Cambrian Explosion

regarding the snails. there are massive differences in extant snail shells. The Gastropoda are the second most diverse order of animals after the insects, with straight shells, coiled shells, conical shells, you name it, and we see them changing through the fossil record, so jlerollin's statement is contradicted by facts. yet again.

when will these people learn not to talk about things that they know nothing about, and stop saying things that were falsified decades ago.

I found the article I was talking about. I'll post it and then we can carry on later. Sorry I have had so little time to give this forum lately.

http://www.unifiedworlds.com/cornet/Why02/why2.htm#Recognition

that link just makes my point. thankyou.

Jet Black said:

that link just makes my point. thankyou.

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I thought it was a good article that exemplified each of our points.

Do you feel that my veiwpoint is completely implausible? Do you feel that a period that contains nearly 90% of the earth's history could not have had many evolutionary cycles possible in that time frame? Is it not possible that life began and evolutionary processes took hold but the life then was destroyed by the climatic environment? Is it not possible that those processes were somewhat different than we see in later strata due to the great time period and the differing environment?

What we do know, is that very little remains of the earth's earliest crust. Most if not all of the evidence is gone. So how can you as a reasonable Scientific person claim that none of this is in the realm of possibility? Please explain.

I have already outlined my main point regarding finding grasses in the precambrian. post #197 goes over this in more detail, but not only are you missing grass, but you are missing their parent group, the angiosperms, then you are missing their parent group in the vascular plants, and then you have a series of technically inferior plants stretching bakwards in time. It's like saying that therapsids, mammals, monotremes and marsupials all existed in the cambrian, but just mamaged to avoid fossilization until the tertiary, when the therapsids marched out in order of mammal-likeness to be fossilized for a few million years, then the rest had a break while the dinosaurs did the same, and then the mammals started marching out in order of similarity to modern mammals. I know that sounds rather extreme, but it is basically what you are looking for with the plants. In short yes, I think looking for grass in the precambrian is completely unreasonable.

Jet Black said:

I have already outlined my main point regarding finding grasses in the precambrian. post #197 goes over this in more detail, but not only are you missing grass, but you are missing their parent group, the angiosperms, then you are missing their parent group in the vascular plants, and then you have a series of technically inferior plants stretching bakwards in time. It's like saying that therapsids, mammals, monotremes and marsupials all existed in the cambrian, but just mamaged to avoid fossilization until the tertiary, when the therapsids marched out in order of mammal-likeness to be fossilized for a few million years, then the rest had a break while the dinosaurs did the same, and then the mammals started marching out in order of similarity to modern mammals. I know that sounds rather extreme, but it is basically what you are looking for with the plants. In short yes, I think looking for grass in the precambrian is completely unreasonable.

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Okay, so do you think that life could only begin once and in the exact way it has? Do you think that if life evolved in the early hadean that it would remain in very simple forms for 90% of the earth's history and then suddenly progress to the life forms found in the late precambrian and early Cambrian? Do you think it impossible for life to have formed progressed to more complex organisms and be totally wiped out without a trace due to the plate tectonics of the earth?

I think it would be pretty unlikely, though I confess it'S a fascinating question. I'll have to have a chat with some geologists about that one.

What is it you're suggesting? that grass evolved twice?

Jet Black said:

I think it would be pretty unlikely, though I confess it'S a fascinating question. I'll have to have a chat with some geologists about that one.

What is it you're suggesting? that grass evolved twice?

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Ah, there is the jet I know and respect. I don't expect you to take this scenerio and accept it without question, what I do want is for you to get outside of the established box and consider possibilities. A scientific mind should always be open for possibility, otherwise science is stagnant and is doomed. Looking at just the time frame here, look at the diversity of life forms in just 10% of earth's history. It is almost unimaginable to me to think that it took from 4.6 billion years ago to 544 million years ago before anything other than simple life forms took hold. It doesn't take a lot of imagination for one to see that life could have started many times in the same way only to be destroyed many times as well.

To me that is a possibility. To me the possibility exists that very primitive forms of the plants and trees could have existed during periods when the fossil record is absent as well.

The scenerio that I feel though is more in what I accept to be more likely is the second scenerio that I gave in my post. But I wanted to see if you could step outside of yourself and at least look at things as possible. It goes against your established mindset but you stepped out of that and your curiosity was touched. Good. Very good. Sometimes I feel that skeptics get their anti-Creationist mindset so established that no matter what is presented, they must crush it due to what it stands for and what most people feel the movement is trying to do. Which I understand completely. But you know me enough to know that I don't jump on the ID bandwagon.

So, I feel that at least you are not closed to possibility or biased from looking at it in a rational way. So whether or not you can see where this scenerio actually happened or not, you looked at it in a good light. kudos.

