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Author Topic:   IC & the Cambrian Explosion for Ahmad...cont..
mark24
Member (Idle past 5194 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 16 of 199 (25232)
12-02-2002 8:25 AM
Reply to: Message 13 by Ahmad
12-02-2002 6:38 AM


Ahmad,
quote:
Then what is "good enough" for you?
Data that positively shows that IC systems can’t evolve.
Thus far you have presented none. I know what IC is, but I don’t know that it can’t evolve. You can present as many examples of IC systems as you like, quote Behe’s opinions as much as you like, BUT, none of this is providing what I’m asking for, nay, what is required!. It doesn’t exist, Ahmad. If it did, evolution WOULD be on the rocks.
quote:
It seems as though you have pre-decided that no matter what the evidence provided, you will keep on regurgitating that "it ain't good enough". By definition as well by many demonstrated examples, IC is a theory that is still open for more research. Exactly what kind of evidence you're looking for is bizarre to me. I gave you positive evidence for the non-evolvability of IC. I even showed you examples.
Once again, where is the POSITIVE evidence that supports your contention that IC is unevolvable?
quote:
IC is evident as I many times said before. IC describes a system whose function is dependent on the interaction of multiple components, such that the removal of even one component results in the complete loss of function. Consider the following equation:
A + B + C + D ~~~> F
where A,B,C, and D represent specific components (gene products) and F represents the function that is elicited by the interaction of these four parts. From this observation, it is evident that F could not possibly evolve by the darwinian evolution, as F requires the presence of all four components. In other words, there would be no selective advantage of having parts A, B, and D compared to an organism having only parts A and B. Why? Because both combinations fail to elicit the function!! So you tell me: HOW CAN SUCH A SYSTEM EVOLVE, in the first place??
You’re doing it again, asking me to show how IC can evolve. Whether I can or can’t doesn’t support your argument at all. You need evidence that goes beyond your own incredulity, that positively supports your contention. This is what I require, & what science requires.
Ultimately you present something like the cilia & say how could that evolve? That is a question, Ahmad, not evidence. Your other tack is to claim because it is IC, it couldn’t evolve, & that’s the end of that! This is an argument by definition, & also an unbacked assertion. Such things do not constitute positive evidence. No positive evidence = argument from incredulity.
Next time you reply, can you come up with something that doesn’t fall into these two categories?
quote:
Mark:
What part of the ToE is specifically contradicted by the Cambrian explosion? If you are going to claim a limit, I expect you to show that limit actually exists.
quote:
ToE predicts "gradual" progressive evolution from simple to complex.
Like prokaryotes to eukaryotes to multicellular eukaryotes, you mean? All this is seen in order in the Precambrian.
quote:
This is where it contradicts evolution.
You’re fundamentally wrong on this score, too. Evolution predicts both increases & decreases in complexity. The Cambrian explosion is not contradicted by your claim, in fact it is entirely in order.
quote:
Now are you denying that "limit" does not exist?
Yes, I do deny this limit exists. Your assumption is incorrect. A progressive simple to complex trend is seen in the fossil record. Unfortunately, not everything that dies gets fossilised, but the trend is there. Abrupt appearances do not falsify evolution, it simply means that gaps exist in the fossil record. If they didn’t, intermediates & transitionals would never get found.
Mark
------------------
Occam's razor is not for shaving with.

This message is a reply to:
 Message 13 by Ahmad, posted 12-02-2002 6:38 AM Ahmad has replied

Replies to this message:
 Message 17 by mark24, posted 12-04-2002 6:31 AM mark24 has not replied
 Message 18 by Ahmad, posted 12-04-2002 2:47 PM mark24 has not replied

  
mark24
Member (Idle past 5194 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 17 of 199 (25403)
12-04-2002 6:31 AM
Reply to: Message 16 by mark24
12-02-2002 8:25 AM


Bump......
Ahmad,
We can take the IC argument to Schrafs thread, "How do we tell the difference, Ahmad?", if you like, since we seem to be asking the same questions.
1/ I would like to continue the Cambrian explosion "falsification" criteria here though.
quote:
"ToE predicts "gradual" progressive evolution from simple to complex. This is where it contradicts evolution."
This was your last answer, & is patently false. Evolution makes no such prediction. A look at almost any cladogram will see the gain of as many features as are lost (generally speaking), & I'm not sure I'm any more complex than a fish, or frog, for example.
So, I ask again, what part of the ToE is specifically contradicted by the Cambrian explosion? If you are going to claim a limit, I expect you to show that limit actually exists. It's not as easy a claim to back up as it first looks, is it?
2/ What is the significance of the Cambrian explosion to your creation POV? The argument you have touted is that major metazoan phyla appear in the lower Cambrian, & that is evidence of creation. Was there a single creation event, or many? Most classes, orders, families, genera etc appear nowhere near the Cambrian, so how are they explained?
The question I was asking (poorly), was at what classification level did creation take place? Did the creator create all families with a single ancestor that subsequently radiated into it's extant genera & species? Or was the same done with classes, orders, or phyla, for example? Another way of asking the same question is at what classification level was life created polyphyletic?
Mark
------------------
Occam's razor is not for shaving with.

