Free Republic
Browse · Search
News/Activism
Topics · Post Article

Skip to comments.

Life's lucky 'kick start'
BBC News ^ | October 13, 2003 | Dr David Whitehouse

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.


TOPICS: Culture/Society; News/Current Events
KEYWORDS: biology; crevolist; evolution; origins
Navigation: use the links below to view more comments.
first previous 1-20 ... 241-260261-280281-300301-314 next last
To: PatrickHenry; <1/1,000,000th%; Alamo-Girl
Now flying fish... there's an interesting theoretical future cladogram.

Fish begat reptiles begat birds, so the path has occurred before. Not sure it could happen without the intermediate step of the reptiles, but why not?

the question is whether there would be sufficient pressures on the population of flying fish to warrant such an evolutionary path, and i can't quite think of any. Maybe is global warming exists, ocean temps do change several degrees, which increases flying fish predation...

... ahh, I could do this all day.
261 posted on 10/17/2003 11:40:59 AM PDT by whattajoke (Neutiquam erro.)
[ Post Reply | Private Reply | To 260 | View Replies]

To: whattajoke
walking catfish. Living, breathing transitional species.
262 posted on 10/17/2003 11:45:24 AM PDT by PatrickHenry
[ Post Reply | Private Reply | To 261 | View Replies]

To: Alamo-Girl; Doctor Stochastic
See above, for some potentially new body plans. Evolution never sleeps!
263 posted on 10/17/2003 11:49:48 AM PDT by PatrickHenry
[ Post Reply | Private Reply | To 262 | View Replies]

To: Alamo-Girl
Finally, if the real cause for so few new body plans (2 or 3) is that the Cambrian explosion gave us development control genes – then I’m still in a quandary as to why such an event has not since recurred, unless of course the regulatory control genes are self-correcting to avoid those kinds of adaptations.

I suspect that the events that took place before the Cambrian were unique. History doesn't exactly repeat itself. Time doesn't move backwards.

264 posted on 10/17/2003 2:34:49 PM PDT by Nebullis
[ Post Reply | Private Reply | To 245 | View Replies]

To: whattajoke
I'm no nerd. I am, however, an Alpha Geek.
265 posted on 10/17/2003 2:50:08 PM PDT by Junior (Kinky is using a feather. Sick is using the whole chicken.)
[ Post Reply | Private Reply | To 242 | View Replies]

To: Alamo-Girl
AG, this is a pretty good review of HOX, all the way from single celled organisms to vertebrates.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=18260

There is, in fact a good deal of HOX gene diversity arising after the Cambrian. The vertebrate lineage in general has multiple HOX clusters which arose by gene duplication; thoise of fishes are quite different from mice and humans.

266 posted on 10/17/2003 2:52:56 PM PDT by Right Wing Professor
[ Post Reply | Private Reply | To 258 | View Replies]

To: AntiGuv
"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.

Using a computer model....

Some more evo 'fact free science'. They do not know what the earth was like before, during or after, so that's good, because it makes any nonsense they say possible.

Jeech, can't these people get a real job?

267 posted on 10/17/2003 7:17:55 PM PDT by gore3000 ("To say dogs, mice, and humans are all products of slime plus time is a mystery religion.")
[ Post Reply | Private Reply | To 1 | View Replies]

To: <1/1,000,000th%
Science is about evidence.

Yes indeed, and this article is not science, it is fantasy. The fact is that there is absolutely no way that gradual Darwinian evolution can explain the humongous variety of living things which appeared within the short span of less than ten million years or why no new animal living forms have arisen since. The Cambrian completely disproves Darwinian evolution, Gould and Eldredge thought so and no Darwinist has ever been able to refute it or give evidence for the gradual evolution of the Cambrian fauna.

268 posted on 10/17/2003 7:24:35 PM PDT by gore3000 ("To say dogs, mice, and humans are all products of slime plus time is a mystery religion.")
[ Post Reply | Private Reply | To 65 | View Replies]

To: <1/1,000,000th%
LOLOL! Thanks for the chuckle!
269 posted on 10/17/2003 7:52:17 PM PDT by Alamo-Girl
[ Post Reply | Private Reply | To 259 | View Replies]

To: PatrickHenry; whattajoke
Thank you for the examples of body plans in transition! I really appreciate it, however I wonder if any such change would be considered a new body plan or another species?
270 posted on 10/17/2003 7:54:59 PM PDT by Alamo-Girl
[ Post Reply | Private Reply | To 263 | View Replies]

To: Nebullis
Thank you so much for your reply!

