posted
OK, I was just asking. Thanks to all of you who answered me politely. That was a long post of swbarnes, but I didn't read any of it. If he had anything interesting to say could someone bring it up?
So if an entire species doesn't have a single male/female pair as it's common ancestor, I take it that the idea is that a population of a species, separated from its parent group, develops over time until the entire population is a separate species from what it originally was? Is this the generally accepted manner in which most or all new species have arisen? If so, are there any known exceptions?
Fugu said this: "However, at no point will there be a break in their development. The population will be interfertile all the time. There is no point we will be able to say 'here is where it stopped being a finch', yet if the change becomes extreme enough, we will look at the beginning and the end and say, 'these are different.'"
Now, is the process I described in the previous paragraph a logical deduction of what must happen because although the changes are so gradual, the fossil record does not ever show this extremely gradual process? And I don't mean something as small as very similar species whose major distinguishing feature is a different size beak. I mean all the huge gaps between whatever led to a bat, and the bat itself.
In other words, is this process (which I understand is essentially a part of punctuated equilibrium) something that shows that Evolution actually happened in spite of what the fossil record shows? Because if so, I think that the idea that the fossil record is just "icing on the cake" might actually be wishful thinking.
Tresopax, I know what the definition of a tautology is. I was alluding to the idea (perhaps not necessarily true) that something that is a tautology may be so by mere virtue of the fact that it is self-evidently true, and one cannot desrcibe what that something is without formulating a tautology. By that reasoning, natural selection is a tautology by the strength of its "self-evident-ness." That reasoning probably has some flaws in it, but I haven't gotten into it. It doesn't really matter to me because like I said before, the process of natural selection does seem to be self evident.
Posts: 1286 | Registered: Dec 2005
| IP: Logged |
posted
Of course, there is the problem that you seem to be ignoring, if evolution had nothing to do with all those organisms:
Where did those fossil species come from, how did they get there, through what mechanism did these different kinds of species exist at different times, where did the current species, that obviously did not exist back then, come from, and where are these processes occuring today, where can we see them, and/or how did those processes stop?
This is just wondering what a decent explanation would be.
Posts: 1577 | Registered: Sep 2005
| IP: Logged |
posted
I mean, seriously, let's assume we know nothing of evolutionary theory, and/or it's totally false:
The biggest question is: How the HECK did those animals and plants that are so very different, get there, where did they go, and why are no modern animals there? How did they occur? etc etc etc.
Further, I'd ask questions about genetics, some of which are very, very interesting.
Posts: 1577 | Registered: Sep 2005
| IP: Logged |
posted
I wasn't ignoring it, Megabyte, I just didn't think it was pertinent.I'm not trying to ascertain what precisely did happen. I'm just asking whether the official explanation holds water, or if it has some pretty gaping holes in it. You're still requiring that before I disregard one theory as impossible or highly unlikely, or at the very least missing some very important and basic premise, that I must first replace it with something better, or fill in that missing premise. A sound strategy if we are to avoid having to abandon the scientific process altogether, but not requiring it of myself allows me in the meantime to entertain the notion that an unscientific cause plays a part.
Posts: 1286 | Registered: Dec 2005
| IP: Logged |
posted
I think the assumption would be that they were created somehow, and something happened in the past that killed off very many of them. Then all the efforts would be directed toward how they were designed, and what the evidence shows about past events that killed off so many creatures. This is what people believed for thousands of years anyway. I think without Evolution getting in the way, they would have found all kinds of confirming evidence for a worldwide flood, especially if they took that as a fact of history and that's what they were looking for.
Posts: 1286 | Registered: Dec 2005
| IP: Logged |
posted
"A sound strategy if we are to avoid having to abandon the scientific process "
"but not requiring it of myself allows me in the meantime to entertain the notion that an unscientific cause plays a part. "
Thank you for being explicit about previous points I gave about you, but regardless:
It's good to try to poke holes in theories. But when a theory is useful, and actually has uses, like evolutionary theory does currently, abandoning it in a practical way before we have something to replace it with would be, well, impractical.
It'd be like abandoning all Newtonian physics as soon as we realized Mercury's orbit wasn't what the theory said it would be.
