A response to evolutionists

Andya gave an excellent synopsis. Just to provide a few more details:A brief synopsis of the development of placental mammals from egg laying reptiles:Theriodont (mammal-like reptiles; egg layers) -> pantothere (monotreme, or egg-laying mammals; c.f. echidna and platypus) -> metathere (marsupial, or pouched mammal; c.f. kangaroo, opossum) -> euthere (placental mammal; all others)Going beyond this, we have to get pretty detailed on the differences between oviparity in reptiles/amphibians, oviparity in pantotheres where the egg (containing limited yolk) develops for a period within the uterus nourished by endometrial secretions, then the gradual development of choriovitelline placenta in the metatheres and finally true placentae in modern mammals. In addition, for it to make sense, you need to understand the trade-off in the maternal dependent growth model where duration and extent of intrauterine and post-natal care are variations that can be operated on by natural selection. Finally, you need to understand the role that may have been played by differential production of the hormone dehydroepiandrosterone in the gradual replacement of egg by placenta over the course of 175 million years, based on comparisons between modern monotremes, marsupials, and placental mammals.If you’d like details, let me know.

Uhh, Delshad - what part of my post didn't you understand? I tried to keep it as simple as your apparent lack of knowledge required. If you really desire to know the answer to your question, the gist of the answer is in my post. If you have specific questions about any element in my response, please show you understand what was originally posted before asking for more - and more technical - details.

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Originally posted by Delshad:
Please Quetzal, dont misunderstand me, I understood very clearly what you were trying to express in your previous post and I`m sorry if you thought otherwise.

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Misunderstand you? I'm afraid I understand you all too well - except that I was willing to grant you the benefit of the doubt. However, I fear you will never understand any evidence presented in answer to your question.

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Its just that, and I hope you agree with me here, NO scientific evidence really proofs your theory to be correct, and ill try to explain why:

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Of course I don't agree. In the first place, it's not my theory. It is the concensus result of a half dozen disciplines from paleontology to embryology and evolutionary developmental biology. In the second, there is quite sufficient evidence to lend high confidence to what I posted. Evidence, by the way, which has been thoroughly tested by multiple methods. Based on your erroneous statement concerning the development of the mammalian ear structures from reptilian jaw bones, I repeat it's unlikely you would be able to understand it.However, I'll give you a second chance to prove me wrong: please explain the differences in reptilian oviparity and monotreme oviparity (probably the easiest bit of evidence) with relation to modern organisms (I figure examination of the fossil evidence is asking you too much). We can take that as a basis for discussion. Obviously, you can claim from there that the differences are based on biblical taxic discontinuity, whereas I will show that the differences are easily derived from natural selection. If you can at least show that much knowledge, I'll consider continuing this conversation.

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Lets say for an example that we are both proffesional archeologists and we both share the same view about evolution ,thus we place each of those fossils we would find into one of the two categories, mammals or reptiles. Then whenever we find a fossil that has its own quite distinct skeletal structure yet resembling one of the categories we have set up(even in a very little way), we hurry to place it under one of the fixed categories or at its peak we would say ,"well it maybe is an ancient subspecie evolving to this or that" and possiblitys that suggest anything else but the theory of evolution is completely out of the question.

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Unless you're talking about the evolution of culture, I don't think archeologists are going to have much to say about evolution - especially the fossil record.On the other hand, I agree with you about the somewhat arbitrary taxonomic designations that occasionally happen. It's quite obvious when you deal with the difference between reptile and mammal characteristics in the synapsids. Of course, that poses absolutely no problem for evolutionary theory - it's what we expect to see: a gradual "fading" in between taxa where the designation "mammal" from "reptile" is pretty arbitrary. Fortunately, molecular phylogentics (the basis of the science of cladistics) helps to confirm or disconfirm classifications based only on morphology - that's why it's so useful.

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That way of thinking isnt so scientific at all because our conclusion will be influenced by the parameters we have set up.

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This makes absolutely no sense whatsoever. Care to explain what you're trying to say? Please keep it simple, you're dealing with an ignorant scientist type.

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And let me once again repeat that each fosil that has been found has all the the features required to live successfull.

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An amazing statement of the obvious. What's your point?

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In other words none of the foosils shows that they were "transitional" forms caused by random mutation because NONE of them has the caracteristics indicating it(asymmetrical forms or useless ineffective halfdone organs).

