttresses or cantilevered structures stay up; wouldn't you agree it would be foolish for me to state "I cannot accept that they can be used in construction"?
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Re: Best proofs of evolution

Postby gmalivuk » Sun May 12, 2013 11:56 pm UTC

gmalivuk wrote:However, if your next post here is a clear and concise list of those parts you do not see providing good prediction, and if that list does not include a number of things that people have already explained to you previously, then I'll let you continue posting here.

If your next post is not that, then I'll temporarily remove your forum-wide posting ability entirely.
Technical Ben wrote:Some questions raised in the other thread, thought it best to post them here.

Izawwlgood wrote:Are you asking what % of mutations are deleterious/neutral/beneficial?

To some extent yes. While the answer "evolution is possible" or "we observe life exists, so evolution must be probable" are somewhat given to me. But those statements don't verify themselves. Being shown the figures would help me have confidence in such claims.

Spoiler:
Technical Ben wrote:So that I can confidently say "If I have a live fruit fly generation today, it's ancestors must have had a mutation in the previous generation to allow it to survive", and not any other possible mechanism (such as other chemical biological factors, feedback systems or learned responses)?
Yes, you can say 'all organisms alive today are so because their ancestors had something that allowed them to survive'. I'm not sure how this fits in with our discussion though.

What tells me that something had to be a mutation? What if it was geographic migration? If I had generations A, B, C, etc, I could erroneously assign C to be the ancestor of A. How would I prevent that error and what should I look for?

Basically, as I brought up in the other thread, I accept 1 person winning the lottery is not only possible, it's probable. I accept that it's probable one person will win each round. But sadly, it's not truthful to state every lottery has a winner. We may argue, "there are many lotteries and many players". However, life has one more obstacle to overcome. Not only must there be a winner each round, the subsequent winners must be drawn from the ancestors of only the previous winners.

So I can accept, and am happy to consider many observations of steps and changes in animals. It's a definite fact of life that they change and adapt to the environment. I'm not sure we can state that such a range of mutations has the probability of stretching indefinitely. Until we can say where it's limits are, I cannot say that the observations of life are within those limits or not.
Nope.
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Re: Best proofs of evolution

Postby ImagingGeek » Mon May 13, 2013 1:09 pm UTC

Technical Ben wrote:What tells me that something had to be a mutation? What if it was geographic migration? If I had generations A, B, C, etc, I could erroneously assign C to be the ancestor of A. How would I prevent that error and what should I look for?

All variation ultimately arises from mutation; migration simply spreads it around. Assuming you were comparing sufficient DNA it would be near-impossible to mistake C as A's ancestor - the accumulation of additional mutations would allow you to determine the correct generational progression (keep in mind, most species accumulate at least one mutation/generation; humans accumulate 80-130/generation). A migrating population would simply move alleles around geographically - they would still accumulate new mutations in patterns consistent with normal evolution, and thus be 'mappable' relative to your A, B & C populations.

Technical Ben wrote:Basically, as I brought up in the other thread, I accept 1 person winning the lottery is not only possible, it's probable. I accept that it's probable one person will win each round.

Lottaries are not an accurate comparison - evolution is cumulative. If the lotto worked like evolution, the winning number would remain the same and you'd get to keep a correct number every time you paid for a draw...

Izawwlgood wrote:I don't know the frequency of mutations that are deleterious/neutral/beneficial, and I wager any answer would require explaining some biochemistry to you. I, however, don't see it as particularly pertinent a point; mutations happen, we know this, and we know this is how evolution occurs. If you want to play a game of math and try and argue something, you'll need to bring it up yourself, because frankly, your level of confidence in the fact that it happens is more or less entirely irrelevant to the discussion. We know that most mutations are deleterious.

Actually, most mutations are neutral* - in humans, 95-98% of mutations in our genomes (compared to chimps) show no signs of selection and thus are neutral. Of the 2-5% that show selection, its split ~80/20 for negative (i.e. mutation was detrimental) vs positive selection. That's not to say the rate of detrimental mutation formation isn't higher - that 80% (which, keep in mind, is 1.6-4% of all mutations) is simply the portion which survived to today; same is true of beneficial alleles (just because its good, doesn't mean it'll spread in a population). Obviously, these numbers are very different for other species. Bacteria, for example, tend to have far fewer neutral mutations.

*neutral mutations can become advantageous or detrimental with changes in the environment or in the presence of complementary mutations/alleles.

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Re: Best proofs of evolution

Postby elasto » Fri May 24, 2013 1:03 am UTC

The best proof of evolution is that it's ongoing right now:

A strain of cockroaches in Europe has evolved to outsmart the sugar traps used to eradicate them. American scientists found that the mutant cockroaches had a "reorganised" sense of taste, making them perceive the glucose used to coat poisoned bait not as sweet but rather as bitter.