This message is a reply to:
 Message 16 by mark24, posted 12-02-2002 8:25 AM mark24 has not replied

Replies to this message:
 Message 19 by Ahmad, posted 12-04-2002 3:11 PM mark24 has replied
 Message 23 by TechnoCore, posted 12-09-2002 8:28 PM mark24 has not replied

  
Ahmad
Inactive Member


Message 18 of 199 (25455)
12-04-2002 2:47 PM
Reply to: Message 16 by mark24
12-02-2002 8:25 AM


quote:
Data that positively shows that IC systems can’t evolve.
I gave you the data with examples.
quote:
Thus far you have presented none. I know what IC is, but I don’t know that it can’t evolve. You can present as many examples of IC systems as you like, quote Behe’s opinions as much as you like, BUT, none of this is providing what I’m asking for, nay, what is required!. It doesn’t exist, Ahmad. If it did, evolution WOULD be on the rocks.
The eamples I have provided previously serve as the evidence of the non-evolvablility of such systems. If you can show how they evolve, then fine and dandy with me. You're on denial no matter how many evidence is given..
quote:
You’re doing it again, asking me to show how IC can evolve. Whether I can or can’t doesn’t support your argument at all. You need evidence that goes beyond your own incredulity, that positively supports your contention. This is what I require, & what science requires.
I gave you the evidence, that I consider as positive. It seems as though you're unwilling to accept it.
quote:
Ultimately you present something like the cilia & say how could that evolve? That is a question, Ahmad, not evidence. Your other tack is to claim because it is IC, it couldn’t evolve, & that’s the end of that! This is an argument by definition, & also an unbacked assertion. Such things do not constitute positive evidence. No positive evidence = argument from incredulity.
Now is an argument from defintion, an unbacked assertion or an argument from incredulity? I even gave you examples of systems where all required componenets are needed for the system to function. They can't evolve thus since all their componenets need to be present from the very moment of their existence.
quote:
Like prokaryotes to eukaryotes to multicellular eukaryotes, you mean? All this is seen in order in the Precambrian.
Then where are the transitions??
quote:
You’re fundamentally wrong on this score, too. Evolution predicts both increases & decreases in complexity. The Cambrian explosion is not contradicted by your claim, in fact it is entirely in order.
How is it in "order"? It surely doesn't fit the traditional evolutionary explanation. Nor is it sufficiently explained by the modern neo-darwinian theories, now is it? Now if evolution predicts both increase and decrease in complexity, which one do you think is more plausible? How is the specified complexity increased. Your explanation gives rise to more question than answers.. I guess.
quote:
Yes, I do deny this limit exists. Your assumption is incorrect. A progressive simple to complex trend is seen in the fossil record. Unfortunately, not everything that dies gets fossilised, but the trend is there. Abrupt appearances do not falsify evolution, it simply means that gaps exist in the fossil record. If they didn’t, intermediates & transitionals would never get found.
How are transitionals and intermediates found with the present situation of the fossil record? And you're wrong. A progressive simple to complex trend is not seen in the fossil record. In fact the greatest morphological differences appear in the lower Phanerozoic rocks, while the rest of the fossil record consists largely of variations of familiar themes.
Regards,
Ahmad

This message is a reply to:
 Message 16 by mark24, posted 12-02-2002 8:25 AM mark24 has not replied

  
Ahmad
Inactive Member


Message 19 of 199 (25457)
12-04-2002 3:11 PM
Reply to: Message 17 by mark24
12-04-2002 6:31 AM


