Posted on 10/16/2003 7:33:43 AM PDT by AntiGuv
The Cambrian Explosion - when life suddenly and rapidly flourished some 550 million years ago - may have an explanation in the reaction of primitive life to some big event.
The explosion is one of the most significant yet least understood periods in the history of life on Earth.
New research suggests it may have occurred because of a complex interaction between components of the biosphere after they had been disturbed by, for example, the break-up of a super-continent or an asteroid impact.
Scientists say the life explosion might just have easily occurred two billion years earlier - or not at all.
Dramatic events
All modern forms of life have their origin in the sudden diversification of organisms that occurred at the end of the so-called Cryptozoic Eon.
Scientists have struggled to explain what might have happened in the previous few hundred million years to trigger such a burst of life.
Certainly, it was a period of history that witnessed the assembly and break-up of two super continents and at least two major glaciation events. Atmospheric oxygen levels were also on the rise.
But what actually caused the Cambrian Explosion is unknown.
Writing in the journal Geophysical Research Letters, Dr Werner von Bloh and colleagues, from the Potsdam Institute for Climate Impact Research, present a new analysis of happened.
They suggest that "feedback" in the biosphere caused it to jump from one stable state without complex life to one that allowed complicated life to proliferate.
"We believe that there was a change in the environment - a slow cooling of the system - that caused positive feedback that allowed the conditions for complex life," Dr von Bloh told BBC News Online.
Self regulation
Using a computer model of the ancient Earth, the researchers considered three components of the biosphere, the zone of life.
These were single-celled life with and without a nucleus, and multicellular life. Each of these three groups have different environmental tolerances outside which they cannot thrive.
The computer model showed there were two zones of stability for the Earth - with or without higher lifeforms - and that 542 million years ago the planet flipped from one to the other.
What caused the flip is not clear. It might have been a continental break-up, or even an asteroid impact.
There is some indication that the Moon suffered a sudden increase in impacts about the same time as the Cambrian Explosion. If so, then the Earth would have been affected as well.
This latest analysis also provides some support for the Gaia hypothesis - the idea that the biosphere somehow acts as a self-sustaining and regulating whole that opposes any changes that would destroy life on Earth.
Intelligent beings
Dr von Blow says that after the Cambrian Explosion there has been a stabilisation of temperature up to the present, and that the biosphere is not playing a passive role.
He also adds that there is an intriguing implication from his research which suggests that had the conditions been only slightly different, the Cambrian Explosion could have occurred two billion years earlier.
An early explosion would have meant that by now the Earth could have developed far more advanced intelligent creatures than humans.
Alternatively it could still be inhabited by nothing more complex than bacteria.
Dr von Bloh says that it will be of great interest when we find other Earth-like worlds circling other stars to see if they have had their own Cambrian explosions yet.
The timing of such events has implications for the search for intelligent life in space, he says.
That depends on your standard of proof. For example, the lifespans of the patriarchs in Genesis far exceed our experience of the normal span of human life. We have not a single documented example of a human living even 150 years; is that not pretty strong evidence Methuselah did not live 900? If you met a man tomorrow who claimed he was 900 years old, would you not be skeptical, for precisely this reason?
The point of the creation story isn't an exact reasoning of just how long it took but to give credit where credit is due.
A large number of people believe evolution was the means by which God accomplished his creation. They are surely giving credit where credit is due, no?
God disagrees with you. "Blessed are they who have not seen and believe." - Jesus to His Apostles after His resurrection.
What more can I say? God values faith and belief. He didn't give us impirical formulas, he gave us faith, hope and love. If you truly seek Him you will find Him. He, Himself, has promised as much.
Okay ... then what's your explanation of the "meteor crator" near Winslow, Arizona? No one saw it. Is it forever a mystery?
Not much. We'll have to agree to disagree. I'm not a proselytizing agnostic; there is a great deal of good in Christianity, and I'm not interested in converting anyone away from it. I'd just like to be extended the same tolerance.
I confess to having difficulty staying on topic.
The trouble with having to witness everything that happens for it to be true, is that there are no witnesses to anything that happened prior to about 1890 currently living. Does that mean your great-great-grandparents don't exist?
Science is about evidence. When there's little evidence, theories become more speculative. This doesn't make it an attack on anyone's religion, unless you don't believe the world around you has any reality.
I would ignore you now except for this:
You are not interested in honest debate and I am not interested in dishonest debate.
I challenge you to show where I have been dishonest on this thread! Your claims and assertions have been shown to be false (Iliad and Odyssey false comparison) and for this I am dishonest?
You are less than irrelevant, you are an insult to HONEST discourse.
Give me a freakin' break! I'm not talking about actual geological record, I'm talking about scientists reaching out with their "beliefs" when they reach the limits of impirical study.
As to your question... could it have been an alien spacecraft??? Disprove it. Science looks at the world and presents answers based on prior occurances. Where they have no prior occurance to rely on... well, see my tagline.
Strawman. My point on this thread hasn't been that scientists have no ability to read impirical and historical evidence. My point has been that some reach into their own beliefs to fill the gaps in their evidence.
The evidence is that came well before the 'Cambian explosion'. Sequence analysis of globins and respiratory proteins indicate that there was lots of oxygen around even before the evolution of the Eukaryotes. That's at least 1 billion years and more likely 2 billion years ago.
My own opinion is that the trigger for evolution of higher life forms was likely biological rather than environmental. I liked the hypothesis that it had to do with the evolution of eyes, which facilitated predation and led to an 'arms race'. I think this is an answerable question; I think that by delving through genomes we'll figure it out, even without fossil evidence; but at the moment the data are not there to answer the question.
This statement I agree with.
But most of these scientists are Christians.
No one accused you of persecuting anyone. You seem to want to take offense.
And many pro-abort Democrats are Catholic... what's your point?
I was only responding to the words you wrote. No offense taken... just pointing out the choice of words.
The Iliad and the Odyssey are FICTION written around an historical event; the sacking of Troy.
This is a dissembling obfuscation. One could just as easily state that the Testaments are FICTION written around historical events. You are the one that previously asserted that because no great inaccuracies have been proven in the historical elements, this then somehow establishes the veracity of the mythological embellishments.
The Iliad & the Odyssey are not by any stretch crucial to this analogy. Indeed, any historical fiction would suffice to establish the same point. That point being, no matter how many facts are accurate, they do not establish the accuracy of additional facts for which no evidence exists.
Here are two examples on either extreme:
1) A ten volume history of the world includes one sentence stating: "Krishna made it so." The accuracy of the other 999.9% of the work does not make that sentence accurate as well.
2) An epic mythological saga describing a cosmic battle of deities includes one sentence stating: "The mountains of Scandinavia trembled." The accuracy of that statement (there is indeed a Scandinavia, which features mountains, which do 'tremble'..) does not establish the accuracy of the remaining 999.9% of the work.
Both previous examples - the Homeric poems and the Hebrew testaments - merely fall somewhere between these two extremes.
A large number of people believe evolution was the means by which God accomplished his creation. They are surely giving credit where credit is due, no?
I won't debate His methods... He uses nature very often to accomplish His purpose (there are those that think the Israelites' crossing of the Red Sea was simply good geological timing). Evolution proving true doesn't disprove God's plan. However, I will say the "science" of evolution is VERY full of holes.
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