Posted on 01/11/2003 9:53:34 PM PST by DWar
There does seem to be quite an emphasis put on the unborn more than the born in terms of their "soul". It has always puzzled me.
That would puzzle me also, because an unborn - or newborn - is truly innocent and ought to go straight to heaven.
Personally, I would be more concerned about the spiritual health of the woman who made such a hard decision.
Seems like everytime she would see a child, it would hurt her deeply. I wonder if such despair would drive her away from her faith.
I count it a red herring when either creationists or evolutionists demand proofs of each other. Evolutionists demand proof of God. Creationists demand an explanation for the order that so permeates the universe if it all happened without some higher being involved.
Strange, how, placed as we are in the universe, few of us are truly able to deliver absolute proofs of anything.
When either side launches into this discussion they place themsleves outside of the strict definition of science. For example, even if one were able to supply an example of a transitional form from a non-deciduate to deciduate placenta, one would be unable to predict via scientific method what is the next step and give demonstration of the same.
And yet evolution cannot be so easily dismissed by common sense. It is no mystery at all to me how one could conjure up all kinds of apparent relationships to explain away a Higher Being to Whom the highest of creatures might be accountable.
But common sense has been woefully lacking for at least a century and a half. Sheez. In the last decade "common sense" in our land elected Klinton for two terms.
Please understand, however, that a great deal of common sense preceded us in history, and that a great majority of people in the world are fully convinced that what we have on our hands is not a random combination of gases and amino acids that somehow developed into our own eyeballs and brains.
Can you blame them for thinking something bigger might be behind all this? Are we taking the right path in cutting ourselves loose from millennia of generations who proclaimed very clearly that Higher Being is involved with the universe?
You've probably got a few years to think about it, so take your time. As for me, real science has yet to disprove any word in the Bible. It's only confirmed what I've known since childhood.
Not a "single evolutionist writer", eh?
In two minutes I turned up:
Benton, M.J. (1990) Vertebrate Palaeontology: biology and evolution. Unwin Hyman, london. pp 377. ISBN 0045660018You're an ignoramus.Colbert, E.H. & Harris, E. (1991) Evolution of the vertebrates: a history of the backboned animals. Wiley-Liss, New York. pp 470. ISBN 0471850748
Kemp, T.S. (1982) mammal-like reptiles and the origin of mammals. Academic Press, New York. pp 363. ISBN 0124041205
Kermack, D.M. & Kermack, K.A. (1984) The evolution of mammalian characters. Croom Helm Kapitan Szabo Publishers, London. pp 149. ISBN 079915349
Or for a nice online overview of the field: here you go
Facts beat rhetoric every time and your side does not have any facts.
Yeah. Sure. Whatever helps you sleep at night.
Evolutionists don't have "any" facts, eh? Here are just a few for starters.
How do you dispute the facts here, please? Or here? Or this?. What, no facts at all here either? Or how about:
Transition from synapsid reptiles to mammals
This is the best-documented transition between vertebrate classes. So far this series is known only as a series of genera or families; the transitions from species to species are not known. But the family sequence is quite complete. Each group is clearly related to both the group that came before, and the group that came after, and yet the sequence is so long that the fossils at the end are astoundingly different from those at the beginning. As Rowe recently said about this transition (in Szalay et al., 1993), "When sampling artifact is removed and all available character data analyzed [with computer phylogeny programs that do not assume anything about evolution], a highly corroborated, stable phylogeny remains, which is largely consistent with the temporal distributions of taxa recorded in the fossil record." Similarly, Gingerich has stated (1977) "While living mammals are well separated from other groups of animals today, the fossil record clearly shows their origin from a reptilian stock and permits one to trace the origin and radiation of mammals in considerable detail." For more details, see Kermack's superb and readable little book (1984), Kemp's more detailed but older book (1982), and read Szalay et al.'s recent collection of review articles (1993, vol. 1).
This list starts with pelycosaurs (early synapsid reptiles) and continues with therapsids and cynodonts up to the first unarguable "mammal". Most of the changes in this transition involved elaborate repackaging of an expanded brain and special sense organs, remodeling of the jaws & teeth for more efficient eating, and changes in the limbs & vertebrae related to active, legs-under-the-body locomotion. Here are some differences to keep an eye on:
# Early Reptiles Mammals
1 No fenestrae in skull Massive fenestra exposes all of braincase
2 Braincase attached loosely Braincase attached firmly to skull
3 No secondary palate Complete bony secondary palate
4 Undifferentiated dentition Incisors, canines, premolars, molars
5 Cheek teeth uncrowned points Cheek teeth (PM & M) crowned & cusped
6 Teeth replaced continuously Teeth replaced once at most
7 Teeth with single root Molars double-rooted
8 Jaw joint quadrate-articular Jaw joint dentary-squamosal (*)
9 Lower jaw of several bones Lower jaw of dentary bone only
10 Single ear bone (stapes) Three ear bones (stapes, incus, malleus)
11 Joined external nares Separate external nares
12 Single occipital condyle Double occipital condyle
13 Long cervical ribs Cervical ribs tiny, fused to vertebrae
14 Lumbar region with ribs Lumbar region rib-free
15 No diaphragm Diaphragm
16 Limbs sprawled out from body Limbs under body
17 Scapula simple Scapula with big spine for muscles
18 Pelvic bones unfused Pelvis fused
19 Two sacral (hip) vertebrae Three or more sacral vertebrae
20 Toe bone #'s 2-3-4-5-4 Toe bones 2-3-3-3-3
21 Body temperature variable Body temperature constant
(*) The presence of a dentary-squamosal jaw joint has been arbitrarily selected as the defining trait of a mammal.