However, carry on asking these questions.
But part of my point is that asking where these fossils came from is a really useful question, and is pretty key to understanding what happened. Why they're there, and why current animals are NOT there, is big. Creating a theory to explain that is a big deal.
But to respond to your questions in the post I responded to, let's see:
You're asking, if I understand you correctly, if the concept that, basically, when a group of animals of a species are separated from another group through the various ways that occur, either geography or death or refusal to mate for one of the many reasons subgroups refuse to mate with each other, etc, and that that separation then allows them to slowly drift genetically, due to mutation, into separate species, while each point inbetween can mate with the groups in time before and after, etc, is working in spite of the fossil record?
Am I getting that right, I'm honestly trying to be sure if I understand your question.
Anyway, answering in response to this, I have several points:
Ring species, for one. In which that very thing has been observed in the real world. If you'd like, I'll find my examples. I can think of two off the top of my head, some species of iguana or something in California and Oregon, and some species of seagull, as well. I'll get you the specific species names, and the interesting data, as soon as I get home from work tonight.
Basically, with the seagulls at least, at one location there are two species, that are defintiely different, and cannot mate with each other. However, in each direction there are other groups of gulls that those two species can also mate with, and then other groups those can mate with, and so on, if you go around the circle in an unbroken line, until eventually you find the other species is part of that same line, where each group can mate with the ones directly East and West of themselves, thought at the two extremes they're different enough to literally be different species.
You know, that description sucked, I'll just cite my sources tonight and hope someone else explains before I get back if you have any trouble understanding my unclear words.
However, these ring species do exist. Theyr'e real. And the separate species are clearly different, with different traits. They aren't as different, say, as birds and lizards, of course. But they're certainly different species. And once species are separate, and mutations continue to accrue without interference from other groups... anyway, I'm not being clear here, I'm sure.
Second: the fossil record basically shows that a bunch of different species existed in the past, in snapshots of periods of time, and different groups of species existed in different periods of time, and our current species didn't exist right then. Further, they suggest that as time went on, the animals of a certain time period, at least some of them, looked similar, though different in some significant ways, to the ones that existed before, and also similar, though different in some significant ways, to animals of later ages.
Take those suspiciously whale-like creatures that lived on land in one age, the creatues that looked similar to those creatures, but lived in water, and then later still, more creatures that looked similar to those previous ones, but more similar to modern whales in multiple respects.
Seriously, I can show multiple examples, but it'll take me a couple minutes and I have work in 20 minutes, so if you can wait six hours I'll be back.
But anyway, it's an interesting point to keep in mind, whatever's true.
Anyway, as for your statement about the whole "group" thing being a part of punctuated equilibrium theory, I was udner the impression it was not specifically a part of that, though I could be wrong. I could show you examples of just that happening in the real world, too, or at least in laboratories.
Posts: 1577 | Registered: Sep 2005
| IP: Logged |
posted
No, don't worry about the ring species things. I know precisely what you're talking about, particularly with the gulls. It's a good illustration of a process that theoretically occurs over time, but represented in the here and now. Therefore, I find this to be empirical evidence of a process that Evolution requires, and quite different from most examples of so-called "evidence" for Evolution.
This is why I don't think ring species are very strong evidence for Evolution as a whole. The process they are akin to is a process that is required to explain large changes over time that have resisted detection in the fossil record. It's like a biologist (or paleontologist) is faced with a huge gaping hole between every major group of species, and then points to ring species and says "this is why you don't see any evidence of change in the fossil record." Not that it's wrong (though I think it is), but it seems somewhat like grasping at straws.
[edit] Not to mention my earlier complaint (in the earlier thread) that ring species only demonstrate a level of change that does not approach what needs to be explained in order for Evolution to be accurate.
Posts: 1286 | Registered: Dec 2005
| IP: Logged |
quote:Originally posted by Reshpeckobiggle: The process they are akin to is a process that is required to explain large changes over time that have resisted detection in the fossil record.
Right. The way that the gradual evolution of the mammal ear resisted detection in the fossil record...
Oh yeah, it didn't. You admitted that the record was there. You just thought it didn't exist, and you were wrong.
