Posted on 01/11/2003 9:53:34 PM PST by DWar
I consider that an excellent question since it was the one think that kept me from becoming a creationist. After some study I found out that the evidence was being forced to fit the theory. The theory, of course, should be conformed to the evidence.
Consider that there are about 6000 known fossil hominids (and I use the term loosely). Only about 1% of them are on display. Why? Because the others don't fit the theory? They are apparently normal looking fossils and don't do anything to promote the picture of gradual evolution.
Indeed it is a problem. The problem is that the differences detailed between egg-laying and live bearing animals are individual only for purposes of detailing, but they very much form a system which requires all the parts to work together:
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. -me-
Not necessary for the first placenta, although later development of such coordination certainly improves the system.
The above is the evolutionist 'leap of faith' through a chasm the size of the Grand Canyon. The only purpose of a placenta is the transfer of nutrients from the mother to the baby through the uterine wall. This alone requires both changes in the uterine wall of the mother, the attachment of the placenta to the uterine wall, and the non-rejection of the 'foreign' body by the mother. This by itself requires numerous changes in the growing baby and the mother as well as numerous specific proteins to be secreted to achieve a successful change in nutritional system. As the following shows:
The mammalian embryo obtains nutrients directly from its mother and does not rely on stored yolk. This adaptation has entailed a dramatic restructuring of the maternal anatomy (such as expansion of the oviduct to form the uterus) as well as the development of a fetal organ capable of absorbing maternal nutrients. This fetal organ ---the chorion ---is derived primarily from embryonic trophoblast cells, supplemented with mesodermal cells derived from the inner cell mass. The chorion forms the fetal portion of the placenta. It will induce the uterine cells to form the maternal portion of the placenta, the decidua. The decidua becomes rich in the blood vessels that will provide oxygen and nutrients to the embryo.
From: Modifications for Development within Another Organism
Let's look at the above problem more closely:
While the embryonic epiblast is undergoing cell movements reminiscent of those seen in reptilian or avian gastrulation, the extraembryonic cells are making the distinctly mammalian tissues that enable the fetus to survive within the maternal uterus. Although the initial trophoblast cells of mice and humans divide like most other cells of the body, they give rise to a population of cells wherein nuclear division occurs in the absence of cytokinesis. The original type of trophoblast cells constitute a layer called the cytotrophoblast, whereas the multinucleated type of cell forms the syncytiotrophoblast. The cytotrophoblast initially adheres to the endometrium through a series of adhesion molecules. Moreover, these cells also contain proteolytic enzymes that enable them to enter the uterine wall and remodel the uterine blood vessels so that the maternal blood bathes fetal blood vessels. The syncytiotrophoblast tissue is thought to further the progression of the embryo into the uterine wall by digesting uterine tissue (Fisher et al. 1989). The uterus, in turn, sends blood vessels into this area, where they eventually contact the syncytiotrophoblast. Shortly thereafter, mesodermal tissue extends outward from the gastrulating embryo (see Figure 11.27D). Studies of human and rhesus monkey embryos have suggested that the yolk sac (and hence the hypoblast) is the source of this extraembryonic mesoderm (Bianchi et al. 1993). The extraembryonic mesoderm joins the trophoblastic extensions and gives rise to the blood vessels that carry nutrients from the mother to the embryo. The narrow connecting stalk of extraembryonic mesoderm that links the embryo to the trophoblast eventually forms the vessels of the umbilical cord. The fully developed extraembryonic organ, consisting of trophoblast tissue and blood vessel-containing mesoderm, is called the chorion, and it fuses with the uterine wall to create the placenta. Thus, the placenta has both a maternal portion (the uterine endometrium, which is modified during pregnancy) and a fetal component (the chorion). The chorion may be very closely apposed to maternal tissues while still being readily separable from them (as in the contact placenta of the pig), or it may be so intimately integrated with maternal tissues that the two cannot be separated without damage to both the mother and the developing fetus (as in the deciduous placenta of most mammals, including humans).
From: Formation of Extraembryonic Membranes
There are numerous 'little' problems within the above that need to be solved for the system to work properly, one of them is oxygen:
The solution to the fetus's problem of getting oxygen from its mother's blood involves the development of a fetal hemoglobin. The hemoglobin in fetal red blood cells differs slightly from that in adult corpuscles. Two of the four peptides of the fetal and adult hemoglobin chains are identical ---the alpha (α) chains ---but adult hemoglobin has two beta (β) chains, while the fetus has two gamma (γ) chains (Figure 15.11). Normal β-chains bind the natural regulator diphosphoglycerate, which assists in the unloading of oxygen. The γ-chain isoforms do not bind diphosphoglycerate as well and therefore have a higher affinity for oxygen. in the low-oxygen environment of the placenta, oxygen is released from adult hemoglobin. in this same environment, fetal hemoglobin does not give away oxygen, but binds it. This small difference in oxygen affinity mediates the transfer of oxygen from the mother to the fetus. Within the fetus, the myoglobin of the fetal muscles has an even higher affinity for oxygen, so oxygen molecules pass from fetal hemoglobin for storage and use in the fetal muscles. Fetal hemoglobin is not deleterious to the newborn, and in humans, the replacement of fetal hemoglobin-containing blood cells with adult hemoglobin-containing blood cells is not complete until about 6 months after birth.