quote:
We can take the IC argument to Schrafs thread, "How do we tell the difference, Ahmad?", if you like, since we seem to be asking the same questions.
Sure.. No problem.
quote:
This was your last answer, & is patently false. Evolution makes no such prediction. A look at almost any cladogram will see the gain of as many features as are lost (generally speaking), & I'm not sure I'm any more complex than a fish, or frog, for example.
So, I ask again, what part of the ToE is specifically contradicted by the Cambrian explosion? If you are going to claim a limit, I expect you to show that limit actually exists. It's not as easy a claim to back up as it first looks, is it?
Alright.. then get back to my original contention. If evolution does not predict what I stated.. what exactly does it predict then? Lame question to ask but seems vital for our discussion. Now as I know.. it is the general increase in complexity. Is it not? But then how did the wide mosaic of living organisms that just "abruptly" appeared with no evolutionary history or no transitional links, take place? Whats more is that the organisms had novel body plans and highly complex anatomical design. The trilobite eye is just one of the examples. This occurence is very unlikely and contrary to the predictions of evolution. How does evolution explain it?
quote:
What is the significance of the Cambrian explosion to your creation POV? The argument you have touted is that major metazoan phyla appear in the lower Cambrian, & that is evidence of creation. Was there a single creation event, or many? Most classes, orders, families, genera etc appear nowhere near the Cambrian, so how are they explained?
Well first appearances for orders peak in the Cambrian and Ordovician, but are more broadly distributed. In contrast, first appearances of families, genera and species are relatively low in the Cambrian, and generally increase through the geologic column but they did exist in the cambrian. Now regarding the question of the number of creation events, its still not clear. We really don't know how many creation events took place but we do know the organisms were created. Two evidence is cited for this:
1. Abrupt appearance of almost all phylas, save bryozoans, in a geologically short period of time (~5-10 mya).
2. Organisms differing highly from one another (at the species level) in design and body plans but were indeed complex.
quote:
The question I was asking (poorly), was at what classification level did creation take place? Did the creator create all families with a single ancestor that subsequently radiated into it's extant genera & species? Or was the same done with classes, orders, or phyla, for example? Another way of asking the same question is at what classification level was life created polyphyletic?
I understood your question now . The answer is: I don't know. Of course, we can all make good predictions. But I have to think over this before I can issue my response. Its a very good question and Insha Allah I will respond to it once I have additional information.
Regards,
Ahmad

This message is a reply to:
 Message 17 by mark24, posted 12-04-2002 6:31 AM mark24 has replied

Replies to this message:
 Message 20 by mark24, posted 12-04-2002 5:18 PM Ahmad has replied

  
mark24
Member (Idle past 5194 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 20 of 199 (25467)
12-04-2002 5:18 PM
Reply to: Message 19 by Ahmad
12-04-2002 3:11 PM


Ahmad,
1/
quote:
Mark:
Like prokaryotes to eukaryotes to multicellular eukaryotes, you mean? All this is seen in order in the Precambrian.
quote:
Ahmad:
Then where are the transitions??
LOL, what would you accept as a transitional eukaryote? A cell with half a mitochondria?
quote:
How is it in "order"? It surely doesn't fit the traditional evolutionary explanation. Nor is it sufficiently explained by the modern neo-darwinian theories, now is it? Now if evolution predicts both increase and decrease in complexity, which one do you think is more plausible? How is the specified complexity increased. Your explanation gives rise to more question than answers.. I guess.
The Cambrian explosion is in order because life first appears as single celled prokaryotes, then more complex eukaryotes appear, then simple eukaryotic multicellular organisms appear, & then more complex ones in the Cambrian.
quote:
How are transitionals and intermediates found with the present situation of the fossil record? And you're wrong. A progressive simple to complex trend is not seen in the fossil record. In fact the greatest morphological differences appear in the lower Phanerozoic rocks, while the rest of the fossil record consists largely of variations of familiar themes.
You are patently, demonstrably wrong. There is a simple to complex trend in the fossil record, but, generally speaking it culminates with the Cambrian explosion. I never said anything but, did I? I plainly said that in most cladograms traits are gained & lost, meaning no particular gain in complexity. Most cladograms being after the Cambrian explosion, of course. However, from the first fossils discovered, there is an overall trend of increasing complexity.
quote:
Ahmed:
Alright.. then get back to my original contention. If evolution does not predict what I stated.. what exactly does it predict then?
Irrelevant to this discussion. You are telling me what refutes evolution regarding the Cambrian explosion. You are inventing strawmen when you claim what you think evolution says.
Anything else that refutes evolution in the Cambrian explosion?
2/
quote:
I understood your question now . The answer is: I don't know. Of course, we can all make good predictions. But I have to think over this before I can issue my response. Its a very good question and Insha Allah I will respond to it once I have additional information.
I look forward to your response.
Whilst you’re researching this, do you accept evolution within genera?
Mark
------------------
Occam's razor is not for shaving with.

This message is a reply to:
 Message 19 by Ahmad, posted 12-04-2002 3:11 PM Ahmad has replied

Replies to this message:
 Message 21 by Ahmad, posted 12-09-2002 2:58 PM mark24 has replied