Your proclamations of what the fossil record does and doesn't show are wrong, and worthless. You proved that yesterday. You just don't know what the fossil record shows.
Your proclaimaitions of what the theory of evolution predicts about the origin of species are also wrong, and just as worthless. You just don't know what the theory of evolution says.
If you are going to ignore me becuase you find the truth insulting, then go on and do so. Everyone else will understand what that says about your character.
Posts: 575 | Registered: Feb 2007
| IP: Logged |
posted
The fossil record shows that extremely gradual process all the time. We're routinely running into groups of fossils of which some seem to be different species, but with which we can find very similar fossils that have very similar fossils that have very similar fossils, all the way to the ones that we call different from the first ones.
An excellent set of examples are the horse-related/ancestral fossils.
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
I just summoned a number of links, and a decent arguement, as I promised I would, and the stupid hatrack refuses to post my post, and then gets rid of the whole thing?!
*Cries* I spent the last half hour on this post that none of you guys got to see... and I have to wake up in five hours, and... and... AHHHHHHH!
quote:What we DON'T teach in science classrooms, though, are anti-scientific ideas, or ideas that are contradicted by the scientific method, as if they are science.
This isn't true. For instance, I was taught in middle school science class that electrons were little balls of mass that traveled in defined circular paths around the nucleus of an atom. This has long been contradicted by the scientific method, yet it was nevertheless taught to me as if it was scientific fact.
quote:Yeah, but Tres, it's taught as an outmoded and ultimately false view of the universe and explaining how our understanding of the universe progressed from geocentric to heliocentric has numerous lessons pertinent to science.
But it is still history being taught in a science class, thus demonstrating that it is definitely NOT true that only claims within the strictly defined bounds of science are discussed in science classes. We also extensively discussed math in science class - that too is not something derived from the scientific method.
On that note, there was at least a small section in the book on creationist disagreements over evolution. I don't think anybody in the class was confused by it. Nobody thought that, merely by discussing the fact that some people disagree with evolution, the book was implying creationism was supported by science.
quote:Tresopax, I know what the definition of a tautology is. I was alluding to the idea (perhaps not necessarily true) that something that is a tautology may be so by mere virtue of the fact that it is self-evidently true, and one cannot desrcibe what that something is without formulating a tautology. By that reasoning, natural selection is a tautology by the strength of its "self-evident-ness."
Being self-evident is never enough to make something a tautology, though. That's not what a tautology is.
A tautology is something that has to be true because of its logical structure. A logical argument is made up of two parts: the actual logic itself (IF, THEN, NOT) and the propositions that the logic manipulates ("dogs can bark", "pigs are pink", "the ocean is big"). So, you could make a logical claim like "IF dogs can bark THEN pigs are pink". If you took out the propositions then it would look something like this: "IF a THEN b". You are left with only the logical structure.
A tautology is when you can take out the propositions, and yet the statement still must be true simply because of the logical structure. "IF a THEN b" is not a tautology because we can imagine plenty of things we could substitute for "a" and "b" which would make the statement false. For instance, "IF dogs can bark THEN dogs are plants" is false. In contrast imagine this logical structre: "IF a AND b, THEN a". No matter what proposition we substitute for "a" and "b", any claim that follows this logical structure must be true, by virtue of the logical structure itself. "IF dogs can bark AND dogs are plants, THEN dogs can bark" is true. "IF a AND b, THEN a" is a tautology.
There are many self-evident claims that are not tautologies. For instance, "IF God is perfectly good THEN God would only do good things" is self-evidently true, but it is not a tautology because the logic is "IF a THEN b" which is not always true.
I don't know what the logical structure of the argument for evolution is, but I'm sure it's not of the sort where the logical structure by itself proves it to be true. Even if it were self-evident, it would not be a tautology.
Having said that, I don't see why being self-evident or beint a tautology are bad things.
Posts: 8120 | Registered: Jul 2000
| IP: Logged |
posted
swbarnes2, I understand how frustrated you must be, but do you really think that constantly insulting Resh (even if you feel it is deserved) is going to shame him into "seeing the light"? Do you really expect to be effective here? No matter how accurate you are or how strong your arguments, all you are doing is strengthening Resh's resolve to be unconvinced.