A North Carolina State University team tested the theory by giving cockroaches a choice of jam or peanut butter. They then analysed the insects' taste receptors, similar to our taste buds.

Researchers from the same team first noticed 20 years ago that some pest controllers were failing to eradicate cockroaches from properties, because the insects were simply refusing to eat the bait. Dr Coby Schal explained in the journal Science that this new study had revealed the "neural mechanism" behind this refusal.

In the first part of the experiment, the researchers offered the hungry cockroaches a choice of two foods - peanut butter or glucose-rich jam [known as jelly is the US]. "The jelly contains lots of glucose and the peanut butter has a much smaller amount," explained Dr Schal. "You can see the mutant cockroaches taste the jelly and jump back - they're repulsed and they swarm over the peanut butter."

In the second part of the experiment, the team was able to find out exactly why the cockroaches were so repulsed. The scientists immobilised the cockroaches and used tiny electrodes to record the activity of taste receptors - cells that respond to flavour that are "housed" in microscopic hairs on the insects' mouthparts: "The cells that normally respond to bitter compounds were responding to glucose in these [mutant] cockroaches," said Dr Schal. "So they're perceiving glucose to be a bitter compound. The sweet-responding cell does also fire, but the bitter compound actually inhibits it - so the end result is that bitterness overrides sweetness."

Highly magnified footage of these experiments clearly shows a glucose-averse cockroach reacting to a dose of the sugar. "It behaves like a baby that rejects spinach," explained Dr Schal. "It shakes its head and refuses to imbibe that liquid, at the end, you can see the [glucose] on the side of the head of the cockroach that has refused it."

Dr Elli Leadbeater from the Institute of Zoology in London said the work was exciting. "Usually, when natural selection changes taste abilities, it simply makes animals more or less sensitive to certain taste types. For example, bees that specialise on collecting nectar are less sensitive to sugar than other bees, which means that they only collect concentrated nectar. Evolution has made sugar taste less sweet to them, but they still like it. In the cockroach case, sugar actually tastes bitter - an effective way for natural selection to quickly produce cockroaches that won't accept the sugar baits that hide poison."

Dr Schal said this was another chapter in the evolutionary arms race between humans and cockroaches. "We keep throwing insecticides at them and they keep evolving mechanisms to avoid them," he said. "I have always had incredible respect for cockroaches," he added. "They depend on us, but they also take advantage of us."


George Beccaloni, Curator of cockroaches, Natural History Museum wrote:The process of natural selection would strongly favour any chance genetic change that caused a cockroach to avoid the bait and therefore death. Since individuals with the trait would have a greater chance of surviving and reproducing, their descendants with the trait would in time replace those that lacked the trait in the cockroach population.

This is the same process that has led to the evolution of antibiotic resistance in disease-causing bacteria, and warfarin resistance in rats.

The discovery of natural selection was one of the greatest scientific breakthroughs of all time and this year sees worldwide celebrations commemorating the 100th anniversary of the death of Alfred Russel Wallace, the naturalist who co-discovered natural selection with Charles Darwin in 1858.


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Re: Best proofs of evolution

Postby cemper93 » Fri May 24, 2013 7:15 am UTC

George Beccaloni, Curator of cockroaches, Natural History Museum wrote:

This is now my new goal in life. Where can I apply?

But yes, this is not the first time humans could observe evolution. The Peppered Moth [url="http://en.m.wikipedia.org/wiki/Peppered_moth_evolution"]have changed their normal color during the industrial revolution[/url]. Though to be fair, the darker variants that were favored by the polluted air in the Britain of the industrial era had existed beforehand, they just became much more common. So the cockroaches are actually the cooler example.

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Re: Best proofs of evolution

Postby tomandlu » Fri May 24, 2013 7:31 am UTC

elasto wrote:The best proof of evolution is that it's ongoing right now:


That's cool, but it probably wouldn't cut much ice with a creationist. They would call this micro-evolution or something, which they accept (they haven't much choice), but they would still reject the idea of large-scale change and speciation.

I was wondering if the best proof is the correlation between the rate of change of junk DNA and active DNA? My argument would go like this:

Similar species have similar genotypes, which is what we would expect via evolution. However, this correlation could be explained by the assertion that similar phenotypes would be based on similar genotypes, irrespective of whether a creator was involved or not (in the same way that cars, despite being different models and makes, share similar engineering).

However, even if a designer was re-using designs, there would be no reason for correlation between the degree of difference between junk and active DNA - i.e. that two species that differ by, say, 5% when comparing active DNA should have a corresponding difference of 5% when comparing junk DNA.

As an analogy, if two students hand in a piece of home-work and the home-work is remarkably similar, I cannot assume that they have copied each other's work. After all, they were both dealing with the same topic. However, if I notice distinct phrasing and identical spelling mistakes, my suspicion that something's up would become acute.
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Re: Best proofs of evolution

Postby cemper93 » Fri May 24, 2013 7:40 am UTC

That would require them to know jack shit about what the DNA even is, which is not very likely.