Indeed, "time doesn't move backwards" from our 4D perception, but dimensionality is a whole 'nother subject.

Do you have a preferred view of what the special Pre-Cambrian conditions might have been?

271 posted on 10/17/2003 7:58:21 PM PDT by Alamo-Girl
[ Post Reply | Private Reply | To 264 | View Replies]

To: Right Wing Professor
Thank you so much for the url! I will read that and the others which have been brought to the table sometime over the weekend. I have company and thus my research time is limited. (sniff...)
272 posted on 10/17/2003 8:00:36 PM PDT by Alamo-Girl
[ Post Reply | Private Reply | To 266 | View Replies]

To: Question_Assumptions
"Wow! The author managed to write that article without mentioning Global Warming even once."

Or God.

273 posted on 10/17/2003 8:34:04 PM PDT by MissAmericanPie
[ Post Reply | Private Reply | To 4 | View Replies]

To: gore3000
The Cambrian completely disproves Darwinian evolution,

Sequoit 7 <<<<< 47 q36, b17ssd18.

n5 6b 22 j3.

274 posted on 10/17/2003 9:00:55 PM PDT by <1/1,000,000th%
[ Post Reply | Private Reply | To 268 | View Replies]

This-is-the-voice-of-world-control PLACEMARKER.
275 posted on 10/18/2003 12:16:17 AM PDT by jennyp (http://crevo.bestmessageboard.com)
[ Post Reply | Private Reply | To 274 | View Replies]

To: AntiGuv
So, what horribly-mutated branch of this Tree of Life resulted in the creation of government parasites?
276 posted on 10/18/2003 12:34:28 AM PDT by Hank Rearden (Dick Gephardt. Before he dicks you.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Alamo-Girl
I wonder if any such change would be considered a new body plan or another species?

A lot of the professional disagreements in this business are about just such issues.

277 posted on 10/18/2003 4:32:44 AM PDT by PatrickHenry
[ Post Reply | Private Reply | To 270 | View Replies]

To: PatrickHenry; Alamo-Girl
A lot of the professional disagreements in this business are about just such issues.

Exactly. And one of the "debates" is actually even more far-reaching. That is, whether trying to guess where evolution will lead is even beneficial or not. I come from the school of population dynamics, where future-casting is commonplace. But that's predicting outcomes of pressures upon populations and how it will affect lifespans and/or densities. When I was doing my thesis, we were careful to discern the difference between, "species x will become species y" and "species x will become a differently selected species x."

Predicting a million years hence is fun, to be sure, but not really beneficial to a greater knowledge. Zoologist Peter Ward published a mass market book on "The future of evolution" a few years ago. But notice; he went straight to a publishing house and skipped that persnickity peer review process. He was having fun, as we are here. (Although, IIRC, it was all rather doom and gloom).

Simply put, as long as there is no need for new body plans, there won't be any new body plans. So the next step is to think about what would cause a need for new body plans. AG, I'd wager you could write up a pretty cool essay parsing your beliefs from the book of Revelation, combining your idea for what the post-Christ's-return environment would look like, think about the new environmental pressures, and go from there. Another world-wide flood? Increased temperatures? Increased volcanism?

The world is your (giant flying) oyster. ; )
278 posted on 10/18/2003 9:15:35 AM PDT by whattajoke (Neutiquam erro.)
[ Post Reply | Private Reply | To 277 | View Replies]

To: whattajoke
... trying to guess where evolution will lead ...

Difficult, if not impossible, because we don't really know how the environment will change (except in the very long term, when everything dies). The best I could do is predict that as the environment changes, any life that survives will -- of necessity -- be adapted to the conditions in that changed environment. That's not much of a prediction, but it's consistent with the theory of evolution.

279 posted on 10/18/2003 9:24:50 AM PDT by PatrickHenry
[ Post Reply | Private Reply | To 278 | View Replies]

To: whattajoke; Alamo-Girl; gore3000; Ogmios
What about vampires? Their bats that became humans, or their humans that became bats. Their a new life form.
280 posted on 10/18/2003 3:42:31 PM PDT by JethroHathAWay (without the cape I would not be able to fly.)
[ Post Reply | Private Reply | To 256 | View Replies]


Navigation: use the links below to view more comments.
first previous 1-20 ... 241-260261-280281-300301-314 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
News/Activism
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson