It seems creationists never get tired of this one. I've lost count of how many times I've been told that it makes evolution impossible, and I just ran into someone using it again over here.
Let's begin by getting something straight. This is the actual, real life, second law of thermodynamics:
∫(δQ/T) ≥0
It is not some kind of cosmic legislation written down in the Universe's list of statutes that states "things shall not get more complex naturally!" It's a mathematical expression. More precisely, it's a mathematical expression that describes a specific set of conditions. But when you need to explain what that means to people who don't "speak math" you have to translate it into english instead, which is where the problem happens.
You can do it well:
"The total energy available to do work in an isolated system can never increase." or... "The total entropy of an isolated system can never decrease" or several other formulations that are all equally valid. (The "isolated system" part is particularly critical)
Or you can do it like creationists:
"The Second Law of Thermodynamics, simply stated, says that everything has a tendency to run down, decay and get worse, if left to itself.
Click the link, I don't make this stuff up. They actually say this. The second law of thermodynamics makes abandoned houses get run down and cars left outside get trashed. It's not just that guy, I've heard this so many times I've lost track. Ugh.
While we're on the subject, you can do the same thing with the meaning of entropy.
Real definition: Entropy = The total energy in a system no longer available to perform work.
Creationist definition: Entropy = Disorder and decay!
Now to get into why creationists have no idea what they're talking about when it comes to thermodynamics we should start by defining some terms...
Entropy: See above
System Boundary: The dividing line between the system you are examining and it's surrounding environment. Can be physical, or simply definitional... but MUST BE SPECIFIED.
Open System: A system which can exchange matter and energy with it's surroundings across the system boundary.
Closed System: A system that can exchange energy but NOT matter across it's boundary.
Isolated System: A system that cannot exchange either matter or energy across it's boundary.
It's only in that last one where the second law says you can't see a decrease in entropy. Where there is no external source of energy providing fuel for the process the system is going to continuously use up the energy it has available to work with until it's all gone.
Creationists try to claim the second law means evolution is impossible because it causes localized decreases in entropy. For the second law to actually say that was impossible evolution would have to be doing this without getting the energy for it from anywhere... the earth would have to be an isolated system that does not receive any external energy input.
So... the next time a creationist tells you the Second Law makes evolution impossible then assuming it's daytime tell them to go outside, look up, and ask them if they see a giant ball of burning plasma in the sky bombarding them with light and heat. (a.k.a.... energy!)
I almost feel embarassed to be burning a post on such a worn out issue, but as long as creationists keep using it people need to keep correcting them I guess.
Showing posts with label Intelligent Design. Show all posts
Showing posts with label Intelligent Design. Show all posts
6.10.2010
The (Vastly) Underappreciated Importance Of Falsifiability
I would say this is something that's usually only properly appreciated by people with a science background... except I've met so many people who work in the sciences who also don't get it that I would feel dishonest making that claim.
The quick and dirty version of the concept of falsifiability is if you're going to make a claim, or present a theory/hypothesis... you need to know how to tell if you're wrong. That sounds like it should be simple and straightforward but it just flies right over the heads of an astounding number of people on a regular basis. Religious people in particular, but it's not just isolated there. I know a disturbing number of people who think of themselves as rational scientifically minded individuals and are actually quite skilled and knowledgeable in the sciences, who simply do not properly appreciate why falsifiability is so important. They reach the point of knowing they have to be able to tell if they're wrong so they can slap a "right" or "wrong" label on an idea and stop there. It's a little more than that.
See, the primary way we figure out if we're wrong about something is we use it to make a prediction, then test it. When we hit a situation where something is unfalsifiable it's generally for one of two reasons.
No... that's useless.
