Evolution and Jesus

[gallo]

Quote by: LOGAN What is nonsensical is to declare any theory as having validity in the physical world.

So the explanations of the causes of events that we observe in the physical world don't have any validity in the physical world, is that what you're saying. Well, at least they have a lot more validity than claiming that the mythology of bronze age nomads is somehow valid. That is more than nonsense. It is the deepest sort of ignorance. Not only doesn't it have any validity, it is a denial of the physical world.

An "IDEA" is still only and idea, paint it, white wash it, declare it truth, tell us that this idea was arrived at through the scientific method, still it is nothing but a speculation based upon a few known facts, nothing more, nothing less, and it certainly is not valid as the TRUTH.

Can you say, "Run-on sentence?" I knew you could! Good for you.

One does not arrive at ideas through the scientific method. In science, one arrives at an idea through observations of reality and a wild guess. That's known as forming an hypothesis in science. The scientific method is used to test that idea to see if does actually have validity "in the physical world." It is tested by making a prediction of another observation that must necessarily be true if the hypothesis is correct. That prediction is then tested. If it works out, then the hypothesis is supported. Scientific theories are accepted by scientists because they have been stringently tested and have passed. Scientific theories are predictive of real events in the physical world. And yet, if we decided to forgo thinking, we might claim that scientific theories have no validity in the physical world. We see an apple fall from a tree and offer an explanation, but of course, according to non-thinking creationists, there is no validity in the physical world.

If indeed it were "empirical", as was suggested....we would empirically have a physical law and not a speculation.

Since I already explained this to you once, you are now being intentionally ignorant. I even explained to you what empirical means. You have now gone from someone who has doubts about science because you don't understand, to someone who is forlornly clinging to magic as an explanation because you don't like reality. And while we are talking about clinging to nonsense as you are doing, what exactly do you mean by "in the physical world?" Obviously you don't mean things like light, heat, the biosphere, gravity, the sun or moon and so forth. And certainly you don't mean living organisms. One would have to be a complete fool to claim that explanations of the physical world lack validity in the physical world.

The semantics used to describe this theory is an indoctrination into secular humanism on a play of words to take advantage of the gullible.

What does science have to do with secular humanism or semantics? Why don't you tell us your version so we can judge who is really gullible. While there is a philosophy of science, science is not a philosophy. Humanism is, but not a philosophy of science. Humanism was the philosophy of many of the founders of my country. It would be nice if you actually tried to educate yourself before you spoke. Otherwise you just make yourself look foolish.

What we are lead to do is to accept this "idea" as truth until a better truth comes along.

To represent science as "truth" is just dishonest. Perhaps if you had the integrity to learn what science is and how it works before you speak. It's a lot better than representing mythology at truth.

The truth does not evolve, what was true yesterday is true today.

And what was mythology yesterday is still mythology today and will be tomorrow. The problem is that science isn't represented as truth, just the best explanations we can figure out from what we know. As we learn more, what is true doesn't change, only our ability to explain in more detail.

An example would be the speculated age of the universe, the "so called truth" has evolved from being declared as 4 billion years to 13.7 billion years in just one generation, showing the absurdity in accepting anyones idea as a truth.

But even you state that it was a speculated age. Why on earth would anyone but a nut case call it truth. Besides, it wasn't in a single generation. Moreover, there hasn't been any evolution involved.

Thus, the first theory/idea was proven to be a lie, why should we blindly accept this next theory/idea as truth, when the last has fallen as a scientific LIE.?

What are you talking about since it wasn't declared to be truth except by the ignorant. "Thus", there was no lie. Moreover, in science, no theory is ever accepted blindly, nor is it accepted as truth. Those particular faults happen to belong to the religious who blindly accept the mythology of an old book as truth.

Instead of declaring the real truth of "we have reached an impasse of human comprehension", we merely speculate as to what that truth "might" be, until science and technology advances to add more speculation on top of an already unfounded speculation of truth.

But there is no impasse in science. We are still learning and still adding to the body of knowledge of science. Speculation is only the first step in advancing science, and science isn't a search for truth.

It's a house of cards waiting to be toppled by the next best idea. Always learning, but never coming to the knowledge of the truth. AND YES, THE "TRUTH" IS OFTEN FOUND TO BE "UNDEBATABLE", for the truth allows no room for human speculation.

Those who place mythology over reality have been saying that for 150 years. My whole career I've been told by religious nuts how creationism is on the verge of upsetting the whole of science. I haven't seen any signs of it yet.

[Rainbow]

Quote by: Zhavric Does Jesus hold any supernatural significance in the beliefs of theistic evolutionists, or is he merely a good person who taught important moral lessons.

The Old Testament vs. The New Testament is the answer.

[Piscean]

Zhevric are you going to attempt to answer my question or were the insults all you had?

