|
Post by solidsquid on Nov 2, 2004 2:57:52 GMT -5
EVOLUTION PT. IIPBS Evolution Resources:You can also download the documentary as well. FossilsFossil is derived from Latin for “dug up”. The fossil record provides a long history of the past ecology of earth going back billions of years. Fossils are not just “preserved bones” of organisms. Fossils can be: eggs, skin impressions, bones, coprolites (fossilized feces), or impression like footprints. UCMP – Geology and Geological Time ScaleSromatolites – Oldest FossilsTransitional FossilsFossil formation is often poorly understood if at all by many. As I stated before, fossils aren’t necessary just bones of extinct animals. Many attack the fossil record for “gaps” and claim it is not reliable or doesn’t prove anything. Fossilization isn’t a snap processes that occurs easily. Because of what is involved in the formation of fossils, it is actually, truly amazing the detail of the fossil record and shows the dedication and hardwork of many scientists and other colleagues of the span of many years. Fossil InformationREFERENCES:1) Levin, H. (1999). The earth through time (6th ed.). Orlando: Harcourt Brace. 2) Pojcta, J. & Springer, D. (2001). Evolution and the fossil record Alexandria: American Geological Institute. 3) Plummer, C., McGeary, D. & Carlson, D. (2003). Physical Geology (9th ed.). New York: McGraw Hill. 4) Wright, K. (2003). The first earthlings. Discover, 3, 24-25. 5) Alters, S. (2000), Biology: Understanding life (3rd ed.). Sudbury: Jones and Bartlett.
|
|
|
Post by solidsquid on Nov 2, 2004 2:58:53 GMT -5
There is not just one technique to date items that are found by scientists. Many creationists attack the methods of dating simply because they do not sync up with the < 10,000 year old biblical time. Relative Dating: Stratigraphy is used as relative dating. It utilizes the sedimentary layers of rock to determine what came before what. The older the layer or "strata", the further down it will be. StratigraphyFrom: encarta.msn.com/encyclopedia_761555455/Geology.htmlThe age of the earth as being older than what biblical text allows was accepted far before modern times and before Darwin's voyage on the Beagle. There is also fluorine analysis. Relative Dating and Fluorine Analysisid-archserve.ucsb.edu/Anth3/Courseware/Chronology/01_Contents.htmlMany methods were devised to extrapolate the age of the earth. However, with the discovery of radioactivity, our ability to say with certainty what the age was found its backing. Radioisotope Dating: This dating, called absolute dating, utilizes the decay of radioactive isotopes as clocks for dating materials. The most widely known method is the C-14 which has a half life of 5,730 years. How Carbon-14 Dating Works Radiocarbon DatingC-14 dating isn't the only method available though. Other methods include: Uranium-Lead method, potassium-argon method, rubidium-strontium method for example. Each has a different half-life and a range of time it can date accurately. So what makes these isotopes "absolute dating"? Plummer et al disucsses the radioactive decay of isotopes: Despite the attacks thrown by creationists, radioisotope dating gives us an extremely accurate timeframe for the age of fossils, artifacts, minerals, etc. Cross-checking is also used in conjunction with radiometric dates to obtain the most accurate and reliable date A Radiometric Dating Resource ListIsochron Dating by Chris StassenRadiometric Time ScaleRadiometeric Dating Does Work! by G. Brent DalrympleRadiometric Dating and the Geological Time Scale: Circular Reasoning or Reliable Tools? by Andrew MacRaeREFERENCES:Jurmain, R., Nelson, H., Kilgore, L., & Trevathan, W. (2000). Introduction to physical anthropology (8th ed.). Belmont: Wadsworth/Thomson. Levin, H. (1999). The earth through time (6th ed.). Orlando: Harcourt Brace. Plummer, C., McGeary, D., & Carlson, D. (2003). Physical geology (9th ed.). New York: McGraw Hill. Pojcta, J. & Springer, D. Evolution and the fossil record (2001). Alexandria: American Geological Institute.