In this context, "predict anything" means no matter what happens, no matter what outcome a test has, you can claim it was predicted by your "theory". To demonstrate why this is so spectacularly pointless, an example of such a "theory":
Newton Vs. The Matter Directing Elves
The quick and dirty version of the concept of falsifiability is if you're going to make a claim, or present a theory/hypothesis... you need to know how to tell if you're wrong. That sounds like it should be simple and straightforward but it just flies right over the heads of an astounding number of people on a regular basis. Religious people in particular, but it's not just isolated there. I know a disturbing number of people who think of themselves as rational scientifically minded individuals and are actually quite skilled and knowledgeable in the sciences, who simply do not properly appreciate why falsifiability is so important. They reach the point of knowing they have to be able to tell if they're wrong so they can slap a "right" or "wrong" label on an idea and stop there. It's a little more than that.
See, the primary way we figure out if we're wrong about something is we use it to make a prediction, then test it. When we hit a situation where something is unfalsifiable it's generally for one of two reasons.
- It can be used to predict nothing.
- It can be used to predict anything.
No... that's useless.
In this context, "predict anything" means no matter what happens, no matter what outcome a test has, you can claim it was predicted by your "theory". To demonstrate why this is so spectacularly pointless, an example of such a "theory":
Newton Vs. The Matter Directing Elves
5.30.2010
Proving Evolution : Post 7 - Piling On... And Finishing Up.
Chromosome Fusions
A lot of animals have different numbers of chromosomes. An often raised objection to evolution is that this means at some point an organism would have been born with a different number of chromosomes from the rest of the population but it wouldn’t have had anything it could mate with that had the same number of chromosomes so the mutation wouldn’t have been preserved. This objection is based on the false idea that animals with different numbers of chromosomes are incapable of interbreeding.
If this was true the existence of modern domesticated horses would be something of a genetic miracle. Domestic horse populations have 64 chromosomes… wild horse populations have 66.
In reality chromosome fissions and fusions are hardly an unknown phenomenon.
One such fusion clearly occurred after the hominids branched off from the rest of the primates. Humans have 23 pairs of chromosomes, all the rest of the primates have 24. Evolutionary theory and the nested hierarchy then tells us this means there was a fusion event which reduced the number of chromosomes in humans to 23 after their ancestors split off from the wider population. If this prediction is true, we should be able to see clear evidence of it in a chromosomal analysis.
Lo and behold:
Chromosome fusion
There is overwhelming evidence that human chromosome 2 is the product of the fusion of two chromosomes which just happen to look basically identical to two chromosomes found in chimpamzees… as seen in the image included in the above link.
Note that this is not just evidence that human and chimp genetic sequences kind of look the same. The telomere and centromere sequences in the middle of human chromosome 2 are clear indication that that chromosome is the product of the combination of two different pre-existing independent chromosomes. If humans had been independently created in their modern form rather than having evolved into it from a common ancestor with other animals there is no reason to expect find something like this in the human genome… but there it is.
Biogeography and Paleobiogeography
Biogeography is the mapping of spatial patterns of biodiversity. Ie: which animals and types of animals are found in which geographic regions. Combined with paleobiogeography, which is the mapping of the same in the fossil record, this presents us with yet another piece of corroborating evidence for evolution. Fossil forms which are morphologically transitional stretching back from modern animals back to earlier ones are found in geographically contiguous locations throughout the record. Obviously this is something which is to be expected if all those transitional forms were to have evolved one from the other. If they were not transitional ancestral organisms but rather just completely independent separately created lineages of some kind there would be no reason to expect the geographical distributions we do observe that they fall into.
Properties of DNA Replication
A lot of animals have different numbers of chromosomes. An often raised objection to evolution is that this means at some point an organism would have been born with a different number of chromosomes from the rest of the population but it wouldn’t have had anything it could mate with that had the same number of chromosomes so the mutation wouldn’t have been preserved. This objection is based on the false idea that animals with different numbers of chromosomes are incapable of interbreeding.
If this was true the existence of modern domesticated horses would be something of a genetic miracle. Domestic horse populations have 64 chromosomes… wild horse populations have 66.
In reality chromosome fissions and fusions are hardly an unknown phenomenon.