[LOGAN]

Quote by: Zhavric Thank you for boldly declaring that you're woefully unaware of the facts surrounding science and evolution. Please take the time to educate yourself. You can begin here. The University of Berkley has put together an excellent walkthrough of the common misconceptions of evolution. Amongst them... Misconception: “Evolution is ‘just’ a theory.” Response: Scientific theories are explanations that are based on lines of evidence, enable valid predictions, and have been tested in many ways. In contrast, there is also a popular definition of theory—a “guess” or “hunch.” These conflicting definitions often cause unnecessary confusion about evolution. Misconception: “Evolution is a theory in crisis and is collapsing as scientists lose confidence in it.” Response: Scientists do not debate whether evolution (descent with modification) took place, but they do argue about how it took place. Details of the processes and mechanisms are vigorously debated. Antievolutionists may hear the debates about how evolution occurs and misinterpret them as debates about whether evolution occurs. Evolution is sound science and is treated accordingly by scientists and scholars worldwide.

Again, please present the Facts that declare evolution as a Physical Law of Nature. As I said, paint it any color you wish its still just an idea gestated within the mind of man, and unprovable. Simply by you or anyone declaring that science somehow validates this theory as factual does not present physical proof, only speculation. In fact, radio carbon dating is based upon a theory that assumes facts not in evidence, and those facts not evidenced are the constant decay rates of radio active materials that are assumed not to have existed at any time in the past before this "decay" morphed some element into another element by the process of decay. As far as any such test can "actually" be validated with any certainty would be that which is presented in recorded history, any statements claiming factual dates past such are only "assumptions" which are unprovable, unless one accepts the theory as valid proof, which it is not. Its the same principle as declaring the date of a fossil because it was found contained with a certain strata of rock...which was dated by the fossils found within it. Its circular reasoning. Again ideas are not facts, any way someone wishes to present them they are still speculated ideas. Thus evolution is not valid as scientific proof of anything, because the theory itself is unprovable. If it were provable it would be proven and not presented as theory. The semantical presentation of Hypothesis and Theory, presented as somehow presenting some theory as resting in empirical evidence is just that, semantics of language to convenience someone of facts which are NOT EVIDENCED. Logan.

[rez]

Quote by: LOGAN Again, please present the Facts that declare evolution as a Physical Law of Nature.

Cell Reproduction
Chromosome pairing
genes.

As I said, paint it any color you wish its still just an idea gestated within the mind of man, and unprovable. Simply by you or anyone declaring that science somehow validates this theory as factual does not present physical proof, only speculation. In fact, radio carbon dating is based upon a theory that assumes facts not in evidence, and those facts not evidenced are the constant decay rates of radio active materials that are assumed not to have existed at any time in the past before this "decay" morphed some element into another element by the process of decay. As far as any such test can "actually" be validated with any certainty would be that which is presented in recorded history, any statements claiming factual dates past such are only "assumptions" which are unprovable, unless one accepts the theory as valid proof, which it is not. Its the same principle as declaring the date of a fossil because it was found contained with a certain strata of rock...which was dated by the fossils found within it.

Changing the topic is not going to help your case. Trying to discredit geology is not helping your case for debunking Biology. It doesn't work like that sir.

Its circular reasoning.

Don't worry about circular reasoning. You need to first work on your own reasoning.

Again ideas are not facts, any way someone wishes to present them they are still speculated ideas.

Ideas are not facts. Zharvic never said they were. Restating the obvious does not help your case in discrediting Biology.

Thus evolution is not valid as scientific proof of anything, because the theory itself is unprovable. If it were provable it would be proven and not presented as theory.

And yet in reality it is a valid scientific explanation and is indeed the most current and best explanation. It is used in all of Biology and Medicine. The Theory of Evolution has shown great success and people are still learning from it.

I think you need to get a reality check and come back with an actually response.

The semantical presentation of Hypothesis and Theory, presented as somehow presenting some theory as resting in empirical evidence is just that, semantics of language to convenience someone of facts which are NOT EVIDENCED. Logan.

Are you an english major? When was the last time you even took a basic english course anyway?

A theory is composed of individual facts. Sorry if it conflicts with your supernatural religion, but thats the way it turned out...

