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Author Topic:   Has natural selection really been tested and verified?
Admin
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Message 166 of 302 (537200)
11-27-2009 2:23 PM
Reply to: Message 164 by RAZD
11-27-2009 11:37 AM


Re: Revised topic: Has speciation been tested and verified.
Hi RAZD,
Please let moderators handle the moderation issues. If you feel you are experiencing problems in discussion then please post to Report discussion problems here: No.2. Otherwise keep the focus on the topic.

--Percy
EvC Forum Director

This message is a reply to:
 Message 164 by RAZD, posted 11-27-2009 11:37 AM RAZD has seen this message but not replied

herebedragons
Member (Idle past 848 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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RAZD
Member (Idle past 1395 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 168 of 302 (537219)
11-27-2009 4:32 PM
Reply to: Message 167 by herebedragons
11-27-2009 3:03 PM


speciation questions
Hi herebedragons, and welcome to the fray.
I do not feel that the ToE is an adequate explaination as to the origins of life ...
You are likely to get a bunch of replies to this comment. The ToE does not attempt to explain the origins of life, that is a separate science called abiogenesis.
Abiogenesis - Wikipedia
quote:
In the natural sciences, abiogenesis, or "chemical evolution", is the study of how life on Earth could have arisen from inanimate matter. It should not be confused with evolution, which is the study of how groups of living things change over time. Amino acids, often called "the building blocks of life", can form via natural chemical reactions unrelated to life, as demonstrated in the Miller—Urey experiment and similar experiments, which involved simulating the conditions of the early Earth. In all living things, these amino acids are organized into proteins, and the construction of these proteins is mediated by nucleic acids. Which of these organic molecules first arose and how they formed the first life is the focus of abiogenesis.
This is a fairly new science, and there are a lot of unknowns involved in it. Suffice to say that at this point we don't know how or when life began, we just know that after some point at least 3.5 billion years ago that there is evidence of life. From that point to the present it appears that evolution is sufficient to explain the diversity 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.
Theories are called theories because they are not facts, rather they are explanations of facts, with the best theories offering the best explanations. Theories can be validated but never proven, and are at best held as tentative approximations of reality until a better theory comes along.
Theories are also falsifiable, which does not apply to facts, and the Theory of Evolution is falsifiable.
Put briefly, the theory of evolution is that the process of evolution - the change in the frequency distribution of hereditary traits in breeding populations from generation to generation - is sufficient to explain the diversity of life as we know it. This can be falsified by demonstrating some part of the diversity of life that is not and cannot be explained by evolutionary processes. The complete sudden appearance of an entirely new type of life, for example.
Where my problem lies is what the limits are that NS can accomplish.
What limits natural selection is two things: the ecology in question, and the hereditary traits available in the breeding population. NS doesn't create new features, it selects among the existing features in the breeding population of adult phenotypes the ones that are best adapted to survive and breed within the ecology.
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 ...)
Indeed it could be a separate thread, however speciation is the point at which diversity in life begins, and this is part of Bolder-dash's revised topic (as far as I can determine), so I think a brief discussion is okay.
Once populations become reproductively isolated, then evolution continues to occur, just within each breeding population rather than the (parent) super-population. Thus one daughter population will evolve through evolution (mutation, natural selection, etc) to adapt to its ecology, and the other daughter population will evolve (in a different way) through evolution (mutation, natural selection, etc) to adapt to its ecology, in much the same way that two different species will evolve differently.
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?
Again, the critical element is whether the populations are reproductively isolated. This isolation can occur pre-mating based on changes to mating behavior. In the Asian Greenish Warbler we see this behavioral isolation in effect:
Greenish warblers
quote:
Greenish warblers (Phylloscopus trochiloides) inhabit forests across much of northern and central Asia. In central Siberia, two distinct forms of greenish warbler coexist without interbreeding, and therefore these forms can be considered distinct species. The two forms are connected by a long chain of populations encircling the Tibetan Plateau to the south, and traits change gradually through this ring of populations. There is no place where there is an obvious species boundary along the southern side of the ring. Hence the two distinct 'species' in Siberia are apparently connected by gene flow. By studying geographic variation in the ring of populations, we can study how speciation has occurred. This unusual situation has been termed a 'circular overlap' or 'ring species'. There are very few known examples of ring species.

