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billygoatkid
climber
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Oct 24, 2006 - 01:23pm PT
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Well I don't know a thing about Biology but I certainly know a thing about logic and evolution is far from it. These are some of the basic questions that I have about it.
It doesn't matter how much you break it down even if you go to the big bang, you still have something from nothing.
If evolution is survival of the fittest how come we evolved from something that still exists? If we evolved from Apes, how come there are still Apes?
If man did evolve through a series of minor changes, would we not find many fossils from the later stages and none from the earliest?
Why is it that shortly after the theory developed we suddenly have an example from almost every stage of transformation but we havn't discovered any early forms since?
For the past 20 years, there hasn't been a significant discovery regarding human evolution but during its controversial period from the 70's to the 90's there were skulls popping up everywhere.
How is it that the fossils dating back 2.5 mya are in much better condition than the ones from 50,000 years ago?
How is the only skeleton (Lucy) from 3.2 million years ago? Did the preservation process suddenly change in the past million years?
How come many of the skulls had plaster work done to reconstruct the majority of the skull?
How come people today with strange attributes, more rounded skull, pronounced eye brows, different tooth structure aren't considered the same as the discoveries from 2 mya?
With the unique human forms that are out there, is it not possible that over the past 20,000 years or so, there were mutations that appeared more ape like?
How come we can't have changed in appearances but not mutated from an ape?
It's not an argument of what is more realistic, evolution or creation, its simply an argument of whether evolution is truly plausible.
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TradIsGood
Fun-loving climber
the Gunks end of the country
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Oct 24, 2006 - 01:44pm PT
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Just trying to distill it down to basics and some scientific rigor.
Sure I knew that the developments in genetics were post Darwin. But the question is do we want to include them in our version of the theory.
And the virus example is intended to get at basic definitional concepts such as reproductive rates if they play a role, the refinement or elimination of the "advantage" concept.
One could argue that the virus example, if it occured as described might violate your current version. So I offer it in case we must refine the theory, or if not, as something that would violate and force refinement of the theory were it to occur. The flu virus of 1918 comes to mind (or ebola-like vs AIDS like viruses). Avian flu may have infected a large human population of southeast asia and perhaps all of the waterfowl of the region (?).
Finally, are we going to eliminate or include speciation. This seems key to at least ruling the so-called fundamentalist arguments as in play or not in play with respect to the theory - Right?
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dirtbag
climber
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Oct 24, 2006 - 01:45pm PT
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Billygoatkid,
Why is it incumbent on us to partake in your exercises in intellectual masturbation? Do a little bit of googling on the subject yourself. Many of the answers to your questions can be found on legitimate scientific websites in a matter of minutes. The fact you are posing such basic questions in such a pointed way rather than doing your own research suggests that you really aren't interested in those answers anyway.
Here's a challenge for all the evolution skeptics: explain how inconsistencies in all the evidence--such as changes observed in fossils, genes, anatomy, ontology, etc.--disprove evolution or more precisely, natural selection. Scientists have had a hard time doing that.
Good luck.
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eeyonkee
Trad climber
Golden, CO
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Oct 24, 2006 - 02:39pm PT
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Sounds like billyGoatKid thinks there's an actual conspiracy among scientists to delude the public about this... Unbelieveable.
I suppose this same type of thing took place during the coupla' centuries? that it took the general public to accept that the world was round or that the sun did not revolve around the earth.
My exasperation with the anti-evolution crowd isn't so much that they don't understand the theory - let's face it, some of it IS hard to understand, and it's hard to really get one's head around the 100's of thousands to millions of years that evolution works its magic across. My exasperation comes from this - where else is the supernatural called upon to explain natural phenomenon? A few centuries ago, the answer would be quite different, of course. But, get real, this is the 21st century! If you don't understand exactly how it works, fine. Most people don't understand relativity or quantum mechanics either. It scares me that America (ranked 24th out of 25 countries, just above Turkey in a recent poll on belief in evolution) is headed towards a new dark ages.
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Aya
Uncategorizable climber
New York
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Oct 24, 2006 - 03:11pm PT
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Sorry - what do geography and speciation have to do with evolution?
