The Cambrian Explosion

[achilles12604]

Besides the apologist answer that God was responsible for this phenomina by some method, does secular science have a theory as to the cause of this sudden explosion of new life all at once? (Remember I do not fall for that God of Gaps theory)

I am looking for science answer to this mystery. Anyone care to enlighten me?

[QED]

I'm inclined to ask "what mystery?". Now I'm no expert on matters of biological evolution but I can understand events like this in broader terms. First we have to see this event* in context with everything going on before and after. Life had been getting along nicely but mostly it was in soft-bodied forms that leave far fewer traces as fossils. I think this is fairly obvious; soft tissue breaks down much more rapidly than harder, skeletal material, so mineralization is much less likely to occur.

So there was still plenty of Precambrian life (Ediacaran being the immediate predecessor to the Cambrian in the late Proterozoic era that began 2.5 billion years ago and ended 543 million years ago at the Cambrian). But all this life appears diminished by its under representation in the fossil record. Cambrian animals were those that had begun to employ harder body parts -- and there are no shortages of benefits that such parts confer -- so once they appeared, there was no going back!

So the "explosion" marks a transition to a (yet another) new innovation in the form of living things. Another impetus for calling it an "explosion" is the huge diversity of body plans seen at that time. There's a lot of technical terminology that I'm deliberately avoiding here, but simply speaking, there were many more tentative solutions being put forward by natural selection at that time. It's like any new product category we might see entering the market today. Think of early aircraft, there were monoplanes, biplanes, triplanes - planes with propellers in all sorts of different places -- only after a while did all these solutions "fight it out" to give us the handful of common practical solutions we see today.

You have to bear in mind that natural selection can be seen as a bunch of independent inventors releasing their products into a very demanding world. Not all solutions to the problem of keeping up with the competition will be successful. So we get the exact same signature in the diversity of basic body plan. Greater initial diversity when the animals find a new "environment" (not just geographical, but by acquiring greater access to existing environments through the development of improved natural technology) ...followed by a period of consolidation when all the rubbish solutions get weeded out.

I'd say that none of this resembles the craft of a skilled designer (something some people expect to see). It's much more like "Learning On The Job".


*In reality a finite period of time lasting many millions of years -- if you think of it like an event on a particular day then you're way off! Perhaps the word Explosion is throwing some people off. It's just one of those cute expressions that smart-ass scientists like to take liberties with.

[Noachian]

I begg to differ (with all respect of your well meaning answer), the cambrian explosion was a habitat in a lost time in Earths history, the small squishy creatures lived on the sea floor round about 7,000 years ago (seems to nearly all human dating methods have failed). When a catyclyms strook this habitat many of the creatures were destroyed and their habitat was preserved. We know that these animals didnt become fossils over millions of years after death, because most (if not all) clams found in the Cambrian are found closed indicating they were fossilized rapidly not over time, other wise we would the clams and other moluscs would be found opened.

[achilles12604]

I was wondering if this would get interesting.

[otseng]

I believe the Cambrian Explosion is another of the blows to Common Descent that evolutionists have failed to explain.

But, before we go into that, let's be clear on what we mean by the Cambrian Explosion.

It is a period when a large variety of complex life suddenly shows up for the first time in the fossil record. And this all happened in a relatively short period of time, around 50 million years.

The Cambrian is a short period in earth history, starting approximately 545 m.y. ago and ending about 490 m.y. ago.

http://wwwalt.uni-wuerzburg.de/palaeont ... /casu6.htm

During this period of 50 million years, "most extant body forms are found". And even more, after the Cambrian explosion, no new phylum-level body plans evolved.

Today, although the fossil record now extends back 3,465 Ma (± 5 Ma, to the Apex Chert, see Schopf 1999, p. 100) and diverse precursors to the Cambrian biotas are gradually becoming understood, it still appears as if a genuinely rapid diversification of form, particularly among the Metazoa ("animals"), did occur in the Cambrian. During this time, most extant body plans are suddenly found in the fossil record. "Definitive representatives of all readily fossilizable animal phyla (with the exception of bryozoans) have been found in Cambrian rocks, as have representatives of several soft-bodied phyla (Valentine et al. 1991)" (Wray et al. 1996). By way of contrast, "it appears that no [new] phylum-level body plans have arisen in the animal kingdom in the last 500 million years" (Arthur 1997, p. 7).

http://www.peripatus.gen.nz/paleontology/Cambrian.html

Given that life first started 3.4 billion years ago (Fossils of the First Life), and the Cambrian Explosion lasted 50 million years, that's only a 1.5 percent time period when complex life all suddenly shows up.

What can account for it? How does it fit into the theory of evolution? That is the mystery.

Also, even Darwin admitted the Cambrian Explosion to be a problem to his theory.

Charles Darwin (Origin of Species 2nd ed. Chapter IX) recognized that the sudden appearance of animal fossils in the Cambrian posed a problem for his theory of natural selection, 'and may be truly urged as a valid argument against the views here entertained.' He suggested that ;'before the lowest [Cambrian] stratum was deposited, long periods elapsed, as long as, or probably far longer than, the whole interval from the [Cambrian] age to the present day; and that during these vast, yet quite unknown, periods of time, the world swarmed with living creatures.'

http://www.peripatus.gen.nz/paleontology/Cambrian.html

[achilles12604]

I believe the Cambrian Explosion is another of the blows to Common Descent that evolutionists have failed to explain.

But, before we go into that, let's be clear on what we mean by the Cambrian Explosion.

It is a period when a large variety of complex life suddenly shows up for the first time in the fossil record. And this all happened in a relatively short period of time, around 50 million years.

The Cambrian is a short period in earth history, starting approximately 545 m.y. ago and ending about 490 m.y. ago.

http://wwwalt.uni-wuerzburg.de/palaeont ... /casu6.htm

During this period of 50 million years, "most extant body forms are found". And even more, after the Cambrian explosion, no new phylum-level body plans evolved.

Today, although the fossil record now extends back 3,465 Ma (± 5 Ma, to the Apex Chert, see Schopf 1999, p. 100) and diverse precursors to the Cambrian biotas are gradually becoming understood, it still appears as if a genuinely rapid diversification of form, particularly among the Metazoa ("animals"), did occur in the Cambrian. During this time, most extant body plans are suddenly found in the fossil record. "Definitive representatives of all readily fossilizable animal phyla (with the exception of bryozoans) have been found in Cambrian rocks, as have representatives of several soft-bodied phyla (Valentine et al. 1991)" (Wray et al. 1996). By way of contrast, "it appears that no [new] phylum-level body plans have arisen in the animal kingdom in the last 500 million years" (Arthur 1997, p. 7).

http://www.peripatus.gen.nz/paleontology/Cambrian.html

Given that life first started 3.4 billion years ago (Fossils of the First Life), and the Cambrian Explosion lasted 50 million years, that's only a 1.5 percent time period when complex life all suddenly shows up.

What can account for it? How does it fit into the theory of evolution? That is the mystery.

Also, even Darwin admitted the Cambrian Explosion to be a problem to his theory.

Charles Darwin (Origin of Species 2nd ed. Chapter IX) recognized that the sudden appearance of animal fossils in the Cambrian posed a problem for his theory of natural selection, 'and may be truly urged as a valid argument against the views here entertained.' He suggested that ;'before the lowest [Cambrian] stratum was deposited, long periods elapsed, as long as, or probably far longer than, the whole interval from the [Cambrian] age to the present day; and that during these vast, yet quite unknown, periods of time, the world swarmed with living creatures.'

http://www.peripatus.gen.nz/paleontology/Cambrian.html

Yes this is exactly what I was refering to.

QED's explaination has one gigantic hole in it. It doesn't at all address what my question was. He simply described what the event was but failed to address how so many new forms of complex life suddenly were able to fossilize so well and in such vast numbers considering that only a "short" (cosmically) time before, very few fossiles were found especially of this magnitude and none of this new type.

I find this statement by him rather interesting considering he is attempting to come from the non-theist point of view.

So the "explosion" marks a transition to a (yet another) new innovation in the form of living things. Another impetus for calling it an "explosion" is the huge diversity of body plans seen at that time. There's a lot of technical terminology that I'm deliberately avoiding here, but simply speaking, there were many more tentative solutions being put forward by natural selection at that time. It's like any new product category we might see entering the market today. Think of early aircraft, there were monoplanes, biplanes, triplanes - planes with propellers in all sorts of different places -- only after a while did all these solutions "fight it out" to give us the handful of common practical solutions we see today.