  
Ahmad
Inactive Member


Message 21 of 199 (26052)
12-09-2002 2:58 PM
Reply to: Message 20 by mark24
12-04-2002 5:18 PM


quote:
LOL, what would you accept as a transitional eukaryote? A cell with half a mitochondria?
Possibly...
quote:
The Cambrian explosion is in order because life first appears as single celled prokaryotes, then more complex eukaryotes appear, then simple eukaryotic multicellular organisms appear, & then more complex ones in the Cambrian.
You don't seem to understand what I want to say. Consider this simple graph obtained from On the Origin of Stasis
According to evolutionary theory, animals had ancestors from which they evolved. Is this explosion of life consistent with an evolutionist interpretation? If these animals, which include some very modern (complex) shelled creatures, sponges, and jawless fish, trilobites did have primitive evolutionary ancestors, where are they to be found in the fossil record? The answer is they aren’t anywhere to be found. Before the Cambrian Period, very few fossil having anything to do with modern phyla are found in the fossil record.
quote:
You are patently, demonstrably wrong. There is a simple to complex trend in the fossil record, but, generally speaking it culminates with the Cambrian explosion. I never said anything but, did I? I plainly said that in most cladograms traits are gained & lost, meaning no particular gain in complexity. Most cladograms being after the Cambrian explosion, of course. However, from the first fossils discovered, there is an overall trend of increasing complexity.
What is the basis for saying there is "an overall trend of increasing complexity"? Now let me choose a group of animal and look at
trends in the record. My favuorite example are the trilobites. I've drawn the following mainly from: Babin, C. 1980, "Elements
of Palaeontology", John Wiley & Sons Ltd, Chichester.
Numerous species of trilobites are found in Lower Cambrian rocks.
They are well differentiated from other arthropods, resulting in
problems for those who wish to trace an evolutionary ancestry.
Babin says their ancestry is "obscure" (p.255).
There are about 1500 genera of trilobites known, with a more or
less consistent decline in number of genera from the Upper
Cambrian to the Permian. From the Upper Ordovician, the number
of genera was always less than that in the Lower Cambrian. Thus,
there is no trend of increasing numbers of genera in the fossil
record.
Evolutionary trends have been analysesd as follows:
(a) Paedomorphosis (where juvenile features become dominant in
the ontogenesis of descendants).
(b) Gerontomorphosis (where adult features become dominant in the
ontogenesis of descendants).
Sometimes, these two trends coexist: for example, the
paedomorphic tendency towards a reduction in the number of
thoracic segments has been observed to coexist with the
gerontomorphic tendency towards the enlargement of the rachis.
Overall, there are no dominant trends and Babin writes that the
data "still tends to be difficult to interpret" (p.262).
Whatever these trends are, can they be interpreted in any way as
an increase in complexity? Neither of the reported trends
involves novel structures - only modifications of existing
structures.
Trilobite morphologies are, of course, very diverse. Cambrian
faunas are distinctive, although some of these forms are also
found in Ordovician strata. A number of variants are found in
the base of the Ordovician, but these are localised
stratigraphically. The dominant Ordovician groups have a much
broader range. Above the Ordovician, according to Nield and
Tucker (1985), "there seems to have been little further
development in the overall design of trilobites, with only minor
variations on the basic themes stated in the early Ordovician"
(p.26).
The conclusion: in the context of trilobites, claims of increasing
complexity in the fossil record appear to lack a solid foundation.
quote:
Irrelevant to this discussion. You are telling me what refutes evolution regarding the Cambrian explosion. You are inventing strawmen when you claim what you think evolution says.
I don't want to think what evolution says but want to hear it from the horse's mouth. What exactly does evolution predict? Its very relevant and certainly not a strawman.
quote:
I look forward to your response.
Whilst you’re researching this, do you accept evolution within genera?
Just like to respond to your previous question:
"At what classification level was life made polyphyletic?"
It's quite hard to be specific in this case. Especially when you're dealing with taxonomy. Since polyphyly implies that the genetic code had multiple independent origins, ascribing it to one classification level can hardly be in general. I'll add some more thoughts to this next time Insha Allah.
Regards,
Ahmad

This message is a reply to:
 Message 20 by mark24, posted 12-04-2002 5:18 PM mark24 has replied

Replies to this message:
 Message 22 by mark24, posted 12-09-2002 7:05 PM Ahmad has replied

  
mark24
Member (Idle past 5194 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 22 of 199 (26092)
12-09-2002 7:05 PM
Reply to: Message 21 by Ahmad
12-09-2002 2:58 PM