Note that there is technically gene flow around the plateau, but in practical terms it takes generations for genes from one end to possibly reach the other end, and the probability of such flow is low, due to the reduced mating in the hybrid zones.
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?
Sometimes yes, sometimes no. It depends on the viability of the hybrids in question to act as go-betweens with fertile and fecund reproduction.
Note too, that there are generally considered to be four forms of speciation events:
Speciation - Wikipedia
quote:
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages.[1][2] Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are geographically isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry or laboratory experiments. Observed examples of each kind of speciation are provided throughout.[3]
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'm not sure if this has been done, but we do have samples of instances where genetic incompatibility has been observed to result following population isolation and subsequent evolution. Thus we know that genetic incompatibility does occur at some point in some cases of speciation.
We also know that full incompatibility is not necessary. Take horses and donkeys and zebras as an example: they can form hybrids, but the hybrids are so rarely fertile\fecund that for all intents and purposes the gene flow is stopped with the deaths before reproduction of the hybrids.
My concern here is that if we do not have genetically incompatable 'species' it would call into question that NS could break that "barrier".
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. As new mutations are added to the mix, more possibilities open up for evolution in general, and natural selection in particular, to take advantage of.
By this means, an arm can develop into a wing, or a skin flap can develop into a gliding surface. We see from convergent evolution that similar adaptations to fit the same ecology can occur in diverse lineages.
Berkeley article on analogous features
quote:
In this module, you learned that homologies are traits that different lineages inherited from their common ancestor. Homologies are evidence that different species shared a common ancestor. Analogies, on the other hand, are similar traits that were not inherited from a common ancestor but that evolved separately. Analogies often exist because two different lineages became adapted for similar lifestyles.
Sugar gliders and flying squirrels look amazingly similar. They are both furry animals of about the same size, with big eyes and a white belly. And they both glide from treetops using a thin piece of skin that is stretched between their legs. This piece of skin helps keep them stable while gliding.
If one of these can evolve from a placental squirrel, and the other evolve from a marsupial possum, then one has to wonder what kind of barrier can exist to block evolution.
Enjoy.
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Edited by RAZD, : ps

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
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This message is a reply to:
 Message 167 by herebedragons, posted 11-27-2009 3:03 PM herebedragons has replied

Replies to this message:
 Message 171 by herebedragons, posted 11-27-2009 10:06 PM RAZD has replied

Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 169 of 302 (537222)
11-27-2009 5:34 PM
Reply to: Message 167 by herebedragons
11-27-2009 3:03 PM


Speciation questions
Hi Herebedragons,
You ask some good questions but I think this thread is already quite fragmented enough. Perhaps you could repost your questions in the existing Understanding the Genetics of Speciation thread?
TTFN,
WK

This message is a reply to:
 Message 167 by herebedragons, posted 11-27-2009 3:03 PM herebedragons has seen this message but not replied

Bolder-dash
Member (Idle past 3620 days)
Posts: 983
From: China
Joined: 11-14-2009


Message 170 of 302 (537246)
11-27-2009 9:57 PM
Reply to: Message 163 by Admin
11-27-2009 9:38 AM


Re: Back to Basics
I'm sure everyone agrees with you. You can't talk about evolution without mentioning random mutations. But you *can* talk about natural selection without mentioning mutations, and several people have attempted to explain this.
That would be fine if I only said I wanted to talk about NS, but that is NOT what I said! I said I wanted to talk about natural selections effect on evolutionary change! That's a hard differentiation to make? You (and everyone else) are going to try to give me a lecture on biology because you can't see what I asked? (See what I mean about evolutionists really having a hard time pulling their eyes of of a microscope?)
I have absolutely no interest to talk about NS as some generic reference to anything you choose to make it mean. You can do that in another thread. I started the thread and I said I wanted to talk about NS as it relates to EVOLUTION.!
Percy, I really think it is disingenuous of you to allow this type of obfuscation to continue for so long. Seems I really touched a nerve with you evolutionists.

This message is a reply to:
 Message 163 by Admin, posted 11-27-2009 9:38 AM Admin has replied

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herebedragons
Member (Idle past 848 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?

This message is a reply to:
 Message 168 by RAZD, posted 11-27-2009 4:32 PM RAZD has replied

Replies to this message:
 Message 173 by RAZD, posted 11-27-2009 11:35 PM herebedragons has seen this message but not replied

RAZD
Member (Idle past 1395 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 172 of 302 (537251)
11-27-2009 10:37 PM
Reply to: Message 170 by Bolder-dash
11-27-2009 9:57 PM