- Paleothyris (early Pennsylvanian) -- An early captorhinomorph reptile, with no temporal fenestrae at all.
- Protoclepsydrops haplous (early Pennsylvanian) -- The earliest known synapsid reptile. Little temporal fenestra, with all surrounding bones intact. Fragmentary. Had amphibian-type vertebrae with tiny neural processes. (reptiles had only just separated from the amphibians)
- Clepsydrops (early Pennsylvanian) -- The second earliest known synapsid. These early, very primitive synapsids are a primitive group of pelycosaurs collectively called "ophiacodonts".
- Archaeothyris (early-mid Pennsylvanian) -- A slightly later ophiacodont. Small temporal fenestra, now with some reduced bones (supratemporal). Braincase still just loosely attached to skull. Slight hint of different tooth types. Still has some extremely primitive, amphibian/captorhinid features in the jaw, foot, and skull. Limbs, posture, etc. typically reptilian, though the ilium (major hip bone) was slightly enlarged.
- Varanops (early Permian) -- Temporal fenestra further enlarged. Braincase floor shows first mammalian tendencies & first signs of stronger attachment to rest of skull (occiput more strongly attached). Lower jaw shows first changes in jaw musculature (slight coronoid eminence). Body narrower, deeper: vertebral column more strongly constructed. Ilium further enlarged, lower-limb musculature starts to change (prominent fourth trochanter on femur). This animal was more mobile and active. Too late to be a true ancestor, and must be a "cousin".
- Haptodus (late Pennsylvanian) -- One of the first known sphenacodonts, showing the initiation of sphenacodont features while retaining many primitive features of the ophiacodonts. Occiput still more strongly attached to the braincase. Teeth become size-differentiated, with biggest teeth in canine region and fewer teeth overall. Stronger jaw muscles. Vertebrae parts & joints more mammalian. Neural spines on vertebrae longer. Hip strengthened by fusing to three sacral vertebrae instead of just two. Limbs very well developed.
- Dimetrodon, Sphenacodon or a similar sphenacodont (late Pennsylvanian to early Permian, 270 Ma) -- More advanced pelycosaurs, clearly closely related to the first therapsids (next). Dimetrodon is almost definitely a "cousin" and not a direct ancestor, but as it is known from very complete fossils, it's a good model for sphenacodont anatomy. Medium-sized fenestra. Teeth further differentiated, with small incisors, two huge deep- rooted upper canines on each side, followed by smaller cheek teeth, all replaced continuously. Fully reptilian jaw hinge. Lower jaw bone made of multiple bones & with first signs of a bony prong later involved in the eardrum, but there was no eardrum yet, so these reptiles could only hear ground-borne vibrations (they did have a reptilian middle ear). Vertebrae had still longer neural spines (spectacularly so in Dimetrodon, which had a sail), and longer transverse spines for stronger locomotion muscles.
- Biarmosuchia (late Permian) -- A therocephalian -- one of the earliest, most primitive therapsids. Several primitive, sphenacodontid features retained: jaw muscles inside the skull, platelike occiput, palatal teeth. New features: Temporal fenestra further enlarged, occupying virtually all of the cheek, with the supratemporal bone completely gone. Occipital plate slanted slightly backwards rather than forwards as in pelycosaurs, and attached still more strongly to the braincase. Upper jaw bone (maxillary) expanded to separate lacrymal from nasal bones, intermediate between early reptiles and later mammals. Still no secondary palate, but the vomer bones of the palate developed a backward extension below the palatine bones. This is the first step toward a secondary palate, and with exactly the same pattern seen in cynodonts. Canine teeth larger, dominating the dentition. Variable tooth replacement: some therocephalians (e.g Scylacosaurus) had just one canine, like mammals, and stopped replacing the canine after reaching adult size. Jaw hinge more mammalian in position and shape, jaw musculature stronger (especially the mammalian jaw muscle). The amphibian-like hinged upper jaw finally became immovable. Vertebrae still sphenacodontid-like. Radical alteration in the method of locomotion, with a much more mobile forelimb, more upright hindlimb, & more mammalian femur & pelvis. Primitive sphenacodontid humerus. The toes were approaching equal length, as in mammals, with #toe bones varying from reptilian to mammalian. The neck & tail vertebrae became distinctly different from trunk vertebrae. Probably had an eardrum in the lower jaw, by the jaw hinge.
- Procynosuchus (latest Permian) -- The first known cynodont -- a famous group of very mammal-like therapsid reptiles, sometimes considered to be the first mammals. Probably arose from the therocephalians, judging from the distinctive secondary palate and numerous other skull characters. Enormous temporal fossae for very strong jaw muscles, formed by just one of the reptilian jaw muscles, which has now become the mammalian masseter. The large fossae is now bounded only by the thin zygomatic arch (cheekbone to you & me). Secondary palate now composed mainly of palatine bones (mammalian), rather than vomers and maxilla as in older forms; it's still only a partial bony palate (completed in life with soft tissue). Lower incisor teeth was reduced to four (per side), instead of the previous six (early mammals had three). Dentary now is 3/4 of lower jaw; the other bones are now a small complex near the jaw hinge. Jaw hinge still reptilian. Vertebral column starts to look mammalian: first two vertebrae modified for head movements, and lumbar vertebrae start to lose ribs, the first sign of functional division into thoracic and lumbar regions. Scapula beginning to change shape. Further enlargement of the ilium and reduction of the pubis in the hip. A diaphragm may have been present.