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I think you're seriously confused as to what constitutes a transitional form - there is no such thing as a "useless" or "half-done organ". Is this some kind of saltationist strawman "evolution" you're playing with? What we see is the gradual improvement, adaptation, or morphological change (could be elimination) of various structures.

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Evolution has no conscioussness and between the time a mutation has ocurred and the time needed to by means of natural selection establish a symmetrical form, there is plenty of time for generation after generation to have traits possessing these "abnormal" shapes.

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Except any mutation that caused such an "abnormal" form (in the sense I think you are using it) would result in the death of the organism either before or immediately after birth. We don't see abnormality in the fossil record because the kind of gross abnormality/hopeful monster you propose wouldn't live. A mutation that effects the phenotype of an organism can only become fixed or dominant in a population IF it is capable of co-existing polymorphically for a period of time with the original allele. It will also only become dominant (generally) if it provides a net survival advantage to the organisms that have it. So your "transitional form = abnormal form" is a ludicrous strawman based on a massive misunderstanding of the science.

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But none exists, I hope youll be able to open your eyes and see things from a different perspective, that is the scientific way of approaching the issue.

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ROTFLMAO. Ahh, me. Thanks for the lecture on scientific epistemology. Too bad it's probably highly unlikely you'll be able to apply the theory.

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There is no established evolutionary relationships between these groups.

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Never said there was. The question Delshad posed was "how could placental mammals develop from egg-laying reptiles?" or words to that effect. The theriodont to eutherian sequence I gave was not intended as an evolutionary chain of descent, rather as a sequence showing how "advanced" forms of reproduction can be derived from more "primitive" forms. Comparing anatomy, physiology, and developmental biology between the three branches of the mammalian tree - using modern organisms - starting with the relatively primitive monotremes, passing through the marsupials, and on to the highly derived placentals, there is a definite "shading" in their systems.Since you asked so nicely:Living monotremes share a number of skeletal affinities with reptiles that are not found in other mammals (for instance, a septomaxillae bone, a lizard-like shoulder, and details of the dentition). This indicates that monotreme clade branched off the main mammalian stem more basally than did the other two. The earliest known "true" monotreme is Steropodon, whose classification is primarily based on teeth/jaw structure. All monotremes lay eggs, but platypus incubate them in a nest while echidna incubate them in a pouch. Sounds sort of marsupial-like, doesn't it? Wouldn't take much of a stretch to go from incubating an egg in a pouch to protecting a neonate in a pouch. Especially since the most primitive marsupials alive today (Didelphia) still create a soft-shelled egg - with yolk! - inside the mother before the practically embryonic neonate emerges to finish development in a pouch.The base of the marsupial/placental split is pretty arbitrary. For example, paleontologists classify Eomaia scansoria as the first "true" placental. However, it retains a number of characteristics like its marsupial bretheren. For example, it has epipubic bones extending forward from its pelvis, and a narrow pelvic outlet which suggest that a short gestation period was followed by parental nurture of the young suspended from the abdomen. The earliest "true" marsupial (from around the same time period) has been suggested as Deltatheridium pretrituberculare. The only reason it's classed as a marsupial rather than placental is tooth replacement pattern (it replaces only three molars, rather than the full set normal in the placentals).All three mammal lineages probably originally derived from one of the Morganucodontidae. Which one remains an open question (and in fact as does the actual location of Morganucodon itself).The theriodonts at the very base of the tree are fairly evenly split between the generic "mammal" and "reptile" classifications. It's often dependent on a single bone when you reach this point as to whether the organism is classed as one or the other. Since all of those critters are extinct (three complete families), which one goes where is pretty moot. However, what IS firmly established is that the Theria form a monophyletic clade.Hope this clarifies my response to Delshad.

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Oh heck with the science, let's just go with the ridicule, browbeating, and insults. Red herrings anyone.

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Speaking of which... It's unlikely you'll find me responding in the fashion you accuse me of - even to you.BTW: Thanks for the support, Adminnemooseus.----------
Note from Adminnemooseus:
Barts edit at the end of message 22:

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Okay Adminnemooseus, I'll save that one for a much more appropraiste posting. My apologies to Quetzal for having jumped the gun, so to speak.

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[This message has been edited by Adminnemooseus, 10-03-2002]