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Author Topic:   Has natural selection really been tested and verified?
herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 42 of 302 (536417)
11-22-2009 11:55 PM
Reply to: Message 41 by Bolder-dash
11-22-2009 10:38 PM


Hi. I'm new to this forum and I am hoping to get some intelligent, yet clear answers to this debate of creation vs. evolution.
Iblis - very poor post. hopefully an admin will take note of it and delete it. I hope this isn't the kind of dialog that will continue in this forum as no one benefits from this type of derogatory slamming.
But Bolder-dash, I do think this appears to be a bit of "bait and switch".
It appears to me that natural selection IS a documented and tested theory. We can observe it happening in populations all around us. What I think the next logical question here is what are limitations on natural selection. Since we can't observe small gradual changes happening over millions of years, it may be an assumption that there are no limitations to what natural selection can accomplish. Let me explain what I am talking about with an illustration:
We have a population of antelope living in Africa (or wherever). The antelope that can run the fastest are the ones that are most likely to survive as the predators (the lions) cannot catch them and will eat the slower antelope. Likewise, the lions that can run the fastest will be more likely to catch the antelope, thus creating a never ending cycle. So, could the antelope eventually be able to run 100MPH? No, there would be a limit as to how fast the antelope could ever run. They would be limited by their muscle and bone structures along with other limiting factors. In order for them to be able to run faster their body structures would need to be modified.
I know this is an oversimplified illustration, and there would be many other ways the antelope could develop to avoid capture by the lions, such as camouflage, evasive maneuvers, ect. I am just using it to illustrate my question. What are the limitations to what natural selection can accomplish?
Thanks

This message is a reply to:
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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 167 of 302 (537206)
11-27-2009 3:03 PM
Reply to: Message 118 by Wounded King
11-26-2009 11:52 AM


Re: General confusion
Hi WK. I am new to this forum and have wanted to get involved with this discussion but havent had time to until now. After sifting through many argumentative and pointless posts, I feel you have some of the most knowlegable posts thats why I am directing this reply to you. I do not feel that the ToE is an adequate explaination as to the origins of life or the existance of life as we know it. I have no problem with "facts of evolution" (when they are indeed facts), what I have a problem with is when "theories of evolution" and "evolutionary history" is presented as fact. I am not suggesting that you or anyone else here has done that, that is just where I come from and why I want to understand some of the questions I have - so I can better make my own conclusions.
I think it is quite obvious that NS has been observed, tested, verified and can be accepted as a "fact of evolution". Where my problem lies is what the limits are that NS can accomplish. I used to think that one so called "boundary" would be speciation. My thinking was that once a species was reprodutively isolated NS could no longer come into play, since reproduction was no longer possible. A few posts that I have read since then, I realize that may be too simplistic. I still have some questions about that topic though. (maybe speciation should be a seperate thread, but since I am talking about it in context of NS ...)
Because a lot of 'species' classifications are based on old fashioned morphological or even simply geographic criteris, they aren't base on the actual establishment of reproductive isolation. Therefore what have been identified by taditional methods as distinct 'species' may still be considered to form part of one breeding population due to gene flow between different populations at hybridisation zones.
I believe this quote was in reference to Galapogos finches and it appears to indicate that the individual 'species' may not actually be reproductively isolated. A quote from the article you cited(Grant and Grant, 2008): "Reproductive isolation in Darwin's finches appears to be entirely prezygotic as there is no evidence of genetic incompatibilities (Grant 1999)". I thought that would make them technically part of the same species. Can reproductive isolation and therfore speciation, be established on pre-mating barriers only? I thought there needed to be genetic incompatability. Could the Galapogos finches still be considered of the same "genetic" species?
Do I understand this correctly: that these hybrdization 'zones' allow enough genes to be shared that it prevents the individual species from becoming genetically incompatable?
Another question. Can genetic incompatability be established by DNA evidence alone? For instance if you compared the DNA from Geospiza fortis to that of Geospiza magnirostris, could the traits that makes the two species genetically incompatable (if they indeed are) be identified? I am curious as to what makes species genetically incompatable and if it is something that can be pointed to.
My concern here is that if we do not have genetically incompatable 'species' it would call into question that NS could break that "barrier". From what I know, the same issues apply to the other examples cited - chichlids and peppered moths.
What are your thoughts?