- Dvinia [also "Permocynodon"] (latest Permian) -- Another early cynodont. First signs of teeth that are more than simple stabbing points -- cheek teeth develop a tiny cusp. The temporal fenestra increased still further. Various changes in the floor of the braincase; enlarged brain. The dentary bone was now the major bone of the lower jaw. The other jaw bones that had been present in early reptiles were reduced to a complex of smaller bones near the jaw hinge. Single occipital condyle splitting into two surfaces. The postcranial skeleton of Dvinia is virtually unknown and it is not therefore certain whether the typical features found at the next level had already evolved by this one. Metabolic rate was probably increased, at least approaching homeothermy.
- Thrinaxodon (early Triassic) -- A more advanced "galesaurid" cynodont. Further development of several of the cynodont features seen already. Temporal fenestra still larger, larger jaw muscle attachments. Bony secondary palate almost complete. Functional division of teeth: incisors (four uppers and three lowers), canines, and then 7-9 cheek teeth with cusps for chewing. The cheek teeth were all alike, though (no premolars & molars), did not occlude together, were all single- rooted, and were replaced throughout life in alternate waves. Dentary still larger, with the little quadrate and articular bones were loosely attached. The stapes now touched the inner side of the quadrate. First sign of the mammalian jaw hinge, a ligamentous connection between the lower jaw and the squamosal bone of the skull. The occipital condyle is now two slightly separated surfaces, though not separated as far as the mammalian double condyles. Vertebral connections more mammalian, and lumbar ribs reduced. Scapula shows development of a new mammalian shoulder muscle. Ilium increased again, and all four legs fully upright, not sprawling. Tail short, as is necessary for agile quadrupedal locomotion. The whole locomotion was more agile. Number of toe bones is 2.3.4.4.3, intermediate between reptile number (2.3.4.5.4) and mammalian (2.3.3.3.3), and the "extra" toe bones were tiny. Nearly complete skeletons of these animals have been found curled up - a possible reaction to conserve heat, indicating possible endothermy? Adults and juveniles have been found together, possibly a sign of parental care. The specialization of the lumbar area (e.g. reduction of ribs) is indicative of the presence of a diaphragm, needed for higher O2 intake and homeothermy. NOTE on hearing: The eardrum had developed in the only place available for it -- the lower jaw, right near the jaw hinge, supported by a wide prong (reflected lamina) of the angular bone. These animals could now hear airborne sound, transmitted through the eardrum to two small lower jaw bones, the articular and the quadrate, which contacted the stapes in the skull, which contacted the cochlea. Rather a roundabout system and sensitive to low-frequency sound only, but better than no eardrum at all! Cynodonts developed quite loose quadrates and articulars that could vibrate freely for sound transmittal while still functioning as a jaw joint, strengthened by the mammalian jaw joint right next to it. All early mammals from the Lower Jurassic have this low-frequency ear and a double jaw joint. By the middle Jurassic, mammals lost the reptilian joint (though it still occurs briefly in embryos) and the two bones moved into the nearby middle ear, became smaller, and became much more sensitive to high-frequency sounds.
- Cynognathus (early Triassic, 240 Ma; suspected to have existed even earlier) -- We're now at advanced cynodont level. Temporal fenestra larger. Teeth differentiating further; cheek teeth with cusps met in true occlusion for slicing up food, rate of replacement reduced, with mammalian-style tooth roots (though single roots). Dentary still larger, forming 90% of the muscle-bearing part of the lower jaw. TWO JAW JOINTS in place, mammalian and reptilian: A new bony jaw joint existed between the squamosal (skull) and the surangular bone (lower jaw), while the other jaw joint bones were reduced to a compound rod lying in a trough in the dentary, close to the middle ear. Ribs more mammalian. Scapula halfway to the mammalian condition. Limbs were held under body. There is possible evidence for fur in fossil pawprints.
- Diademodon (early Triassic, 240 Ma; same strata as Cynognathus) -- Temporal fenestra larger still, for still stronger jaw muscles. True bony secondary palate formed exactly as in mammals, but didn't extend quite as far back. Turbinate bones possibly present in the nose (warm-blooded?). Dental changes continue: rate of tooth replacement had decreased, cheek teeth have better cusps & consistent wear facets (better occlusion). Lower jaw almost entirely dentary, with tiny articular at the hinge. Still a double jaw joint. Ribs shorten suddenly in lumbar region, probably improving diaphragm function & locomotion. Mammalian toe bones (2.3.3.3.3), with closely related species still showing variable numbers.
- Probelesodon (mid-Triassic; South America) -- Fenestra very large, still separate from eyesocket (with postorbital bar). Secondary palate longer, but still not complete. Teeth double-rooted, as in mammals. Nares separated. Second jaw joint stronger. Lumbar ribs totally lost; thoracic ribs more mammalian, vertebral connections very mammalian. Hip & femur more mammalian.
- Probainognathus (mid-Triassic, 239-235 Ma, Argentina) -- Larger brain with various skull changes: pineal foramen ("third eye") closes, fusion of some skull plates. Cheekbone slender, low down on the side of the eye socket. Postorbital bar still there. Additional cusps on cheek teeth. Still two jaw joints. Still had cervical ribs & lumbar ribs, but they were very short. Reptilian "costal plates" on thoracic ribs mostly lost. Mammalian #toe bones.
