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Quetzal
Member (Idle past 5894 days)
Posts: 3228
Joined: 01-09-2002


Message 98 of 111 (67342)
11-18-2003 11:44 AM
Reply to: Message 87 by keith63
11-18-2003 7:19 AM


There's quite a bit in this post that is in error. I'd be happy to expand on any of the following responses with citations from either primary or secondary (mostly books) literature if desired.
1. Miller/Urey experiment. We have now known for years that the early earths atmosphere looked nothing like the organic soup Miller and Urey used in their experiment. Oxygen has always been in the atmosphere and if you mix oxygen into any mix you can't get the amino acids they produced. If you can't get the starting material then you certainly can't get started and the whole macroevolutionary idea becomes a mute point.
In the first place, Miller's experiment was merely designed to show that a simple gas mixture could give rise to biologically significant molecules when acted upon by a "natural" energy source. Although his putative atmosphere has been called into question (rather than the strongly reducing atmosphere of Miller, a more weakly reducing atmosphere of mostly CO2 and nitrogen is more in line with the geology), a number of other researchers (such as Orgel, Szathmary, etc) have since shown peptide and amino acid formation under other conditions. Moreover, it apparently doesn't require ANY atmosphere, as discovered in the Murchison meteorite (the same amino acids found by Miller in almost the same proportions).
In the second place, your statement concerning oxygen is at best misleading. Yes, oxygen has always been a component of the Earth's atmosphere. However, the existence of extensive BIFs and large pyrite inclusions in the oldest depositions show that the amount of oxygen was exceptionally low in the early atmosphere - around 1% of current levels. This state of affairs continued until around 1.8 gya - when BIFs disappear from the geological column (see, for example, the Gunflint Formation or the geology of the Belcher Islands). The presence of siderite and uraninite from gravel beds older than than about 2.2 gya - and their absence from younger beds - is another indicator of the lack of signficant quantities of atmospheric or oceanic oxygen in the good old days. Finally, the absence of red beds prior to 2.2 gya - and their subsequent presence obviously - is a final indicator that oxygen only became a factor in the second half of Earth's history.
At least in the textbook I most routinely refer to (Futuyma, D, 1998 "Evolutionary Biology" 3d edition, Sinauer), especially Chapter 7 ppg 166-168, discusses both the pluses and minuses of Miller's experiments.
Another point about the Miller/Urey experiment that never hits the text books. Their experiment produced tar which really messes up their results so they remove the tar. Now correct me if I'm wrong but that is intellegence. Also the experiment produced both right and left handed amino acids and only left handed ones are found in living things.
The evolution of homochirality is being debated on another thread, so I won't bother to derail this one. Since you're a teacher, you probably have access to Bailey, JM 1998 RNA-directed amino acid homochirality FASEB Journal 12:503-507, or look up Ghadiri's work in Saghatelian, A., Yokobayashi, Y., Soltani, K., & Ghadiri, M. R., 2001, "A chiroselective peptide replicator" Nature 409:797-801.
2. The fossil record is an imbarrassment to evolutionists. If you were really to evaluate the fossil record with an open mind you would see that it really supports the creation model which says that things reproduced after their "kind."
You might want to expand on this a bit - what aspects of the fossil record support "created kinds"? What is a kind, anyway? Please be specific - use reference to actual fossils to support your assertion.
3. Darwin himself said that the fossil evidence was his weakest point but he was confident that more fossils would be found. Well they have and what we find our all the major phyla already formed with no transitions, just like the bible said we would.
I beg your pardon? What does "all major phyla already formed with no transitions" mean? Which phyla, specifically, and when (relatively speaking) did these form?
4. Peppered moths turning black, bacteria becoming resistant to antibiotics, and finch beaks getting larger are not evidences of macroevolution. They are simply populations expressing variation which already exists. What a huge leap evolutionists make. You might as well say that if you cross a dark mouse with a white mouse and you get a dark mouse then it's possible to turn a mouse into a donkey.
I actually covered a similar topic in the Micro/Macro thread here. Feel free to jump in there with any questions.
Why don't the textbooks mention that in the finch population the years after the drought, which caused their beaks to become larger, their beaks went right back to their normal size. No genetic changs, just expressions of variation which already existed.
If you're referring to the Grants' observation of beak variation in their Geospiza species during the early 1980's drought, then no one ever attempted to call the variation "evolution". As you pointed out, it was a temporary change in allele frequencies in the population caused by environmental pressures. It was, however, quite a graphic demonstration of the eliminative power of natural selection. It was way too short a timeframe for the changes to become permanent - although there's no reason to assume the changes wouldn't have persisted ("evolved") if the environmental change had been permanent. AFAIK, this particular example isn't taught as anything more than what it is - natural selection in action.
OTOH, if you're attempting to refute the evolution of Darwin's 14 finch species from a blue-backed grassquit (Volatinia jacarina) - IOW, all of island biogeography - you'd better be prepared to refute all of the modern molecular and genetic evidence that links them. Besides, I don't think they're much more than illustrative. I prefer the Tenrecidae of Madagascar for discussion of island biogeography if you want to go down this route.
Most all of the problems you mention aren't problems except to creationists. Textbooks generally only cover basic concepts and provide some examples, especially at secondary school level. They don't generally have either the space or time to deal with every single issue - they provide concensus. I'm unfamiliar with the text you said you used - perhaps you could give the complete title? However, the ones I have seen are fairly good, and most biology texts that aren't devoted specifically to evolution (like Futuyma's) generally have such a huge amount of material to cover that evolution is pretty small potatoes - although I like the treatment in Daniel, Ortleb and Biggs' 1997 "Life Science", McGraw-Hill (6th and 7th grade) that my #1 daughter used last year. Of course, she was in a good school going through a middle years International Baccalaureate program...

This message is a reply to:
 Message 87 by keith63, posted 11-18-2003 7:19 AM keith63 has replied

Replies to this message:
 Message 105 by keith63, posted 11-18-2003 1:04 PM Quetzal has not replied

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