This message is a reply to:
 Message 118 by Wounded King, posted 11-26-2009 11:52 AM Wounded King has replied

Replies to this message:
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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 171 of 302 (537248)
11-27-2009 10:06 PM
Reply to: Message 168 by RAZD
11-27-2009 4:32 PM


Re: speciation questions
Thanks Razd. I guess I shouldn't have begun my post the way I did. I didn't mean to come across as ignorant of what the ToE is and isn't and what theories are and aren't. I was just trying to briefly state my reasons for coming to this forum.
By recomendation of Wounded King, I will take this discussion of speciation to the thread that he suggests. I believe you had a similar post on that thread. By the way, it was helpful, thanks.
My second problem with NS is that it doesn't appear to always select the best trait for survival. By the definition of NS
Natural selection - the process that selects among the existing phenotypes of a species those that are best able to survive and breed, by the simple expedient of their survival and breeding within the ecology in question. This results in a descendant population with (a) a different frequency of hereditary traits from the parent population, and (b) a population that is better fit to survive and breed in the ecology in question.
traits that improve the ability of the species to survive are selected for. And while I realize that it is somewhat speculative, I am not sure that traits we find in modern examples are always the most fit for survival.
The example I am thinking of is bipedalism in humans. While we now consider bipdalism to be a significant advantage, I doubt our ancestors would have. Monkeys can climb trees, run and move faster, jump from branch to branch, and so on ... While walking on two legs would be a major hinderance. Especially to the first creatures to do so.
Possibly pressure from predators was minimal, and our ancestor did not need to be able to escape? Could it have been as we developed tools we needed to be more upright? It is just that this is an example where NS appears to be going against the rules, so to speak.
I don't really think that our ancestors stood up more and more (as I have read in some texts) and this drove the evolutionary change. NS says that the change is there in the population and is just selected on based on fitness for survival. So if they became more upright there was a distinct advantage to that change, based on survivability.
Considering the amount of biological change that would need to take place to go from quadrapeds to bipeds, I think it is something that needs to be considered. And in my mind, it goes against the principle of NS.
Any thoughts?

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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 224 of 302 (537389)
11-28-2009 10:14 AM
Reply to: Message 177 by Peg
11-28-2009 12:30 AM


Re: Speciation
thats what im intersted in...biological barriers
Peg - I too am interested in these "biological" barriers. I have been told that no such barriers exist, as NS is opportunistic - it works with the materials it has and keeps "evolving".
and the reason is because if it occurs among other species and if its a part of evolution, then it would surely happen among humans too
obviously, just because it hasn't happened doesn't mean it can't. But I do wonder why it hasn't happened and why the criteria for speciation is not consistantly applied.
Razd writes:
speciation is where diversity begins, as during speciation events a parent population divides into two daughter populations that become reproductively isolated, stop sharing genetic material, and then evolve along different paths due to different ecologies and selection pressure. The daughter populations become increasingly diverse from each other after the speciation event, for the simple reason that there is no process to make them to be similar.
I also understand that there does not need to be genetic or biological isolation for speciation to occur, only reproductive isolation.
Again Razd wrote:
Again, the critical element is whether the populations are reproductively isolated. This isolation can occur pre-mating based on changes to mating behavior.
There have been several examples of human populations being reproductively isolated.
1. Maya Indians - South America from about 2000BC to 900AD.
2. Current populations of indiginous peoples in both South America and Africa who do not breed either by ethnic choices or geographical isolation.
3. Native American Indians - Supposed to have immigrated to North America at least 12,000 years ago and possibly as far back as 50,000 years. Plenty of time to speciate, don't you think?
4. I understand the Ancient Egyptians were isolated for thousands of years (primarily by choice), but I don't have details or references right now.
Just these four examples provide plenty of opportunity for human evolution, or more precisely speciation, but has not been shown to have happened. Each of these examples faced vastly different environmental pressures and ecologies. One may argue that evolution has occured, as we have varing skin colors, average heights, limb lengths, facial structures, ect. But none have been classified as a new species. These variations would be enough to classify a new species in Greenish warblers, Galapogos finches, Peppered moths and others. I wonder if it is actually a stretch to consider these specimens have truly "speciated".
I have no problem accepting that 'evolution' has indeed occurred in all the above examples, but I question the extent of it. And I question the accuracy of taking the above examples and extrapolating them into the following statement:
Razd:
By this means, an arm can develop into a wing, or a skin flap can develop into a gliding surface.
I am still convinced there are "biological barriers" (I am using that term because I don't know how else to refer to it) to evolution. What is the evidence to the contrary? Honestly I still have more studing to do on the Greenish warbler and the Galapogos finches, but as far as I could tell, reproductive isolation is established by social and morphological reason only, not biological.
Thoughts any one??

This message is a reply to:
 Message 177 by Peg, posted 11-28-2009 12:30 AM Peg has replied

Replies to this message:
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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 228 of 302 (537394)
11-28-2009 10:28 AM
Reply to: Message 218 by Dr Adequate
11-28-2009 8:55 AM


Re: Back to Basics
* sigh *
We're not talking about two different species.
Has speciation occurred in Galapogos finches or not? Or has it been observed anywhere for that matter? I have info on Grenish Warblers and peppered moths and I am not convinced that either one is truely speciation.

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 Message 218 by Dr Adequate, posted 11-28-2009 8:55 AM Dr Adequate has replied

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 Message 233 by Dr Adequate, posted 11-28-2009 11:02 AM herebedragons has replied
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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 258 of 302 (537487)
11-29-2009 12:04 AM
Reply to: Message 233 by Dr Adequate
11-28-2009 11:02 AM


Re: Back to Basics
Hahaha. Good one Dr A. Were you testing me?
You left out part of the quote from CreationWiki (I wonder why???)
Corrected quote from CreationWiki:
Speciation, or the formation of a new species, does occur with some regularity, but this process can easily be prescribed as the result of intelligent design.
And the closest quote I could find on Answers In Genesis are:
As creationists, we fully accept the fact that adaptation / natural selection can occur rapidly. In fact, such processes (and perhaps other genetic factors) would have occurred rapidly after the Flood, producing variation within the animal kinds.
I have read the creationist literature, but have not used it on this forum. It would be dismissed as creationist propaganda. I am thinking for myself and asking questions about issues that bother me about the ToE. My concern with natural selection is that there are barriers to what it can accomplish. - and natural selection is the thread topic
For instance, one barrier, or boundary if you will, would be the organism must be living. Non living things cannot evolve by NS. You can’t apply NS to rocks or amino acids or proteins. That is undisputed! Correct?
What I am proposing (or maybe supposing) is that another barrier to NS is genetic incompatibility. The studies for NS that I looked at - the Galapagos finches, the Greenish warbler, the peppered moths, and the cichlids all apparently can still interbreed. Thus this biological barrier has not been broken. Have I misinterpreted these studies?
Before we can talk about breaking a barrier, we would need to show that one exists. NS is opportunistic: it takes the opportunities provided by mutations and matches them to the opportunities provided by ecologies to select individual phenotypes that are best suited to survive and reproduce within the ecologies.
I gave examples of several human populations that have been reproductively isolated for thousands of years and yet no new human species have developed. Why? Because they can still interbreed and produce viable offspring. So this supports the idea that a genetic barrier exists.
This is what Bolder-Dash is trying to accomplish in this thread:
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.
But if we can’t get past the first barrier - by that I mean biological incompatibility - how can you possibly explain complex body parts, common descent or even how one class of organism can turn into another class.
So, no. I don’t think the debate is over.

This message is a reply to:
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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 259 of 302 (537488)
11-29-2009 12:10 AM
Reply to: Message 257 by Coyote
11-28-2009 11:15 PM


Re: What science can "prove?"
seriously? I never saw Bolder-dash mention his religious beliefs even once. Neither did he mention creation as a potential theory. Maybe you doubt his genuinely wanting to learn anything, but why call him a religious creationist???? Because he doubts the ToE? Ridiculous.

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 Message 257 by Coyote, posted 11-28-2009 11:15 PM Coyote has replied

Replies to this message:
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herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


Message 260 of 302 (537489)
11-29-2009 12:15 AM
Reply to: Message 248 by Peg
11-28-2009 6:16 PM


Re: Speciation
not much response to this, huh? except that now we know that there are 1,202,920,000 sheep in the world. not a lot of help

This message is a reply to:
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