- Exaeretodon (mid-late Triassic, 239Ma, South America) -- (Formerly lumped with the herbivorous gomphodont cynodonts.) Mammalian jaw prong forms, related to eardrum support. Three incisors only (mammalian). Costal plates completely lost. More mammalian hip related to having limbs under the body. Possibly the first steps toward coupling of locomotion & breathing. This is probably a "cousin" fossil not directly ancestral, as it has several new but non-mammalian teeth traits.
GAP of about 30 my in the late Triassic, from about 239-208 Ma. Only one early mammal fossil is known from this time. The next time fossils are found in any abundance, tritylodontids and trithelodontids had already appeared, leading to some very heated controversy about their relative placement in the chain to mammals. Recent discoveries seem to show trithelodontids to be more mammal- like, with tritylodontids possibly being an offshoot group (see Hopson 1991, Rowe 1988, Wible 1991, and Shubin et al. 1991). Bear in mind that both these groups were almost fully mammalian in every feature, lacking only the final changes in the jaw joint and middle ear.
- Oligokyphus, Kayentatherium (early Jurassic, 208 Ma) -- These are tritylodontids, an advanced cynodont group. Face more mammalian, with changes around eyesocket and cheekbone. Full bony secondary palate. Alternate tooth replacement with double-rooted cheek teeth, but without mammalian-style tooth occlusion (which some earlier cynodonts already had). Skeleton strikingly like egg- laying mammals (monotremes). Double jaw joint. More flexible neck, with mammalian atlas & axis and double occipital condyle. Tail vertebrae simpler, like mammals. Scapula is now substantially mammalian, and the forelimb is carried directly under the body. Various changes in the pelvis bones and hind limb muscles; this animal's limb musculature and locomotion were virtually fully mammalian. Probably cousin fossils (?), with Oligokyphus being more primitive than Kayentatherium. Thought to have diverged from the trithelodontids during that gap in the late Triassic. There is disagreement about whether the tritylodontids were ancestral to mammals (presumably during the late Triassic gap) or whether they are a specialized offshoot group not directly ancestral to mammals.
- Pachygenelus, Diarthrognathus (earliest Jurassic, 209 Ma) -- These are trithelodontids, a slightly different advanced cynodont group. New discoveries (Shubin et al., 1991) show that these animals are very close to the ancestry of mammals. Inflation of nasal cavity, establishment of Eustachian tubes between ear and pharynx, loss of postorbital bar. Alternate replacement of mostly single- rooted teeth. This group also began to develop double tooth roots -- in Pachygenelus the single root of the cheek teeth begins to split in two at the base. Pachygenelus also has mammalian tooth enamel, and mammalian tooth occlusion. Double jaw joint, with the second joint now a dentary-squamosal (instead of surangular), fully mammalian. Incipient dentary condyle. Reptilian jaw joint still present but functioning almost entirely in hearing; postdentary bones further reduced to tiny rod of bones in jaw near middle ear; probably could hear high frequencies now. More mammalian neck vertebrae for a flexible neck. Hip more mammalian, with a very mammalian iliac blade & femur. Highly mobile, mammalian-style shoulder. Probably had coupled locomotion & breathing. These are probably "cousin" fossils, not directly ancestral (the true ancestor is thought to have occurred during that late Triassic gap). Pachygenelus is pretty close, though.
- Adelobasileus cromptoni (late Triassic; 225 Ma, west Texas) -- A recently discovered fossil proto-mammal from right in the middle of that late Triassic gap! Currently the oldest known "mammal." Only the skull was found. "Some cranial features of Adelobasileus, such as the incipient promontorium housing the cochlea, represent an intermediate stage of the character transformation from non-mammalian cynodonts to Liassic mammals" (Lucas & Luo, 1993). This fossil was found from a band of strata in the western U.S. that had not previously been studied for early mammals. Also note that this fossil dates from slightly before the known tritylodonts and trithelodonts, though it has long been suspected that tritilodonts and trithelodonts were already around by then. Adelobasileus is thought to have split off from either a trityl. or a trithel., and is either identical to or closely related to the common ancestor of all mammals.
- Sinoconodon (early Jurassic, 208 Ma) -- The next known very ancient proto-mammal. Eyesocket fully mammalian now (closed medial wall). Hindbrain expanded. Permanent cheekteeth, like mammals, but the other teeth were still replaced several times. Mammalian jaw joint stronger, with large dentary condyle fitting into a distinct fossa on the squamosal. This final refinement of the joint automatically makes this animal a true "mammal". Reptilian jaw joint still present, though tiny.
- Kuehneotherium (early Jurassic, about 205 Ma) -- A slightly later proto-mammal, sometimes considered the first known pantothere (primitive placental-type mammal). Teeth and skull like a placental mammal. The three major cusps on the upper & lower molars were rotated to form interlocking shearing triangles as in the more advanced placental mammals & marsupials. Still has a double jaw joint, though.
- Eozostrodon, Morganucodon, Haldanodon (early Jurassic, ~205 Ma) -- A group of early proto-mammals called "morganucodonts". The restructuring of the secondary palate and the floor of the braincase had continued, and was now very mammalian. Truly mammalian teeth: the cheek teeth were finally differentiated into simple premolars and more complex molars, and teeth were replaced only once. Triangular- cusped molars. Reversal of the previous trend toward reduced incisors, with lower incisors increasing to four. Tiny remnant of the reptilian jaw joint. Once thought to be ancestral to monotremes only, but now thought to be ancestral to all three groups of modern mammals -- monotremes, marsupials, and placentals.