One such fusion clearly occurred after the hominids branched off from the rest of the primates. Humans have 23 pairs of chromosomes, all the rest of the primates have 24. Evolutionary theory and the nested hierarchy then tells us this means there was a fusion event which reduced the number of chromosomes in humans to 23 after their ancestors split off from the wider population. If this prediction is true, we should be able to see clear evidence of it in a chromosomal analysis.
Lo and behold:
Chromosome fusion
There is overwhelming evidence that human chromosome 2 is the product of the fusion of two chromosomes which just happen to look basically identical to two chromosomes found in chimpamzees… as seen in the image included in the above link.
Note that this is not just evidence that human and chimp genetic sequences kind of look the same. The telomere and centromere sequences in the middle of human chromosome 2 are clear indication that that chromosome is the product of the combination of two different pre-existing independent chromosomes. If humans had been independently created in their modern form rather than having evolved into it from a common ancestor with other animals there is no reason to expect find something like this in the human genome… but there it is.
Biogeography and Paleobiogeography
Biogeography is the mapping of spatial patterns of biodiversity. Ie: which animals and types of animals are found in which geographic regions. Combined with paleobiogeography, which is the mapping of the same in the fossil record, this presents us with yet another piece of corroborating evidence for evolution. Fossil forms which are morphologically transitional stretching back from modern animals back to earlier ones are found in geographically contiguous locations throughout the record. Obviously this is something which is to be expected if all those transitional forms were to have evolved one from the other. If they were not transitional ancestral organisms but rather just completely independent separately created lineages of some kind there would be no reason to expect the geographical distributions we do observe that they fall into.
Properties of DNA Replication
Proving Evolution: Post 6 - Phylogenetic Analysis
Previously we skimmed over the creation of a phylogenetic tree with a simplified example of how they are constructed using only a few major genetic characteristics. In the last post we touched on how even much less obvious genetic characteristics can also be analyzed for phylogenetic relationships… like ERVs. As the discussion progresses the importance of the nested hierarchy and it’s nontrivial nature will continue to become more apparent. Like in the case of ERVs it goes significantly beyond such superficially obvious observations as “we never expect to find snakes producing orange juice”. It applies right down to the molecular level even to genetic sequences which have absolutely no reason, from the standpoint of observing the “obvious” groupings of organisms, to display nested hierarchical patterns... except that evolutionary theory says they should because of their patterns of common ancestry.
When actually constructing a consensus phylogenetic tree such as the one shown at (Life on Earth) not only are a great many genetic traits taken into account, but a rigorous mathematical analysis of the actual DNA sequences of the organisms in question (where such DNA is available) is done to create cladograms (the branching diagrams showing patterns of descent) with the highest possible percentage confidence. These techniques have been tested in situations where the correct evolutionary relationships are already independently known for an absolute certainty to verify that they do in fact not simply produce an evolutionary relationship but the correct evolutionary relationship to within a very low margin of error..
One example:
http://mbe.oxfordjournals.org/cgi/reprint/19/2/170.pdf
In the paper above the researchers started with an original sample of DNA from Trypanosoma cruzi. They bred it over successive generations and allowed it to continually mutate, and every 70 generations 2 of the resulting DNA sequences were isolated at random and then used to found new populations. This process was repeated 4 times until 16 different ancestral DNA sequences had been generated. A rough diagram illustrating the process is shown in Figure 1 on page 2 of the paper.
Now this might not sound like much… but the number of possible phylogenetic trees that can be generated for a group of N different related genetic sequences increases in a steeply exponential manner as N increases. That number is described by the equation: (2N-3)!/((2^(N-2)) (N-2)!).
For 2 organisms this gives us only 1 possible tree (which should be obvious).
For 3 organisms it gives us 3 possible trees.
For 5 it gives us 105.
For 10 it gives us over 34 million.
For 16 organisms that gives us a total of (29!)/((2^14)(14!)) = 29!/1.428x10^15 = 6.19028x10^15 possible phylogenetic tree diagrams that can be generated. Picking the correct one isn’t something you can do by luck... unless of course you can beat better than 6 quintillion to 1 odds. And if that's the case, why aren't you in Vegas right now?