Oncedeceived said:

A scientific mind should always be open for possibility, otherwise science is stagnant and is doomed.

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in science, anything is possible. that doesn't make it plausible though.

It is almost unimaginable to me to think that it took from 4.6 billion years ago to 544 million years ago before anything other than simple life forms took hold.

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well with evolution, complexity is built upon complexity. if you consider the remarkable complexity of the cell itself, it may have taken a very long time for this complexity to evolve to the point where multicellular forms became useful. also consider that before sexual reproduction evolved, evolution would have taken place much more slowly. according to what i have read, the genomes of asexually reproducing species can accumulate at most 1 bit of information per generation, while sexually reproducing species can accumulate up to (square root of G) bits of information per generation, where G is the size of the genome. that's a pretty big difference.

It doesn't take a lot of imagination for one to see that life could have started many times in the same way only to be destroyed many times as well.

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i think that is a distinct possibility, though one not currently in evidence. i would not be that surprised it you were right about that.

To me that is a possibility. To me the possibility exists that very primitive forms of the plants and trees could have existed during periods when the fossil record is absent as well.

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this on the other hand, is much less of a possibility. from what we know of evolution, it will never take the exact same path twice. even when convergent evolution occurs, there are always distinct genetic and structural differences. if life did arise twice, we would not expect evolution to make the same species twice, independantly. if you consider the millions of steps in going from single celled creatures to vascular plants, to angiosperms, to grasses, the odds of that happening are virtually nil.

and let's suppose for the sake of argument, that this could occur. wouldn't that mean that the entire order in genesis is unfalsifiable?

Oncedeceived said:

A scientific mind should always be open for possibility, otherwise science is stagnant and is doomed.

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It is not a matter of what is possible, it is a matter of evidence. Sure, it's possible that grasses existed in the Cambrian, or even Pre-cambrian, but where is the evidence? Also, an open mind is not even needed given the fact that digs are ongoing as we speak. Very recently it was widely accepted that grasses and dinosaurs did not coexist. This was shown to be false by recent discoveries, not because a scientist had an open mind but because of evidence.

Looking at just the time frame here, look at the diversity of life forms in just 10% of earth's history. It is almost unimaginable to me to think that it took from 4.6 billion years ago to 544 million years ago before anything other than simple life forms took hold.

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It is amazing, and the secrets may be unlocked in the field of Evolutionary Developmental Biology (Evo-Devo). Complex, multicellular animals go through a developmental stage that is controlled by Hox genes. Evo-Devo research takes the view that evolution of the developmental process is the driving force in biological complexity. What is interesting is that as you move up through the Kingdom Animalia and look for Hox genes you will find that major advances in anatomical novelty may very well have been caused by duplications of Hox genes. The Cnidarians, for example, are a simple phyla within animalia and they have relatively few Hox genes when compared to other phyla such as Chordata.

I can't remember which paper I read it in, but it talked about how the Cambrian Explosion and other sudden advances in anatomical novelty may have come about through "increasing the tools in the tool box", or the duplication of Hox genes and transcription factors.

It doesn't take a lot of imagination for one to see that life could have started many times in the same way only to be destroyed many times as well.

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Sure, it's completely possible. However, those other lineages may have died off or were absorbed into other lineages through endosymbiosis or horizontal gene transfer. What we do have is a monophyletic genetic tree linking all eukaryotes together, from the simplest protist to the most complex mammal.

To me that is a possibility. To me the possibility exists that very primitive forms of the plants and trees could have existed during periods when the fossil record is absent as well.

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Sure, it's possible which is why proposed evolutionary time scales are testable and falsifiable.

Oncedeceived said:

To me that is a possibility. To me the possibility exists that very primitive forms of the plants and trees could have existed during periods when the fossil record is absent as well.

.

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I feel that this is remote to the point of impossibility.

The problem I have with this hypothesis is the ubiquity of Angiosperm fossils in the geological record in the form of pollen.

Pollen is highly diagnostic of Angiosperms, it is completely different to the pollen of other plant types, it is also ubiquitous in sedmentary rocks. It can be found in just about any type of sedimentary rock due to its small size and ability to travel huge distences and the fact that it is produced in vast quantities.

caravelair said:

in science, anything is possible. that doesn't make it plausible though.

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How can something be "possible"in that it can be capable of happening, existing, or being true without contridicting proven facts, laws or circumstances and still remain implausible. Implausible would mean that it would remain in the area of improbable which then relegates it to the "not likely to occur, or have occurred" realm which is contridictory in terms. If something is in the realm of possiblity, it is then in the realm of plausible. It may be of a low probability, which is probably more to your thinking. But then it becomes more subjective than reality.

well with evolution, complexity is built upon complexity. if you consider the remarkable complexity of the cell itself, it may have taken a very long time for this complexity to evolve to the point where multicellular forms became useful. also consider that before sexual reproduction evolved, evolution would have taken place much more slowly. according to what i have read, the genomes of asexually reproducing species can accumulate at most 1 bit of information per generation, while sexually reproducing species can accumulate up to (square root of G) bits of information per generation, where G is the size of the genome. that's a pretty big difference.

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True but new evidence provides support that reproduction occurred much earlier than thought. So early in fact, that the length of time between precambrian and Cambrian seems all that more immense.

i think that is a distinct possibility, though one not currently in evidence. i would not be that surprised it you were right about that.

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True, and the evidence is so limited as to be almost non-existant.

this on the other hand, is much less of a possibility. from what we know of evolution, it will never take the exact same path twice.

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True, so it could have been possible that the differences in the path could lead to some pretty exotic organisms. We see this in the deep oceans as well. There could have been a whole different type of plants, trees and they could have evolved in a very different manner than what we see in the fossil record today.

even when convergent evolution occurs, there are always distinct genetic and structural differences. if life did arise twice, we would not expect evolution to make the same species twice, independantly. if you consider the millions of steps in going from single celled creatures to vascular plants, to angiosperms, to grasses, the odds of that happening are virtually nil.

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But you are not looking at the possible pathways that could lead to similiar if not the same type of organisms. Grasses could have been quite different than what evolved in the period after the precambrian.

and let's suppose for the sake of argument, that this could occur. wouldn't that mean that the entire order in genesis is unfalsifiable?

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Again, we see an order in which the land surface is covered by water. If this was proven to be impossible then this would falsify Genesis. IF mankind were shown to be presented as created before all life forms this would falsify Genesis. Now you can say that Genesis 2 does this, and in your mind that might falsify Genesis. But don't expect me to think it does; not because I am making excuses but because the Christian Bible is a tool for the Christian and in the Christian worldview one must address the Bible. So what may seem totally unreasonable to you (Genesis 1/Genesis 2) is totally reasonable to the Christian worldview. I don't expect you to understand that per se, but I just want you to understand my viewpoint and look at the merits of that view. Do you see what I mean?

Sorry no more time.

Oncedeceived said:

How can something be "possible"in that it can be capable of happening, existing, or being true without contridicting proven facts, laws or circumstances and still remain implausible. Implausible would mean that it would remain in the area of improbable....

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something can be possible and still be improbable. anything with odds greater than zero is possible. but there are a lot of numbers that are greater than zero and still incredibly small. for example, if i were to roll a 6 sided die 500 times in a row, it's possible that i could roll a 6 every single time. it's also extremely improbable, and if you told me you did that, i wouldn't believe it unless you showed me some proof.

True but new evidence provides support that reproduction occurred much earlier than thought.

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really? sounds interesting, what is the evidence?

So early in fact, that the length of time between precambrian and Cambrian seems all that more immense.

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it is a long time, but i bet scientists have some good theories about why it took so long. i don't know that much about it myself.

True, and the evidence is so limited as to be almost non-existant.

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almost, but not totally non existant. we do find fossils from this time period, and none of them are plants, and all of them are relatively simple. if more complicated life forms evolved earlier, why didn't any of them fossilize? why did only the simple soft bodied ones survive?

and if we suppose that evolution did happen twice, wouldn't other types of organisms still have come before plants anyways? sea dwelling ones, for example.

also, if plants came before animals, how could things like insect and bird pollinated flowers have evolved? for example, genesis specifically mentions fruit bearing trees. fruit exists as a method of using animals to disperse seeds. how could it have evolved before animals existed?

True, so it could have been possible that the differences in the path could lead to some pretty exotic organisms. We see this in the deep oceans as well. There could have been a whole different type of plants, trees and they could have evolved in a very different manner than what we see in the fossil record today.

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the thing is, with the way the nested hierarchy of species is, anything that evolved independantly wouldn't fit into the hierarchy, and you wouldn't be able to classify anything as a part of the groups our modern species fit into. if something plant-like evolved, i doubt you would really be able to call it a plant, and certainly nothing that could be classified as grasses could have evolved. for that to happen, it would have to follow the same evolutionary path which is unlikely to the point of virtual impossibility. and the thing is, genesis talks about modern species of plants - grasses, fruit bearing trees, etc. not some wild and exotic plant-like things.

But you are not looking at the possible pathways that could lead to similiar if not the same type of organisms. Grasses could have been quite different than what evolved in the period after the precambrian.

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but then they wouldn't be grasses.

Again, we see an order in which the land surface is covered by water. If this was proven to be impossible then this would falsify Genesis.

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could you explain this a little more, including how one might falsify the claim?

IF mankind were shown to be presented as created before all life forms this would falsify Genesis.