Ahmad,
A few questions.
1/ The last coelacanth fossil was dated at about 80 million years ago, yet they exist today. Where are the missing fossils?
2/ Holocepheli (a group of cartilagenous fish) appear during the Carboniferous, throughout the Permian, not a single example is found in the Triassic, yet are found through the Jurassic to present. Where are the missing fossils?
3/ Testudines (turtles) appear briefly at the Triassic/Jurassic boundary. There is a gap of 50 million years, whereupon they become common from the late Jurassic to present. Where are the missing fossils?
4/ Monotreme mammals appear briefly in the Cretaceous, they do not appear in the fossil record again until about 5 million years ago. Where are the missing fossils?
5/ Paleognathae (e.g. Ostrich) appear briefly during the Paleocene. No more examples exist until the Miocene. Where are the missing fossils?
6/ Sphenodonts appear briefly at the Triassic/Jurassic boundary, again at the Jurassic Cretaceous boundary, & no more. There even exists a living example, the Tuatara. Where are the missing fossils?
(FYI. All info taken from spindle diagrams in "Vertebrate Palaeontology". Michael J Benton. 2nd ed. 2002)
I ask you to consider that potentially small populations of soft bodied organisms, that molecular evidence you have cited says exist, may not have fossilised in sufficient quantities & detail to be able to corroborate the existence of said molecular phylogeny (among others) beyond the Cambrian.
But I would be interested in where the fossils in 1/ to 6/ allegedly disappeared to?
quote:
Ahmad:
What is the basis for saying there is "an overall trend of increasing complexity"? Now let me choose a group of animal and look at....
Already answered:
quote:
There is a simple to complex trend in the fossil record, but, generally speaking it culminates with the Cambrian explosion. I never said anything but, did I? I plainly said that in most cladograms traits are gained & lost, meaning no particular gain in complexity. Most cladograms being after the Cambrian explosion, of course. However, from the first fossils discovered, there is an overall trend of increasing complexity.
That is to say, for at least the fifth time. The first organisms to appear are single celled prokaryotes, then single celled eukaryotes, then multicellular eukaryotes. That, as I have explained, is a general increase in complexity seen in the fossil record. I have already qualified that not much more complexity appears after the Cambrian.
Why would the first organisms to appear be the simplest, followed by successive increases? Let's recap; the first bacteria appear circa 3 bya, the eukaryotes appear circa 1.5 bya, then multicellular life appears 0.5 to 0.9 bya. Seems like a general increase to me.
Mark
------------------
Occam's razor is not for shaving with.
[This message has been edited by mark24, 12-09-2002]
[This message has been edited by mark24, 12-09-2002]

This message is a reply to:
 Message 21 by Ahmad, posted 12-09-2002 2:58 PM Ahmad has replied

Replies to this message:
 Message 27 by mark24, posted 12-15-2002 7:38 PM mark24 has replied
 Message 30 by Ahmad, posted 12-29-2002 1:42 PM mark24 has replied

  
TechnoCore
Inactive Member


Message 23 of 199 (26105)
12-09-2002 8:28 PM
Reply to: Message 17 by mark24
12-04-2002 6:31 AM


Ahmad, as I see it the problem with IC's is something like this:
You can't prove that something does NOT exist within an infinite set of possibilities.
The opposite is easy. To prove that something actually does exist, all
that is needed is to present a example of it.
In your case, Ahmad, you try to prove that there is no solution to a problem, when actually all you can prove is that YOU cant find a solution.
(i.e you cant imagine a way for them to have evolved.
Still you cannot dismiss that someone might have a more vivid imagination than you, and has thought of a way.)
Its like claiming there can't exist any 3 legged animals, just because you haven't seen any. You can't prove there isn't.
You can however easily prove that there are 4 legged animals.
Has there been some matematical approches to this ic-problem?
TechnoCore !

This message is a reply to:
 Message 17 by mark24, posted 12-04-2002 6:31 AM mark24 has not replied

  
[xeno]Julios
Inactive Member


Message 24 of 199 (26606)
12-14-2002 4:53 PM


I'm new here, and I haven't carefully read the entire thread, but as technocore has indicated, there are some fundamental dynamics that seem to occur when having these discussions.
The evolutionist will always be able to provide "positive" evidence, by merely engaging in thought experiments using "natural" selection as a model. Perhaps this is indicative of the low level of falsifiability of the theory.
Creationists on the other hand, who are open to the possibility that a guiding intelligence factors in, will never really be able to provide positive evidence. The only conceivable way I can think of to do so, would be to present proof of a designer.
The evolutionist will be able to take any "evidence" of intelligent oversight, and ascribe the design to probability, and selective pressures, etc. Even in IC, there is always the final resort of postulating that the system arose against the odds...
Thus, ultimately, the best a creationist can do (imo), is to provide NEGATIVE "evidence" to the contrary based on statistical improbabilities. This reflects a reasonable argument, rather that logical proof, and is mirrored by the nature of faith - i.e. it is reasonable to postulate the existence of God since it is reasonable to believe we have free will, and it is very hard to conceive how to explain free will without a divine component.
I realize that not all proposed solutions of the origins and complexities of life are dichotomies of god vs nature, and I have been rather simplistic in the post, but only for sake of clarity.
peace
Marwan
Julios, 12-14-2002

Replies to this message:
 Message 25 by Percy, posted 12-14-2002 7:47 PM [xeno]Julios has replied

  
Percy
Member
Posts: 22388
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 25 of 199 (26617)
12-14-2002 7:47 PM
Reply to: Message 24 by [xeno]Julios
12-14-2002 4:53 PM