Blight - you asked me what evolution states directly after the post where I wrote what it stated. Please go back and reread.
You said that Ed and graniteclimber disagree. They do not. Ed is saying that the evidence YOU want - the appearance of a new limb - is non-observable. That is true. graniteclimber says that the evidence for the mechanism of evolution is observable. That is true as well. If you accept that evolution does not state that simple unicellular organisms evolved into multicellular ones with complex organs, limbs and apparatuses (apparati?), then you should understand this. Of course, if you do not accept that that is what evolution states, then again, the conversation is moot.
edit: had a thought - the sudden appearance of an entire new limb on an organism would probably be evidence for creationism, really...
Re: mutations
If you google mutation, you will quickly find that mutations are simply a change in genetic material. They can be an addition, a subtraction, or simply a rearrangement. I don't know what you mean by "replication". Certainly, one type of mutation may be when a portion of the genetic code is replicated and incorporated.
There are certainly mutations that are "sustainable". Obviously, the answer "look around you, the diversity of life is the evidence" is not going to suffice. However, you say that simple organisms will suffice; there are plenty of laboratory experiments which demonstrate the emergence of beneficial mutations. As an example: there were some folks who took a single E. coli cell. A single cell, therefore by definition lacking genetic variation. They allowed this cell to replicate through 2000 generations, which, since bacteria reproduce by binary fission, should have yielded a whole bunch of E. coli that was identical assuming that there were no mutations. Of course this was not the case; mutations did happen. One of these mutations was called "Ara"; essentially, Ara+ bacteria are white and Ara-bacteria are red. The Ara mutation does not affect fitness: they tested this by growing the + and - types together. Their relative representations in the overall population did not change. Basically, the Ara+ and Ara- bacteria were the same (they came from the same, original, single cell). They then took portions of these cells and grew them at different temperatures, freezing them periodically (you can freeze E. coli and later thaw it out and it will just go back to doing what it does). After a long time, they took samples of the cells - from the original ones up to the ones that had been grown for many generations at a a different temperature, and then, because they had samples that were both Ara+ and Ara-, they were able to grow them together and let them compete. They were able to see which were doing better by observing the relative proportions of colors. The upshot of it all was that all of the E. coli were originally derived from a SINGLE CELL. By the end, there were different populations that had adapted to living at different temperatures. Since they were all originally derived from the same genotype, the adaptations to the new temperatures must have been based on new mutations - adaptive mutations. (I know this was kind of oversimplified, but check Bennett, A., R. Lenski and J. Mittler. 1992. Evolutionary adaptation to temperature. I. Fitness responses of Escherischia coli to changes in its thermal environment. Evolution 46: 16-30 and the subsequent studies those guys did for more in depth info on that particular example).
I'm not going to get very in depth with this because I'm totally biochemistried out and besides, it isn't really my thing, but for evidence for the evolution of novel biochemical pathways in E. coli, check out for example the work of Barry Hall. Basically, he demonstrated the evolution of an entire lactose metabolization pathway, starting with a mutation causing a change in enzyme structure allowing hydrolysis of lactose (in bacteria which previously could not use lactose), a mutation in the regulatory gene such that it this new enzyme would be produced when lactose was present, and a subsequent third mutation causing the production of an enzyme which would break down latose into something that would cause the production of permease, which is needed to allow lactose to enter the cell and be utilized for energy. Okay, so this is not the evolution of an arm, but it's the evolution of a pretty complex biochemical pathway and a pretty good example of mutation and selection working to give rise to a complex, novel adaptation.
I don't know what changes must be possible without interference means; perhaps you mean that any experiments done in a laboratory are unacceptable as evidence?
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 03:50pm PT
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Tradisgood,
"The net effect in either case being that the temporarily advantaged Va drives out Vb, followed by its own extinction, despite the fact that Vb might have been sufficiently communicable to infect and live indefinitely in a population."
The spread of pathogens is a sub-field in its own right as the evolution of viruses, etc. is different in many ways from that of complex organisms, but of course the same basic rules apply. This is probably a good example as any because understanding pathogens is of much greater relevance to us in our everyday lives then "ivory tower" speculation about our ancestors.