[gallo]

Quote by: LOGAN Again, please present the Facts that declare evolution as a Physical Law of Nature. As I said, paint it any color you wish its still just an idea gestated within the mind of man, and unprovable. Simply by you or anyone declaring that science somehow validates this theory as factual does not present physical proof, only speculation. In fact, radio carbon dating is based upon a theory that assumes facts not in evidence, and those facts not evidenced are the constant decay rates of radio active materials that are assumed not to have existed at any time in the past before this "decay" morphed some element into another element by the process of decay. As far as any such test can "actually" be validated with any certainty would be that which is presented in recorded history, any statements claiming factual dates past such are only "assumptions" which are unprovable, unless one accepts the theory as valid proof, which it is not. Its the same principle as declaring the date of a fossil because it was found contained with a certain strata of rock...which was dated by the fossils found within it. Its circular reasoning. Again ideas are not facts, any way someone wishes to present them they are still speculated ideas. Thus evolution is not valid as scientific proof of anything, because the theory itself is unprovable. If it were provable it would be proven and not presented as theory. The semantical presentation of Hypothesis and Theory, presented as somehow presenting some theory as resting in empirical evidence is just that, semantics of language to convenience someone of facts which are NOT EVIDENCED. Logan.

I notice that you are unable to respond to my posts. Those are the ones where I explained where you are wrong and answered your questions. For example, science is not a process of formulating laws. Laws are only part of the data that goes into the development of theories. And, AGAIN, evolution is not an idea, it is an observation. I gave you some examples but you seem to prefer to close your eyes and stamp your fist and continue to spout the same errors.

Following your logic, the earth is flat and the sun circles around it, along with the stars, piles of trash will breed vermin, and night air causes diseases. How do you atually function in the modern world?

[LOGAN]

Quote by: Zhavric Thank you for boldly declaring that you're woefully unaware of the facts surrounding science and evolution. Please take the time to educate yourself. You can begin here. The University of Berkley has put together an excellent walkthrough of the common misconceptions of evolution. Amongst them... Misconception: “Evolution is ‘just’ a theory.” Response: Scientific theories are explanations that are based on lines of evidence, enable valid predictions, and have been tested in many ways. In contrast, there is also a popular definition of theory—a “guess” or “hunch.” These conflicting definitions often cause unnecessary confusion about evolution. Misconception: “Evolution is a theory in crisis and is collapsing as scientists lose confidence in it.” Response: Scientists do not debate whether evolution (descent with modification) took place, but they do argue about how it took place. Details of the processes and mechanisms are vigorously debated. Antievolutionists may hear the debates about how evolution occurs and misinterpret them as debates about whether evolution occurs. Evolution is sound science and is treated accordingly by scientists and scholars worldwide.

If indeed you have "facts" concerning evolution and you can "prove" that evolution is indeed factual you are entitled to a cash reward offered by other scientists. Why have you not rushed to claim this reward? Others have tried and failed, even to the point of suing and using the the American Court system...and have always failed, time after time. The facts are there are a great many intelligent men of science that believes as do I, that evolution is not based upon "empirical scientific evidence" at all and can offer valid proof that evolution can never be proven using the "scientific method".

Correlation of the Bible and Science

[Zhavric]

Quote by: LOGAN If indeed you have "facts" concerning evolution and you can "prove" that evolution is indeed factual you are entitled to a cash reward offered by other scientists.

That's the dumbest thing I've read in hours. Evolution is proven. We've observed speciation in a laboratory setting. Support your claim with evidence in your next post or I will conclude you are unwilling / unable to do so.

The rest of your post was a pathetic evasion of the facts I presented. You're going to have to stop presenting lies and start debating honestly if you want to participate in the debate.

Below is a list of observed instances of speciation (speciation being a fancy word for evolution). Why don't you go through and explain how each one, specifically, is incorrect.

5.0 Observed Instances of Speciation
The following are several examples of observations of speciation.

5.1 Speciations Involving Polyploidy, Hybridization or Hybridization Followed by Polyploidization.


5.1.1 Plants
(See also the discussion in de Wet 1971).

5.1.1.1 Evening Primrose (Oenothera gigas)
While studying the genetics of the evening primrose, Oenothera lamarckiana, de Vries (1905) found an unusual variant among his plants. O. lamarckiana has a chromosome number of 2N = 14. The variant had a chromosome number of 2N = 28. He found that he was unable to breed this variant with O. lamarckiana. He named this new species O. gigas.

5.1.1.2 Kew Primrose (Primula kewensis)
Digby (1912) crossed the primrose species Primula verticillata and P. floribunda to produce a sterile hybrid. Polyploidization occurred in a few of these plants to produce fertile offspring. The new species was named P. kewensis. Newton and Pellew (1929) note that spontaneous hybrids of P. verticillata and P. floribunda set tetraploid seed on at least three occasions. These happened in 1905, 1923 and 1926.

5.1.1.3 Tragopogon
Owenby (1950) demonstrated that two species in this genus were produced by polyploidization from hybrids. He showed that Tragopogon miscellus found in a colony in Moscow, Idaho was produced by hybridization of T. dubius and T. pratensis. He also showed that T. mirus found in a colony near Pullman, Washington was produced by hybridization of T. dubius and T. porrifolius. Evidence from chloroplast DNA suggests that T. mirus has originated independently by hybridization in eastern Washington and western Idaho at least three times (Soltis and Soltis 1989). The same study also shows multiple origins for T. micellus.

