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.
His sister or a niece. Just as Noah's grandchildren intermarried. No need for the unsouled from a very practical point of view.
Don't resent your lineage, pre-human. </sarcasm
Sure, the guy lived to be very old if Adam's age (930 yrs.)is any indication. How many kids could you have if your viability were extended 800 years.
Cain's brother Seth may have married his sister and had children of which Cain could have wed. More likely Cain married a sister rather than a niece.
Greatly simplified, it is thus:
First, she used the "basic idea" that a "spirit" is actually an organism, composed of DNA that only "organizes" (and has the ability to do so) when it wishes. Other than that, it is as air. Considering the makeup of some fungi and seagoing colonies of life, not TOO far off. The "spirit" is basically more of a "colony" of molecules, which posseses a consciousness.
Second, (again in the novels) One such "spirit" which was attracted to human blood invaded the body of an Egyptian queen millennia ago, and fused with its DNA, causing a change in her most basic genetics. In essence, the spirit became a "symbiote" with the human, and the result was a blood-thirsting vampire. The alteration also altered the woman's (whose name was Akasha) aging process, essentially stopping it cold.
When the symbiotic lifeform (vampire) killed a victim, by sending some of her own blood back into the victim, she could also sent some of the symbiotic blood as well, thus creating a new symbiotic vampire as the "spirit's" DNA then fused with that of the new victim.
In essence, Ms. Rice attempted to explain the existance of her vampires without using anything "supernatural" or "unexplained". The result was that the reader (and the charecters) had, even in the "world" of the novels, a basic framework of rules the creatures HAD to operate under.
The "spirit's" DNA was susceptible to the Sun's rays, for example, and if it was exposed, it would die, thus killing the creature. Fire, too, was fatal. However, physical wounds were not, as the symbiotic DNA acted to heal them even as they were made. Further, the creature would die if starved of blood.
The "spirit" DNA also adapted the host in ways to make it more survivable...in addition to the longeviety, it also cured the human diseases present, and altered the human's looks to a point where they were pleasing to look at, the better to hunt victims.
Given what we now know of how parasites and symbiotic lifeforms do business (e.g., altering their victims' body chemistry), it was a good job of coming up with an explanation, which is more than some writers had done up to that point. Ms Rice, it seems, spent as much time with a science journall or two as she did creating her stories.
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