- Peramus (late Jurassic, about 155 Ma) -- A "eupantothere" (more advanced placental-type mammal). The closest known relative of the placentals & marsupials. Triconodont molar has with more defined cusps. This fossil is known only from teeth, but judging from closely related eupantotheres (e.g. Amphitherium) it had finally lost the reptilian jaw joint, attaing a fully mammalian three-boned middle ear with excellent high-frequency hearing. Has only 8 cheek teeth, less than other eupantotheres and close to the 7 of the first placental mammals. Also has a large talonid on its "tribosphenic" molars, almost as large as that of the first placentals -- the first development of grinding capability.
- Endotherium (very latest Jurassic, 147 Ma) -- An advanced eupantothere. Fully tribosphenic molars with a well- developed talonid. Known only from one specimen. From Asia; recent fossil finds in Asia suggest that the tribosphenic molar evolved there.
- Kielantherium and Aegialodon (early Cretaceous) -- More advanced eupantotheres known only from teeth. Kielantherium is from Asia and is known from slightly older strata than the European Aegialodon. Both have the talonid on the lower molars. The wear on it indicates that a major new cusp, the protocone, had evolved on the upper molars. By the Middle Cretaceous, animals with the new tribosphenic molar had spread into North America too (North America was still connected to Europe.)
- Steropodon galmani (early Cretaceous) -- The first known definite monotreme, discovered in 1985.
- Vincelestes neuquenianus (early Cretaceous, 135 Ma) -- A probably-placental mammal with some marsupial traits, known from some nice skulls. Placental-type braincase and coiled cochlea. Its intracranial arteries & veins ran in a composite monotreme/placental pattern derived from homologous extracranial vessels in the cynodonts. (Rougier et al., 1992)
- Pariadens kirklandi (late Cretaceous, about 95 Ma) -- The first definite marsupial. Known only from teeth.
- Kennalestes and Asioryctes (late Cretaceous, Mongolia) -- Small, slender animals; eyesocket open behind; simple ring to support eardrum; primitive placental-type brain with large olfactory bulbs; basic primitive tribosphenic tooth pattern. Canine now double rooted. Still just a trace of a non-dentary bone, the coronoid, on the otherwise all-dentary jaw. "Could have given rise to nearly all subsequent placentals." says Carroll (1988).
- Cimolestes, Procerberus, Gypsonictops (very late Cretaceous) -- Primitive North American placentals with same basic tooth pattern.
So, by the late Cretaceous the three groups of modern mammals were in place: monotremes, marsupials, and placentals. Placentals appear to have arisen in East Asia and spread to the Americas by the end of the Cretaceous. In the latest Cretaceous, placentals and marsupials had started to diversify a bit, and after the dinosaurs died out, in the Paleocene, this diversification accelerated. For instance, in the mid- Paleocene the placental fossils include a very primitive primate-like animal (Purgatorius - known only from a tooth, though, and may actually be an early ungulate), a herbivore-like jaw with molars that have flatter tops for better grinding (Protungulatum, probably an early ungulate), and an insectivore (Paranyctoides).
The decision as to which was the first mammal is somewhat subjective. We are placing an inflexible classification system on a gradational series. What happened was that an intermediate group evolved from the 'true' reptiles, which gradually acquired mammalian characters until a point was reached where we have artificially drawn a line between reptiles and mammals. For instance, Pachygenulus and Kayentatherium are both far more mammal-like than reptile-like, but they are both called "reptiles".
You can't make up in volume what you lack in substance. Your points will stand or fall on their own (or is that the problem?) If you feel that you need to support a point, a URL is sufficient to provide a link for further reading. And if you can't put something into your own words, perhaps you don't understand it well enough to use it.
Now on with the show...
As I've long said, properly understanding something is the first requisite of having a chance of actually rebutting it.
Unfortunately, you clearly did not understand my post. Please go back and reread it now before you repeat the mistakes you make here, keeping in mind the following highlights:
1. Contrary to your claim, the egg-laying to placental transition NEED NOT have happened in "one generation". The reason is:
2. As the hammerhead shark method of gestation makes entirely clear, it's perfectly workable to have placental feeding IN ADDITION TO egg-style yolk-feeding of the embryo. Thus:
3. Rather than needing to do the "switchover" in, as you preposterously claim, "one generation", what you have overlooked is the mechanism of: A) start with egg-based yolk-feeding. B) Over however many generations it takes, *add* placental feeding to yolk-feeding. C) Over however many generations it takes, phase out yolk-feeding and leave placental feeding as the primary embryonic nutrition source.
Thus, you were flatly wrong when you declared that there was no "gradualistic" way to transition from one to the other, because there *is* a workable, *gradualistic* pathway which you failed to consider as a possibility. QED.
As a sidebar issue, note that:
4. I don't need to demonstrate that it *did* happen that way, since that wasn't the claim being examined. The claim was *your* claim that it *couldn't* happen in *any* gradualistic way, period. In order to prove you wrong, I only need to demonstrate a *workable* gradualistic pathway that you had overlooked which allowed multi-generational change to occur without "breaking" the system. I did that.
And:
5. Evolution isn't even on the table here, since you claimed to have ruled out any "gradualistic" development BY ANY METHOD -- and my counterexample works as a gradualistic development method NO MATTER WHAT DRIVES IT.
Now let's look over your response...
While your detailing of live birth in sharks and other species is very interesting, for the sake of brevity, I shall not discuss it here since not even evolutionists would claim that mammals descended from sharks.