5.1.1.4 Raphanobrassica
The Russian cytologist Karpchenko (1927, 1928) crossed the radish, Raphanus sativus, with the cabbage, Brassica oleracea. Despite the fact that the plants were in different genera, he got a sterile hybrid. Some unreduced gametes were formed in the hybrids. This allowed for the production of seed. Plants grown from the seeds were interfertile with each other. They were not interfertile with either parental species. Unfortunately the new plant (genus Raphanobrassica) had the foliage of a radish and the root of a cabbage.

5.1.1.5 Hemp Nettle (Galeopsis tetrahit)
A species of hemp nettle, Galeopsis tetrahit, was hypothesized to be the result of a natural hybridization of two other species, G. pubescens and G. speciosa (Muntzing 1932). The two species were crossed. The hybrids matched G. tetrahit in both visible features and chromosome morphology.

5.1.1.6 Madia citrigracilis
Along similar lines, Clausen et al. (1945) hypothesized that Madia citrigracilis was a hexaploid hybrid of M. gracilis and M. citriodora As evidence they noted that the species have gametic chromosome numbers of n = 24, 16 and 8 respectively. Crossing M. gracilis and M. citriodora resulted in a highly sterile triploid with n = 24. The chromosomes formed almost no bivalents during meiosis. Artificially doubling the chromosome number using colchecine produced a hexaploid hybrid which closely resembled M. citrigracilis and was fertile.

5.1.1.7 Brassica
Frandsen (1943, 1947) was able to do this same sort of recreation of species in the genus Brassica (cabbage, etc.). His experiments showed that B. carinata (n = 17) may be recreated by hybridizing B. nigra (n = 8) and B. oleracea, B. juncea (n = 18) may be recreated by hybridizing B. nigra and B. campestris (n = 10), and B. napus (n = 19) may be recreated by hybridizing B. oleracea and B. campestris.

5.1.1.8 Maidenhair Fern (Adiantum pedatum)
Rabe and Haufler (1992) found a naturally occurring diploid sporophyte of maidenhair fern which produced unreduced (2N) spores. These spores resulted from a failure of the paired chromosomes to dissociate during the first division of meiosis. The spores germinated normally and grew into diploid gametophytes. These did not appear to produce antheridia. Nonetheless, a subsequent generation of tetraploid sporophytes was produced. When grown in the lab, the tetraploid sporophytes appear to be less vigorous than the normal diploid sporophytes. The 4N individuals were found near Baldwin City, Kansas.

5.1.1.9 Woodsia Fern (Woodsia abbeae)
Woodsia abbeae was described as a hybrid of W. cathcariana and W. ilvensis (Butters 1941). Plants of this hybrid normally produce abortive sporangia containing inviable spores. In 1944 Butters found a W. abbeae plant near Grand Portage, Minn. that had one fertile frond (Butters and Tryon 1948). The apical portion of this frond had fertile sporangia. Spores from this frond germinated and grew into prothallia. About six months after germination sporophytes were produced. They survived for about one year. Based on cytological evidence, Butters and Tryon concluded that the frond that produced the viable spores had gone tetraploid. They made no statement as to whether the sporophytes grown produced viable spores.

5.1.2 Animals
Speciation through hybridization and/or polyploidy has long been considered much less important in animals than in plants [[[refs.]]]. A number of reviews suggest that this view may be mistaken. (Lokki and Saura 1980; Bullini and Nascetti 1990; Vrijenhoek 1994). Bullini and Nasceti (1990) review chromosomal and genetic evidence that suggest that speciation through hybridization may occur in a number of insect species, including walking sticks, grasshoppers, blackflies and cucurlionid beetles. Lokki and Saura (1980) discuss the role of polyploidy in insect evolution. Vrijenhoek (1994) reviews the literature on parthenogenesis and hybridogenesis in fish. I will tackle this topic in greater depth in the next version of this document.

5.2 Speciations in Plant Species not Involving Hybridization or Polyploidy


5.2.1 Stephanomeira malheurensis
Gottlieb (1973) documented the speciation of Stephanomeira malheurensis. He found a single small population (< 250 plants) among a much larger population (> 25,000 plants) of S. exigua in Harney Co., Oregon. Both species are diploid and have the same number of chromosomes (N = 8). S. exigua is an obligate outcrosser exhibiting sporophytic self-incompatibility. S. malheurensis exhibits no self-incompatibility and self-pollinates. Though the two species look very similar, Gottlieb was able to document morphological differences in five characters plus chromosomal differences. F1 hybrids between the species produces only 50% of the seeds and 24% of the pollen that conspecific crosses produced. F2 hybrids showed various developmental abnormalities.