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no it wouldn't, because you could always say it's possible that the other life forms evolved earlier, and that the evidence has been destroyed, just as you are doing with the grasses example. that has been my point for a while now. grasses appear later in the fossil than animals, contrary to the order in genesis. you say that this doesn't falsify the order because it's possible that grasses evolved earlier and the evidence has been destroyed. if humans came before grasses (or any other species) in the fossil record, you could still say that grasses (or whatever species) evolved earlier, and the evidence has just been destroyed. do you get my point here? i don't know how you could get around that.

Baggins said:

I feel that this is remote to the point of impossibility.

The problem I have with this hypothesis is the ubiquity of Angiosperm fossils in the geological record in the form of pollen.

Pollen is highly diagnostic of Angiosperms, it is completely different to the pollen of other plant types, it is also ubiquitous in sedmentary rocks. It can be found in just about any type of sedimentary rock due to its small size and ability to travel huge distences and the fact that it is produced in vast quantities.

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Athough true, we have already shown that there was a long period of time that grasses were present and there were no fossil record of them being there. So we know that they can be present and be absent in the sedmentary rocks.

Loudmouth said:

It is not a matter of what is possible, it is a matter of evidence. Sure, it's possible that grasses existed in the Cambrian, or even Pre-cambrian, but where is the evidence?

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Remember lack of evidence does not necessarily mean absence of evidence.

Also, an open mind is not even needed given the fact that digs are ongoing as we speak. Very recently it was widely accepted that grasses and dinosaurs did not coexist. This was shown to be false by recent discoveries, not because a scientist had an open mind but because of evidence.

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Exactly, and Scientists had always claimed that there were no grasses before the Dino's were extinct. So what is to say that this could be true of what Scientists are saying now...that grasses are evident with the dinosaurs but probably no earlier? We could find them even earlier than what we believe now and you would say the same thing, correct?

It is amazing, and the secrets may be unlocked in the field of Evolutionary Developmental Biology (Evo-Devo). Complex, multicellular animals go through a developmental stage that is controlled by Hox genes. Evo-Devo research takes the view that evolution of the developmental process is the driving force in biological complexity. What is interesting is that as you move up through the Kingdom Animalia and look for Hox genes you will find that major advances in anatomical novelty may very well have been caused by duplications of Hox genes. The Cnidarians, for example, are a simple phyla within animalia and they have relatively few Hox genes when compared to other phyla such as Chordata.

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True, but if I am correct, Hox genes are transfer genes and they only transfer what is already there. They do not bring in something new, if I understand correctly.

I can't remember which paper I read it in, but it talked about how the Cambrian Explosion and other sudden advances in anatomical novelty may have come about through "increasing the tools in the tool box", or the duplication of Hox genes and transcription factors.

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Again, if I understand correctly, the tools must already be present to transfer.

Sure, it's completely possible. However, those other lineages may have died off or were absorbed into other lineages through endosymbiosis or horizontal gene transfer. What we do have is a monophyletic genetic tree linking all eukaryotes together, from the simplest protist to the most complex mammal.

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True, but that does not mean that it couldn't have happened similarly earlier and then been destroyed.

Or differently either for that matter.

Sure, it's possible which is why proposed evolutionary time scales are testable and falsifiable.

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Only if the evidence is found.

Oncedeceived said:

Athough true, we have already shown that there was a long period of time that grasses were present and there were no fossil record of them being there. So we know that they can be present and be absent in the sedmentary rocks.

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I don't agree with this statement.

When was this period when grasses were abundant but their fossils weren't.

There may be some rock types that don't preserve pollen very well, but I doubt there are long periods of geological time when the whole earth is devoid of grass pollen.

But I am willing to bow to scientific evidence

Oncedeceived said:

Athough true, we have already shown that there was a long period of time that grasses were present and there were no fossil record of them being there. So we know that they can be present and be absent in the sedmentary rocks.

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can you say the same for pollen?

Baggins said:

There may be some rock types that don't preserve pollen very well, but I doubt there are long periods of geological time when the whole earth is devoid of grass pollen.

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i'm not sure if they are able to match up fossilized pollen with grasses specifically. keep in mind these wouldn't be the species of grass we see today, so their pollen may have been different. nevertheless, the argument could easily be extended to angiosperms in general, so then we wouldn't have this problem.

Oncedeceived said:

Remember lack of evidence does not necessarily mean absence of evidence.

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Keep telling yourself that. And in 50 years, when we still haven't found Cambrian grass, keep telling yourself that.
With all the research that has been done on Cambrian rocks, you don't think we would find at least some hint of grass? After all, we have found paleosols, but no grass.

Exactly, and Scientists had always claimed that there were no grasses before the Dino's were extinct.

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Not really. It was predicted that grass originated in the Mesozoic, but no one had found evidence for it yet. Now we do have some evidence.