Chemical Forums
Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: bistones on February 04, 2010, 04:28:52 AM
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I know that it has been 'proven', but my question is, has it actually been observed by somebody? Yes, we can see the similarities between different subspecies and species but that alone is not proof that they evolved from each other. Has anyone actually seen it happen?
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http://www.search.com/reference/Nylon_eating_bacteria (http://www.search.com/reference/Nylon_eating_bacteria)
Evolution has not been proven definitively as a theory.
It is such a slow process in longer lived animals that it is difficult to observe and comment definitively. However, in microrganisms with their shorter lifespans multi-generational changes can be observed.
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Evolution has been observed in a number of animals:
The lizards of Pod Mrcaru have been observed to change within a human life span. In the 36 years since they were introduced from the neighbouring island of Pod Kopiste the two population have diverged from each other due to the slightly different environment on each island.
http://www.physorg.com/news127667797.html and http://www.sciencedaily.com/releases/2008/04/080417112433.htm
Male guppies have seen to change from brightly coloured to dull depending on the degree of predation. Female guppies appear to like brightly coloured males but they stand out to predators.
http://evolution.berkeley.edu/evosite/lines/IVCexperiments.shtml
As JGK has posted there are lots of experiments that have seen evolution in bacteria as so many generations occur in a short period of time.
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There might be fruit fly studies
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Evolution has not been proven definitively as a theory.
i dont want to start an ideological war becuase god knows i will lose but evolution is a theory just as gravity is a theory, while it is accepted as exsiting by the scientific community there is always room for modification to the exsiting rules.
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i dont want to start an ideological war becuase god knows i will lose but evolution is a theory just as gravity is a theory, while it is accepted as exsiting by the scientific community there is always room for modification to the exsiting rules.
Yes. But, there is a widespread misunderstanding about the meaning of the word "theory" when it is applied to science. For a large number of people, theory is synonymous of supposition: an idea that has been proposed but not fully proved, and therefore somehow doubtful. But, in science, this is absolutely not the case!! A theory is a scientific concept that has reached a very high degree of achievement after being tested and over-tested countless times. It is a very large and solid piece of work. Saying to a scientist that evolution or gravity is "just" a theory, it is like saying to a mountaineer that the Everest is "just" a mountain... :o
To take your example, gravity: Its law was first formulated by Newton. And then, a few centuries later, Einstein came to change all that with his relativity. Does it mean Newton law is not valid anymore? No, its validity is still the same. It simply means that relativity has a larger validity window (relativity is valid at speeds near the speed of light, while Newton law is not). It is more general.
To illustrate it: imagine you have "apple" theory, which explains every apple. And then, someone propose and demonstrate the "fruit" theory, which explains every fruit. Does it make the "apple" theory wrong? No, it still applies for apples, but it isn't valid for oranges... :)
Beyond the simple notion clarification, I react to this topic because when someone says "evolution is just a theory", there is often the idea of intelligent design behind. I don't know if it is the case here, perhaps not, but nonetheless the ambiguity is there.
What highly irritates me with intelligent design, is when people try to deconstruct the work done by numerous scientists (theory of evolution) in order to promote their beliefs. It is outrageous obscurantism, not less. Intelligent design is not science: people working on it have set the conclusions from the start (following their religious beliefs) and they try to make the data fit that conclusion in order to support it... This is simply anti-scientific, unacceptable. >:(
I realise that my last paragraph is potentially polemic. Nevermind ;D I think it needed to be said, so everything is clear.
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It is labeled as the "theory" of evolution. If it was accepted universally, it would be called the "law" of evolution.
My take on the theory of evolution is as follows: Evidence is strong for evolution. The theory holds very true with respect to animals which adapt or evolve as a result of their environment. Birds and their beaks on one island vs. another. The theory has "holes" or gaps, with respect to evidence, when one animal evolved from another. The anti-evolutionists have a hard time understanding the gradual aspect of evolution over many years.
I believe personally the theory is law on Earth. Possibly evolution/life works differently on an alien planet.
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It is labeled as the "theory" of evolution. If it was accepted universally, it would be called the "law" of evolution.
Interesting remark, you may well be right.
My view point on it is a little different: I see theories as large concepts which cover a broad subject, and laws as narrow concepts which are often reduced down to a single equation (particularly in physics).
For example in chemistry: We have the atomic theory which states that matter is made of atoms, themselves made of protons, neutrons and electrons... It's very general and cover the whole subject. And you have plenty of laws: Beer-Lambert law, Le Chatelier's principle,... Here is a list of laws in science http://en.wikipedia.org/wiki/List_of_scientific_laws_named_after_people. (Remark, I never realised there was so many of them! And particularly a lot in thermodynamics: people like to get famous ;D)
The use of names and labellings in science is an interesting subject, and not taught at school (at least for me, I have never had any formal lecture about history of science in my entire curriculum :-\).