Will Va drive out Vb as a practical matter? Depends on the organism and the population.
Let's assume that the host organism reproduces via sexual reproduction (and if not that species may not be long for this earth!). A convincing case has been made that the major advantage of sexual reproduction is to ensure variation from generation to generation to increase survivability with regard to pathogen attacks.
Thanks to the variation we would expect in a sexually reproducing host, we can also expect (most of the time) a certain number of the population to survive or be immune to Va and/or Vb infections. Or some may be susceptible to Va but not Vb, or vice versa.
Also if the population is divided into sub-populations (think: different villages, different wolf packs, etc.) as is usually the case. Va might wipe out an infected sub-population quickly enough that it doesn't spread to other sub-populations. To the extent that Vb has infected hosts that are not killed by Va (and in a viable population, you'd expect this), Vb would have the advantage by not killing of its hosts to quickly.
Viruses don't think or have intentions of course, but we can think of them each as individuals, each just wanting to survive and reproduce, without intending the host to die. Are you familiar with Garret Hardin's "Tragedy of the Commons?" Think of the viruses as the cows and the host as the commons.
If you are a virus killing of your host before you can spread to other hosts is not a desirable attribute. If the virulence is a result of a mutation, this was not a desirable mutation long-term and will be self-limiting. And to the extent that Va eliminates or reduces Vb's hosts, Vb will be impacted.
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 04:05pm PT
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"Finally, are we going to eliminate or include speciation. This seems key to at least ruling the so-called fundamentalist arguments as in play or not in play with respect to the theory - Right?"
Its not needed for a discussion of the basic process of evolution or what is sometimes referred to as "micro-evolution" but it is important in discussing "macro-evolution."
Macro-evolution is what is controversial and what everyone wants to discuss, but I believe that at least some understanding of micro-evolution is needed as foundation to understand macro-evolution. Many of the attempts to find fault with macro-evolution involve a misunderstanding of concepts on the micro-evolution level.
If you don't understand arithmetic, you don't have a chance to understand algebra. OK, that's not a very good analogy but I think it makes my point.
Aya, Rokjox & Tradisgood, thanks for starting a stimulating discussion! Good work.
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Aya
Uncategorizable climber
New York
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Oct 24, 2006 - 04:13pm PT
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Given that natural selection is a purely statistical process, the arithmetic/algebra analogy may have been more apt than you thought.
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 04:17pm PT
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"edit: had a thought - the sudden appearance of an entire new limb on an organism would probably be evidence for creationism, really..."
Yes, that was my thought as well. If a new organ appeared overnight, that would be the best possible evidence that I know of for the "intelligent design" theory. While it wouldn't by itself disprove evolution, it would require us to thoroughly re-examine our assumptions about how it works.
Aya, I am glad you are part of this discussion. If you think I've unduly mutilated (pun intented) anything in my posts, please feel free to jump in and correct it.
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 05:02pm PT
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Billygoatkid,
Good questions. I'll answer a few. You can easily google the rest
"It doesn't matter how much you break it down even if you go to the big bang, you still have something from nothing."
The Big Bang theory is in the field of Astrophysics, not evolution.
"If evolution is survival of the fittest how come we evolved from something that still exists? If we evolved from Apes, how come there are still Apes?"
First, we didn't involve from apes, we are a species of ape. Second, you're thinking of speciation as a ladder. This is a common misconception. Think of it as a tree, with each species being a branch.
Assume you take two pairs of hamsters and put them on isolated islands. Further assume that hamsters thrive and populate the island. Given enough years(as in tens of thousands and millions of years)and if they don't go extinct, these populations will fork first into sub-species and then into species.
"If man did evolve through a series of minor changes, would we not find many fossils from the later stages and none from the earliest?"
I understand that there are more fossils found from the later stages then the earliest. But the early fossils get much more attention in the press.
"Why is it that shortly after the theory developed we suddenly have an example from almost every stage of transformation but we haven't discovered any early forms since?"