|
|
|
Post by solidsquid on Nov 2, 2004 3:01:24 GMT -5
Natural Selection and other mechanisms of Evolution: Natural Selection is defined by Audesirk as: Natural selection is one of the most important if not the most important item in describing and researching into evolution. It is also probably the least well understood concept by the general public. People are fired at with phrases like "survival of the fittest" which was first coined by Herbert Spencer in support for his Social Darwinism which is a social theory and NOT a biological model for evolution. Jurmain et al. describe natural selection in action by telling about the peppered moth: This is where the misunderstanding that "fitness" is a tautology. What may incur a benefit to a species at one point in time may become a deteriment later. For some, the idea that fitness equals "power" or "being bigger and stronger" is inescapable and promotes the misunderstanding of natural selection. Drickamer et al. comments on this: Drickamer's last note points out another area of ignorance about natural selection. Natural selection works upon individuals BUT it is populations that evolve. Natural selection is also evident in strains of bacteria that become resistant to antibiotics. Natural selection should not be confused with artificial selection. Artificial selection is evident in domestic dog breeding. Alters comments on this: Natural SelectionHow Natural Selection Worksanthro.palomar.edu/evolve/evolve_2.htmReferences:1) Audesirk, T., Audesirk, G. & Byers, B. (2002). Biology: Life on earth. (6th ed.). Upper Saddle River: Prentice Hall. 2) Jurmain, R., Nelson, H., Kilgore, L. & Trevathan, W. (2000). Introduction to physical anthropology. (8th ed.). Stamford: Wadsworth/Thomson. 3) Drickamer, L., Vessey, S. & Jakob, E. (2002). Animal behavior: Mechanisms, ecology, evolution. (5th ed.). New York: McGraw Hill. 4) Alters, S. (2000). Biology: Understanding life. (3rd ed.). Sudbury: Jones and Bartlett.
|
|
|
Post by solidsquid on Nov 2, 2004 3:11:29 GMT -5
Here's some information I used for another forum, so of the information overlaps. Speciation is the process of a new independent species diverging from another existing species. Contrary to some creationist claims, new species don’t “pop” up out of nowhere. science.howstuffworks.com/evolution6.htmevolution.berkeley.edu/evosite/evo101/VSpeciation.shtmlen.wikipedia.org/wiki/SpeciationFirst we have to know what is meant by calling some group of organisms a species. “Species” is latin for “appearance”: www.mc.maricopa.edu/dept/d10/asb/anthro2003/origins/speciation.htmlThis definition is the biological species concept. Dr. Levin goes deeper into the species concept: Reproduction plays a crucial role in the formation of new species as well as other factors such as time. To continue on, we’d need a definition for what constitutes speciation. The definition is fairly simple and straightforward. The processes that lead to this formation are four major items, as Drickamer notes: Now, evolution not occurring is at the heart of the Hardy-Weinberg Equilibrium. They showed that without an forces acting on alleles, there would be evolution. This was summed up in their famous equation: p2 + 2pq +q2 = 1It represents a null model. Much akin to a null hypothesis used in experimental research. However, in order for something like this to ever occur, there must be some conditions that must be met: 1. There must be no mutation. 2. There must be no gene flow. 3. There population must be very large. 4. All the mating must be random. 5. There must be no natural selection. This, of course, would be next to impossible. Mutation, gene flow, natural selection, sexual selection, and small populations all occur and this drives evolution. These groups discussed are the major players, so to speak, but many items can contribute – compounding variables, as it were. MUTATIONSPoirier and McKee give a brief description of mutations: Mutation carries such a bad connotation with it. It is usually thought of as being a “bad” thing. However, depending on what change the mutation incurs, it may be “bad”, “good” or neutral for that individual. Pojcta and Springer comment on mutations: Somewhere along the line a mutation will provide an individual with a trait that aids it in its environment. This individual, being more prosperous in such an environment, will reproduce and spread its genes out within the population. The more offspring that carry this advantageous trait, the more that will reproduce. Mutations are always said to be uncommon. This is true but not to mean they only happen “once in a blue moon”, to use a time worn cliché. In fact, according to Agrawal: Also, earlier this year (January), a team of researchers at UCI reported that key mutations in the mtDNA of human cells may have allowed our migrating ancestors to adapt to the colder and more northerly climates. Also in the news of mutations: in June of this year, a story was reported in the New England Journal of Medicine about a German 4 year old who exhibited extraordinary muscle growth. He was born with a mutated DNA segment that blocks the protein myostatin which limits muscle growth. In a report on the subject from the Associate Press: Having such incredible strength may just hold advantages for the boy as he grows, provided it doesn’t hurt any other traits necessary for his normal development to adulthood. In a less complex natural dynamic reminiscent of our hunter-gatherer ancestors, such a mutation would definitely let the boy enjoy a hardy life. And his children might be even bigger and stronger than he is. Also some items within the human genome were discovered after its complete sequencing: NATURAL SELECTIONNatural selection is very misunderstood. Natural selection is all about reproduction…producing the most and most viable offspring. Audesirk defines natural selection: Natural selection will depend on the organism’s environment. Natural selection doesn’t work cause genetic changes and acts only on individuals, the result of natural selection on the individuals when viewed from a population perspective is evolution. Genetic variability gives the raw material with which natural selection works. Competition, predation, symbiosis, sexual selection, kin selection all contribute to the natural selection process. The tail of the peacock is an excellent example of sexual selection at work. Even more subtle processes are being explored and researched such as symmetry breaking: And niche construction:
