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Author Topic:   Has natural selection really been tested and verified?
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


(1)
Message 246 of 302 (537446)
11-28-2009 5:50 PM
Reply to: Message 1 by Bolder-dash
11-21-2009 7:40 AM


Hi Bolder-dash,
I thought I'd add a voice to the collective, maybe you'll be more satisfied with your debate experience with me. Maybe not.
Can people point to tests that have verified that natural selection causes evolutionary change? What tests have they conducted? Do these tests accurately mimic the real world?
There are tests that demonstrates natural selection exists. I get the feeling that accept that natural selection is a process that actually happens.
Does it cause evolutionary change?
Well - natural selection is a force that alters allele frequencies in a population. So yes, it is a cause of evolutionary change.
I feel that this isn't what you were actually asking, though. Maybe you are asking whether natural selection has been shown to have been a mechanism behind the entirety of natural history? I'm not sure - so forgive me for sounding dense and asking for clarification on this point.
I would like to stipulate that talking about bacteria (in any form) does not qualify as any type of test, because ultimately we must be taking sexual reproduction, where choices are being made into account-so bacteria is out.
Again this is confusing - I'm not sure why we ultimately must be talking about sexual reproduction and why choices are important?
I read recently where an editor of Discovery Magazine stated that Darwin provided a testable mechanism for evolutionary change
Are you able to track down that article or interview or whatever it was? I'd like to read it so that I might be better positioned to answer your questions.
The supposition made by the magazine editor (not by me)was that Darwin's idea of natural selection has been tested to be the driving force of evolutionary change (including of course changes in body structures, and living systems, etc).
Again - I can't comment on the opinions of a person when I can't read their words. There is certainly strong evidence indicating that seemingly disparate life forms are related and the best explanation for adaptive change that we have is natural seleciton. There are tests that demonstrate that natural selection plays a vitally important role in adaptive changes to populations, are these what you are looking for? Then evidence for this has been produced in this thread as far as I can tell.
Furthermore, to really provide more evidence that it truly is random mutations, and natural selection of populations dying out that didn't receive this beneficial mutation, I would think you would need to show something like a test in which other individuals within this population happened to have resistance to all kinds of other fatal diseases, which they have never even been exposed to, which they also received through a random mutation-like some might be resistant to bubonic plague, or Kluver-Bucy Syndrome, or the Ebola virus or Lou Gehrig's disease even though they have never seen or heard of these.
Sounds like a test - but it doesn't strike me as the only one. Could we not observe a certain allele that we know confers resistance to a certain disease that exists at a certain frequency throughout a mega-population (such as humans) - and observe how in areas where that certain disease is more common the frequency of the disease resistant allele is higher than normal?
Something like sickle-cell anaemia? Which occurs with a greater frequency in those that have a recent ancestry with people who have been exposed to malaria than those that don't.
The other studies mentioned, such as Galapagos finches and Peppered moths, these are all old stories about evolution, but in what way do they test or show the randomness of the mutations and that caused these shifts in populations?
They don't. They instead show the non-randomness of natural selection acting on populations with variation.
And also, since in cases like the Galapagos finches, the populations oscillate back to their original forms of shorter beaks, under different environmental conditions, we have to show the same processes happening twice-first a random mutation causes longer beaks to sprout and then those get chosen within the population, and then later wouldn't you know it, another "random" mutation comes along and the exact same slow weeding out process of mates choosing the best beak sizes happens again; and fortuitously the need for a certain beak size remains the single most important consideration for mate selection over the vast spaces of time that natural selection requires. Quite amazing.
It's probably more likely that the allele for shorter beaks isn't entirely eradicated during the period that long beaks are advantageous and so doesn't need to be 're-mutated'. There are almost certainly variations in beak sizes for finches: and some of that variation is certainly genetically based. Under some conditions certain sizes have an impact on the chances for successfully reproducing. Where this is the case, we have natural selection.
Or even more amazing still, we have a entire list of traits we are selecting for over many many years of generations, overlapping each other- lung capacity, tail size, genital size, coloration, chirping sound, eyesight, nest building techniques, proper digestive gland sizes, and on and on..and each and every one of these needs is remaining constant long enough after all these random mutations occurred to eventually trickle their way through the selection process. So each time a beak size is being chosen for, all of these other criteria, and about 100,000 = others are also being selected for. It must be a tough choice for a pretty female finch to decide.
Female finches, like female humans, don't directly assess the genetic fitness of a mate before mating. They don't sit there and think 'I want my kids to have a long beak, but I want better eyes too..." The finches just carry on as ever, and those that have kids with the 'wrong' sized beak find their kids not doing as well as those that have kids that have the right sized beak.
But yes - there are lots of traits. Some of them are optimum or sufficiently near a local optimum already and so any variation in them is selected against. There are some that are not optimum for present conditions, any variation which is more optimum which is heritable will increase in frequency over the generations as long as it remains more optimum than average.
I appreciate your participation, but honestly I wasn't coming here to get a 6th grade lecture from you-I come here seeking depth and insight.
I'm going to stop here on this note: You can't have your cake and eat it too. When you talk about female finches having difficult decisions, about mutations fortuitously popping up at just the right time at the right place, you demonstrate that there are some fundamental misapprehensions about the concepts under discussion.
So we end up with a dilemma: On the one hand you come here seeking depth and insight, but you haven't yet grasped the basics. If we try and correct the simple and fundamental misconceptions we risk being accused of patronising or insulting you or of avoiding the points you are raising. If we try and answer your questions with depth - we risk talking past one another and getting confused.
It seems there has been plenty of talking past one another and a fair amount of perceptions of condescension. I'm at a loss as to what to do next? How do you think we should proceed next?