No, discoveries are still being made. Look no further then the latest front cover of National Geographic. However, it's my observation that these discoveries get less attention then they did in the past. Some palaeontologists might disagree, but the real breakthroughs in more recent times have been though applying molecular biology. While still very relevant, the hominid fossil record is simply less important to understanding human evolution then it was in the past. IMO,
When you look at fossils, you are limited to the fossils at hand. There are often gaps. And there is always a subjective element in comparing fossils. Molecular biology is less subjective. In the 1960's, the application of molecular biology to human evolution almost literally turned the field upside down.
Most of your remaining questions have to do with the hominid fossil record, not evolution per se. You could throw away every hominid fossil that has ever been discovered and there would still be sufficient compelling evidence to prove evolution.
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TradIsGood
Fun-loving climber
the Gunks end of the country
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Oct 24, 2006 - 05:28pm PT
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granite - you got it. But the question of viruses was posed specifically to get at your definition of reproductive rates. How does one measure the rate? In the example given, one might try for a classical instantaneous rate and a differential equation, but sooner or later, that equation stops being a linear d.e. (population saturation or elimination...)
In other words, trying to get out of the really loosy, goosy definitions like "advantageous" and define what it means to be higher rate. For example, when Va(t0) starts out say in a population equal to Vb(t0), it soon outnumbers Vb(t1). But if it wipes out the village, except for the Vb escapees, (or eliminates all of the susceptible, then Ra(at that time, t2) = 0, and Rb >> Ra. So we have a problem.
At one time Ra >> Rb, and at another Rb >> Ra. Trying to fit that back into your original statement a few posts back is awkward, at best. I hope you see where I am going here - rigor.
Aya, in the title, after all, is "origin of the species". Darwin really does not pose a mechanism for the "origin" to my thinking, but merely a mechanism (selection) for controlling the count of the species.
So that is why I ask whether we include speciation (perhaps opening up the monkey business) or rule it out of the theory (making it of little interest to the monkey maniacs, but ceding all of the fun stuff to another theory).
I think granite addressed "geographic" issues pretty well. Most reproduction requires at least temporary, contemporaneous, physical co-location. Populations are affected by their location getting feedback from it.
:-)
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Aya
Uncategorizable climber
New York
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Oct 24, 2006 - 05:33pm PT
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I'm clearly still not understanding. Evolution is one mechanism by which speciation can occur. Speciation has no bearing on the theory of evolution, i.e., it does not need to "be included" in it?
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 05:43pm PT
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Rokjok, Good post on fossilisation. You ever notice that in magazines and museums you see paintings and mobiles of swamps and volcanoes? You'd think that in prehistoric times the earth was one big swamp, broken up by volcanoes here and there! They show that because the vast majority of fossils are found in areas of sedimentation, either in swamp or lowlands or due to volcanic ash.
You don't see very many fossils from animals and mountainous areas because you don't have much sedimentation there and therefore very few (if any) fossils.
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eeyonkee
Trad climber
Golden, CO
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Oct 24, 2006 - 06:12pm PT
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I must be missing something here about the speciation issue. As TradIsGood mentioned, the introduction of the theory to the world was in a book called the 'Origin of Species'. Of course the theory of evolution is concerned with speciation. Darwin thought that there was more or less a continuum between "varieties" within a species and characteristics between species. But it was the genesis of new species that clearly interested Darwin and required explanation.
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 06:25pm PT
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"granite - you got it. But the question of viruses was posed specifically to get at your definition of reproductive rates. How does one measure the rate? In the example given, one might try for a classical instantaneous rate and a differential equation, but sooner or later, that equation stops being a linear d.e. (population saturation or elimination...)
"In other words, trying to get out of the really loosy, goosy definitions like "advantageous" and define what it means to be higher rate. For example, when Va(t0) starts out say in a population equal to Vb(t0), it soon outnumbers Vb(t1). But if it wipes out the village, except for the Vb escapees, (or eliminates all of the susceptible, then Ra(at that time, t2) = 0, and Rb >> Ra. So we have a problem.
"At one time Ra >> Rb, and at another Rb >> Ra. Trying to fit that back into your original statement a few posts back is awkward, at best. I hope you see where I am going here - rigor."