|
|
|
Post by solidsquid on Nov 2, 2004 3:12:28 GMT -5
Continued:
Back to natural selection. One of the more popular examples to show natural selection was that of the peppered moth. Jurmain comments on this example:
A poignant, modern day change in the climate of the earth is being shown to be affecting many species. This sort of environmental pressure will undoubtedly result in some hardcore natural selection. Grossman sums it up succinctly:
Three categories of selection (based on their effects on a population) are recognized:
1. Directional selection 2. Stabilizing selection 3. Disruptive selection
Audesirk explains each one:
To summarize natural selection in a few words, Morris probably says it well:
|
|
|
Post by solidsquid on Nov 2, 2004 3:12:52 GMT -5
Continued again: GENE FLOWGene flow is a short, sweet and simple process. It is simply the flow of genes…that is introduction of genes from one population to another. GENETIC DRIFTGenetic drift is simply a change in the allele frequencies of a small population. It often involves what is known as a population bottleneck in which the size of the population is drastically reduced. The resulting generations will show that bottleneck because of the survivors reproduction. What happens is called the founder effect. The result Jurmain explains in more detail: The Lancaster County, Pennsylvania Amish are an example of the founder effect in that they carry a high prevalence of the Ellis-van Creveld syndrome, a genetic defect. They are descended from a small group of founders of approximately 200. SPECIATIONSpeciation comes in basically two forms: allopatric and sympatric. Allopatric speciation involves geographic isolation through maybe migration or geological occurrences. Sympatric speciation occurs when two populations share the same area. These mechanisms don’t take into account “spontaneous” speciation in polyploidy organisms like in many plants (which have multiple copies of chromosomes). In allopatric speciation, you begin with a population. Somehow the population is separated into two groups by, say, a natural phenomenon like a river changing course and isolating the two groups so they cannot come into contact with each other. Over time each will evolve to their respective environments to meet each ones selective pressures. Over time each group may become so different that they may not even be able to interbreed, this would constitute two different species. hoopermuseum.earthsci.carleton.ca//allopatric/present.htmSympatric speciation can occur when, say, climate changes force an ecological change like growing trees within a grass plane, creating two distinct habitats. Those staying within the wooded area will be under different pressures than the grasslands. Over time and through genetic divergence, the two habitat residents may become so different as to become unable to interbreed and this would result in two distinct species. Other factors could be involved in the evolution as well such as sexual selection (tree animals vs. grass animals); or temporal factors regarding circadian rhythms of the animals such as one becoming more nocturnal and the other remaining active during the day. A process called adaptive radiation can contribute to quick and varied speciation. Audesirk comments: When the dinosaurs went extinct at the K-T boundary, the mammals experience adaptive radiation by invading habitats that were formerly occupied by the dinosaurs…this allowed for the explosion of mammal species. This can also be seen in invasive species, when they are introduced to a new region by accident. This shows how powerful extinction of a species can be in jump starting the evolution of another. As hinted at earlier, with the speciation types comes isolating mechanisms. There are premating and post mating isolating mechanisms. Premating mechanisms include: geographical isolation, ecological isolation, temporal isolation, behavioral isolation, and mechanical incompatibility. Postmating mechanisms include: gamete incompatibility, hybrid inviability, and hybrid infertility. Geographic isolation would be like explained earlier. Ecological isolation as well. Temporal isolation may involve, like mentioned earlier, activity habits or, as in plants, pollination times. Behavioral isolation may be items such as courtship rituals. Mechanical incompatibility is self explanatory…the parts don’t fit or work together. Gamete incompatibility is the inability of one species’ gametes to fertilize another. Hybrid inviability means that a hybrid offspring doesn’t grow to maturity. Hybrid infertility is best shown by the mule, the infertile offspring of a horse and a donkey. www.talkorigins.org/indexcc/CB/CB100.htmlwww.talkorigins.org/indexcc/CB/CB101.htmlwww.talkorigins.org/indexcc/CB/CB101_2.htmlwww.talkorigins.org/indexcc/CB/CB102.htmlwww.talkorigins.org/indexcc/CB/CB150.htmlReferences:1) Audesirk, T., Audesirk, G., & Byers, B. (2002). Biology: Life on earth (6th ed.). Upper Saddle River: Prentice Hall. 2) Levin, H. (1999). The earth through time (6th ed.). Orlando: Harcourt Brace. 3) Drickamer, L., Vessey, S., & Jakob, E. (2002). Animal behavior (5th ed.). New York: McGraw Hill. 4) Poirier, F. & McKee, J. (1999). Understanding human evolution (4th ed.). Upper Saddle River: Prentice Hall. 5) Pojcta, J. & Springer, D. (2001). Evolution and the fossil record Alexandria: American Geological Institute. 6) Agrawal, A. F. (2002). Genetic loads under fitness-dependent mutation rates. Journal of evolutionary biology 15, 1004-1010. 7) Freeland, S. & Hurst, L. (2004). Evolution encoded. Scientific American 290(4), 84-91. 8) Stewart, I. (2003). How the species became. New Scientist 180(2416), 32- 35. 9) Laland, K. & Odling-Smee, J. (2003). Life’s little builders. New Scientist 180(2421), 43-45. 10) Jurmain, R., Nelson, H., Kilgore, L., & Trevathan, W. (1999). Introduction to physical anthropology. (8th ed.). Belmont: Wadsworth/Thomson. 11) Grossman, D. (2004). Spring forward. Scientific American 290(1), 84-91. 12) Morris, R. (2002). The big questions: Probing the promise and limits of science. New York: Henry Holt.