Re: Back to Basics - so what do you want?
Bolder-dash,
Please consider that if not one person here understands what you are trying to talk about, that the fault is in your failure to communicate what you want to talk about.
I started the thread and I said I wanted to talk about NS as it relates to EVOLUTION.!
Does this mean that you want to talk about the effects of random mutations or not?
Do you want to discuss first what evolution is, and then what natural selection means in that context? Or do you want to discuss first what natural selection is, and then how that fits into the context of evolution?
Do you agree with this definition of evolution?
Evolution is the change in the frequency distribution of hereditary traits in breeding populations from generation to generation.
If not, why not?
Do you agree with this definition of natural selection?
Natural selection - Wikipedia
quote:
Natural selection is the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.
If not, why not?
Do you agree with the rest of the article as it continues
quote:
... It is a key mechanism of evolution.
The natural genetic variation within a population of organisms means that some individuals will survive and reproduce more successfully than others in their current environment. For example, the peppered moth exists in both light and dark colors in the United Kingdom, but during the industrial revolution many of the trees on which the moths rested became blackened by soot, giving the dark-colored moths an advantage in hiding from predators. This gave dark-colored moths a better chance of surviving to produce dark-colored offspring, and in just a few generations the majority of the moths were dark. Factors which affect reproductive success are also important, an issue which Charles Darwin developed in his ideas on sexual selection.
Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic (heritable) basis of any phenotype which gives a reproductive advantage will become more common in a population (see allele frequency). Over time, this process can result in adaptations that specialize organisms for particular ecological niches and may eventually result in the emergence of new species. In other words, natural selection is an important process (though not the only process) by which evolution takes place within a population of organisms.
Natural selection is one of the cornerstones of modern biology. The term was introduced by Darwin in his groundbreaking 1859 book On the Origin of Species,[1] in which natural selection was described by analogy to artificial selection, a process by which animals and plants with traits considered desirable by human breeders are systematically favored for reproduction. The concept of natural selection was originally developed in the absence of a valid theory of heredity; at the time of Darwin's writing, nothing was known of modern genetics. The union of traditional Darwinian evolution with subsequent discoveries in classical and molecular genetics is termed the modern evolutionary synthesis. Natural selection remains the primary explanation for adaptive evolution.
Is there any part of that which you disagree with? What and why?
See also the section on Evolution by means of natural selection - is this what you want to discuss?
There is also a section that relates to speciation, the formation of new species and how natural selection contributes to this process. This is where diversity increases - is this what you want to discuss?
Please give us something other than complaints to work with. I'm happy to discuss these things with you, but you need to lead the discussion with some idea of what you want to accomplish and what your expectations for resolution are.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 170 by Bolder-dash, posted 11-27-2009 9:57 PM Bolder-dash has not replied

Replies to this message:
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RAZD
Member (Idle past 1395 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 173 of 302 (537255)
11-27-2009 11:35 PM
Reply to: Message 171 by herebedragons
11-27-2009 10:06 PM


Re: speciation questions
Hi again, herebedragons,
My second problem with NS is that it doesn't appear to always select the best trait for survival. By the definition of NS ...
...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.
Part of the problem is that "survival of the fittest" is a misleading paradigm, and a better one would be "survival of the barely able" -- any individual that survives and breeds passes on their genes to the next generation, so just good enough is enough to pass the NS "test".
Over time the more successful ones, if repeatedly tested will prevail in higher numbers, but the marginal ones will still be a part of the mix.
The example I am thinking of is bipedalism in humans....
It might be best to take this to another topic:
Evolutionary History of Apes is one that is open, and discusses ancient ancestors. See Message 18.
Enjoy.

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
 Message 171 by herebedragons, posted 11-27-2009 10:06 PM herebedragons has seen this message but not replied

Arphy
Member (Idle past 4423 days)
Posts: 185
From: New Zealand
Joined: 08-23-2009


(1)
Message 174 of 302 (537256)
11-27-2009 11:46 PM
Reply to: Message 170 by Bolder-dash
11-27-2009 9:57 PM


Re: Back to Basics
Hi Bolder-dash
This has gotten a bit complicated and I just want you guys to be on the same page, so maybe this works, or maybe not, I'm willing to give it a go.
I am not an evo, but hopefully this definition sits alright with them (note, I am not trying to give a biology lesson, I am just trying to show some common ground).
As such NS doesn't have any effect on evolutionary change (well, depends on what you mean by evolutionary change). If you mean "change" in organisms then this "change" occurs through mutations. If you mean "change" in ecosystems, then these changes are because of NS acting on organisms. So NS does not change a particular organism, but mutations do. NS selects whole genomes, It works with what is already there, it doesn't add anything new, it may "highlight" a feature of a group of organisms or "discriminate" against a feature but it doesn't actually change anything in the organisms themselves. So yes, i agree with the evos, NS and RM are completly different topics. They are both a vital parts in the general theory of evolution but as such are very different components.
RM is about change in individual organisms, NS is about change in populations of organisms.
The above alright? Maybe the last line was all that was needed. Not sure if everything was expressed fantasticly, but please let's find some common ground.
I may be in disagreement with the evos here but, Coming back to your initial post I would say that evolutionists seem to portray RM and existing variation as the driver of the theory of evolution and NS is the driver of the General theory of evolution.