5.2.2 Maize (Zea mays)
Pasterniani (1969) produced almost complete reproductive isolation between two varieties of maize. The varieties were distinguishable by seed color, white versus yellow. Other genetic markers allowed him to identify hybrids. The two varieties were planted in a common field. Any plant's nearest neighbors were always plants of the other strain. Selection was applied against hybridization by using only those ears of corn that showed a low degree of hybridization as the source of the next years seed. Only parental type kernels from these ears were planted. The strength of selection was increased each year. In the first year, only ears with less than 30% intercrossed seed were used. In the fifth year, only ears with less than 1% intercrossed seed were used. After five years the average percentage of intercrossed matings dropped from 35.8% to 4.9% in the white strain and from 46.7% to 3.4% in the yellow strain.

5.2.3 Speciation as a Result of Selection for Tolerance to a Toxin: Yellow Monkey Flower (Mimulus guttatus)
At reasonably low concentrations, copper is toxic to many plant species. Several plants have been seen to develop a tolerance to this metal (Macnair 1981). Macnair and Christie (1983) used this to examine the genetic basis of a postmating isolating mechanism in yellow monkey flower. When they crossed plants from the copper tolerant "Copperopolis" population with plants from the nontolerant "Cerig" population, they found that many of the hybrids were inviable. During early growth, just after the four leaf stage, the leaves of many of the hybrids turned yellow and became necrotic. Death followed this. This was seen only in hybrids between the two populations. Through mapping studies, the authors were able to show that the copper tolerance gene and the gene responsible for hybrid inviability were either the same gene or were very tightly linked. These results suggest that reproductive isolation may require changes in only a small number of genes.

CONTINUED

[Zhavric]

5.3 The Fruit Fly Literature


5.3.1 Drosophila paulistorum
Dobzhansky and Pavlovsky (1971) reported a speciation event that occurred in a laboratory culture of Drosophila paulistorum sometime between 1958 and 1963. The culture was descended from a single inseminated female that was captured in the Llanos of Colombia. In 1958 this strain produced fertile hybrids when crossed with conspecifics of different strains from Orinocan. From 1963 onward crosses with Orinocan strains produced only sterile males. Initially no assortative mating or behavioral isolation was seen between the Llanos strain and the Orinocan strains. Later on Dobzhansky produced assortative mating (Dobzhansky 1972).

5.3.2 Disruptive Selection on Drosophila melanogaster
Thoday and Gibson (1962) established a population of Drosophila melanogaster from four gravid females. They applied selection on this population for flies with the highest and lowest numbers of sternoplural chaetae (hairs). In each generation, eight flies with high numbers of chaetae were allowed to interbreed and eight flies with low numbers of chaetae were allowed to interbreed. Periodically they performed mate choice experiments on the two lines. They found that they had produced a high degree of positive assortative mating between the two groups. In the decade or so following this, eighteen labs attempted unsuccessfully to reproduce these results. References are given in Thoday and Gibson 1970.

5.3.3 Selection on Courtship Behavior in Drosophila melanogaster
Crossley (1974) was able to produce changes in mating behavior in two mutant strains of D. melanogaster. Four treatments were used. In each treatment, 55 virgin males and 55 virgin females of both ebony body mutant flies and vestigial wing mutant flies (220 flies total) were put into a jar and allowed to mate for 20 hours. The females were collected and each was put into a separate vial. The phenotypes of the offspring were recorded. Wild type offspring were hybrids between the mutants. In two of the four treatments, mating was carried out in the light. In one of these treatments all hybrid offspring were destroyed. This was repeated for 40 generations. Mating was carried out in the dark in the other two treatments. Again, in one of these all hybrids were destroyed. This was repeated for 49 generations. Crossley ran mate choice tests and observed mating behavior. Positive assortative mating was found in the treatment which had mated in the light and had been subject to strong selection against hybridization. The basis of this was changes in the courtship behaviors of both sexes. Similar experiments, without observation of mating behavior, were performed by Knight, et al. (1956).

5.3.4 Sexual Isolation as a Byproduct of Adaptation to Environmental Conditions in Drosophila melanogaster
Kilias, et al. (1980) exposed D. melanogaster populations to different temperature and humidity regimes for several years. They performed mating tests to check for reproductive isolation. They found some sterility in crosses among populations raised under different conditions. They also showed some positive assortative mating. These things were not observed in populations which were separated but raised under the same conditions. They concluded that sexual isolation was produced as a byproduct of selection.