[xeno] Julios writes:
The evolutionist will always be able to provide "positive" evidence, by merely engaging in thought experiments using "natural" selection as a model. Perhaps this is indicative of the low level of falsifiability of the theory.
A thought experiment is not evidence. Anyone claiming that a hypothetical scenario is evidence in favor of evolution is incorrect. Such exercises are merely projections of an evolutionary framework onto a puzzle of natural history.
Thus, ultimately, the best a creationist can do (imo), is to provide NEGATIVE "evidence" to the contrary based on statistical improbabilities.
The Creationist argument from unlikeLihood is most often raised in reference to abiogenesis, the origin of life. There is nothing fundamentally wrong with this type of arguments, but it has to address the actual scenario proposed by evolutionists. For example, Creationists often state that the likelihood of a cell coming together spontaneously from constituent chemicals is 1 in 1^100. Evolutionists would agree and feel untroubled, since they propose no such scenario.
--Percy

This message is a reply to:
 Message 24 by [xeno]Julios, posted 12-14-2002 4:53 PM [xeno]Julios has replied

Replies to this message:
 Message 26 by [xeno]Julios, posted 12-14-2002 8:43 PM Percy has not replied

  
[xeno]Julios
Inactive Member


Message 26 of 199 (26620)
12-14-2002 8:43 PM
Reply to: Message 25 by Percy
12-14-2002 7:47 PM


quote:
Originally posted by Percipient:
A thought experiment is not evidence. Anyone claiming that a hypothetical scenario is evidence in favor of evolution is incorrect. Such exercises are merely projections of an evolutionary framework onto a puzzle of natural history.
Agreed - I should have put quotation marks around the word evidence.
quote:
Originally posted by Percipient:
The Creationist argument from unlikeLihood is most often raised in reference to abiogenesis, the origin of life. There is nothing fundamentally wrong with this type of arguments, but it has to address the actual scenario proposed by evolutionists. For example, Creationists often state that the likelihood of a cell coming together spontaneously from constituent chemicals is 1 in 1^100. Evolutionists would agree and feel untroubled, since they propose no such scenario.
--Percy

Right - I agree fully. My point was to pinpoint the fact that a creationist cannot provide positive evidence in the same way that evolutionists can.

This message is a reply to:
 Message 25 by Percy, posted 12-14-2002 7:47 PM Percy has not replied

  
mark24
Member (Idle past 5194 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 27 of 199 (26674)
12-15-2002 7:38 PM
Reply to: Message 22 by mark24
12-09-2002 7:05 PM


bump...

This message is a reply to:
 Message 22 by mark24, posted 12-09-2002 7:05 PM mark24 has replied

Replies to this message:
 Message 28 by mark24, posted 12-20-2002 6:36 AM mark24 has not replied

  
mark24
Member (Idle past 5194 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 28 of 199 (27466)
12-20-2002 6:36 AM
Reply to: Message 27 by mark24
12-15-2002 7:38 PM


bump....
------------------
Occam's razor is not for shaving with.

This message is a reply to:
 Message 27 by mark24, posted 12-15-2002 7:38 PM mark24 has not replied

  
Minnemooseus
Member
Posts: 3941
From: Duluth, Minnesota, U.S. (West end of Lake Superior)
Joined: 11-11-2001
Member Rating: 10.0