This message is a reply to:
 Message 1 by Bolder-dash, posted 11-21-2009 7:40 AM Bolder-dash has replied

Replies to this message:
 Message 256 by Bolder-dash, posted 11-28-2009 10:31 PM Modulous has replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


(2)
Message 276 of 302 (537555)
11-29-2009 10:34 AM
Reply to: Message 256 by Bolder-dash
11-28-2009 10:31 PM


natural selection, sexual selection, common ancestry
I believe that you and other have served to complicate the question unnecessarily.
Or perhaps the question was ambiguous, and we're trying to figure out what it is exactly you were asking - that's always a possibility, right?
The quote was simply from a longer editors notes section. What he meant is basically irrelevant, because I was never asking what he meant, it was simply as a way of mentioning that this got me to thinking-what do we actually know about evolution and its testability. Its that simple. The ToE contains the principles (as others have stated) of RM, NS, and change over a vast amount of time. There was never any need to make the discussion more complicated than this.
Well, yes, evolution is testable and it has been tested. But it's a very wide topic to discuss broadly. Perhaps we can focus on one aspect and take it from there?
They will claim that face symmetry is more beautiful to us, because that indicates better health of the individual, and thus we would select for this over time (illogical) but this is the claim.
This is a thread (and has been a thread) all of its own - How can evolution explain body symmetry?. You assert it is illogical, but you don't provide any reasons for it being illogical.
So now science has to show, that not only can NS (by the use of RM!) make complex body parts through a RM creating some small advantage of survivial in a population, and slowly becoming selected for, and then as it becomes a more common trait in the population, a further mutation down the bloodline could be added to that mutation (if you don't agree this is the claim the ToE, ie. Dawkins and so man others, makes for how complex body parts can be formed, please provide your own idea of how the theory claims this is possible) to eventually shape this form.
Thank you at least for clarifying the subject for us. It might be easier if you pick a 'complex body part' that you want to discuss the evolution of and then dedicate a thread to that. It's just without focus the topic tends to spread about all over the place and nobody gets any satisfaction. I offer my five and a half years as a member here as evidence that on the subject of topic sprawl, I have some idea what I am talking about.
In broad terms the thing to do would be to show that two organisms with differing 'complex body parts' are related and share a common ancestry. Then we know there must be an explanation for this. We have already shown that natural selection leads to adaptive changes to a population's genetics. Together these two facts alone constitute evidence of natural selection's role in larger scale evolution. It's not a mountain yet - but it's a start.
I would like to add that bacteria have complex parts too - and they are massively diverse. It's a common impression that all bacteria are bacteria are bacteria - but it's a little unfair!
Of course I am not saying that female finches sit around making a choice, I think it is you who is not getting it. I am saying that science claims subconscious choices have lead to all kinds of traits being selected for- like the plumage colors of male birds for instance.
But to be clear - this is sexual selection. A specific form of natural selection. It isn't typical of natural selection.
The point I made, which I don't think should be so hard to understand is that if birds were making subconscious choices of rating their partners health based on their plummage colors, at the same time they would also be making subconscious choices about their beak size, about their nest making skills, about their length of their wingspans, and every other bird trait you want to think of, because we are claiming that all of the traits we see on earth are created by NS.
Hopefully now we can see that natural selection does not imply sexual selection. It is often the case where sexual selection is acting in the opposite direction to general natural selection. For instance - if we suppose a peacock's tail is sexually selected for its size, there is also natural selection cutting in limiting the size of the tail (peacock's with bigger tails attract more predators perhaps). So yeah - the 'choices' a finch might make are not the be all and end all of natural selection. The environment, including other species, weather patterns, even other genes in the gene pool, can exert selective pressure too.
So frankly, for you or anyone else to say that its because I am not understanding the basics is frankly just bs.
It certainly appears that you have confused natural selection with the mate selection made by an animal. If that's not the case, maybe you can at least see how the confusion arose.
Can we test in any way shape or form Dawkin's theoretical model of how an eye might have formed for instance (Nilsson and Pelger's attempts to show scientifically how it could have happened was laughable).
Without knowing what you found laughable about it I can't help, sorry. The answer is, we can. Whether you think it is sufficient is not for me to say.
Why was it necessary to complicate the discussion? The question started out very broad, to allow it to be narrowed over time.