5.3.5 Sympatric Speciation in Drosophila melanogaster
In a series of papers (Rice 1985, Rice and Salt 1988 and Rice and Salt 1990) Rice and Salt presented experimental evidence for the possibility of sympatric speciation. They started from the premise that whenever organisms sort themselves into the environment first and then mate locally, individuals with the same habitat preferences will necessarily mate assortatively. They established a stock population of D. melanogaster with flies collected in an orchard near Davis, California. Pupae from the culture were placed into a habitat maze. Newly emerged flies had to negotiate the maze to find food. The maze simulated several environmental gradients simultaneously. The flies had to make three choices of which way to go. The first was between light and dark (phototaxis). The second was between up and down (geotaxis). The last was between the scent of acetaldehyde and the scent of ethanol (chemotaxis). This divided the flies among eight habitats. The flies were further divided by the time of day of emergence. In total the flies were divided among 24 spatio-temporal habitats.

They next cultured two strains of flies that had chosen opposite habitats. One strain emerged early, flew upward and was attracted to dark and acetaldehyde. The other emerged late, flew downward and was attracted to light and ethanol. Pupae from these two strains were placed together in the maze. They were allowed to mate at the food site and were collected. Eye color differences between the strains allowed Rice and Salt to distinguish between the two strains. A selective penalty was imposed on flies that switched habitats. Females that switched habitats were destroyed. None of their gametes passed into the next generation. Males that switched habitats received no penalty. After 25 generations of this mating tests showed reproductive isolation between the two strains. Habitat specialization was also produced.

They next repeated the experiment without the penalty against habitat switching. The result was the same -- reproductive isolation was produced. They argued that a switching penalty is not necessary to produce reproductive isolation. Their results, they stated, show the possibility of sympatric speciation.

5.3.6 Isolation Produced as an Incidental Effect of Selection on several Drosophila species
In a series of experiments, del Solar (1966) derived positively and negatively geotactic and phototactic strains of D. pseudoobscura from the same population by running the flies through mazes. Flies from different strains were then introduced into mating chambers (10 males and 10 females from each strain). Matings were recorded. Statistically significant positive assortative mating was found.

In a separate series of experiments Dodd (1989) raised eight populations derived from a single population of D. Pseudoobscura on stressful media. Four populations were raised on a starch based medium, the other four were raised on a maltose based medium. The fly populations in both treatments took several months to get established, implying that they were under strong selection. Dodd found some evidence of genetic divergence between flies in the two treatments. He performed mate choice tests among experimental populations. He found statistically significant assortative mating between populations raised on different media, but no assortative mating among populations raised within the same medium regime. He argued that since there was no direct selection for reproductive isolation, the behavioral isolation results from a pleiotropic by-product to adaptation to the two media. Schluter and Nagel (1995) have argued that these results provide experimental support for the hypothesis of parallel speciation.

Less dramatic results were obtained by growing D. willistoni on media of different pH levels (de Oliveira and Cordeiro 1980). Mate choice tests after 26, 32, 52 and 69 generations of growth showed statistically significant assortative mating between some populations grown in different pH treatments. This ethological isolation did not always persist over time. They also found that some crosses made after 106 and 122 generations showed significant hybrid inferiority, but only when grown in acid medium.

5.3.7 Selection for Reinforcement in Drosophila melanogaster
Some proposed models of speciation rely on a process called reinforcement to complete the speciation process. Reinforcement occurs when to partially isolated allopatric populations come into contact. Lower relative fitness of hybrids between the two populations results in increased selection for isolating mechanisms. I should note that a recent review (Rice and Hostert 1993) argues that there is little experimental evidence to support reinforcement models. Two experiments in which the authors argue that their results provide support are discussed below.

Ehrman (1971) established strains of wild-type and mutant (black body) D. melanogaster. These flies were derived from compound autosome strains such that heterotypic matings would produce no progeny. The two strains were reared together in common fly cages. After two years, the isolation index generated from mate choice experiments had increased from 0.04 to 0.43, indicating the appearance of considerable assortative mating. After four years this index had risen to 0.64 (Ehrman 1973).

Along the same lines, Koopman (1950) was able to increase the degree of reproductive isolation between two partially isolated species, D. pseudoobscura and D. persimilis.

5.3.8 Tests of the Founder-flush Speciation Hypothesis Using Drosophila
The founder-flush (a.k.a. flush-crash) hypothesis posits that genetic drift and founder effects play a major role in speciation (Powell 1978). During a founder-flush cycle a new habitat is colonized by a small number of individuals (e.g. one inseminated female). The population rapidly expands (the flush phase). This is followed by the population crashing. During this crash period the population experiences strong genetic drift. The population undergoes another rapid expansion followed by another crash. This cycle repeats several times. Reproductive isolation is produced as a byproduct of genetic drift.

Continued...