Remark, scientists are not always very rigorous with their terminology. And so, they are partly to blame for the misunderstanding caused. For example, there is the superstring theory http://en.wikipedia.org/wiki/Superstring_theory. It is called a "theory", but is it really? Physicists have no direct proof of it (they can't reach energies high enough: so they can't experiment on it, no matter how eager they are to test it). And I think pretty mathematics alone is not enough to qualify for a "theory". ???
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The big problem with the evolutionary theory is that it really isn't composed of one theory...but many different theories that have accumulated over the years about the origin of species and life. Some of these theories are better established by experiment than others. For example, I don't think any scientist is arguing against the idea that a random mutation occurring within a member of a given species can create a noticeably different phenotype which can be passed on by the offspring of the mutant and later come to be a "labelled" by us as a separate species (the problem to begin with is that our "lines" separating one animal from another come from us...not mother nature herself). We have many experiments demonstrating the effects of DNA mutations on proteins and phenotypes to support the mechanism behind the theory.
On the other hand, it was scientists initially (not ID advocates) who wondered if the "abiotic theory of life" was right (this theory is another one of these "adjunct theories" which is now packaged in with evolutionary theory as a whole by most scientists). It seems hard for a serious scientist to accept that if you zap a pool of inorganic chemicals long enough that things like human beings and the empire state building will eventually arise out of it. The mathematics tell us that this scenario is possible, but at the same time extremely unlikely. So there are arguments both for and against this theory. And yet, if you even dare to suggest that this part of the theory needs more experimental evidence (because umm...it really does need more) before it is accepted along with the rest of evolution then you are classified as some sort of religious freak who "automatically" denies all the other parts of the theory! That is what frustrates me about talking about evolutionary theory. It would be like if I questioned string theory for its lack of experimental evidence (and I DO question it for this reason) that I would then be accused of denying the rest of Physics such as the laws of electromagnetism and thermodynamics along with it. Nonsense! Different story. The latter two theories have tons of experimental evidence to back them up and the former has none. We should be allowed to pick and choose which parts of a subject we think are better than others without being labeled a traitor if we don't accept the whole thing!
Its dumb, but that is our present state of affairs and is the reason why in my mind the theory of evolution has stagnated (the irony here is that the theory itself is not evolving as other scientific theories do) despite the explosion of molecular biology half a century ago. It really hasn't changed much since the 1800s despite many advances in molecular biology since that time. The reason why it is not changing is that molecular biologists are reluctant to challenge certain parts of it for fear that they will be labeled as evangelical hacks! The Intelligent Designers are also to blame for creating this environment. Anytime a decent scientist starts to question some aspects of the evolutionary theories (such as the issue with the probabilities involved in the abiotic theory) automatically their arguments are co-opted and used as "proof" that ALL of evolutionary theory (even the ummm...very likely to be true parts) is wrong and that their faith based initiative is right. The evolutionists in retaliation, who don't want to see the potentially minor instances of BS in their theories replaced by the COMPLETE BS (at least in a scientific sense, since NONE of it is testable) in Intelligent Design, attack any and all questioning to protect evolution. In the end, the only thing we will eventually lose in all of this is our chance to find out more about the truth concerning the topic. And that is really a shame.
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Thanks for your answer. :)
On the other hand, it was scientists initially (not ID advocates) who wondered if the "abiotic theory of life" was right (this theory is another one of these "adjunct theories" which is now packaged in with evolutionary theory as a whole by most scientists). It seems hard for a serious scientist to accept that if you zap a pool of inorganic chemicals long enough that things like human beings and the empire state building will eventually arise out of it. The mathematics tell us that this scenario is possible, but at the same time extremely unlikely. So there are arguments both for and against this theory.
I had a look at the abiotic theory http://en.wikipedia.org/wiki/Abiogenesis.
My first thought is: At the beginning of our universe, the big bang was far too hot to allow any trace of life. But we are alive today. So, simple logic says that life was necessarily created from inert matter at some point, somewhere. The only real questions are how it happened, which mechanism? Abiogenesis is the only explanation by default. Or, do you suggest a god that would use inert matter and purposefully build life from it? That explanation gives rise to more questions than answers...
I don't think it is so hard to imagine the first bacterias emerging from inert matter if you give it enough time (a billion year, it takes a long while) and proper conditions. Then life is started and ready to spread. As for humans and Empire State building, it is a matter of evolution from the bacterias. It is not directly related with abiogenesis.