I honestly wish I could say otherwise, but judging from this thread I would not want to have you arguing for my side of any debate.
Posts: 1810 | Registered: Jan 1999
| IP: Logged |
posted
Hey Resh, question for ya. You said earlier something to the effect of "understanding implies belief and vice versa". Now I happen to disagree with this statement, but I can't remember whether you do or not. Care to refresh my memory? Thanks!
Posts: 1810 | Registered: Jan 1999
| IP: Logged |
quote:Originally posted by Tresopax: There are many self-evident claims that are not tautologies. For instance, "IF God is perfectly good THEN God would only do good things" is self-evidently true, but it is not a tautology because the logic is "IF a THEN b" which is not always true.
- - - emphasis added - - -
You went too far with this example. By many definitions of "perfectly good" and "only do good things", the two are the same. I mean they DO mean virtually the same thing. So you're saying "IF a THEN a", which is a tautology.
It's actually close to "IF you are tall THEN you are at least 6 feet tall". Being able to formulate the same thing in two different ways doesn't build "tautology free" statements.
quote:This isn't true. For instance, I was taught in middle school science class that electrons were little balls of mass that traveled in defined circular paths around the nucleus of an atom. This has long been contradicted by the scientific method, yet it was nevertheless taught to me as if it was scientific fact.
Then your science teacher was at fault. Because that is scientific theory. And any good science teacher, or at least the text book, should explain that what is taught in science classes are the best theories we have given the evidence, not facts that are absolutely true and can never be changed.
Posts: 3852 | Registered: Feb 2002
| IP: Logged |
Well, Ameterasu is the direct lineal ancestor of the current Emperor of Japan. Naturally that god would have to exist, or the current emperor would never have been born.
See? Evidence of the divine. (don't give me any of that silliness about the possibility tha tthey made it up for political reasons, were wrong, or anything like that. The Shinto religion and the emperor say it, that settles it, I believe it.)
Posts: 1577 | Registered: Sep 2005
| IP: Logged |
quote:And any good science teacher, or at least the text book, should explain that what is taught in science classes are the best theories we have given the evidence, not facts that are absolutely true and can never be changed.
That wasn't true either though - it wasn't even the best theory science had at the time. In fact, it was completely disproven, at the time they taught it to us. They already knew that electrons were not solid spheres that traveled in defined circular paths.
The reason they taught it to us was because the science teachers wisely realized that 12-year-olds would not understand the concept of electrons if they tried to explain actual quantum mechanics in middle school. We needed to be able to think of electrons in a more concrete way, even though electrons weren't really the way we were taught to think of them.
My point here is that science class is not sacred. There is no rule that we must strictly limit what is taught in a science classroom in any way. What really matters is that the students end up understanding what they need to.
Now.... whether Intelligent Design is something students need to understand is debateable. But, if your argument is that it shouldn't be in classrooms, one should not assert the reason is because "only correct science belongs in science class". That premise just isn't true. At least some nonscience belongs in science class - and possibly even some false science too.
quote:You went too far with this example. By many definitions of "perfectly good" and "only do good things", the two are the same. I mean they DO mean virtually the same thing. So you're saying "IF a THEN a", which is a tautology.
I don't agree that "perfectly good" = "only doing good things". For instance, it is possible to be imperfect (or even evil) but somehow still end up only doing good things, by accident.
Posts: 8120 | Registered: Jul 2000
| IP: Logged |
quote:Originally posted by Tresopax: I don't agree that "perfectly good" = "only doing good things". For instance, it is possible to be imperfect (or even evil) but somehow still end up only doing good things, by accident.
You can always twist definitions like that. I did say that they were virtually the same. Choose another example, less ambiguous. If you please.
posted
Okay, you could say "IF squares are four-sided closed shapes THEN squares have four corners" is self-evident. But it is not a tautology.
Posts: 8120 | Registered: Jul 2000
| IP: Logged |
posted
"This isn't true. For instance, I was taught in middle school science class that electrons were little balls of mass that traveled in defined circular paths around the nucleus of an atom. This has long been contradicted by the scientific method, yet it was nevertheless taught to me as if it was scientific fact."