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Re: Best proofs of evolution

Postby screen317 » Fri May 24, 2013 10:04 pm UTC

tomandlu wrote:
elasto wrote:The best proof of evolution is that it's ongoing right now:


That's cool, but it probably wouldn't cut much ice with a creationist. They would call this micro-evolution or something, which they accept (they haven't much choice), but they would still reject the idea of large-scale change and speciation.

I was wondering if the best proof is the correlation between the rate of change of junk DNA and active DNA? My argument would go like this:

Similar species have similar genotypes, which is what we would expect via evolution. However, this correlation could be explained by the assertion that similar phenotypes would be based on similar genotypes, irrespective of whether a creator was involved or not (in the same way that cars, despite being different models and makes, share similar engineering).

However, even if a designer was re-using designs, there would be no reason for correlation between the degree of difference between junk and active DNA - i.e. that two species that differ by, say, 5% when comparing active DNA should have a corresponding difference of 5% when comparing junk DNA.

As an analogy, if two students hand in a piece of home-work and the home-work is remarkably similar, I cannot assume that they have copied each other's work. After all, they were both dealing with the same topic. However, if I notice distinct phrasing and identical spelling mistakes, my suspicion that something's up would become acute.
What we used to think of as "junk" DNA isn't actually junk, so I don't think this would help.

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Re: Best proofs of evolution

Postby ahammel » Fri May 24, 2013 10:08 pm UTC

screen317 wrote:What we used to think of as "junk" DNA isn't actually junk, so I don't think this would help.
s/junk DNA/neutral mutations/ and that's a decent argument, though.
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Re: Best proofs of evolution

Postby Izawwlgood » Fri May 24, 2013 10:34 pm UTC

Tom, some cool mol bio for you;
I forget the species, but I recall learning about that for one 'trick' of it's transcription and replication process, it needs to coordinate the activity of two proteins. The first protein needs to 'get turned on', and about 1 hour later, the second protein needs to 'turn it off'. The organism orchestrates this by filling the space between the two proteins with an enormous amount of 'junk DNA', and only using a single promoter sequence. So, the first promoter sequence binds transcriptional machinery, and transcription churns out mRNA for the first protein and a long chain of jibberish. Some cleavage event occurs at the beginning of the gibberish, and the protein is translated, and transcription continues churning down the line, producing junk, until about an hour transpires and the transcriptional machinery hits the second protein. Another cleavage event occurs just upstream the actual coding region (or maybe the mRNA is chunked up as it's produced due to a lack of caps, 5' UTRs, etc, I can't recall), and presto, second protein mRNA is ready to go.

tl;dr: Junk DNA in some organisms acts as time keeper.

The 'spacing of genes' along the chromosome is something that can affect their function.
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Re: Best proofs of evolution

Postby elasto » Sat May 25, 2013 12:24 am UTC

tomandlu wrote:That's cool, but it probably wouldn't cut much ice with a creationist. They would call this micro-evolution or something, which they accept (they haven't much choice), but they would still reject the idea of large-scale change and speciation.

I never really understood that argument. What prevents something that can change a little over a short time changing a lot over a longer time?

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Re: Best proofs of evolution

Postby Copper Bezel » Sat May 25, 2013 1:45 am UTC

Just a guess, but I'd say they'd consider those variations to be effectively random over longer time periods - fluctuations this way or that, but without a real cumulative effect.
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Re: Best proofs of evolution

Postby elasto » Sat May 25, 2013 5:23 am UTC

Copper Bezel wrote:Just a guess, but I'd say they'd consider those variations to be effectively random over longer time periods - fluctuations this way or that, but without a real cumulative effect.

But why would they think that? Natural selection is a proven thing - eg. these beetles heavily outcompeting beetles who like sweet foods. While individual fluctuations will be random, trends won't be, they'll always head towards greater fitness - because, well, natural selection!

Eventually, the cumulative differences will be enough to be a new species. It would take active, external intervention to prevent that from happening - and why would God, if he exists, be interested in doing that?

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Re: Best proofs of evolution

Postby tomandlu » Sat May 25, 2013 5:36 am UTC

elasto wrote:
tomandlu wrote:That's cool, but it probably wouldn't cut much ice with a creationist. They would call this micro-evolution or something, which they accept (they haven't much choice), but they would still reject the idea of large-scale change and speciation.

I never really understood that argument. What prevents something that can change a little over a short time changing a lot over a longer time?


As I said, they accept micro-evolution because it's observable and cannot be denied - dogs, the pepper moth, etc. However, I've no idea where they draw their line in the sand. I'd assume, for example, that they accept that any pair of animals that can breed have a common ancestor. So, lions and tigers, yes, but I've no idea whether they think domestic cats and lions are related or not.

