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Author | Topic: Problems with the first life | |||||||||||||||||||||||
mihkel4397 Inactive Member |
References?
Mihkel
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mihkel4397 Inactive Member |
The relevance of the quote was to counter your blanket statement that I have misunderstood Crick. Have I?
Mihkel
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Chiroptera Inactive Member |
Good heavens! You need me to supply references? The Ediacaran Fauna are talked about in almost any paleontology book that speaks about preCambrian evolution, even popular science books. The molecular data indicating divergence of the major phyla over the last billion years is relatively new, but has been mention in journals like Science and I imagine should have been mentioned in the popular science press. How could you have possibly never seen this information? You could not have missed this information if you have done any real study of this. If you haven't studied this, then how the h*** can you think that you are going to be telling the rest of us what is fact and what is fiction?
I suggest going to a good library, preferably the science library are at a university, and looking in the evolutionary biology section. The library should be able to help you with this. At any rate, here is what I found after a couple minutes using Google: Here is some brief information on the Ediacaran fauna. I use this site because I like the palaeos web site (they have nice cladograms, and I am a nut for cladograms). Okay, I admit the molecular chronology is a bit harder to find -- a lot of the references are journals that I can read from my computer because my university has a subscription, but you may not have access. Hopefully, you can read this article; if not, here is a portion of the abstract:
Different time estimation methods yielded similar results (within 5%): vertebrate-arthropod (964 million years ago, Ma), Cnidaria-Bilateria (1,298 Ma)....
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JonF Member (Idle past 194 days) Posts: 6174 Joined: |
The relevance of the quote was to counter your blanket statement that I have misunderstood Crick. Have I? Yes, or perhaps you've misrepresented him. He did not claim that abiogenesis on Earth was impossible, nor did he claim to have any realistic estimate of how probable or improbable it was. An honest man, armed with all the knowledge available to us now, could only state that, in some sense, the origin of life appears at the moment to be almost a miracle so many are the conditions which would have had to have been satisfied to get it going. But this should not be taken to imply that there are good reasons to believe that it could not have started on the earth by a perfectly reasonable sequence of fairly ordinary chemical reactions. The plain fact is that the time available was too long, the many microenvironments on the earth's surface too diverse, the various chemical possibilities too numerous and our own knowledge and imagination too feeble to allow us to be able to unravel exactly how it might or might not have happened such a long time ago, especially as we have no experimental evidence from that era to check our ideas against. (Francis Crick, Life Itself, Its Origin and Nature, 1981, p. 88) {empahsis added - JonF}
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pink sasquatch Member (Idle past 6048 days) Posts: 1567 Joined: |
The most conservative estimates indicate that random mutations of the chimp genome to that of Homo Sapiens would take some 100 million generations or something on the order of a billion years. Would you explain how these estimates were made? Or provide an accessible source that describes them?
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
If you're up to it, it seems to me that the Ediacaran Fauna are deserving of a topic of their own. What is in this topic is pretty much destined to be lost in the bulk of postings.
Moose Professor, geology, Whatsamatta U Evolution - Changes in the environment, caused by the interactions of the components of the environment. "Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham
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mihkel4397 Inactive Member |
Thanks for the references!
I was very interested, as I surmised that this must be fundamental information, less than 5 years old. I am only familiar with Ediacaran fossils of primitive clumps and pancakes, lacking any of the distinguishing features of the species of the Cambrian explosion. Best, Mihkel
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mihkel4397 Inactive Member |
That was very good - thanks!
May I in return give you a quote from Richard Dawkins (The Blind Watchmaker), which I believe is very much at the heart of the matter: "As long as we can speculate freely about naturalistic explanations to nature and life we shall keep ignoring all the evidence that points to intelligent design, no matter how strong this evidence is, and even if it takes engaging in scientificacrobatics." This sums up a large portion of the discussion. Mihkel
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mihkel4397 Inactive Member |
I provided three references in an earlier posting 02/16/05.
Mihkel
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Chiroptera Inactive Member |
This would be an interesting topic. Unfortunately, I am not an expert in this, and I would have to do a lot of research to write something worthy of being an original post; right now, I don't have the time for it. It would be very good for me to learn something new, so maybe I'll make it a project that I'll eventually do. So maybe at some point in the future, if no one else does it in the meantime (hint, hint), the Ediacaran fauna will appear as a new topic.
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jar Member (Idle past 420 days) Posts: 34026 From: Texas!! Joined: |
I provided three references in an earlier posting 02/16/05. If you are refering to Message 120 then they weren't of much use.
Basic References: M. Radman and R. Wagner, "The High Fidelity od DNA Duplication", Scientific American, August 1988. Mettler at al, "Population Genetics and Evolution", Prentice Hall, Englewood Cliffs, NJ, 1988. A scientific, but more popular reference (useful in that it shows a simplified version of the calculation principles): Gerald L. Schroeder, "The Science of God" pp. 119-123.Broadway Books, 1998. "The High Fidelity od {sic} DNA Duplication" is on Why are so few mistakes made when DNA is duplicated? The next is simply a referal to a text. The third is certainly not something even a Christian would take seriously. But no where have you given anyone anything to go on other than your assertions. Aslan is not a Tame Lion
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crashfrog Member (Idle past 1492 days) Posts: 19762 From: Silver Spring, MD Joined: |
I can find no indication that Dawkins actually spoke or wrote these words.