Airplanes were carefully planned and executed instruments designed and controlled by vast amounts of human intellect. Are you suggesting that the vastness of the body designes and the quickness with which they appeared suggest some sort of goal or design? Perhaps as with the planes, and intelligence behind the changes?

The point of this discussion is that there were very different and vast amounts of new creatures which were all very complex (remember my algea DNA strand post [urlhttp://debatingchristianity.com/forum/viewtopic.php?t=3678&postdays=0&postorder=asc&start=10] here[/url])

You have to bear in mind that natural selection can be seen as a bunch of independent inventors releasing their products into a very demanding world. Not all solutions to the problem of keeping up with the competition will be successful. So we get the exact same signature in the diversity of basic body plan. Greater initial diversity when the animals find a new "environment" (not just geographical, but by acquiring greater access to existing environments through the development of improved natural technology) ...followed by a period of consolidation when all the rubbish solutions get weeded out.

So all of these intermetiary creatures suddenly appeared after litterally billions of years without their existence, and then poof, they are gone completely extinct a short time later? Not on of these intermediate creatures was worthy of continuing on for slightly longer?

I suggest that God purposfully instrumented these stepping stone creatures and forced mutations suddenly and quickly during various stages of evolution. We see this pattern several times throughout creation and incidentally it occurs with similar creatures as mentioned in the creation account which was written by people with absolutly ZERO knowledge of anything remotely scientific. This coincidence is pretty amazing. To me anyway. Ya'll make up your own minds if this is wierd to you.

[QED]

I believe the Cambrian Explosion is another of the blows to Common Descent that evolutionists have failed to explain.

Do you mean Evolutionists have failed to explain the Cambrian Explosion? What explanations (other than mine above!) have you heard of and dismissed?

Given that life first started 3.4 billion years ago (Fossils of the First Life), and the Cambrian Explosion lasted 50 million years, that's only a 1.5 percent time period when complex life all suddenly shows up.

What can account for it? How does it fit into the theory of evolution? That is the mystery.

I don't think that's a particularly accurate way to portray the spread of complexity over time. As I mentioned, the Cambrian saw a "gear change" when hard body parts became common, prior to this we should expect an under-representation in the fossil record. But I think there's a useful model that most of us are familiar with: Moore's Law. If we accept animals as examples of natural technology (can we argue that they are not?) then we should not be surprised to see complexity exponentiating. The "gear change" I mentioned would be one of many as certain boundaries are finally overcome, but each transition could precede an exponential growth that, when viewed from a distance, would resemble an explosion.

Look at the way human technology has developed with an accelerating pace. It's characterised by the development of key enabling features that overcome the initial inertias. I think History reflects this image very well, with precious little going on in caves for vast stretches of time, then a shift to farming and village communities and so on with each distinct phase being fuelled by some breakthrough or other. As time goes on The Law of Accelerating Returns stamps the indelible mark of an explosion (as viewed from a distance).

But there are other important factors that come into play, stability can also set in when there is no drive to innovate. This is described as Punctuated Equilibrium, something that makes every bit of sense and shapes the lower region of the exponential curve.

[QED]

QED's explaination has one gigantic hole in it. It doesn't at all address what my question was. He simply described what the event was but failed to address how so many new forms of complex life suddenly were able to fossilize so well and in such vast numbers considering that only a "short" (cosmically) time before, very few fossiles were found especially of this magnitude and none of this new type.

I submitted my previous post before I saw yours. I think the key word from that post is "enabling". Do you not recognize the significance of this from your own experiences? It only takes one novel development to start an avalanche of spin-off's. But I daren't draw on any more analogies from the human world lest you severely over-interpret them!

I find this statement by him rather interesting considering he is attempting to come from the non-theist point of view.