|
|
Filter
Seasoned Citizen
An opposing thumb has made all the difference!!
Posts: 221
|
Post by Filter on Nov 2, 2004 13:29:49 GMT -5
"Question is: Can you tell me anything you know about evolution, any one thing, any one thing that is true?" He could've gotten an equal reaction by asking, "Can you tell me when you all stopped beating your spouses?" A question of truth to a scientist should be received with blank stares (if it ever happened as described, I doubt). It is not a matter of truth, but rather the best and most thoroughly reviewed ideas to date that is of concern. Climb aboard a modern airliner and you can be rest assured that statistically you are on one of the safest forms of travel today. But make no mistake that you are on a craft that would be considered the ideal mechanism of flight one hundred years from now. Do we attack aerospace scientists today because of an aircraft design handbook written in the 1920's? Of course not. We understand that is a process of continuing improvement. Why then the attacks on Darwin? My point is, you have people who believe there is a truth, a real account of the creation if you will. But the mistake (or at least this particular questions, not originally yours), is that people are holding the scientific method to the same standard simply because it is in direct challange to their truth. Also, great job SolidSquid! I hope it is appreciated.
|
|
|
Post by droskey on Nov 2, 2004 13:42:12 GMT -5
Epton How is this different from the way other scientific theories are taught? For instance, how is evolution taught differently than the theory of heliocentricity.
Also, to teach a scientific theory, the theory does not have to be proven beyond a shadow of a doubt. It merely has to be supported by the evidence and be the "best that we currently have". Catastrophism is not supported by the evidence. Neither is the theory that biota has been static. I'm not sure if that is uniformitarianism. Evolution is taught because it is the best that we have given the data and the current state of scientific knowledge. The other theories are lacking.
Also note, that evolution does not have to explain every detail and every step along the way. It has to provide testable hypothesis and in the end give a plausible explanation for the observations that are made. Evolution does this. Specific theories about how sexual reproduction arises can be hotly debated without hurting the overall theory.
So I ask again, how is evolution treated differently than other scientific theories in the educational system? Is it treated differently than gravitation or heliocentricity? I don't believe that it is.
|
|
|
Post by droskey on Nov 2, 2004 13:43:04 GMT -5
Thanks for all the posts, solidsquid. I'll have to come back and read them when I have more time.
|
|
|
Post by solidsquid on Nov 2, 2004 14:02:46 GMT -5
No problemo.
|
|
Epton
Maverick's Chew Toy
Posts: 8
|
Post by Epton on Nov 2, 2004 20:52:43 GMT -5
Excellent Posts solidsquid, and almost near impossible to respond to in its entirety.
I just got off a plane in new york so i have a lull.
i saw your explanation of the Geoligic Coloum and The fossil dating systems.
here is an example of Discrepancys. and i apologise, i am not at my best right now.
The principal of Faunal succesion states that groups of fossils occur in a definite stratigraphic order, and can be used to date rocks. the major proponent of this Principle Geroges Cuvier stated that a fossil species that disappears from the strata, it will not reappear higher up in the rock record. this means that fossils can be used to date rocks, and that the disappearance of a species from the stratigraphic record is viewed as evidence of the extinction of a species or its evolutionary alteration into another kind of organism.
the statment that "fossils can be used to date rocks" contain several Uniformitarian and Evolutionary assumptions which would be challenged by a catastrpohist. the major one would be coelacanth. a six foot long fishassumed to be extinct because their fossils had not been found stratigraphically higher than Devonian and Jurassic Rock. according to the Principal of Faunal succesion this Fish should be extint.