But even if he did, why would he be wrong? We know intelligent design isn't parsimonious; there's only one known intelligent species in the universe, and we weren't around at the time. There's no avaliable intelligence at the time to do the designing. Therefore naturalist explanations continue to be the most parsimonious. This message has been edited by crashfrog, 02-16-2005 16:25 AM
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Quetzal Member (Idle past 5898 days) Posts: 3228 Joined: |
Hi mihkel: could you give me a page number for the Dawkins quote, please? It doesn't ring any bells, although I admit it's been awhile since I read Watchmaker. Thanks.
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Chiroptera Inactive Member |
quote: Right now, if my understanding is correct, it is a matter of controversey whether which if any of the modern phyla are represented among the Ediacaran fauna. I think that it is the traditional consensus, still not entirely refuted, that the Ediacaran fauna represent early forms of the modern phyla; it was a new and still not entirely accepted idea that the Ediacaran fauna were a entirely different experiment in body plan. I believe that Stephen Jay Gould was a proponent of the latter idea; it fits very nicely in his beliefs there is nothing special about the species that exist today, they just happen to be the ones that exist, if one were to "run the movie over again from the beginning" life on earth could possibly be very different. It could be that the Ediacaran fauna were completely different than exists today. The idea is that the Ediacaran fauna were the dominant life forms on the planet, and the ancestors of today's fauna were a very minor part of the preCambrian ecosystems. Then a mass extinction wiped out most of the Ediacaran fauna, allowing the remaining species (our ancestors) to take over and occupy the vacant niches. One cause for the mass extinction, I believe, is that shortly before the Cambrian the earth was in a very cold state -- it is believed that the oceans may even have almost frozen completely solid, except around deep sea hydrothermal vents. This is the so-called "Snow Ball Earth" theory. At any rate, it is very, very premature to state definitely that the ancestors of modern phyla were merely single celled organisms that "suddenly" evolved at the Cambrian Explosion. Not only may the Ediacaran fauna represent early forms of some of the modern phyla, but there are tracks and burrows made by worm-like creatures, and it is accepted that all the major phyla (except, perhaps, the sponges and jellyfish) all evolved from worm-like creatures. And the molecular evidence suggests strongly that the different phyla diverged several hundred million years before the Cambrian. Of course, even though there is a divergence there is still the question: did the major body plans that define the different phyla develop over these several hundred million years? Or, was there very little differentiation, the ancestors of each of the major phyla being various species of worms that were, at that time, still virtually indistinguishable in morphology for most of this time, and the different major body plans then evolved relatively quickly, say over several tens of millions of years before the Cambrian? At any rate, I repeat, there is no evidence that the Cambrian Explosion represents a sudden event; it was "sudden" only in geologic sense, occurring over tens of millions of years which is plenty of time for major evolutionary changes to occur. And it must be stressed that the only thing the Cambrian Explosion represents is the sudden appearance of hard, easily fossilized body parts in several different phyla. Let us repeat this together; the Cambrian Explosian, in so far as it records something, does not record the sudden appearance of radically new animals, it represents the first appearance of hard, easily fossilized body parts.
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JonF Member (Idle past 194 days) Posts: 6174 Joined: |
The most conservative estimates indicate that random mutations of the chimp genome to that of Homo Sapiens would take some 100 million generations or something on the order of a billion years.
Would you explain how these estimates were made? Or provide an accessible source that describes them? Well, one of his references is The Science of God: The Convergence of Scientific and Biblical Wisdom by Gerald L. Schroeder. Dr. Schroeder is a physicist living in Israel. I haven't read any of his books. He's a day-age creationist with a unique slant; the first day was 8 billion years, the second was 4 billion years, the third was 2 billion years, and so on. It takes some pretty imaginative and convoluted apologetics to make events of the last 15.75 (according to him) billion years into the Biblical description of creation, and of course you have to ignore a few internal contradictions (he says we're in the afternoon of the sixth day, but following his calculations tells us we're about halfway through the fifth day). As far as I've been able to tell there's no evidence for his view; the reason he proposes it is thet he likes it. He has a web site at The Hidden Face Of God: How Science Reveals The Ultimate Truth. He discusses the probability of evolution at Evolution: Rationality vs. Randomness. If his calculations in his earlier book are as muddled and founded on misunderstandings as the calculations at that page ... for example:
quote: Note how he totally ignores the factor of selection, and appears to be presenting the probability that abiogenesis is proposed to have occured solely by random assambly of all the proteins involved in a complex modern organism; he probably deserves an award for the stupidest strawman argument of all time. And later:
quote: There is no "eye gene" with 130 sites, nor are there 20 possibilites at each "site" of a gene, nor do all visual systems in all animals have the same combination of amino acids in the genes that control their eyes. He's right that it couldn't have happened by chance, but ...
quote: Which is more misunderstandings compounded with assuming his conclusion. But wait, there's more ...
quote: Yes, the big finish is a totally unrelated non-sequitur!. Predictably, Answers in Genesis doesn't think much of his theories: Gerald Schroeder and his new variation on the ‘Day-Age’ theory. From an online review of his first book, Fitting the Bible to the Data:
quote: All in all, an amusing loon, not to be taken seriously.
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