wrote:
big snip
http://www.answersingenesis.org/tj/v9/i1/dating.asp?vPrint=1
Humor me for a minute, and have a read. I'd be very interested in
your critique of the article. Remember, I'm interested in truth and
if the article has flaws or errors or whatever I'd like to know
about it. There are other articles that address the problems
in the other processes cited above.
first consider the source:
"Dr Andrew Snelling is a geologist with a B.Sc. (Hons) from The
University of New South Wales and a Ph. D. from The University of
Sydney...., but now also works full-time with the Creation Science
Foundation where he contributes to Creation Ex Nihilo magazine and edits
the Creation Ex Nihilo Technical Journal. He resides in Brisbane, Australia.
Second, the example you cite doesn't negate the technique, it just calls
for caution in selecting a site with an appropriate geomorphology to
ensure an accurate date, free from confounding variables. what the
article really says is that Koongarra, Australia is not a good site for
dating. I have no problem with the report other than the o so loaded
publication-
"UPHOLDING THE AUTHORITY OF THE BIBLE FROM THE VERY FIRST VERSE"
------------------------------------------------------------------------------
Now tim, you have claimed that measurements are off by orders of
magnitude. could you provide me with such evidence? Who has
reproducibly got such variance? And I don't mean due to incompetence.
I'm trying to find the actual paper (to make sure that I can read
the context), but my reference includes the following:
"Processes of rock alteration may render a volcanic rock useless for
potassium-argon dating . . We have analyzed several devitrified glasses
of known age, and all have yielded ages that are too young. Some gave
virtually zero ages, although the geologic evidence suggested that
devitrification took place shortly after the formation of a deposit."
*J.F. Evernden, et. al., "K / A Dates and Cenozoic Mannalian Chronology
of North America," in American Journal of Science, February 1964, p. 154.
Granted, there have been a number of 'studies' done that have hand
selected rock samples that exhibit discordant ages. However,
"so frauds have occured. they don't negate the theory."
We should be able to examine the processes in use, and discuss
flaws in reasoning as well as results.
By the way, many of the presuppositions of these methods you've
stated have primary flaws in reasoning that invalidates their
results. Such as I've explained in a prior post about radioactive
half life.
As I recall you questioned the stability of the half-lives of
radioactive isotopes? Doesn't your computer(s) keep track of time via
an atomic clock? at least by reference ? Again I would like to see
any any evidence as to the variance in half-lives.
I'm not suggesting that radio-active half-lives have changed.
What's in view is variances between the different methods
used. For example, the isotope ratio at the time of the
formation of the sample, or ion migrate in and out of the
sample (the assumption of a closed system).
vide infra
radiometric dating, when performed by experienced scientists, and
reviewed by peers, is the best method for determining the ages on lots
of stuff, and far and away better than consulting the often transcribed
oral history of a desert tribe from thousands of years ago.
Look, an unobserved series of historical events happened. No
transitional species have ever been found (notwithstanding several
publications' attempts to present them from time to time) that
has stood up to scrutiny.
what? just in terms of human evolution, australopithecenes
evolutionarily precede "homo" genera. Within Homo, are a series of
species such as erectus, habilis, and on and on. And if you look at
the dna the relationships are overwellminingly obvious. There is a
gradual change in the dna as you move across the spectrum of life.
My dna is more like a chimpanzee's than the chimpanzee's is like a
gorilla's. Put another way, the dna of a sea squirt is more like
mine than it is to a salmonella bacteria. One must really try hard
to not see the relationships among life.
So you're saying that DNA has been collected from all the skeleton
fragments that were used to construct this tree of descent? I'd
be interested to see that. What is the degree of sequence match
between the australopithecenes skeleton and one of us?
dna doesn't survive more than a few ten's of thousands of years, under
the best of circumstances. Fossils don't have dna. The dna is from
extant species. the closer the dna sequences, the closer the
phylogenetic relationship.
Since there are no DNA sequences in the fossils, then how do you
make the link? Do I understand you to mean that you look at
living species today that seem to have the characteristics of
the fossils? I mean, at one point dinosaurs were believed to be
cold-blooded, and now some belief warm-blooded. There is an incredible
difference in physiology between the two!
actually they may have been in between, or at least some species were
warm, some cold, based on fossil evidence. And I am not so sure I would
describe their physiology as that different, based on comparisons of
extant reptiles and mammals. They both have a variety of hemoglobin
circulating to deliver oxygen to mitochondria in their cells for aerobic
respiration, both are capable of anaerobic metabolism for generation of
energy when oxygen is not delivered to the cells fast enough, etc, etc.
In fact, all procaryotes, that is nucleated organisms use the exact same
mitochondria as you and I the major engine of our our metabolism.
My understanding of trying to establish phylogenetic relationships
in the lab right now is by digesting some of test material and
the comparison material in a sequence of enzymes with the intent
of selecting sequences of DNA out of each. They then try to
compare the 'compositions' by doing a statistical analysis by looking
at the quantities of each of the selected sequences. Is this correct?
not quite, but sort of. Lets talk about protein first, the stuff dna
codes for. Hemoglobin is a good example. It is the oxygen carrier for
distribution of oxygen in a great number of animals. If I look at the
specific amino acid sequence in hemoglobin, I see that is my hemoglobin
is essentially identical to the hemoglobin of every human on the planet.
(ok if you have tay-sachs disease or sickle cell anemia, you have a
single amino acid substitution) If I examine the hemoglobin of a
chimpanzee, it is only sightly different. If I examine that of a howler
monkey, more so, and a cow even more so. Hence the obvious
phylogenetic relationship. Now you may not think you evolved from a
cow, (and actually you didn't)but you did evolve from an organism
preceded both human and cows.
If this is the case, it's kind of like looking at a iguana and
a cow, concluding that they might have a phylogenetic relationship
(both have four legs, eat food, breathe air, etc) and stuffing
each of them through a meat grinder.
you're right, they are related, at least more closely than a slime mold
and a cow.
Well, we see white specks, red specks, lots of liquid red stuff.
They must be related! :-) I know, this is over-simplified
but isn't it essentially the truth?
the devil's in the details
I'm sure that the design of the process is supposed to select
from the end of the strand, etc but given how enzymes work
you will get selection from throughout the strand. Hence,
you really can't conclude too strongly about relationships
(especially when trying to determine genetic descent!)
sure you can. I can cut individual amino acids off either end of the
strand, I can selectively cut a chain only between a specific pair of
amino acids, etc. and yes I can know erectly the sequence. The advent
of the manipulation of DNA is even better because their is more
"information" in dna than the polypeptides it codes for. But that is a
longer story. But then I am employing the understanding gained thru
application of the atomic THEORY. Get it, it's a theory, and it works to
explain a broad realm of knowledge.
And now I must conclude and get what I do, teach about doing science.
sorry to cut off the discussion. maybe more when I have time.
--
Bob Allen
http://ozarker.org/bob
"Science is what we have learned about how to keep
from fooling ourselves" — Richard Feynman
---
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