In the end, it comes down to one thing - humans and apes never shared a common ancestor, and every thing else is in service of that belief.

If one was inclined to be generous, one might say that variation around a mean doesn't necessarily imply that the mean can change, and that 'bigger' and 'has wings and can fly'* are fundamentally different things, not just different scales, but that's all I've got...

* i.e. they might accept a domestic cat and a lion are related, but not a mouse and a bat.
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Re: Best proofs of evolution

Postby PM 2Ring » Sat May 25, 2013 6:14 am UTC

elasto wrote:
Copper Bezel wrote:Just a guess, but I'd say they'd consider those variations to be effectively random over longer time periods - fluctuations this way or that, but without a real cumulative effect.

But why would they think that?

Because in their worldview random action is destructive, or at best neutral, so a constructive process implies intelligent planning and action.

elasto wrote:Natural selection is a proven thing - eg. these beetles heavily outcompeting beetles who like sweet foods. While individual fluctuations will be random, trends won't be, they'll always head towards greater fitness - because, well, natural selection!

Sure, but that argument is unlikely to be acceptable to a person who's already certain that undirected natural selection cannot be a constructive process.

Unfortunately, mere logic has little effect on someone who is committed to the doctrine of Intelligent Design, especially if they believe that it's sinful to doubt the teachings of their religion. They don't want to be convinced that evolution through natural selection can explain the diversity of species - they already "know" that evolution is wrong, and they want other people to abandon this sinful doctrine.

elasto wrote:Eventually, the cumulative differences will be enough to be a new species. It would take active, external intervention to prevent that from happening - and why would God, if he exists, be interested in doing that?


Good point. And I think I may have tried that tack in my attempts to explain evolution to creationists. But it's been many years since I've attempted such discussions, since they are generally frustrating and unlikely to achieve anything positive.

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Re: Best proofs of evolution

Postby screen317 » Sat May 25, 2013 6:42 am UTC

PM 2Ring wrote:
elasto wrote:
Copper Bezel wrote:Just a guess, but I'd say they'd consider those variations to be effectively random over longer time periods - fluctuations this way or that, but without a real cumulative effect.

But why would they think that?

Because in their worldview random action is destructive, or at best neutral, so a constructive process implies intelligent planning and action.

elasto wrote:Natural selection is a proven thing - eg. these beetles heavily outcompeting beetles who like sweet foods. While individual fluctuations will be random, trends won't be, they'll always head towards greater fitness - because, well, natural selection!

Sure, but that argument is unlikely to be acceptable to a person who's already certain that undirected natural selection cannot be a constructive process.

Unfortunately, mere logic has little effect on someone who is committed to the doctrine of Intelligent Design, especially if they believe that it's sinful to doubt the teachings of their religion. They don't want to be convinced that evolution through natural selection can explain the diversity of species - they already "know" that evolution is wrong, and they want other people to abandon this sinful doctrine.

elasto wrote:Eventually, the cumulative differences will be enough to be a new species. It would take active, external intervention to prevent that from happening - and why would God, if he exists, be interested in doing that?


Good point. And I think I may have tried that tack in my attempts to explain evolution to creationists. But it's been many years since I've attempted such discussions, since they are generally frustrating and unlikely to achieve anything positive.

Can we please stop using blanket statements? Fundamentalist creationists, sure. Young-Earth creationists, sure. Not all.

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Re: Best proofs of evolution

Postby elasto » Sat May 25, 2013 8:11 am UTC

PM 2Ring wrote:Sure, but that argument is unlikely to be acceptable to a person who's already certain that undirected natural selection cannot be a constructive process.

Why would they be certain of that when many current examples of undirected natural selection being constructive are available - eg. undirected natural selection producing beetles who avoid poison bait, or bacteria evolving resistance to antibiotics? Or do they not regard such genetic changes as constructive?

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Re: Best proofs of evolution

Postby tomandlu » Sat May 25, 2013 8:51 am UTC

elasto wrote:
PM 2Ring wrote:Sure, but that argument is unlikely to be acceptable to a person who's already certain that undirected natural selection cannot be a constructive process.

Why would they be certain of that when many current examples of undirected natural selection being constructive are available - eg. undirected natural selection producing beetles who avoid poison bait, or bacteria evolving resistance to antibiotics? Or do they not regard such genetic changes as constructive?


I honestly don't believe that a committed creationists cares what his objection is based on. The primary motive is to deny man's common ancestry with the apes. The method of denial is irrelevant.
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Re: Best proofs of evolution

Postby gmalivuk » Sat May 25, 2013 2:56 pm UTC

screen317 wrote:Can we please stop using blanket statements? Fundamentalist creationists, sure. Young-Earth creationists, sure. Not all.
Did anyone ever say "all"?
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