This message is a reply to:
 Message 170 by Bolder-dash, posted 11-27-2009 9:57 PM Bolder-dash has not replied

Arphy
Member (Idle past 4423 days)
Posts: 185
From: New Zealand
Joined: 08-23-2009


Message 175 of 302 (537258)
11-27-2009 11:53 PM
Reply to: Message 172 by RAZD
11-27-2009 10:37 PM


Re: Back to Basics - so what do you want?
Hi RAZD
I was just looking at your definition of evolution and noticed something. Isn't "Evolution is the change in the frequency distribution of hereditary traits in breeding populations from generation to generation." really just a definition of Natural selection? I mean, this doesn't really make make any reference to variation or mutations at all? What is the difference between your definition for evolution and your definition for NS "Natural selection is the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations."? It seems to say the same thing except using different words. I mean "change in frequencey" is basically natural selection. Isn't it?

This message is a reply to:
 Message 172 by RAZD, posted 11-27-2009 10:37 PM RAZD has replied

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ICANT
Member
Posts: 6769
From: SSC
Joined: 03-12-2007
Member Rating: 1.5


Message 176 of 302 (537259)
11-28-2009 12:19 AM
Reply to: Message 172 by RAZD
11-27-2009 10:37 PM


Re: Back to Basics
Hi RAZD,
You quoted wikipedia where it says:
RAZD writes:
Natural selection - Wikipedia
quote:
Natural selection is the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.
This is how I thought you had explained this in another thread.
Correct me if I get this wrong.
I understand this to say that if you start with one species of finches with small beaks they would develop the large beaks over a period of time.
But that is not what the study shows.
That is why I was asking my question about what that test showed.
It does not show the finches with small beaks developing large beaks from the small beaks, or the opposite way.
It shows 14 different species of finches that have different size beaks and during wet times the small beak finches increase in number and the large beak finches decrease in number. In dry times the large beak finches increase in number and the small beak finches decrease in number.
Now if that is evolution I am sold.
Concerning Darwins finches wikipedia says:
Darwin's finches - Wikipedia
quote:
Darwin's finches (also known as the Galpagos Finches or as Geospizinae) are a group of 14 or 15 species of Passerine birds, now placed in the tanager family rather than the true finch family. They were first collected by Charles Darwin on the Galpagos Islands during the second voyage of the Beagle. Thirteen are found on the Galpagos Islands and one on Cocos Island.
You can find some interesting information on the finches
Here .
God Bless,

"John 5:39 (KJS) Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me."

This message is a reply to:
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Peg
Member (Idle past 4920 days)
Posts: 2703
From: melbourne, australia
Joined: 11-22-2008


Message 177 of 302 (537261)
11-28-2009 12:30 AM
Reply to: Message 147 by Wounded King
11-27-2009 4:27 AM


Re: Speciation
Wounded King writes:
The possible exception is in the form of pre-mating isolation in behavioral rather than genetic terms since some insular ethnic groups prefer to keep marriages within their own populations. But this is a social rather than a biological barrier.
thats what im intersted in...biological barriers
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

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Replies to this message:
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Peg
Member (Idle past 4920 days)
Posts: 2703
From: melbourne, australia
Joined: 11-22-2008


Message 178 of 302 (537262)
11-28-2009 12:42 AM
Reply to: Message 149 by Iblis
11-27-2009 4:42 AM


entertaining and educational
that was an entertaining read
and i mean that in all sincerity
Edited by Peg, : No reason given.

This message is a reply to:
 Message 149 by Iblis, posted 11-27-2009 4:42 AM Iblis has not replied

Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 179 of 302 (537267)
11-28-2009 2:04 AM
Reply to: Message 177 by Peg
11-28-2009 12:30 AM


Re: Speciation
thats what im intersted in...biological barriers
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
There are changes among the various human groups; the Human Races classes I took detailed a lot of these changes.
But none resulted in speciation; all human populations are of one species and fully capable of interbreeding.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

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

Replies to this message:
 Message 180 by Peg, posted 11-28-2009 2:51 AM Coyote has replied

Peg
Member (Idle past 4920 days)
Posts: 2703
From: melbourne, australia
Joined: 11-22-2008


Message 180 of 302 (537277)
11-28-2009 2:51 AM
Reply to: Message 179 by Coyote
11-28-2009 2:04 AM


Re: Speciation
Coyote writes:
There are changes among the various human groups; the Human Races classes I took detailed a lot of these changes.
But none resulted in speciation; all human populations are of one species and fully capable of interbreeding.
do you see speciation occuring any time soon and if it were to happen, what would be the precursor?

This message is a reply to:
 Message 179 by Coyote, posted 11-28-2009 2:04 AM Coyote has replied

Replies to this message:
 Message 181 by Coyote, posted 11-28-2009 3:24 AM Peg has not replied
 Message 183 by Bolder-dash, posted 11-28-2009 4:37 AM Peg has replied

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