If you were doing an experiment in a lab, you'd need to have to better define "advantageous," probably by units of time or number of generations. As in measuring almost anything, the precise increments you use are largely arbitrary.
As you can see, in the "real world" things get complicated very fast. Whether a specific mutation (or set of mutations) is good or bad depends on the circumstances so outside the lab, you're stuck with loosy, goosy, unless you chose one method of measurement and stick with that.
Human intelligence is often thought of as one of the most successful adaptations ever. But it has been pointed out that if this intelligence is used to foment a nuclear or bio-chem war that exterminates the human species, it can be seen as a maladaptation. Again, you'd have Ra >> Rb at one time, and Rb >> Ra at another. (You don't even have to go that far--any time a person uses his or her intelligence to commit suicide, you can consider the intelligence necessary to do so a maladopation.)
Or how about the KT extinction? I understand that most species that survived hade relatively small bodies. Most of the species with larger bodies went extinct. Larger bodies, in that particular situation, turned out to be a maladoptation. Oops.
But we should think of the process of evolution working on the level of the individual, with individuals competing against other individuals. Some say, that even looking at the level of the individual is too high a level and that it really operates at a genetic level. See Richard Dawkin's "The Selfish Gene" for example. (If only read one of Dawkin's books, this is the one to read.)
Evolution is just an unguided process-- a process that operates in the moment. It does not look forward (or backwards), it just happens. Most definitions of fitness (fitness being the measure of "success" in evolution) that I've seen do not try to take into account long-term consequences, because that gets very speculative, very fast.
I would expect that epidemiologists are very interested in the effect on the host (with the host being us!), but I suspect that is because saving lives (of us hosts) is the ultimate goal.
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TradIsGood
Fun-loving climber
the Gunks end of the country
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Oct 24, 2006 - 06:28pm PT
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No, I am confused. Looking for a rigorous definition of the theory. Does evolution explain the development of (new) species or not? We know today about chromosomes, that both plant and animal genetic material is all made from the same few building blocks, that those blocks can be very accurately, but not perfectly replicated by well understood chemical processes, but that they are organized differently.
We even know that a specific gene can me manufactured - not that this is relevant.
So does the concept of species belong in the theory or not. And if in, what is the definition of species, and what is its role in the theory?
Maybe it is time to restate? Include modifications to granites original? Getting close to 50 posts trying to get a statement of the theory that we can agree on... :-)
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Aya
Uncategorizable climber
New York
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Oct 24, 2006 - 06:49pm PT
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I don't know how many more ways I can express what I'm trying to say.
Evolution is a mechanism by which speciation can occur.
I wish I could come up with an analogy, but I can't.
It's exactly as eeyonkee says, however: Darwin was concerned with the development of new species and was looking for an explanation. The explanation he came up with was natural selection.
Natural selection is an example of one evolutionary process. It is essentially the non-random difference in the rate of survival/reproduction of organisms. Certainly there are other evolutionary processes, and these processes can contribute to speciation as well.
I guess I'm not really helping or clarifying. I'm trying to say that evolution is one way to explain speciation, but speciation is not necessary to explain evolution.
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Maysho
climber
Truckee, CA
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Oct 24, 2006 - 07:15pm PT
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Hey you all,
I just want to thank you for the stimulating conversation, I am learning a lot, I know it takes time and effort to stay in this game, just letting you know that I am appreciating this as an always-trying-to-learn scientific neophyte, sideline observer.
Peter
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graniteclimber
Trad climber
Nowhere
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Oct 24, 2006 - 07:29pm PT
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"...evolution is one way to explain speciation, but speciation is not necessary to explain evolution."
Exactly, assuming that my evolution we are referring to only the "mechanism" (micro-evolution, or what I have been referring to as the "process" of evolution) as opposed to also looking at what the mechanism has produced over time (macro-evolution--really nothing less then trying to reconstruct the history of life, including speciation).
Regarding the effect of intelligent life (us, tinkering with things), that does not suspend the process of evolution, it only changes the environment in which it operates.
The symbiotic relationship of people and dogs is not unlike many other symbiotic relationships in the animal world involving less intelligent creatures.
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