Message 29 of 199 (27481)
12-20-2002 11:24 AM


A nice posting has happened in Yahooland, at the "Evolution versus Creationism" group. The message is titled "The Cambrian "Explosion" in the real world. It is from Ray T. Perreault, responding to a JimG. The following is it, in it's entirety.
quote:
JimG--1) The Cambrian explosion, when most of the phyla in existence today sprang into existence in a just a few million years, with no sign of any likely preceding, ancestral forms (as the theory requires).
This is not entirely accurate. It is a very popular simplification, and
among the various cults of Creationists, the last phrase has become added
as a mantra. For a full picture, the Vendian must be taken into account,
as well as the Ordovician Period following the Cambrian. Only thus, can
the actual context of the event be bracketed properly.
THE VENDIAN
General Fauna--The Vendian is the latest Precambrian, with a fauna
dominated by flat, large, organisms of poorly known biology. They have a
quilted body plan, as opposed to the tubular organization of standard
animals. There is little evidence of internal organs. Seilacher has
proposed the Kingdom Vendobionta for these oddities. In addition to the
Vendobionta, there are a number of organisms which are referrable to
Animalia, and seem to represent early representatives of modern phyla.
Sponges, jellyfish and sea pen octocorals (Charnia) are fairly certainly
documented. Spriggina bears a very close resemblance to trilobites, but
lacks eyes (not a problem, many later trilobites do, too) and the
post-cephalic region is not trilobed. In the earliest Cambrian
trilobites, the Olenellids, the trilobed post-cephalic region is followed
by a long "tail" in some genera, which is reminiscent of the Spriggina
condition. The later portion is only occasionally preserved.
Tribrachidium is held by some to be an ancestral echinoderm, I personally
have doubts. It does resemble an edrioaster, but those do not appear
until the Ordovician. Collectively, these are termed the Ediacarian
Fauna. There are Precambrian trails of a type made by worms, but no body
fossils are known. Thus, it is definite that the Cambrian "Explosion"
has antecedants. Charnia was first described in 1958, so the information
is not new.
There have been a very few recent discoveries of Vendian animals which
secreted tubes for habitation, but little is known of them as yet.
Preservation--There is a major preservational difference in Vendian vs.
Paleozoic fossil assemblages. This is due to the microbial mats endemic
in the Vendian. These mats existed because no efficient grazing animals
existed yet. The mats likely consisted of a framework of filamentous
plants with single celled micro-organisms and infiltrated mud. Vendian
faunas are preserved as impressions into these mats, and have a more
three-dimensional structure. Preservation of soft-bodied creatures after
the Vendian is in the form of very thin films, almost two dimensional.
Vendian/Cambrian transition--The Vendian ended with a major biotic
change, which involved the disappearance of the microbial mats, and near
extinction of the Vendobionta. Recent recognition of preservation modes
of the Vendian vs. Cambrian led to recognition of Vendobionts as late as
middle Cambrian. Efficient mulloscoid grazers with radulas are
considered to be the cause of destruction of the microbial mats.
THE CAMBRIAN
Basal Cambrian (Tommotian)--As research on Cambrian paleontology
increased in the 70s and 80s, it became clear that a good definition of
the beginning of the Cambrian was necessary. Formerly, it was the first
trilobites, but it became clear that there was a considerable undefined
pre-trilobite section. By international convention, in 1990, the base of
the Cambrian was defined biostratigraphically as the first appearance of
the "small shelly fauna." This is a mostly microscopic array of
extremely varied shapes of skeletal elements, most of which defy any
attempt at identification. It has a nearly worldwide distribution, and
is an easily identified marker zone. This is the point where hard parts
became very common in the fossil record. The few which have been
identified from the somewhat later lagerstatten show that basically
soft-bodied creatures were studded with numerous plates of several
shapes.
In some sections, a zone is recognized below the base of the small shelly
fauna with animal trackways of legged and legless types, but almost no
hard parts.
Identifiable animals in these beds include sponge spicules, grazing
molluscs, and brachiopods, a phylum of filter feeding lophophorates.
Lophophorate phyla also include acorn worms, bryozoa, echinoderms, and
the chordate phyla.
The base of the Tommotian is dated at app. 540 MA.
LATER CAMBRIAN FAUNAS
The best known soft-bodied faunas cluster around the middle Cambrian, in
various parts of the world. The first studied, Burgess Shale, is about
the youngest in age. The Chinese fauna is somewhat earlier, and is still
under study. These lagerstatten are augmented by well-preserved hard
part faunas of widespread occurrence.
General aspects--Trilobites dominate, everywhere. Most phylum level
invertebrates have made their first appearance by now, but at the class
level, not many would be recognizable today. Molluscs are represented by
hyolithids, monoplacophores, and several rare species which cannot be
assigned to known classes without difficulty. Echinoderms are present,
the only living class is sea cucumbers. Others belong to the extinct
subphyla Homalozoa and Blastozoa. No echinoderm shows the characteristic
five fold symmetry clearly until the latest Cambrian. Crustacean and
chelicerate arthropods have appeared, but not Uniramia.
There are no vertebrates. Chordates are represented by genera similar to
Amphioxus. Terrestrial life is completely absent, with the possible
exception of lichens.
Faunas show a high disparity, i.e., much diversification at the phylum
and class level, even more than today, with little diversification at
lower taxonomic levels. Differences between phyla and classes are
blurry, since the lineages had not yet retrenched from the original
adaptive radiations. The Chinese are at the forefront of evolutionary
studies on these lines.
Even at this time, there is evidence of reliction and extinction at high
taxonomic levels. Most of the Tommotian shellys are already gone. The
original armor of small sclerites and spines studded into the skin has
been replaced by larger shells. This has been theorized as a fusion of
the smaller elements into larger compound plates, but such a development
shows its derivation. More likely, one or a few plates expanded, the
others were suppressed.
The phylum Archaeocyatha, considered more primitive than sponges, were
the first animal reef builders from the lower Cambrian. They died out
totally in the middle Cambrian.
Entrenchment of phylum level taxa--The lagerstatten show a large number
of organisms whose affinities fit no phylum as recognized in
post-Cambrian times. Most show characters that combine phyla, or
characters of one phylum combined with unique alien characters.
Entrenchment of phyla was accomplished by extinction of lineages as much
as by further evolution of surviving lineages. This extinction appears
to have happened shortly after the Burgess, as late Cambrian show
entrenchment in high progress.
LATE CAMBRIAN/ORDOVICIAN DEVELOPMENTS
From the late Cambrian through the end of the Ordovician, almost all
marine invertebrate classes made their first appearance. Many archaic
Cambrian lineages disappeared or relicted during this time, as well.
After the Ordovician, only terrestrial life, and a very few marine
classes remained to appear. There was still considerable extinction to
follow, and many organisms of the time would be alien to us. But after
the Ordovician, the seas did look recognizable.
General aspects--The first true corals appeared in the Ordovician, as the
extinct Rugosa and Tabulata.
Echinoderms expanded and diversified explosively in the latest Cambrian
and Ordovician, and all classes appeared by the end. Many went extinct,
as well. Pentameral forms quickly took dominance. Brachiopods
diversified rapidly.
The phyla Bryozoa, Hemichordata, and Conodonta first appeared in the
latest Cambrian.
Gastropods evolved from the Monoplacophora in late Cambrian, bivalves and
nautiloid cehpalopods first appeared in the Ordovician.
Arthropods continued to diversify rapidly, with most crustacean and
chelicerate classes appearing. The subphylum Uniramia appeared in the
Silurian.
The first well-known vertebrates appeared in the upper Ordovician, as the
jawless ostracoderms. No fish until the Silurian.
CONCLUSIONS
The phyla Cnidaria, Porifera, Arthropoda, and possibly Echinodermata
predate the Cambrian on the basis of fossil evidence. Trace fossils
indicate worm phyla present as well.
The Cambrian "Explosion" was stretched out over a period at least 30
million years, and may be an artifact of visibility and preservation as
much as rapid diversification.
The base of the Cambrian is defined as the first appearance of abundant
hard parts, not as the first multicelled life.
Disparity of phylum level taxa as defined from the post Cambrian is
partly a result of extinction of early phylum level lineages, eliminating
many connecting forms.
Climatic changes about 15 million years after the Vendian extinction
resulted in widespread shallow epicontinental seas offering multitudinous
new niches for adaptive radiation.
Ray
Moose
[This message has been edited by minnemooseus, 12-20-2002]