When actually constructing a consensus phylogenetic tree such as the one shown at (Life on Earth) not only are a great many genetic traits taken into account, but a rigorous mathematical analysis of the actual DNA sequences of the organisms in question (where such DNA is available) is done to create cladograms (the branching diagrams showing patterns of descent) with the highest possible percentage confidence. These techniques have been tested in situations where the correct evolutionary relationships are already independently known for an absolute certainty to verify that they do in fact not simply produce an evolutionary relationship but the correct evolutionary relationship to within a very low margin of error..
One example:
http://mbe.oxfordjournals.org/cgi/reprint/19/2/170.pdf
In the paper above the researchers started with an original sample of DNA from Trypanosoma cruzi. They bred it over successive generations and allowed it to continually mutate, and every 70 generations 2 of the resulting DNA sequences were isolated at random and then used to found new populations. This process was repeated 4 times until 16 different ancestral DNA sequences had been generated. A rough diagram illustrating the process is shown in Figure 1 on page 2 of the paper.
Now this might not sound like much… but the number of possible phylogenetic trees that can be generated for a group of N different related genetic sequences increases in a steeply exponential manner as N increases. That number is described by the equation: (2N-3)!/((2^(N-2)) (N-2)!).
For 2 organisms this gives us only 1 possible tree (which should be obvious).
For 3 organisms it gives us 3 possible trees.
For 5 it gives us 105.
For 10 it gives us over 34 million.
For 16 organisms that gives us a total of (29!)/((2^14)(14!)) = 29!/1.428x10^15 = 6.19028x10^15 possible phylogenetic tree diagrams that can be generated. Picking the correct one isn’t something you can do by luck... unless of course you can beat better than 6 quintillion to 1 odds. And if that's the case, why aren't you in Vegas right now?
5.29.2010
Proving Evolution : Post 5 - Non Coding Genetic Sequences
Alright… so we’ve covered radiometric dating and why it’s considered reliable, the geologic column and the fossil record conforming to overall evolutionary expectations, the existence of transitional sequences within the fossil record showing evidence of past evolutionary events, and the distribution of genetic characteristics among modern life that conforms to the pattern produced by a biological evolutionary process in which traits are inherited from common ancestry. We’ve covered that the fossil record also overlays that distribution to a high degree of accuracy with characteristics in inner nested groups in the hierarchy having their first representations later in the fossil record.
Next piece of evidence. Vestigial and other non-coding genetic characteristics.
Vestigial genetic sequences.
Looking at the nested hierarchy shown in the third image of post 4 in this series we can see humans and chimps (along with the rest of the primates) are grouped inside a larger group of animals. Their grouping also indicates a recent evolutionary divergence from that group. This is corroborated by the fossil record. Now… the members of this larger group of animals are capable of synthesizing ascorbic acid, also known as vitamin C. Humans and primates are not. As our little evolutionary branch of the tree only recently diverged from the rest of the group, and since large scale gene deletions are extremely rare (usually a gene is disable because of a disabling mutation… it is not completely removed from the DNA) if evolutionary theory is correct we should expect to still be able to find clear evidence of the genetic sequence responsible for the synthesis of ascorbic acid in humans and primates (even though we are not capable of such synthesis) and subsequently compare it to the functional sequence in other animals and determine what alteration made to it caused it to become non-functional. This is a prediction unique to evolution, relying entirely on the premise that we inherited our genetic material from an ancestral source we share in common with those other animals in the larger group.
This prediction was confirmed in the early 1990s with the identification of the L-gulano-gamma-lactone oxidase genetic code in humans and primates. Subsequent analysis showed it had experienced a frame shift mutation that had caused it to become non-coding.
Let me summarize this again to ensure it is fully understood.
1. Humans and primates do not produce their own ascorbic acid. From simple direct observation there is NO reason to think they would have the genetic code required to do so.
2. The nested hierarchical structure humans and primates fit into within an evolutionary framework however indicates that they diverged from a wider group at a time when ascorbic acid synthesis was already present in the genome of the group, and thus that genetic information should have been inherited.
