Isn't the "science" of intelligent design an oxymoron? On Tue, Jun 8, 2010 at 11:47 AM, G Money <[email protected]> wrote: > > This is wonderful. > > I would love to see an equally well crafted summary of the "science" of > intelligent design...if anyone has that in them. > > Great stuff Judah. > > On Mon, Jun 7, 2010 at 4:29 PM, Judah McAuley <[email protected]> wrote: > >> >> Evolution is a very commonly misunderstood term and the >> socio-political use of the word doesn't really match up with the >> scientific use, leaving things rather muddy. Even within the >> scientific realm there is a lot you have to specify in order to really >> get to what you mean by the word, it's a big discipline. It is kind of >> like saying "I don't believe in Physics" when really you may just be >> disputing the validity of String Theory or the Copenhagen >> Interpretation. >> >> Getting back to macro evolution and micro evolution, those are terms >> commonly used outside of the discipline to distinguish between >> phenotypic (stuff you can see, like beak shape or fur color) change >> within a species over time versus the act of speciation, that is, the >> formation of a new species. The first kind is often called micro >> evolution and is really kind of a red herring because, broadly >> speaking, everyone has agreed on that for hundreds of years. People >> saw the change in heritable characteristics (those that can be passed >> on to children) long before the time of Darwin and Lyle. Gregor Mendel >> laid out the concept of what we now call Mendelian Genetics (obviously >> he didn't know anything about DNA), showing how heritable traits were >> passed on in pea plants at the same time that Darwin was publishing >> his work. Mendel was a priest and there was no theological trouble >> with his work because it was just documenting how a species passes on >> variation. Those who try to dispute Creationism by showing incremental >> evolution within a species are doing them a disservice because that >> really isn't the heart of the dispute at all. >> >> Then we get to what Kris is calling Macro Evolution, which is a term >> used to refer to the production of a new species from an existing >> species. This is where the dispute over "evolution" really comes into >> play, it isn't a disagreement about whether things evolve, it is a >> disagreement about speciation. Darwin called his work "On the Origin >> of Species" or, in the long form, "On the Origin of Species by Means >> of Natural Selection, or the Preservation of Favoured Races in the >> Struggle for Life". The title of his work is the key here, he wanted >> to show a mechanism for the creation of new species from existing >> species. >> >> Darwin had a couple of key insights and, put together, they are >> generally known as "descent with modifications and preferential >> survival". It works thusly: >> >> 1. In every generation, there are multiple values in a population for >> a heritable trait >> 2. Those values are not passed on with complete fidelity. Some >> offspring will get one value for a trait, some another value, some a >> value not obviously present in the parents. >> 3. Those values can have differential survival outcomes, ie, members >> with one value may be more likely to survive and pass on that value >> than members with another value. >> >> This, in a nutshell, forms the basis of Evolution, why species change. >> Darwin then went on to show that that algorithm (though he would not >> have called it that) can produce speciation. As a side note, people >> differ in their distinction on what constitutes a species. Some people >> take a very cut and dried line that says two populations are different >> species if they cannot breed and produce viable offspring. While that >> is the easiest way to define it, it isn't very useful in a practical >> context because then you have to explain why lions and tigers aren't >> different species. More generally, a species is usually defined as a >> population that is genetically and physiologically distinct and that >> does not naturally interbreed with another population. So while lions >> and tigers can mate and produce offspring, they do not do so in the >> wild and they form distinct populations and have important genetic and >> physiological differences. The bit about interbreeding, of course, >> goes out the window when you are talking about asexually reproducing >> (and especially self propagating) organisms. >> >> There are a couple different methods of speciation normally >> recognized. The most common kinds are called Allopatric and Peripatric >> speciation. These both are a result of separation of populations of a >> given species, usually geographically. For instance, a segmenting of >> the range of a species due to deforestation where the populations in >> the two new regions no longer encounter one another much because their >> range isn't contiguous any longer. These two populations start out >> with differences in their genetic make up that would normally be a >> wash when the whole population is interbreeding. However, due to the >> lack of ongoing contact between the populations, the differences >> between the pool of variation combined with the continuing process of >> descent with modification and natural selection can produce enough >> variation over many generations to make the two populations distinct >> enough that they not only do not but can not interbreed successfully. >> This is known as allopatric speciation. >> >> Peripatric speciation is a more extreme version of allopatric >> speciation, usually involving substantial geographic separation like >> the formation or colonization of islands. It is also the subject of >> the discipline known as Island Biogeography. Basically, there are >> times when otherwise unreachable spots are reached by a group of >> individuals, like when land bridges appear during periods of extremely >> low sea levels. These new populations may then be cut off again and >> this new, isolated, population will be characterized by having a very >> small pool of genetic diversity to start with. This is known as the >> Founder Effect. In these cases, traits which might be very rare in the >> parent population become much more common in the child population >> because of the small number of individuals contributing to the overall >> starting pool. The founder effect, combined with the fact that >> natural selection often rewards different characteristics in a small, >> island setting than it does on a large contiguous region, often means >> that these isolated populations will diverge quickly and dramatically >> from the parent population. Peripatric speciation is the reason why >> Australia largely has marsupial mammals whereas marsupial mammals are >> quite rare everywhere else. They got cut off early in the changes in >> mammalian physiology and due to low gene flow in from the outside, the >> trend continued there but diverged elsewhere. >> >> There are other types of speciation discussed, such as sympatric >> speciation. Sympatric speciation is a hotly disputed area, however, as >> it hypothesizes how two species can arise in the same area without >> substantial separation. As far as I'm aware, there aren't any >> instances of this type of speciation that have been shown to happen in >> the wild, but I haven't really studied the subject in awhile, so I'm >> not sure what the current state of research on sympatric speciation >> is. >> >> Speciation has been observed in the laboratory in a number of >> experiments. The most common (among animals) are with Drosophila, >> fruit flies, because of their short generation time, wide use in the >> lab and high rate of natural genetic variability. A summary of some of >> the instances of observed speciation can be found here: >> http://www.talkorigins.org/faqs/faq-speciation.html It also contains >> a further discussion of what constitutes a species and a discussion of >> the Biological Species Model. >> >> A lot to digest, I know, but hopefully it will help people thinking >> about the arguments around Evolution and, more specially, that we are >> really talking about an argument regarding speciation. >> >> Cheers, >> Judah >> >> >> >> On Mon, Jun 7, 2010 at 11:08 AM, Kris Sisk <[email protected]> wrote: >> > >> >>Is the dogs/wolves example even an example of evolution? Isn't it >> >>domestication? >> >> >> > >> > Domestication is usually a perfect example of that type of evolution. I >> think that micro evolution is the one that would be wolves to dogs, but I >> never could keep the two terms straight for some reason. Another example >> would be the finches observed by Darwin just prior to writing the Origin of >> the Species. They had obviously evolved differing beaks for differing >> purposes, but they were all still finches. If those finches had evolved into >> hummingbirds, for example, that would be macro evolution (assuming I haven't >> gotten the two terms mixed up). >> > >> > Now before anyone jumps down my throat, I'm just illustrating the point. >> > >> >> > >
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Order the Adobe Coldfusion Anthology now! http://www.amazon.com/Adobe-Coldfusion-Anthology-Michael-Dinowitz/dp/1430272155/?tag=houseoffusion Archive: http://www.houseoffusion.com/groups/cf-community/message.cfm/messageid:320612 Subscription: http://www.houseoffusion.com/groups/cf-community/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/groups/cf-community/unsubscribe.cfm