I would suspect that if you had a good science teacher, he said "This is enough for us to understand right now," or something along those lines. Whether or not you remember the teacher saying something like, or whether or not the teacher was a good teacher, I don't know.
Posts: 4112 | Registered: May 2001
| IP: Logged |
quote: You went too far with this example. By many definitions of "perfectly good" and "only do good things", the two are the same. I mean they DO mean virtually the same thing. So you're saying "IF a THEN a", which is a tautology.
I agree with Tresopax on this example. You say that his two statements mean "virtually the same thing" but even if we grant that they do then it is still not a tautology. "IF virtually a THEN a" is NOT a tautology, "meaning virtually the same thing" is different from being the same thing for logical construction purposes.
And now a totally off-topic question: Hey Reshpeckobiggle, does your screen name mean something/have significance/come from somewhere in particular? I've just been curious about that in most of these threads.
quote:Originally posted by Enigmatic: You say that his two statements mean "virtually the same thing" but even if we grant that they do then it is still not a tautology. "IF virtually a THEN a" is NOT a tautology, "meaning virtually the same thing" is different from being the same thing for logical construction purposes.
Fair enough. It is not a tautology. My point was closer to: this is virtually a tautology. Tresopax gave a nice Logical explanation, but then “ruined” it with an ambiguous example. IMO.
quote:The reason they taught it to us was because the science teachers wisely realized that 12-year-olds would not understand the concept of electrons if they tried to explain actual quantum mechanics in middle school. We needed to be able to think of electrons in a more concrete way, even though electrons weren't really the way we were taught to think of them.
My point here is that science class is not sacred. There is no rule that we must strictly limit what is taught in a science classroom in any way. What really matters is that the students end up understanding what they need to.
Now.... whether Intelligent Design is something students need to understand is debateable. But, if your argument is that it shouldn't be in classrooms, one should not assert the reason is because "only correct science belongs in science class". That premise just isn't true. At least some nonscience belongs in science class - and possibly even some false science too.
I'm really not at all okay with this notion. Science should be taught incorrectly because some people assume that it's the only way to make it understood to some audiences?
No. Absolutely not.
That's not a wise decision. It's a terrible decision.
Posts: 15421 | Registered: Aug 2005
| IP: Logged |
posted
Wait, why do we have to go to the extremes ? “Simplifying” is not equivalent with “incorrect”.
I mean, is Newton’s Mechanics INCORRECT? We know Einstein got it better, but the “basic” form (or rather the “particular case”) is not to be thrown out (from the class room).
The same with the “planetary system” model of the atom. It is a model. It is a simplified model. Why would presenting it as such be wrong?
quote:Originally posted by suminonA: Wait, why do we have to go to the extremes ? “Simplifying” is not equivalent with “incorrect”.
I mean, is Newton’s Mechanics INCORRECT? We know Einstein got it better, but the “basic” form (or rather the “particular case”) is not to be thrown out (from the class room).
The same with the “planetary system” model of the atom. It is a model. It is a simplified model. Why would presenting it as such be wrong?
A.
This is an important distinction. Newtonian physics may be "wrong," insofar as we have since figured out that reality is more complex than his three laws, and that at certain scales those laws no longer provide sufficient accuracy. However, Newtonian physics as a model (i.e. as a theory) is still commonly used for everyday applications like architecture and industrial design, because the theory sufficiently approximates reality at that level.
I agree with Samprimary that Tresopax's example is actually a case of science taught badly, rather than "teachers wisely realiz[ing] that 12-year-olds would not understand the concept of electrons if they tried to explain actual quantum mechanics in middle school." Unlike Newtonian physics, the electrons-as-orbiting-particles model is just plain wrong, period. It has been falsified completely, and again unlike Newtonian physics, cannot even be used in lieu of the more complex orbital model in "simpler" applications. In suminonA's words, this isn't a simplification- it's incorrect.
As someone who was also taught that model in elementary school, I actually found it incredibly frustrating in high school and college having to unlearn the incorrect things I'd been taught, upon my introduction to orbital theory. I would rather have been taught about orbitals to begin with, even if the details might have gone over my 10 year old head.