3. Since we do not produce ascorbic acid, and since it would be unusual to have an entire gene simply deleted in entirety from the genome, evolutionary theory and evolutionary theory alone predicts we should find vestigial genetic code for the production of ascorbic acid which was inherited from an earlier common ancestor in the human and primate genomes… and which has since been deactivated by mutation.
4. They looked for it. They found it. Deactivated by a frame shift mutation that wiped out the end of the sequence on that gene. Prediction confirmed.
Once again… I can’t stop someone from looking at this clear example of evidence of common evolutionary descent and declaring “it just looks that way because it was designed that way” but at this point, whether it’s impossible to disprove that statement or not, it would be beginning to get silly… proposing that the same non functional section of genetic code would be designed into humans and primates… and in such a way that it looked just like a functional piece of code in other animals that had undergone a mutation. If you want to design an organism that doesn’t synthesize its own ascorbic acid you sure as heck don’t need to give it most of the genetic code to do so only to make it not do so!
And this is hardly the only example of a vestigial genetic sequence that fit this pattern…. Olfactory receptor genes, RT6 protein genes, etc… the genetic code of all kind of organisms is packed with pseudogenes that used to code for something in an ancestor… still codes for that same function in related organisms, but has been disabled in one particular group by a crippling mutation while the bulk of the genetic code remains present.
Continuing on that line, there is also the matter of endogenous retroviral insertions.
Next piece of evidence. Vestigial and other non-coding genetic characteristics.
Vestigial genetic sequences.
Looking at the nested hierarchy shown in the third image of post 4 in this series we can see humans and chimps (along with the rest of the primates) are grouped inside a larger group of animals. Their grouping also indicates a recent evolutionary divergence from that group. This is corroborated by the fossil record. Now… the members of this larger group of animals are capable of synthesizing ascorbic acid, also known as vitamin C. Humans and primates are not. As our little evolutionary branch of the tree only recently diverged from the rest of the group, and since large scale gene deletions are extremely rare (usually a gene is disable because of a disabling mutation… it is not completely removed from the DNA) if evolutionary theory is correct we should expect to still be able to find clear evidence of the genetic sequence responsible for the synthesis of ascorbic acid in humans and primates (even though we are not capable of such synthesis) and subsequently compare it to the functional sequence in other animals and determine what alteration made to it caused it to become non-functional. This is a prediction unique to evolution, relying entirely on the premise that we inherited our genetic material from an ancestral source we share in common with those other animals in the larger group.
This prediction was confirmed in the early 1990s with the identification of the L-gulano-gamma-lactone oxidase genetic code in humans and primates. Subsequent analysis showed it had experienced a frame shift mutation that had caused it to become non-coding.
Let me summarize this again to ensure it is fully understood.
1. Humans and primates do not produce their own ascorbic acid. From simple direct observation there is NO reason to think they would have the genetic code required to do so.
2. The nested hierarchical structure humans and primates fit into within an evolutionary framework however indicates that they diverged from a wider group at a time when ascorbic acid synthesis was already present in the genome of the group, and thus that genetic information should have been inherited.
3. Since we do not produce ascorbic acid, and since it would be unusual to have an entire gene simply deleted in entirety from the genome, evolutionary theory and evolutionary theory alone predicts we should find vestigial genetic code for the production of ascorbic acid which was inherited from an earlier common ancestor in the human and primate genomes… and which has since been deactivated by mutation.
4. They looked for it. They found it. Deactivated by a frame shift mutation that wiped out the end of the sequence on that gene. Prediction confirmed.
Once again… I can’t stop someone from looking at this clear example of evidence of common evolutionary descent and declaring “it just looks that way because it was designed that way” but at this point, whether it’s impossible to disprove that statement or not, it would be beginning to get silly… proposing that the same non functional section of genetic code would be designed into humans and primates… and in such a way that it looked just like a functional piece of code in other animals that had undergone a mutation. If you want to design an organism that doesn’t synthesize its own ascorbic acid you sure as heck don’t need to give it most of the genetic code to do so only to make it not do so!