But... in 1938 a coelacanth was caught in the nets of a south african fishng vessal, evidencing that no evolutionary change in the supposed 70 million years since its disappearance from the rock reord. since then, LIVE coelacanths have been photographed using a submersible on the floor of the indian ocean. this fish and i belive there are other examples just like this, prove there is no connection between whether an organism is found in rock strata and whether it was alive on the planet when those strata were laid down.
so, if in fact animals can disappear from the fossil record and reappear in unalterd forms in the present, the change in fossils from one stratigraphic level to the next cannot be viewed as evidence of Uniformitarianism/Evolution.
Suppose then, the Catastrophists response. Ecological zonation resulting from transgressing flood waters coupled with mobility and capacity to escape those waters.
ok. now neither theory proves it, and i am sure there are many of you with facts to debunk the Catastrophic model, being as it isnt altogether foolproof. my point is, on this single topic of the many that were put forth, is that Evolution isnt 100% reliable, with this example not even 50%.
Just some thoughts.
Thank you.
and again Thank you very much solidsquid, apparently no going on holiday for the ever faithful eh? well everyone have a great evening. im going to go check some of your election results.
Thanks again
|
|
kronus
Maverick's Chew Toy
A closet atheist. looking for communication with fellow freethinkers.
Posts: 19
|
Post by kronus on Nov 2, 2004 21:58:12 GMT -5
Solidsquid
I'm not attacking the theory, I'm saying it is incomplete. Evolition is only a part of the whole story. You missed the point.
|
|
|
Post by solidsquid on Nov 3, 2004 11:08:43 GMT -5
The principal of Faunal succesion states that groups of fossils occur in a definite stratigraphic order, and can be used to date rocks. the major proponent of this Principle Geroges Cuvier stated that a fossil species that disappears from the strata, it will not reappear higher up in the rock record. this means that fossils can be used to date rocks, and that the disappearance of a species from the stratigraphic record is viewed as evidence of the extinction of a species or its evolutionary alteration into another kind of organism. the statment that "fossils can be used to date rocks" contain several Uniformitarian and Evolutionary assumptions which would be challenged by a catastrpohist. the major one would be coelacanth. a six foot long fishassumed to be extinct because their fossils had not been found stratigraphically higher than Devonian and Jurassic Rock. according to the Principal of Faunal succesion this Fish should be extint. That technique is a relative dating method, not absolute and is utilized in the field with cross-checks. Geologists understand that there is not always going to be a perfect sedimentation, layer upon layer. Too many variables come into play that may change that strata. Dates are not reached upon one method alone. The coelacanths living today are not the same exact creatures as lived millions of years ago, the title "living fossil" is actually quite inaccurate. Evolution works through environment, if a morphology is adapted well to the environment and no major change occurs, that will persist for a very long time. However, morphological changes are not the only item considered in evolution. And there are even observable morphological differences in the living and the fossil coelacanths. www.talkorigins.org/indexcc/CB/CB930_1.htmlwww.don-lindsay-archive.org/creation/coelacanth.html As I explained above, the two aren't the same, the modern coelacanth, doesn't have a fossil record to speak of. The fossil and living are of entirely different families. Also, as I explained in my earlier posts, fossilization isn't a common process...it takes certain environmental requirements to fossilize. Even if this wasn't the case this has ability to strike a large wound in the evolutionary evidence nor does it tip the scales in favor of a catastrophic view. Besides the obvious questions of where did all that damn water come from; what is known about floods and their dynamics, it would be impossible to have created such as is seen in the strata. Nothing is 100% reliable. Scientific theories don't claim to be. However, given the past few hundred years of research, the evidence points towards a certain theory and is sure isn't creationism.
|
|
|
Post by solidsquid on Nov 3, 2004 11:11:09 GMT -5
Solidsquid I'm not attacking the theory, I'm saying it is incomplete. Evolition is only a part of the whole story. You missed the point. In a sense you are correct. Evolution on deals with change in living populations. Other items such as the origin of life do not fall under it. So, I suppose if you're talking about some grand unified theory of existence, then, yes you are correct.
|
|
|
Post by vertigo on Nov 3, 2004 14:02:33 GMT -5
Isn't the creation vs. evolution debate precisely about the origin of life? Are you saying that evolution is a red herring?
|
|