Teaching creationism is, if anything, worse than teaching the orbiting electron model. At least the latter was actually scientific, and was duly disproven and therefore shelved as a theory based on the data. Creationism (or "intelligent design") is not scientific in the slightest, as it makes no predictions and cannot be falsified. This, by definition, should disqualify it from inclusion in science classes. Evolution, on the other hand, has 150 years worth of solid evidence backing it up- if you think about it, that's more than the theory of relativity.
Posts: 1321 | Registered: Sep 1999
| IP: Logged |
quote:Unlike Newtonian physics, the electrons-as-orbiting-particles model is just plain wrong, period. It has been falsified completely, and again unlike Newtonian physics, cannot even be used in lieu of the more complex orbital model in "simpler" applications. In suminonA's words, this isn't a simplification- it's incorrect.
I beg to disagree. The Bohr model of the atom (planetary model), although much simpler than the full quantum mechanics model, is neither falsified nor wrong. It is generally considered obsolete but it is worth mentioning that this simplified model is still used in X-ray and Auger spectroscopy because it is accurate enough for most applications.
Posts: 12591 | Registered: Jan 2000
| IP: Logged |
posted
Resh: I'm guessing that you haven't read "The Blind Watchmaker" by Dawkins, as it directly addresses many of the points you've made in recent discussions.
I would recommend it to you, not because I think it will change your mind - I'm sure that if you choose to ignore the basic premises the rest of the book won't convince you - but it is fascinating and quite well written. Even if you don't believe a bit of it, I personally found quite interesting all the various discussions we've had here recently, laid out in greater detail by an expert. Quite enlightening, to my mind.
Posts: 3950 | Registered: Mar 2006
| IP: Logged |
quote:I agree with Samprimary that Tresopax's example is actually a case of science taught badly, rather than "teachers wisely realiz[ing] that 12-year-olds would not understand the concept of electrons if they tried to explain actual quantum mechanics in middle school." Unlike Newtonian physics, the electrons-as-orbiting-particles model is just plain wrong, period. It has been falsified completely, and again unlike Newtonian physics, cannot even be used in lieu of the more complex orbital model in "simpler" applications. In suminonA's words, this isn't a simplification- it's incorrect.
Yes. Thank you. Thank you for adding to this. You use the Bohr model as a simplified model for things like, say, demonstrating chemical relationships in a visual format. It does not come accompanied inherently with misinformation, nor should it. You can demonstrate a valence shell with a line without teaching anyone that it's like a 'planetary orbit' of an electron 'planet' or anything like that.
Posts: 15421 | Registered: Aug 2005
| IP: Logged |
quote:Unlike Newtonian physics, the electrons-as-orbiting-particles model is just plain wrong, period. It has been falsified completely, and again unlike Newtonian physics, cannot even be used in lieu of the more complex orbital model in "simpler" applications. In suminonA's words, this isn't a simplification- it's incorrect.
I beg to disagree. The Bohr model of the atom (planetary model), although much simpler than the full quantum mechanics model, is neither falsified nor wrong. It is generally considered obsolete but it is worth mentioning that this simplified model is still used in X-ray and Auger spectroscopy because it is accurate enough for most applications.
My bad. It's been a long while since I took basic chemistry, and I know next to nothing about physics. Still, it should be pointed out that this only further supports the idea that even obsolete scientific theories have more predictive value than non-scientific pseudotheories like intelligent design.
So let me amend my comments above: the Bohr model may not describe reality as accurately as orbital theory, but like Newtonian physics (as well as Darwin's original, pre-genetics conception of evolutionary theory), it was arrived at using scientific principles. Therefore, it is not surprising that, within certain constraints, it can still be useful so long as its limitations based on modern data are kept in mind.
And Samp, no need for the passive aggression, eh? I can admit my errors. Unless that was all meant seriously. It's kind of hard to tell with you, sometimes.
Posts: 1321 | Registered: Sep 1999
| IP: Logged |
posted
Since I am openly and clearly stating my disagreement with an idea I have no idea how that became 'passive aggression?'
Posts: 15421 | Registered: Aug 2005
| IP: Logged |
posted
I was referring to this part of your statement:
quote:Yes. Thank you. Thank you for adding to this.