And this is hardly the only example of a vestigial genetic sequence that fit this pattern…. Olfactory receptor genes, RT6 protein genes, etc… the genetic code of all kind of organisms is packed with pseudogenes that used to code for something in an ancestor… still codes for that same function in related organisms, but has been disabled in one particular group by a crippling mutation while the bulk of the genetic code remains present.
Continuing on that line, there is also the matter of endogenous retroviral insertions.
Proving Evolution: Post 4 - The Nested Hierarchy
This is one of the most fundamental concepts which need to be understood if you want to properly grasp the evidence for evolution. It describes the structure of the pattern of biological diversity produced by an evolutionary process. Evolution is the only process ever proposed which predicts and explains such a pattern.
The nested hierarchy is a consequence of the way in which genetically heritable traits are transmitted from generation to generation. For an illustration, see the following:
“NGT” represents a point at which a new genetic trait is introduced to a population which through natural selection comes to be spread throughout that population to the point where it reaches fixation in the genome. From that point on it will be heritable by all the future generations of that population. Such an event can occur at any time, in any group, but due to the nature of biological reproduction and genetic heritability it can be propagated only “downstream” of the point at which it is introduced. So, the earlier in the process a new trait is acquired, the wider a cross-section of the final population it will be present in. Any traits acquired after that point will be found grouped into smaller and smaller cross-sections of the population and always completely contained within the groupings of earlier acquired traits.
For example, let's say that trait "D" up there was the introduction of, say, a specific alteration to the eye of one species that significantly improved it's visual acuity. That species up top on the other hand, developing along that path that leads to them having traits "A" and "F"... their eyes suck. Well, they're out of luck. Because that new trait for improved vision is only able to be passed on through inheritance so they're not getting it. It can only propagate downstream in the process.
To contrast, if we were examining the products of a common design process we not only could, but would expect to see such outcomes all the time. If while working it’s way along those branching design paths a designer came up at some point with that “D” trait and noticed… “hey, this works better than anything I’m using over on that “AF” development line” then of course any designer would utilize that knowledge in his other designs. For example: The human eye vs. the octopus eye. The eyes on an octopus are far superior in design to our eyes. Their optic nerves attach in a manner which does not produce a blind spot in their vision, that same attachment anchors their retinas, and because all the nerve connections come in through the rear of the eye they do not degrade visual acuity. In our eyes the optics nerve pokes through the back of the eye causing a blind spot which our brains must constantly imperfectly correct for, because our retinas are not anchored by the nerve attachments a sharp blow to the head can detach them, and because the nerve attachments are in the front they get in the way of incoming light screwing up our visual acuity. Any designer who knew how to build an octopus eye would know there was a better way to design an eye than that. The evidence indicates however that the octopus evolutionary path simply experienced optical development which was superior to anything that occurred in human ancestry after the two branched off from each other… and after that branching occurred there was no way in which to share the advances experienced on one line with the other. Not within an evolutionary framework.
Now, what do we see when we look at the pattern of biological diversity present today? Here’s an example using 30 major examples (animated gif, modified from the universal phylogenetic tree diagram in Doug Theobald’s “29 evidences for macroevolution”. Takes a little while to cycle through.)
The nested hierarchy is a consequence of the way in which genetically heritable traits are transmitted from generation to generation. For an illustration, see the following:
“NGT” represents a point at which a new genetic trait is introduced to a population which through natural selection comes to be spread throughout that population to the point where it reaches fixation in the genome. From that point on it will be heritable by all the future generations of that population. Such an event can occur at any time, in any group, but due to the nature of biological reproduction and genetic heritability it can be propagated only “downstream” of the point at which it is introduced. So, the earlier in the process a new trait is acquired, the wider a cross-section of the final population it will be present in. Any traits acquired after that point will be found grouped into smaller and smaller cross-sections of the population and always completely contained within the groupings of earlier acquired traits.