Boggle... Did you actually not understand the point being made there, or are you just trying to misrepresent what I actually said in the hopes anyone will swallow it? Or perhaps you're just trolling.
Hint: "Descent" wasn't relevant to the point being made, nor did I in any way claim that it was, or that descent was even involved.
Hint #2: It was a good point, and your dodging of it doesn't help your case any. You can't weaken a point by closing your eyes and hoping it'll go away. An honest debater would concede the point, or rebut it head-on.
According to you all that is needed for a change from egg laying is to get rid of the egg shell and attach the baby to the uterus and there you are!
I said those were the only "major" steps necessary, yeah.
A complete change in mode of reproduction.
I spent several thousand words explaining in detail why you were wrong when you claimed it was a "complete change" in the method of reproduction -- did you not bother to read it?
Problem is that science tells us it is not that easy.
To borrow an old phrase, you use science the way a drunk uses a lamppost -- for support instead of illumination. You frequently argue against science and scientific methods when it suits you, but then you aren't shy about digging frantically for "scientific" support when your own concepts start eroding.
Ok, let's look at what you've got...
[biology primer cut-and-paste snipped]
Without the above happening - with the cooperation of both the baby and the mother, there will be no pregnancy and no reproduction.
Some of it yes, some of it no (for example, the interdigitation limiters aren't necessary for non-deciduate placentas, so they're hardly a necessary "starter feature").
But you're just trying to muddy the waters. That in no way invalidates any of the points I made in my post to you, nor repairs any of the multiple flaws in your original erroneous claim.
See point #3 above: Retention of the yolk-feeding method allows "gradualism" however long it takes to cobble together a combination of changes which enables the first successful placenta. It's not true that th ere would be "no pregnancy and no reproduction" until all the changes were in place, since the *pre-existing* reproduction method would work just fine until a new method became workable.
Did you not understand post #378?
Eggs of course do not have a placenta. Without it though, mammalian reproduction would be impossible.
Wrong again. As I pointed out in my post #378 (you *did* read it, didn't you?) marsupials don't have placentas (most of them, anyway) and yet their "mammalian reproduction" is, obviously, not "impossible".
Furthermore, *again* as I showed in my post #378 (try *reading* it before you try to rebut it, please), eggs actually *do* have "placentas" in a sense -- the extraembryonic tissues that allow an embryo to develop successfully in an egg are the *same* structures that make placentas workable.
Are you ignoring these issues, or just pretending to? Neither option inspires confidence...
There is a quite a bit necessary for a placenta to do its job:
[Cut-and-paste says:] The placenta is the link between a fetus and its mother about the exchange of substances and the thermoregulation. At the childbirth it will be replaced by digestive system, lungs and kidneys of the newborn, for the exchange of substances. The thermoregulation will be driven by the central nervous system through the control of the blood circulation and of the metabolism.
...all of which is the case for egg-hatched reproduction as well. So much for requiring a "change"...
[Cut-and-paste says:] Other placental functions: * Production of hormones * Transmission of chemical messages * Regulation of the resistances of the fetal circulation * Regulation of oxygenation of the fetal blood. How and how much these functions are achieved is still mainly unknown.
...all of which are refinements to the reproductive process which were made possible after primitive placental birth was developed, and are not necessary requirements for the first appearance of placental feeding. Immaterial to the argument, which I shouldn't have to remind you, is about whether placentas could *first* arise *at all*.
The proper perfusion of the placental vessels is a prerequisite for the complete growth of the fetus. From: Physiology of Fetoplacental Circulation
Again, if you had *read* my post #378, you'd see examples demonstrating that "complete" growth of the fetus is not a necessary function of the first placenta in order for it to be highly useful. Some marsupials are examples of this.
Does not seem like something you can just say 'abracadabra' and arise by random chance!
Straw man. It happened neither by "abracadabra", nor by "random chance" acting alone. NOR is a Darwinian origin even at issue here, refer back to point #5 above if you're still unclear on that point. You're wrong even *apart* from any argument about Darwinian evolution as a method.
At birth there has to be a complete change from blood circulation through the mother to circulation through the baby,
Horse manure, fetal blood circulation is *never* "through the mother". From the start, the embryo has its *own*, *self-contained* blood system.
this includes a complete switch in the lung function of the baby from its being a consumer of oxygen to an acquirer of oxygen:
Gee, just like in a hatching egg... Again, no change necessary there. And again, just as I had *already* pointed out in post #378. Try understanding it next time.
[cut-and-paste says:] In the fetus, the systemic, pulmonary and umbilical circulations have several links. The umbilical and placental circulations are a temporary system for the life and the growth of the fetus, that is abandoned at the childbirth, when drastic changes take place transferring the function of gas exchange from the placenta to the lungs.
Gee, again, just like *also* happens in an animal hatching out of an egg. *Again*, no change necessary there. I covered this already -- do you need a refresher course?
Does not seem like it could have happened with a single mutation does it?
Sigh. There you go with your "single mutation" fetish again. See point #3 above.
Furthermore, I again refer you to the fact that the "switchovers" you focus on are *already* present and working in egg-hatched species. So they hardly have to be added by *any* number of mutations in order to be put into identical service for placental birth.
The transfer of blood requires a very complex system:
Again you are in error -- there is no "transfer of blood".
[Cut-and-paste says:] we can classify the placental vessels as follows: + chorionic vessels; + vessels of the cotyledons; + capillary vessels in the villi; + paravascular capillary network. The villi can be classified in 5 main groups: stem villi, mature and immature intermediate villi, terminal villi and to mesenchimal villi [20]. From: Anatomy of the Fetal Side
Again, all present in egg-hatched vertebrates, except for the final branches of the villi, and while those increase efficiency, they aren't necessary for the success of a primitive placenta.