*shrug* It was unnecessary, if you ask me, but whatever. I have no desire to turn Junior Mod like Resh, so let me restate my apologies for my factual error. Shall we move on with our lives?
Posts: 1321 | Registered: Sep 1999
| IP: Logged |
posted
I try to thank people when they state portions of things I would like to have stated but didn't or couldn't as well and it's all serious and a 100% offhand 'thanks' -- I'm really actually seriously thanking you and continuing on your point!
Posts: 15421 | Registered: Aug 2005
| IP: Logged |
posted
Hi, everybody. I'm completely backed up with everything right now, and I have a vacation planned leter this week, so I might not get any time to post. Interesting (albeit off-topic) discussions. Tresopax, you know what you're talking about, but I think you are misunderstanding me. Try to look at what I'm saying from a different angle.
Mike, here's a hint: "Reshpeckobiggle," said Puddleglum. "Oh! screamed the Queen, gathering her skirts close about her ankles. "The horrid thing! It's alive." "He's quite all right, your Majesty, really, he is," said Scrubb hastily. "You'll like him much better when you get to know him. I'm sure you will."
Posts: 1286 | Registered: Dec 2005
| IP: Logged |
quote:Originally posted by Samprimary: I try to thank people when they state portions of things I would like to have stated but didn't or couldn't as well and it's all serious and a 100% offhand 'thanks' -- I'm really actually seriously thanking you and continuing on your point!
Oh, damn. In that case, egg on my face and foot crammed solidly in my mouth. Sorry, Samp.
Posts: 1321 | Registered: Sep 1999
| IP: Logged |
The title of this article annoys me. Is Human Evolution Accelerating? I understand the argument but the headline upsets me- like its oversimplified.
Posts: 1001 | Registered: Mar 2006
| IP: Logged |
posted
Now that I'm a bit less busy, I thought I'd talk about about some basic concepts like I said I would. I'm assuming that everyone knows certain things like DNA --> RNA --> protein, what nucleotides are, and the basics of how DNA replication works. If you don't know, that's fine -- you can either look things up or you can ask me questions if you don't know what a word means or you're confused about something.
Without further ado, I present Basic Molecular Biology Part I: PCR Primer*
The first thing you should know about is a technique called polymerase chain reaction (PCR). It's similar to the way your cells copy DNA, except it happens in a test tube. When your cells do it, there are a bunch of enzymes that do things. First, the two strands of DNA are separated, and then some short, complementary starter sequences called "primers" are added to the DNA. It would be something like this:
Once the primers are on, an enzyme called polymerase moves along each single strand, adding the proper complementary nucleotides to the end of the growing strand as it moves. Polymerase needs the primer to get started.
PCR is a similar process. Let's say I have a bunch of DNA from E. coli and I want to make copies of it. I take E. coli DNA and mix it with some polymerase, some primers, and some single nucleotides. Instead of using enzymes to separate the DNA, I use a cycle of heating and cooling. First, I heat the DNA up. That "melts" everything so there are just single strands floating around. Then I cool it down so that the primers can bind to the DNA. Then I warm it up a bit to the temperature that the polymerase works best at, and the polymerase latches on to the primers and adds nucleotides to the ends of them, thus making complementary strands to the original DNA. This happens several times, and in the end, you have a bunch of copies of the DNA that you put in.
posted
There's a way of copying DNA in a test tube. You start at a particular point, and make the copy longer, one nucleotide at a time. Do you know what I mean when I say that the strands are complementary?
Posts: 3546 | Registered: Jul 2002
| IP: Logged |
posted
Huh. I guess I killed the thread. <really obscure molecular biology joke> Maybe there was a ddNTP in that post? </joke>
Posts: 3546 | Registered: Jul 2002
| IP: Logged |
posted
I understood it (not the joke, the previous post) and I have zero education in molecular biology beyond whatever was touched on in high school biology class, FWIW. Thanks for sharing.
Posts: 3275 | Registered: May 2007
| IP: Logged |
Printer-friendly view of this topic
![[Razz]](tongue.gif)
![[Smile]](smile.gif)
![[Big Grin]](biggrin.gif)
![[Evil]](graemlins/evil.gif)
![[Wink]](wink.gif)
![[ROFL]](graemlins/rofl.gif)