My second thought: As you said, mathematics say the abiogenesis is possible but extremely unlikely. But, the universe is huge with billions of billions of stars, some with planets. So, although the probability of life starting on a specific planet is extremely small, given the huge number of planets, life has a good probability to rise from inert matter somewhere at some point. Recent discoveries of exoplanets suggest that the number of planets in the universe is enormous.
Actually, what seems the most convincing for me is what I explained first: life had to start from inert matter at some point. I see no way out from this simple fact. ::)
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There are other ways to explain the origin of life outside of the abiotic theory without invoking some sort of "God" or other supernatural explanation. For example, there is the age old debate between the modern abiotic theory and the seeding theory as an explanation for how life arose on earth:
http://www.semp.us/publications/biot_reader.php?BiotID=450
What upsets me I suppose is that biologists aren't even introduced to these alternative theories anymore in mainstream education (even though as you can see from the site, this other theory was suggested by Arrhenius and Kelvin among others). And there is no funding to test for them. It is sort of like, you either take the abiotic theory at face value or become a priest :-\
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Seeding theory just pushes abiotic moment back in time and away from Earth, so in no way it falsifies abiotic theory in general.
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Yes, but it introduces the idea that life may not have originated directly here on earth in a pool of chemicals which is the central argument in what we call the "abiotic theory". Therefore, it offers the tantalizing possibility to dodge many of the mathematical difficultites that draw the abiotic theory into question to begin with (nevermind the benefit to astronomy if we were to find solid evidence for the space seeding theory!). This idea should at least be tested so we can try to find evidence that decides between the different possibilities before we incorporate one or the other into evolutionary theory. Without going into its history there is strong resistance at the moment against testing this theory...largely out of political fear that the ID nuts will use it as an argument to claim "Darwinian Evolution is wrong" since the abiotic theory has been pushed so much with it to this point. Which is stupid! If other sciences worked this way, we'd still be measuring heat as the "caloric".
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@renge ishyo Evolution deals only with inherited changes to species over time. The question to how life first arose is a separate question and does not effect the validity of Darwinian Evolution in the slightest. Do not try to cloud one issue by raising the other; that is pseudo-scientific rubbish. As Borek and cth have pointed out life did come from elementary particles giving rise to atoms which gave rise to simple inorganic chemicals which combined together to give DNA and single cell life which then evolved. That happened somewhere in the universe since the big bang. We are the proof that it did occur. The probability of it happening was very long but there has been a long time and many planets for it to happen on. I think it happened here on Earth and we are now here to ask how and why only because it did happen here a few billion years ago.
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I mentioned that it was a separate theory before...but the issue is clouded because the abiotic theory IS packed in with what we refer to when we say "Darwinian evolution". Didn't you study it along with evolution? Don't you accept it as part of evolution? The two shouldn't be so intimately linked (as it wasn't Darwins idea at all), but if you question the abiotic theory people will automatically think you disbelieve all of evolution as well. Try it at parties if you don't believe me! This was more or less what I meant when I said evolutionary theory is really many theories and not one theory, and that it's problems stem from this. I have merely gotten off the point by further discussing the particular example I chose...sooo, how bout another example?
Another theory that should at least be thoroughly tested at the molecular level is Lamarckism. This was the old idea that there might be molecular mechanisms that allow an organism to modify it's genetic code based on adaptations to the environment. This is another old idea that doesn't invoke a "God" and should be taken seriously by biologists, but it is nevertheless shunned from academics because at one point in time it was seen as an alternative to the "everything arises from random mutation" idea that has become the mainstream thought in Darwinian theory. What if both mechanisms end up being true? How can we tell if we don't test for both? In a way, modern Darwinian theory has turned into something more like an atheists version of the church of Galileo's time, suppressing any ideas and observations that might modify or change the dogma. It is sad, but it has become the same sort of thing that it originally rebelled against.
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Actually, I have some difficulty to understand your point Renge. But, perhaps we are not talking about the same thing? When you said:
Yes, but it introduces the idea that life may not have originated directly here on earth in a pool of chemicals which is the central argument in what we call the "abiotic theory".
You are mentioning "earthly abiogenesis", while I am refering to abiogenesis in general (be it earthly or extraterrestrial). Am I right?
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You are mentioning "earthly abiogenesis", while I am refering to abiogenesis in general (be it earthly or extraterrestrial). Am I right?
Yes, I am not disagreeing with you at all cth! The seeding theory IS also an abiogenetic theory as far as I am concerned (that's my argument; it should be on equal footing as far as testing is concerned with the other). Although some have pointed out to me that it is not *necessarily* an abiogenetic theory (which umm...is why I think it is not on equal footing); nevertheless, it is strongly implied by the details that scientists put forth concerning how it come about that it is abiogenetic (and when I talk about a theory put forth by others it carries with it the ideas put forth by others). This is what I mean when I say it should be tested along with other ideas such as the one currently in vogue that life originated here directly on earth in a pool of chemicals and not elsewhere. Borek is right when he says that the seeding theory pushes back the problem, but that is O.K. with me, especially if one day evidence shows up and it ends up being true! Why should evolution operate on our proposed time table here on earth anyways? The theory might even get stronger if that linear timetable suddenly is blasted right open.