  
Ahmad
Inactive Member


Message 30 of 199 (28063)
12-29-2002 1:42 PM
Reply to: Message 22 by mark24
12-09-2002 7:05 PM


Mark,
quote:
I ask you to consider that potentially small populations of soft bodied organisms, that molecular evidence you have cited says exist, may not have fossilised in sufficient quantities & detail to be able to corroborate the existence of said molecular phylogeny (among others) beyond the Cambrian.
I should remind you that fossils of soft-bodied organisms are famously found in Cambrian Preservat-Lagerstatten such as the Burgess Shale and the Chengjiang locality in China. Fossil bacteria are reported from both Precambrian and Phanerozoic rocks. Why would depositional conditions favor preservation of bacteria in both Precambrian and Phanerozoic rocks, but soft-bodied multicellular organisms only in the Phanerozoic and uppermost Precambrian? The fossil record is obviously incomplete, but there is no evidence it is so incomplete it would not preserve fossils of soft-bodied organisms for half their supposed geologic history!!
quote:
But I would be interested in where the fossils in 1/ to 6/ allegedly disappeared to?
I haven't the slightest idea. Species appear and disappear abruptly, according to scientists and they show no "gradual evolution" but "the sudden explosion of one group at the expense of another". Thats the sole problem of evolution. Where, indeed, are the missing fossils... the missing links?
quote:
That is to say, for at least the fifth time. The first organisms to appear are single celled prokaryotes, then single celled eukaryotes, then multicellular eukaryotes. That, as I have explained, is a general increase in complexity seen in the fossil record. I have already qualified that not much more complexity appears after the Cambrian.
You have generalized it greatly. Only if you go into details of the trend, you might realize how incredibly random it is (like I have described in the case of the trilobites).
quote:
Why would the first organisms to appear be the simplest, followed by successive increases? Let's recap; the first bacteria appear circa 3 bya, the eukaryotes appear circa 1.5 bya, then multicellular life appears 0.5 to 0.9 bya. Seems like a general increase to me.
Interesting but would you consider the remarkable similarities between bacteria billions of years old and present bacteria? Have they not undergone evolution of any sort?
Regards,
Ahmad

This message is a reply to:
 Message 22 by mark24, posted 12-09-2002 7:05 PM mark24 has replied

Replies to this message:
 Message 31 by edge, posted 12-29-2002 2:39 PM Ahmad has not replied
 Message 32 by mark24, posted 12-30-2002 8:34 AM Ahmad has not replied
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