From: Fetal Hemoglobyn
I could go on and on, however, let's just show the problem of adhesion:
The mouse blastocyst hatches from the zona by lysing a small hole in it and squeezing through that hole as the blastocyst expands (Figure 11.25). A trypsin-like protease, strypsin, is located on the trophoblast cell membranes and lyses a hole in the fibrillar matrix of the zona (Perona and Wassarman 1986; Yamazaki and Kato 1989). Once out, the blastocyst can make direct contact with the uterus. The uterine epithelium (endometrium) catches the blastocyst on an extracellular matrix containing collagen, laminin, fibronectin, hyaluronic acid, and heparan sulfate receptors. The trophoblast cells contain integrins that will bind to the uterine collagen, fibronectin, and laminin, and they synthesize heparan sulfate proteoglycan precisely prior to implantation (see Carson et al. 1993). Once in contact with the endometrium, the trophoblast secretes another set of proteases, including collagenase, stromelysin, and plasminogen activator. These protein-digesting enzymes digest the extracellular matrix of the uterine tissue, enabling the blastocyst to bury itself within the uterine wall (Strickland et al. 1976; Brenner et al. 1989).
Implantation
Finally, lets show the developmental system of an egg:
This is a picture of a 4 day quail embryo. It is on the yolk with the some of the egg shell removed. Notice the large vessels which are required to provide the nutrients necessary for the rapid development if the embryo. The heart and eye are evident by somewhat obscured by the presence of a new membrane structure, the allantois. The allantois grows from the umbilicus (belly button) and has two primary functions. First it is a waste storage area for the embryo and it will be the gas exchange organ while the embryo is confined in the egg. After hatching, the chick will leave the allantois in the shell. The heart is the red structure in the middle of the embryo and the eye is visible as a dark area in the head.
Compare the above to the picture of the human developmental system in Post# 257 .
Again, each step requires numerous other steps as well as coordination of all the steps. The reductionism of evolutionists does not cut it. The steps are numerous and have to be precisely timed, they need various genes, proteins and organs.
How many people how many times have to explain to you what evolutionists actually claim so you can get on topic? Can you read?
How many times do I have to tell you that I do not accept what evolutionists claim? All the 'cr_evo' threads are essentially about whether the claims of evolutionists are correct or not.
The evolutionist claim is nonsense. We call the classification mammals, not three earboners for a reason. Further, as this discussion has shown, sharks have very diverse means of reproduction even though they are all fish. Since this discussion is about reproduction the fossil record is totally irrelevant to it and whatever bones EVOLUTIONISTS wish to call mammals is also irrelevant.
defenses of ignorance and absurdity
ig·no·rance n. The condition of being uneducated, unaware, or uninformed.
E.g., post 14: "In physics, the Second Law of Thermodynamics...it is scientifically impossible for a less complex system, organic or inorganic, to move from the less to the more complex."
ab·surd`i·ty n. That which is absurd; an absurd action; a logical contradiction.
E.g., a contradictory non sequitur from the article--"First, there should be a lot more [transitional fossils] if Darwin's theory is correct. Second, 99 percent of the biology of an organism is in its soft anatomy, which you cannot access in a fossil..."
I suspect that you are a paranoid schizophrenic and don't know it. I gave specific examples in response to your post. Please show me you worth responding to.
Right after you explain the didactic usefulness of the obfuscation of systematic discontinuities throughout your theory.
Lemme guess... you got a "Word-a-Day" calendar for Christmas? Remember those press conferences after Mike Tyson's handler's got him one. Hee! But to the point I think you were attempting to make, variation, heredity, and reproductive success are the three legs of biology. The mechanisms of each are identifiable and quantifiable, provide a framework for categorizing fossils, justify the use of animal subjects for testing human medical technology, assist geologists in strata identification, and marks the results of comparative genome analysis as more than random noise. What does you theory do?
I contend that the evos' failure to deal with the origin of matter and the Prime Mover disqualifies them from continued building on a defective foundation.
Feel free to contend whatever you wish; your audience is not obligated to agree. Music theory has little to say on the origin of air. Meteorology has little to say on the origin of water. The origin of matter is NOT in the domain of biology.
I contend that it is logically impossible to rule out a Creator.
I agree. It is also impossible to demonstrate the existence of such.
Having destroyed the foundation of your theory, it collapsed. Now you want to continue to discuss your discredited theory?
Hrm, I think I missed that part. You are aware, of course, that saying does not make it so? Tell you what, next time you destroy the theory of evolution, get your special effects guys to rig a couple of firepots, or put a big dramatic chord in the soundtrack so we can better identify it. While you're at it, maybe you could write a spooky "bad guy" theme to play when an evo posts so the lurkers can keep track of the characters.
But back on topic, your contention that the theory of evolution needs to explain the origin of the universe is a pretty silly one. Most off-the-rack creationists only want it to explain the origin of life.
I'm serious, man. Your disordered thinking is disturbing. Your FR web page does in words what a Louis Wain painting does with colors. If you are socially isolated or have an extraordinarily exciting or fearful life, you might want to seek professional help.
Whatever you say...
But what that might possibly have to do with an examination of how placental embryo feeding may have come about, though, remains tucked under your tinfoil hat.
I am not interested in arguing with you.
Imagine my disappointment.
Your mind is made up.
No, actually, it's not. I'm quite open to changing my mind if I'm shown any evidence that points to a different conclusion. Screeching about irrelevant issues like "global warming", however, doesn't count.
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