Nevertheless, it is not what modern students are taught when they are introduced to the "abiotic theory". The term "abiotic theory" is now being directly associated with "earthly abiogenesis" in the mainstream community with the miller-urey experiment as its strongest experimental support. This theory, whether you are for it or not, is questionable at present. The reason why this theory is so popular is because evolutionary descriptions are currently focused on linking one species to another here on earth. Adding in the possibility of new genes being delivered to species here on earth from space would basically invalidate all the work these scientists are doing if it was shown to be the case. So the earth abiogenesis then becomes the accepted theory for modern evolutionists out of convenience. Yay! In the past, there have been other terms used for the earthly abiogenesis theory such as "spontaneous generation", but the problem there is who is to say the seeding theory can't have seeds that "spontaneously generated" themselves somewhere in space? It would be easier to get the terminology straightened out if we would at least acknowledge that some issues concerning evolution still remain to be conclusively resolved.
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You guys are funny. The term law is used when there is a formula E=mc^2, the term theory is used when describing nature. This strict usage has slackened starting in the early 1900s.
To address the OP's question, I believe the first speciation event was observed by David Reznick. As I'm not a biologist I'm not familiar with the exact paper. However the public's misconceptions of evolution are addressed in this 2009 paper by none other than David Reznick. It is forum policy not to distribute copyright material, but in this instance I think it would be prudent to bend that rule. See attachment.
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Mitch (what happened to Dr. Mitch?) that article was mostly about finding molecular justification for a few of Darwin's original ideas. The funny thing that both sides don't seem to get is that most of the criticism of "Darwinian Evolution" has nothing to do with Darwin's ideas, but with ideas lumped in with it later on. When someone says "Darwinian Evolution" it is sort of like how "Newtonian Physics" came to represent all of classical physics including classical electrodynamics even though Newton personally said nothing on these matters. While there are some that deny all of evolution and so would disagree with the ideas in the Origin of Species, these people are just as nuts as the people that accept the whole thing at face value.
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Still a doctor, it was just a passive way to let everyone know.
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Another theory that should at least be thoroughly tested at the molecular level is Lamarckism. This was the old idea that there might be molecular mechanisms that allow an organism to modify it's genetic code based on adaptations to the environment.
I do not believe evolution to be a feedback system, as Lamarckism suggests. I believe the evidence is showing that gradual changes, give rise to slightly better survival odds. better survival = higher probability to reproduce & pass on genes. We we see everyday is a result of many gradual changes.
Those are my two cents, but I must pay respect to Mayner, Darwin, Dawkins, and few other authors I have read.
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I do not believe evolution to be a feedback system, as Lamarckism suggests. I believe the evidence is showing that gradual changes, give rise to slightly better survival odds. better survival = higher probability to reproduce & pass on genes. We we see everyday is a result of many gradual changes.
And this is precisely what the molecular evidence doesn't go along with...gradual changes. Even if you take into account extinctions, the taxonomy at the DNA level overall does not reinforce the simple linear macroscopic designations. The most obvious example of this are the archaea, which were supposed to be the primordial species that gradually changed into bacteria which in turn gradually changed into us. Except err...it is now known that genetically the archaea have more in common with us than they do with the bacteria (although they still do have a lot of overlap with bacteria as well in ways that we don't)! Crap. And sometimes we see strange things down there, like two species thought to be unrelated at all showing more genetic overlap in certain places than ones we believed were more related, etc. Basically the nice gradual change idea is sort of like an idealized family tree whereas the genetic code indicates things were more like a Shakespeare play...
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you forgot mutation which can add genetic information
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I don't remember what the original question was. My thoughts are most people are confused about "Evolution." They struggle with gradualism and the concept of time. Most people want prove (for example), one day there was a reptile, it laid an egg, and the egg hatched into a bird. This would easily connect the reptile to bird theory, but it simply did not happen & could not happen this way. Another example would be an ancient cat birthed two cubs, one with stripes and one with a mane; giving rise to tigers and lions. This did not happen, either. Speciation requires group separation with low probability of interbreeding. This takes time.
Speciation has been proven in plants. For example, scientists have found "Plant C" (in the wild), it looks a little like "Plant A" but also looks similar to "Plant B". In a lab this scientists cross pollenate Plant A with Plant B, and "Plant C" is formed.