For example, let's say that trait "D" up there was the introduction of, say, a specific alteration to the eye of one species that significantly improved it's visual acuity. That species up top on the other hand, developing along that path that leads to them having traits "A" and "F"... their eyes suck. Well, they're out of luck. Because that new trait for improved vision is only able to be passed on through inheritance so they're not getting it. It can only propagate downstream in the process.
To contrast, if we were examining the products of a common design process we not only could, but would expect to see such outcomes all the time. If while working it’s way along those branching design paths a designer came up at some point with that “D” trait and noticed… “hey, this works better than anything I’m using over on that “AF” development line” then of course any designer would utilize that knowledge in his other designs. For example: The human eye vs. the octopus eye. The eyes on an octopus are far superior in design to our eyes. Their optic nerves attach in a manner which does not produce a blind spot in their vision, that same attachment anchors their retinas, and because all the nerve connections come in through the rear of the eye they do not degrade visual acuity. In our eyes the optics nerve pokes through the back of the eye causing a blind spot which our brains must constantly imperfectly correct for, because our retinas are not anchored by the nerve attachments a sharp blow to the head can detach them, and because the nerve attachments are in the front they get in the way of incoming light screwing up our visual acuity. Any designer who knew how to build an octopus eye would know there was a better way to design an eye than that. The evidence indicates however that the octopus evolutionary path simply experienced optical development which was superior to anything that occurred in human ancestry after the two branched off from each other… and after that branching occurred there was no way in which to share the advances experienced on one line with the other. Not within an evolutionary framework.
Now, what do we see when we look at the pattern of biological diversity present today? Here’s an example using 30 major examples (animated gif, modified from the universal phylogenetic tree diagram in Doug Theobald’s “29 evidences for macroevolution”. Takes a little while to cycle through.)
5.27.2010
Proving Evolution: Post 1 - Dating Methods
First, a note on the title of the series of posts. Science does NOT "prove" things. Anything. Ever. (No, really... not anything). "Proof" is for math and alcohol. What we are really talking about here is "evidentially supported to the greatest extent manageable". But if you say that then people who don't understand science just declare "Aha! But you didn't PROVE it!" ...as if that was relevant. So, we end up with titles like this. Any science purists out ther who are outraged at the inexact terminology, my abject apologies.
Now, getting down to things. This is a series of posts I wrote up a long, long time ago while banging my head against the brick wall that is "people on the internet who believe in Creationism". I think it does a pretty decent job of covering a LOT of information while maintaining a balance between being not so technical the average non-scientific type can't understand it if they take a real shot at it... but technical enough that it remains accurate and not distorted by horrendous over-simplification. I'll be throwing them up here over he next week or so.
====================================
Dating Methods
Carbon (C14) Dating:
C14 dating is used to date the remains of organic, air breathing organisms up to approximately 50,000 years old. While living these organisms breathe the atmosphere, which contains trace amounts of the radioactive isotope Carbon 14 that is constantly being produced in the upper atmosphere through neutron bombardment. So long as they are alive the C14 content of their bodies will remain in equilibrium with the C14 content of the atmosphere. When they die respiration ceases, along with the intake of any new quantities of C14. Over time the C14 decays with a half-life of 5568 years into N14. By measuring how much C14 remains un-decayed the time elapsed since the death of the organism can be determined.
A common misperception of C14 dating is that it relies on the assumption that atmospheric C14 levels remained constant in the past so that we can know how much C14 an organism started off with. While this was an assumption made when the technique was first developed about half a century ago it has not been the case for several decades. Historical atmospheric C14 concentrations have been charted and calibrated using both dendochronology and lake varves which incorporate organic sediment in their annual deposition layers. One particularly good example of this is Lake Suigetsu in Japan where cores have been drilled to a depth of 45,000 annual layers. Because of the layering process we have an independent count of exactly how old every layer is… and because the layers incorporate organic material (the remains of a surface algae which dies off every year and sinks to the bottom of the lake) each layer can be C14 dated as well, and using these two data points the atmospheric C14 content can be charted all the way back for the entire time span encompassed by the varve core. This data (cross-checked against multiple other sites and methods) then allows us to apply C14 dating to other sites already knowing how fluctuations in atmospheric C14 concentrations in the past will effect the results… and allowing us to calibrate out error that would otherwise be introduced due to those past fluctuations.
