Fossil Discovery Shakes Up Evolutionary Theories
Conventional wisdom has it that the first animals evolved in the ocean.
Now researchers studying ancient rock samples in South China have found that the first animal fossils are preserved in ancient lake deposits, not in marine sediments as commonly assumed.
These new findings not only raise questions as to where the earliest animals were living, but what factors drove animals to evolve in t
More..he first place.
For some 3 billion years, single-celled life forms such as bacteria dominated the planet. Then, roughly 600 million years ago, the first multi-cellular animals appeared on the scene, diversifying rapidly.
The oldest known animal fossils in the world are preserved in South China's Doushantuo Formation. These fossil beds have no adult specimens - instead, many of the fossils appear to be microscopic embryos.
"Our first unusual finding in this region was the abundance of a clay mineral called smectite," said researcher Tom Bristow, now at the California Institute of Technology in Pasadena. "In rocks of this age, smectite is normally transformed into other types of clay. The smectite in these South China rocks, however, underwent no such transformation and have a special chemistry that, for the smectite to form, requires specific conditions in the water - conditions commonly found in salty, alkaline lakes."
The researchers collected hundreds of rock samples from several locations in South China. All their analyses suggest these rocks were not marine sediments.
"Moreover, we found smectite in only some locations in South China, and not uniformly as one would expect for marine deposits," Bristow said. "Taken together, several lines of evidence indicated to us that these early animals lived in a lake environment."
This discovery raises questions as to how and why animals appeared when they did.
"It is most unexpected that these first fossils do not come from marine sediments," said researcher Martin Kennedy, a geologist at the University of California at Riverside.
"Lakes are typically short-lived features on the Earth's surface, and they are not nearly as consistent environments as oceans are," he explained. "So it's surprising that the first evidence of animals we find is associated with lakes, which are far more variable environments than the ocean. You'd expect the first appearance of animals to be in the most conservative, stable environments we could imagine."
It remains possible, Kennedy noted, that animal fossils of similar or older age exist that remain to be found that are marine in origin. However, at the very least, this work suggests "that animals had already taken on the ability to deal with the environmental fluctuations one sees in lake environments," he said. "That suggests that their evolutionary response is much more rapid that I would have supposed, and that the earliest animals were far more diverse than imagined."
If animals did first develop in lakes, one aspect of lake environments that could have spurred on their evolution is how much easier it is for air to percolate through them, given how much shallower they typically are than the ocean.
"The most popular explanation for the evolution of animals has to do with the increase in oxygen in Earth's atmosphere at that time," Kennedy told LiveScience. "It's possible that lakes were the first to benefit from that increase in oxygen."
TIME TO CHANGE THE SCIENCE BOOKS, AGAIN.. -Maxisminion Less..
Added: Jul 28 2009 In: education
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Comments - sort by newest to oldest
Makes sense to me. I would imagine that life first arose in a puddle because the components for life would need to stay in close proximity to each other. If it was in the sea they would just drift apart.
I would think that life would need to stay in a confined space until a membrane was formed.
The beauty of science is that it is self correcting and accepts new evidence as it arrives. If science was a finished product why would there still be any scientists?
My 2 cents.
Posted Jul-28-2009 by "Epidope" (R)
oh dear..... creationists are going to have a field say with this
Posted Jul-28-2009 by "XxGaLoSxX" (R)
"DAY"
Posted Jul-28-2009 by "XxGaLoSxX" (R)
I dont give a **** how we came about. I just know that them ****ers had no TV and beer, I do. And it is more important to know were we are going then were we came from.
Posted Jul-28-2009 by "acidcasual" (R)
Your optimism has no place in this world. Good point, though.
Posted Jul-28-2009 by "tpwdct" (R)
LMAO at the darwin fags!
Posted Jul-28-2009 by "Rob1984" (B)
Is that a band?
Posted Jul-28-2009 by "PH-DEE" (R)
"For some 3 billion years, single-celled life forms such as bacteria dominated the planet"
this does not bode well for creationist in the least... it's only more evidence of science and it's propensity to get to the facts before darting off into fantasy like so many lazy thinkers....
Posted Jul-28-2009 by "chartsky" (R)
This posting deals with abiogenesis , not evolution .There are many ideas on the hows and whys of how and where life first formed . Ocean , lake , swamp , small puddle , it is an interesting but unimportant point to the overall theory .
Posted Jul-28-2009 by "ComradeAgopian" (R)
I think we should cut poor scientists some slack. Trying to pull 3 billion years' worth of fiction out of your arse in no easy task.
Posted Jul-28-2009 by "XAMOMH^I" (R)
one thing is very common in science theories..THEY KEEP ON CHANGING
Posted Jul-28-2009 by "detonati" (R)
Not exactly a "debunking" of evolution. There's not a whole lot of difference between a briney lake and the saltwater of the sea. This link - salty water - has long been thought to be the origins of life on earth, so if anything, it confirms that life starts as a result of ideal chemical conditions in an aquatic environment, not an old man sitting on a cloud in the sky.
Also worth pointing out that they mention the age of these fossil beds being somewhere near 600 million years old goes against the Creationist assertion that the Earth is only 10,000 years old.
Posted Jul-28-2009 by "picklethepug" (R)
Meanwhile religion stays the same, NO MATTER WHAT! The extremists even go as far as threatening and or killing people who beg to differ with the established religion.
Do me a favor and look up "faith" and compare it to "delusion"...
Posted Jul-28-2009 by "Epidope" (R)
why is amniotic fluid basically seawater? hmmmm, better not use my brain this one cuz my evolution is being "shaken up" right now
Posted Jul-28-2009 by "Poster101" (R)
yeah thats the way science works, it takes evidence from reality, and bases theories on it, it doesnt take blind magic at face value.
Posted Jul-28-2009 by "bacon" (R)