[Zhavric]

Dodd and Powell (1985) tested this hypothesis using D. pseudoobscura. A large, heterogeneous population was allowed to grow rapidly in a very large population cage. Twelve experimental populations were derived from this population from single pair matings. These populations were allowed to flush. Fourteen months later, mating tests were performed among the twelve populations. No postmating isolation was seen. One cross showed strong behavioral isolation. The populations underwent three more flush-crash cycles. Forty-four months after the start of the experiment (and fifteen months after the last flush) the populations were again tested. Once again, no postmating isolation was seen. Three populations showed behavioral isolation in the form of positive assortative mating. Later tests between 1980 and 1984 showed that the isolation persisted, though it was weaker in some cases.


Galina, et al. (1993) performed similar experiments with D. pseudoobscura. Mating tests between populations that underwent flush-crash cycles and their ancestral populations showed 8 cases of positive assortative mating out of 118 crosses. They also showed 5 cases of negative assortative mating (i.e. the flies preferred to mate with flies of the other strain). Tests among the founder-flush populations showed 36 cases of positive assortative mating out of 370 crosses. These tests also found 4 cases of negative assortative mating. Most of these mating preferences did not persist over time. Galina, et al. concluded that the founder-flush protocol yields reproductive isolation only as a rare and erratic event.

Ahearn (1980) applied the founder-flush protocol to D. silvestris. Flies from a line of this species underwent several flush-crash cycles. They were tested in mate choice experiments against flies from a continuously large population. Female flies from both strains preferred to mate with males from the large population. Females from the large population would not mate with males from the founder flush population. An asymmetric reproductive isolation was produced.

In a three year experiment, Ringo, et al. (1985) compared the effects of a founder-flush protocol to the effects of selection on various traits. A large population of D. simulans was created from flies from 69 wild caught stocks from several locations. Founder-flush lines and selection lines were derived from this population. The founder-flush lines went through six flush-crash cycles. The selection lines experienced equal intensities of selection for various traits. Mating test were performed between strains within a treatment and between treatment strains and the source population. Crosses were also checked for postmating isolation. In the selection lines, 10 out of 216 crosses showed positive assortative mating (2 crosses showed negative assortative mating). They also found that 25 out of 216 crosses showed postmating isolation. Of these, 9 cases involved crosses with the source population. In the founder-flush lines 12 out of 216 crosses showed positive assortative mating (3 crosses showed negative assortative mating). Postmating isolation was found in 15 out of 216 crosses, 11 involving the source population. They concluded that only weak isolation was found and that there was little difference between the effects of natural selection and the effects of genetic drift.

A final test of the founder-flush hypothesis will be described with the housefly cases below.

5.4 Housefly Speciation Experiments


5.4.1 A Test of the Founder-flush Hypothesis Using Houseflies
Meffert and Bryant (1991) used houseflies to test whether bottlenecks in populations can cause permanent alterations in courtship behavior that lead to premating isolation. They collected over 100 flies of each sex from a landfill near Alvin, Texas. These were used to initiate an ancestral population. From this ancestral population they established six lines. Two of these lines were started with one pair of flies, two lines were started with four pairs of flies and two lines were started with sixteen pairs of flies. These populations were flushed to about 2,000 flies each. They then went through five bottlenecks followed by flushes. This took 35 generations. Mate choice tests were performed. One case of positive assortative mating was found. One case of negative assortative mating was also found.

5.4.2 Selection for Geotaxis with and without Gene Flow
Soans, et al. (1974) used houseflies to test Pimentel's model of speciation. This model posits that speciation requires two steps. The first is the formation of races in subpopulations. This is followed by the establishment of reproductive isolation. Houseflies were subjected to intense divergent selection on the basis of positive and negative geotaxis. In some treatments no gene flow was allowed, while in others there was 30% gene flow. Selection was imposed by placing 1000 flies into the center of a 108 cm vertical tube. The first 50 flies that reached the top and the first 50 flies that reached the bottom were used to found positively and negatively geotactic populations. Four populations were established:

Population A + geotaxis, no gene flow
Population B - geotaxis, no gene flow
Population C + geotaxis, 30% gene flow
Population D - geotaxis, 30% gene flow

Selection was repeated within these populations each generations. After 38 generations the time to collect 50 flies had dropped from 6 hours to 2 hours in Pop A, from 4 hours to 4 minutes in Pop B, from 6 hours to 2 hours in Pop C and from 4 hours to 45 minutes in Pop D. Mate choice tests were performed. Positive assortative mating was found in all crosses. They concluded that reproductive isolation occurred under both allopatric and sympatric conditions when very strong selection was present.

Hurd and Eisenberg (1975) performed a similar experiment on houseflies using 50% gene flow and got the same results.

TalkOrigins Archive: Exploring the Creation/Evolution Controversy

[RealRockingham]

Quote by: leegao I'm guessing by proving that liberal Christians do not take the Bible literally, you are in turn saying that they are capable of conforming their beliefs to best accommodate their liking. My question then would be why the Liberal Christians have not tried to rationalize God yet.