Amazing what can be done with a single mutation eh!
Amazing how stubbornly you stick to the "single mutation" fallacy.
Nothing requires the changes to be a "single mutation" (nor in a "single generation"), nor do most of your alleged "changes" actually need to happen at all, because they *aren't* "changes" -- they are features and mechanisms *already* present in egg-hatched species.
But then, this was already explained to you in post #378. What's your excuse for not understanding it?
CHANGES IN THE MOTHER:
[cut-and-paste snipped]
Amazing what little is needed to change from egg laying to live bearing - just a complete change in the mother!
Sorry, but none of that is required for a primitive placental gestation. They can be added as refinements after the initial system is in place.
And the production of a few hormones is hardly a "complete change in the mother", so don't overstate the issue.
IMMUNOLOGICAL REJECTION PROBLEMS:
[Cut-and-paste snipped]
Of course the above problem had to be solved before a single baby was born since immunological rejection causes loss of pregnancy.
You really need to try reading your own sources before you offer them in alleged support of your claims. Your quoted material says no such thing. It only says that rejection sometimes occurs, *not* that there's a special system in place which "solves" the problem and that rejection would invariably occur without it.
Furthermore, it's clear that egg-hatched species already have immunosuppressive systems, since sperm cells are not rejected on their way to the ovum, and the fertilized ovum (which is likewise "foreign" to the mother) is not rejected as it passes down the birth canal and gets built into an egg.
One of the purposes of the amniotic sac is to prevent immunological problems with the mother:
[Cut-and-paste says:] since the bag of waters prevents bacteria from entering the uterus by acting as a barrier, membranes aren't usually ruptured until delivery is imminent.
That's sweet, but irrelevant, since eggs have amniotic sacs too.
Yet again, I must ask you to learn something about egg-laying as a method of reproduction before you make a fool of yourself declaring what might or might not be a big "change" when compared to placental birth.
The amniotic fluid plays an important part in the baby's development:
[Cut-and-paste snipped]
Seems the amniotic sac is a pretty essential part of the baby's excretory system.
Yup. Sure is. Just like it is in eggs, too. Yet again, you might want to learn something about it before you make yet another mistake about what does and does not need to be added/changed in order to go from eggs to placentas...
The umbilical cord is of course essential in this whole process. It is not as simple as one would think:
[cut-and-paste snipped]
Seems that the jelly around the umbilical cord is quite necessary. Even with the strong service Wharton's jelly provides in preventing knotting, babies die because of the cutting off of the blood supply.
Yup, sure is. By the way, eggs have umbilical cords and take care to prevent twisting as well...
CONCLUSIONS:
Seems we need quite a lot to happen for this transformation!
"Seems" not after all, once we snip out all the parts of your long list that a) are *already* present in eggs, thus requiring no "transformation", and b) weren't necessary for the first placenta but were later improvements.
In fact, gosh, once you take out all that hand-waving, we're left with the issues I already covered in my post #378. Amazing.
Even the individual processes within the system which are necessary to accomplish the change over are quite complex and could not have arisen as a result of a single mutation.
Big whoop-de-doo, since as I already spelled out in great detail in post #378, they need not happen in "a single mutation", nor "a single generation. Reread point #3 above if you're still unclear on this concept. Or hell, reread post #378, I already covered this.
So... Did you not read post #378 before you attempted to rebut it, or did you not understand it, or are you purposely avoiding the parts of it that you know cause problems for your claim? Inquiring minds want to know.
Further, all the processes are interrelated. The separation of the umbilical cord has to signal a changeover to breathing by lungs and blood circulation wholly within the baby.
Already present in egg-layers, fella.
The joining of the baby to the uterine wall starts the signaling of changes in the mother. In fact, the whole process can be seen as a very careful interaction between the baby and the mother.
Not necessary for the first placenta, although later development of such coordination certainly improves the system.
As a result of all the above, I think it should be pretty clear to those who have an open mind that at no point is there a possibility that the changes necessary to achieve a transformation of the reproductive system from egg laying to mammalian live birth can be achieved in a single generation.
"Single generation", eh? You're a broken record. Reread point #3 above, and post #378. WE ALREADY COVERED THAT. So why do you lamely pretend that we haven't?
There are way too many changes needed to make a claim that all these changes could have occurred in any sort of gradual manner
...so you claim, without actually making a case for it. All your arguments so far have been of the faulty "one mutation, one generation" variety. If you're going to shift gears now and insist that gradual change is ruled out, you're going to have to prove *why*. If you're going to try that now, be very sure that you're working on a *minimal* set of *necessary* changes, and *not* a laundry-list of *modern* features which are not only more advanced than any likely first placenta, but are even more advanced than many other mammalian placentas (e.g. cows). Good luck.
and that they are far too many to have occurred suddenly in a stochastic manner.
They didn't, nor did they need to, which is exactly why you were dead wrong in your post #257, and why you would be well advised to just admit that you were wrong and retract it rather than bluster on.
Let's see what you've got...
Now, pay attention. We are going to ask scientific questions, questions you did not answer.
Okay, but if they're not relevant to the points I made, then I'm afraid they won't count as the promised "holes" the size of the "Grand Canyon" which you promised us.
Is it true that many if not most species of sharks have remained virtually unchanged for millions of years? Well, yes it is. If that is so, where is the vaunted Darwinian change?