Now, getting down to things. This is a series of posts I wrote up a long, long time ago while banging my head against the brick wall that is "people on the internet who believe in Creationism". I think it does a pretty decent job of covering a LOT of information while maintaining a balance between being not so technical the average non-scientific type can't understand it if they take a real shot at it... but technical enough that it remains accurate and not distorted by horrendous over-simplification. I'll be throwing them up here over he next week or so.
====================================
Dating Methods
Carbon (C14) Dating:
C14 dating is used to date the remains of organic, air breathing organisms up to approximately 50,000 years old. While living these organisms breathe the atmosphere, which contains trace amounts of the radioactive isotope Carbon 14 that is constantly being produced in the upper atmosphere through neutron bombardment. So long as they are alive the C14 content of their bodies will remain in equilibrium with the C14 content of the atmosphere. When they die respiration ceases, along with the intake of any new quantities of C14. Over time the C14 decays with a half-life of 5568 years into N14. By measuring how much C14 remains un-decayed the time elapsed since the death of the organism can be determined.
A common misperception of C14 dating is that it relies on the assumption that atmospheric C14 levels remained constant in the past so that we can know how much C14 an organism started off with. While this was an assumption made when the technique was first developed about half a century ago it has not been the case for several decades. Historical atmospheric C14 concentrations have been charted and calibrated using both dendochronology and lake varves which incorporate organic sediment in their annual deposition layers. One particularly good example of this is Lake Suigetsu in Japan where cores have been drilled to a depth of 45,000 annual layers. Because of the layering process we have an independent count of exactly how old every layer is… and because the layers incorporate organic material (the remains of a surface algae which dies off every year and sinks to the bottom of the lake) each layer can be C14 dated as well, and using these two data points the atmospheric C14 content can be charted all the way back for the entire time span encompassed by the varve core. This data (cross-checked against multiple other sites and methods) then allows us to apply C14 dating to other sites already knowing how fluctuations in atmospheric C14 concentrations in the past will effect the results… and allowing us to calibrate out error that would otherwise be introduced due to those past fluctuations.
4.18.2010
People Don't Understand Probability
For my first substantive post here I'm going to take a look at an issue that's bugged me for some time. Reading a recent article written by Ervin Laszlo that once again demonstrated the problem is actually what finally pushed me to go ahead and start blogging.
The argument he presents is one a lot of people throw around without really understanding what they're saying. It can be basically summed up as "This thing happened... it was amazingly unlikely this thing happened by chance... therefore something must have caused/created/designed it." In order to illustrate why that article is completely wrong I usually find it's easier to deal with a different example of highly improbable outcomes occurring.
The odds of winning the Powerball lottery purchasing a single ticket are roughly 1 in 195 million. Let's say last week Joe Lucky bought one ticket and won the jackpot. The odds of him doing this by chance were, as stated, 195 million to 1. That's ridiculously unlikely. Do we therefore conclude the lottery was somehow designed to make him win since it was so unlikely that he would win by chance?
No, we don't. Most people understand that we don't. What most people do not fully understand is the reason we don't.
The argument he presents is one a lot of people throw around without really understanding what they're saying. It can be basically summed up as "This thing happened... it was amazingly unlikely this thing happened by chance... therefore something must have caused/created/designed it." In order to illustrate why that article is completely wrong I usually find it's easier to deal with a different example of highly improbable outcomes occurring.
The odds of winning the Powerball lottery purchasing a single ticket are roughly 1 in 195 million. Let's say last week Joe Lucky bought one ticket and won the jackpot. The odds of him doing this by chance were, as stated, 195 million to 1. That's ridiculously unlikely. Do we therefore conclude the lottery was somehow designed to make him win since it was so unlikely that he would win by chance?
No, we don't. Most people understand that we don't. What most people do not fully understand is the reason we don't.
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