So the "explosion" marks a transition to a (yet another) new innovation in the form of living things. Another impetus for calling it an "explosion" is the huge diversity of body plans seen at that time. There's a lot of technical terminology that I'm deliberately avoiding here, but simply speaking, there were many more tentative solutions being put forward by natural selection at that time. It's like any new product category we might see entering the market today. Think of early aircraft, there were monoplanes, biplanes, triplanes - planes with propellers in all sorts of different places -- only after a while did all these solutions "fight it out" to give us the handful of common practical solutions we see today.

Do me a slight courtesy and reflect on the trouble I have been going to to establish a natural designer/inventor/intelligence or whatever, in nature. I have also described animals as examples of natural technology. These are a way of putting things so they can be understood in terms more familiar to us. It doesn't actually follow that there are little people-like things involved behind the scenes though.

Airplanes were carefully planned and executed instruments designed and controlled by vast amounts of human intellect. Are you suggesting that the vastness of the body designes and the quickness with which they appeared suggest some sort of goal or design? Perhaps as with the planes, and intelligence behind the changes?

Solutions. The apparent designs we see are natural solutions. Innovation is perpetuated by the need to keep up with innovations going on elsewhere. Each type of animal is operating not in a vacuum, but in a "sea" of competing animals. Is there anything you see that suggests there is no such "arms race"?

So all of these intermetiary creatures suddenly appeared after litterally billions of years without their existence, and then poof, they are gone completely extinct a short time later? Not on of these intermediate creatures was worthy of continuing on for slightly longer?

Who's saying that? Without looking it up I can't tell you all the Phylums that persisted through this period, but I do remember that Chordates were one of them, and that we are Chordates. AFAIK there is only one new phylum seen to appear after the Cambrian -- Bryozoans, or moss animals.

I suggest that God purposfully instrumented these stepping stone creatures and forced mutations suddenly and quickly during various stages of evolution. We see this pattern several times throughout creation and incidentally it occurs with similar creatures as mentioned in the creation account which was written by people with absolutly ZERO knowledge of anything remotely scientific. This coincidence is pretty amazing. To me anyway. Ya'll make up your own minds if this is wierd to you.

It don't get it. The traditional view of creation by fiat wouldn't seem to match the painfully gradual curve of billions of years of painstaking effort by cyanobacteria in transforming the atmosphere into something more usable. I don't see example of this sort of patience in your stories of Genesis.

[achilles12604]

I suggest that God purposfully instrumented these stepping stone creatures and forced mutations suddenly and quickly during various stages of evolution. We see this pattern several times throughout creation and incidentally it occurs with similar creatures as mentioned in the creation account which was written by people with absolutly ZERO knowledge of anything remotely scientific. This coincidence is pretty amazing. To me anyway. Ya'll make up your own minds if this is wierd to you.

It don't get it. The traditional view of creation by fiat wouldn't seem to match the painfully gradual curve of billions of years of painstaking effort by cyanobacteria in transforming the atmosphere into something more usable. I don't see example of this sort of patience in your stories of Genesis.

Just because religious interpreters throughout the ages have refused to open their eyes to science does not negate that they can coexist. Many parts of the bible were written in poetic form, not to be taken litterally but rather as symbolism or metaphores for deeper truths.

Some Christians read the bible as a textbook. This was not how is was designed. This pattern of being stiffnecked apparently has caused non-theists to think that all christians demand a litteral interpretation of Genesis (ie 1 day being exactly 24 of our hours). A fundemental flaw in the logic of both sides.

[Wyvern]

Besides the apologist answer that God was responsible for this phenomina by some method, does secular science have a theory as to the cause of this sudden explosion of new life all at once? (Remember I do not fall for that God of Gaps theory)

I am looking for science answer to this mystery. Anyone care to enlighten me?

First off you need to understand that when the word sudden is used in this context it actually means tens of millions of years.

Here's a possible explanation though mind you nowhere near enough is known about the period to come to any definite resolution on the matter. The cambrian explosion happened between two extinction events. The first was happened in the vendian period just prior to the cambrian. Granted there is debate whether an actual extinction event occurred during the vendian, however if you accept this as happening it makes perfect sense that there would be an explosion of new organisms to fill the various niches left open from the previous extinction event.
Just as the KT event killed off the dinosaurs and allowed mammals to take over all the niches that suddenly were opened up, again this happened over millions of years but even so it is considered a period of relatively rapid speciation.