Irrelevant to the points being made in post #378. Sorry, no hole, try again. As explained in a recent post, the argument that gore3000 and I are having is entirely apart from the issue of what might or might not be driving the "gradual changes" he declares to be impossible.
And did egg-layers transition into live-birthers? Or the reverse? How do you know? What is the evidence? They clearly are all currently viable, so which of the 3 is the product of survival advantage?
Irrelevant to the points being made in post #378. Sorry, no hole, try again. The argument was over the mere theoretical possibility of such transitions, not whether they did or did not occur in what order.
Sort of embarrassing to be asked these questions, isn't it?
No, not at all. Is it embarrassing for you to have missed the point of my post so badly?
Particularly since you don't have the answers. But take heart. Neither does anyone else.
Wow, what an amazing assertion. Perhaps you could document it.
And hang in there, there's more.
I can't wait.
Whichever way the transformation occurred, which is wholly speculative at this point, what was the mechanism?. Chance? You allude to chance as the "reason" when you point to lengthy periods of time between supposed events.
Irrelevant to the points being made in post #378. Sorry, no hole, try again.
Well then, how about mutation?
Irrelevant to the points being made in post #378. Sorry, no hole, try again.
Let's talk a little more about homology, structural similarities. Seems widely varying species have been known for centuries to exhibit surprisingly similar organic structures, which would seem to be impossible if Darwinian Evolution looks anything like a tree.
Not true at all, you clearly don't understand "Darwinian Evolution". It in no way bars different species from arriving at the same "solutions" to the problems of survival. But again, irrelevant to the points being made in post #378. Sorry, no hole, try again.
I refer you to Icons of Evolution by Johathan Wells.
*snicker* I've read his website. Wells is an idiot. Or incredibly dishonest. Neither option inspires confidence.
To quote you back to yourself: OOPS!
You seem to have forgotten to document where I am allegedly in error. Keep trying.
You have not shown us, Dan.
Sure I have -- I set out to show that gore3000 was operating on several false assumptions and erroneous logic, and I did so.
But the Evol Claque is ecstatic, back slapping and shouting -- I think I even saw Patick on a table in the center of the room waving his hands.
Sigh, back to preaching again so soon? I was still waiting for the gaping "holes" you promised to identify in my post #378.
For all the pretty pictures and the volume of rhetoric, Dan, I'm underwhelmed.
Likewise.
Sorry, no holes identified. I await your apology.
As for your multiple attempts to broaden (*very* broaden) the subject in this post, I'm resisting your cheesy effort to distract attention from the points I actually *did* make in post #378, and thereby divert attention from the debunking of gore3000's faulty argument.
I do have answers for your tangential questions, but this is not the time to deal with them. One thing at a time. However, I can't say that I'm all that confident that you would even benefit from the answers, since the way that you chose to "answer" all of your own questions indicates that you're not interested in learning, you're just interested in hearing yourself talk. Any answers contrary to the ones you already think you "know" will likely bounce off your forehead with a sharp "ping".
Convince me that's not the case and perhaps we'll talk.
Psst: UC Riverside study suggests placentas can evolve in 750,000 years or less
and which Dan Day tried to refute in Post# 378 and I convincingly dismissed in Post# 425
*snort*. Pretty cocky, aren't you? Check out my critique of your "dismissal" in post #509.
Originally the word liberal meant social conservatives(no govt religion--none) who advocated growth and progress---mostly technological(knowledge being absolute/unchanging)based on law--reality... UNDER GOD---the nature of GOD/man/govt. does not change. These were the Classical liberals...founding fathers-PRINCIPLES---stable/SANE scientific reality/society---industrial progress...moral/social character-values(private/personal) GROWTH(limited NON-intrusive PC Govt/religion---schools)!
Evolution...Atheism-dehumanism---TYRANNY(pc/liberal/govt-religion/rhetoric)...
Then came the SPLIT SCHIZOPHRENIA/ZOMBIE/BRAVE-NWO1984 LIBERAL NEO-Soviet Darwin/ACLU America---the post-modern evolution age of illogic - - - dissonance (( noise )) ! ! !
Main Entry: dis·so·nance
Pronunciation: 'di-s&-n&n(t)s
Function: noun
Date: 15th century
1 a : lack of agreement; especially : inconsistency between the beliefs one holds or between one's actions and one's beliefs -- compare COGNITIVE DISSONANCE
b : an instance of such inconsistency or disagreement
2 : a mingling of discordant sounds; especially : a clashing or unresolved musical interval or chord
Your efforts are most appreciated. I fear, however, that when they "rebut" you by merely repeating their former points, you will give up and go away from these threads. Don't do that. conserve your powder; the battle is far from over.
Your debate opponents may, if they wish, use this post to visualize that I'm still "on a table in the center of the room waving his hands." (Whatever that means.)
The one word that may explain your post.
Personally, I think the fundamentalist christians do more to drive people away from "believing" than anything or anyone else.
Why should deliberately careless distortions of observations and theories to conform to a predetermined belief, and vilifying close-minded defenses of ignorance and absurdity drive people away? You speak as though people are turned off by attacks on human thought.
Full stop. You maintain that chance is at the heart of everything, to include quantum mechanics and Evolution. Does that about cover it? Yet you do not appreciate or will not acknowledge that chance explains nothing and that it is thus not science. I therefore can't help you because you do not understand English. Re your suggestion as to me and my "Fundie bud[d]ies", kindly address subsequent such posts to someone else. Your bias is showing.
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