Because they don't have to.

A god that works VIA natural processes is not incompatible with science. Thus their is no scientific neccesity to take it further.

[Zhavric]

Quote by: RealRockingham Because they don't have to. A god that works VIA natural processes is not incompatible with science. Thus their is no scientific neccesity to take it further.

The problem here, though, is that liberal Christianity makes ZERO sense. The bible is either the inspired word of god or it isn't. One or the other. It isn't the inspired word of god for you and just a book for me. It can't be. It has to be one or the other. So, liberal Christians who sort of take a lighweight figurative view of the bible make no sense. I have far more respect for fundamentalists who, though completely wrong, are at least slightly more intellectually honest than their "progressive" peers. Liberal Christians pick and choose which parts of the bible to observe while discarding most of it. "Genesis is a myth, but Jesus was real. God just couldn't hate homosexuals even though the bible is black and white about it. The old testament says 'an eye for an eye', the new testament says 'turn the other cheek', but we do neither."

Finally, saying "god works through natural processes" is no different from saying "Zeus makes lightning through storm systems" or "It's Apollo that keeps the nuclear furnace of the sun going." It's intellectually bankrupt. We can always add a fictional level to any natural phenomenon but with evidence it stays just that: fiction.

[gela]

The problem here, though, is that liberal Christianity makes ZERO sense. The bible is either the inspired word of god or it isn't. One or the other. It isn't the inspired word of god for you and just a book for me. It can't be. It has to be one or the other. So, liberal Christians who sort of take a lighweight figurative view of the bible make no sense. I have far more respect for fundamentalists who, though completely wrong, are at least slightly more intellectually honest than their "progressive" peers. Liberal Christians pick and choose which parts of the bible to observe while discarding most of it. "Genesis is a myth, but Jesus was real. God just couldn't hate homosexuals even though the bible is black and white about it. The old testament says 'an eye for an eye', the new testament says 'turn the other cheek', but we do neither."

Liberal christians accept that the Bible was written by the hands of man, and its thus imperfect. God might have influenced it - but so did man.

They pick and choose, because they have the brains to realise certian things in the Bible are wrong, while other things have some credit.

I will always respect people who can use their own brains to realise whats right and wrong in the bible, over those who blindly follow.
So what if they want to cling to their belief in god? A belief in a god isn't what causes damage.

[Zhavric]

Quote by: gela Liberal christians accept that the Bible was written by the hands of man, and its thus imperfect. God might have influenced it - but so did man.

Which is a tremendous cop out. Every liberal Christian should take every part of the bible figuratively. Instead, they pick and choose which they want to believe and which they want to think are literal... which has far more to do with desire and political agenda than any genuine search for truth or (god forbid) reason.

They pick and choose, because they have the brains to realise certian things in the Bible are wrong, while other things have some credit.

No. They choose what they've been indoctrinated to believe is true. People don't walk on water or come back from the dead. If someone says it happened then they're wrong. Yet even the most liberal Christians still believe the resurrection happened... which it didn't.

I will always respect people who can use their own brains to realise whats right and wrong in the bible, over those who blindly follow.

We have a word in our language for those who have honestly and adequately discovered what's wrong in the bible and rejected it: atheists.

So what if they want to cling to their belief in god? A belief in a god isn't what causes damage.

Of course it is. God is the underpinning of every other harmful biggotted belief Christians have.

[leegao]

Because they don't have to. A god that works VIA natural processes is not incompatible with science. Thus their is no scientific neccesity to take it further.

Yet rationalization is not solely attributed to science.

Secondly, can you define how you are using the terms "Natural Processes" in your post?

[tivodan1116]

Quote by: Zhavric The problem here, though, is that liberal Christianity makes ZERO sense. The bible is either the inspired word of god or it isn't. One or the other. It isn't the inspired word of god for you and just a book for me. It can't be. It has to be one or the other. So, liberal Christians who sort of take a lighweight figurative view of the bible make no sense. I have far more respect for fundamentalists who, though completely wrong, are at least slightly more intellectually honest than their "progressive" peers. Liberal Christians pick and choose which parts of the bible to observe while discarding most of it. "Genesis is a myth, but Jesus was real. God just couldn't hate homosexuals even though the bible is black and white about it. The old testament says 'an eye for an eye', the new testament says 'turn the other cheek', but we do neither."

Except as I've explained to you before, and you refuse to address since it ruins your argument (talk about intellectual dishonesty), the Bible is not a book. It is a collection of works written over a time period of over a thousand years and only collected very recently, relatively speaking.

Saying the truth of the Bible is an all-or-nothing proposition is like saying that we must accept the Neils Bohr (incorrect) model of the atom AND the chemical formula for water, because they are both in the volume of work we call "Chemistry"...