It wasn't. You asked for evidence of natural selection causing evolutionary change and you got it. You then went on to clarify that you meant to ask whether there was evidence for the evolution of complex body parts through neo-Darwinian processes. The difference between what you appeared to be asking and what you meant to ask caused some confusion. Hopefully we can move on from there. Sometimes even the most obvious looking point one tries to make on a forum turns out to be understood differently by everybody that reads it to infuriating results. It is a bit of an art trying to balance ambiguity, condescension, post length and simplicity.
What do we know in this modern age of science, 200 years after the birth of Darwin, that shows how his big picture can all be put together to show how all the forms of life came to be how they are today.
A hell of a lot. Enough to fill a lifetime of learning, by which time a whole new lifetime's worth of knowledge will have no doubt surfaced. And then some. And a bit more.
That I mentioned NS and didn't go into more details at the very beginning about RM and genetic drift, and every other details that goes into your theory, and how it all ties together is a complete smokescreen-because many discussions start off broad by necessity because its the beginning of the topic, not ten steps down the ladder of complexity. if you need to include every smaller point that you wanted to discuss in the very opening paragraph, that would be a very very long paragraph I would suggest.
There are some words which cover such large paragraphs. Instead of recounting the entire body of knowledge that is the theory of evolution and then finishing with 'has this been tested and verified' you could instead have simply asked in your OP - "has the theory of evolution been tested and verified as the explanation for how life has changed on earth over time?" Very short and very general and it would have been rejected as a new topic because of this.
The answer is yes - go read some papers, some books and so on. It cannot be simply covered in a debate like this forum deals with.
You could just start a debate that focuses on the eye.
If that isn't possible to be talked abut on this site (that is, what scientifically proves NS actually works the way you claim it does), without all of your constant assertions that all us whacky creationists just don't know what we are talking about, then I don't know what is.
If you aren't sure what topics are encouraged, and which ones are too general or ambiguous - then don't start any new topics. Just read through some ongoing ones, some older ones and get a feel for things. With broad topics things tend to devolve into meta-debate like this one has, so we try and avoid them since they aren't particularly constructive.
I will say at this point though, that originally I came here actually wanting to learn something about what science can prove nowadays, but when I see the scarcity of people who are able to follow one simple logical step to the next (like understanding that just because I prefaced a question by talking about an article in Discovery magazine-that doesn't mean you need to know what context the magazine said this. It is me asking the question now, not Discovery magazine. Its like saying, I was walking down the street and I saw an ad for milk, and I got to thinking, is milk good for our bodies-and then someone saying, well, that depends, tells us what the ad said exactly....geez.), I frankly no longer hold out a lot of hope for having conversations with many people here who can have a logical conversations without bungling the meaning of every sentence and then accusing me of not knowing what I am talking about.
Once again - we have evidence that communication difficulties cause problems. You just up and insulted my intelligence because I wanted to read the article that got you to thinking because I had an idea about how to develop the discussion in a constructive way. You didn't need to launch into a sixth grade lecture about how sometimes people will come across something that 'gets them to thinking'.
Now - here you are, "wanting to learn something about what science can prove nowadays" - which to me suggests that you indeed have a self-confessed problem with the basics. You can learn a lot at this site, if you stop being hostile for a moment. I was trying to be pleasant and civil and take a fouled conversation and lift it out of the soil. But I was a little unclear on what you wanted, so I asked.
If you want to learn - my suggestion is that you create a debate around a small topic. This will allow focussed discussion on that subject, and not only might you learn about that topic, but you might learn some general principles that can be applied elsewhere. Asking for general principles first can work - but I personally think it is more difficult...especially when you don't have a single person who is here to teach you - but instead a crowd of people who come here argue.
If you want to reply, please don't be an arse about it. Maybe we can use this opportunity to discuss something interesting, who knows? If you want to learn some interesting background then you might try the 29+ Evidences for Macroevolution if you haven't already done so, it's a fairly standard internet document and you'll be exposed to it before too long if you keep exploring this subject.
If you don't accept common ancestry has been demonstrated there seems precisely no point trying to give evidence that natural selection was responsible for it. So, do you accept common ancestry?
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 256 by Bolder-dash, posted 11-28-2009 10:31 PM Bolder-dash has replied

Replies to this message:
 Message 281 by Bolder-dash, posted 11-29-2009 12:25 PM Modulous has seen this message but not replied

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