Intelligent Design Film to Premiere at Sam Noble Oklahoma Museum of Natural History Sept. 29

SYDNEY: The sudden appearance of large animals more than 500 million years ago may be due to a huge increase of oxygen in the world's oceans, according to Canadian researchers.

The mystifying, abrupt appearance of large animals, known as 'Darwin's Dilemma', is a problem that has perplexed scientists right back to Charles Darwin himself, said the study's lead author, Guy Narbonne, a palaeontologist at Queen's University in Ontario.

Geochemical studies have determined the oxygen levels in the world's oceans at the time ancient sediments at Avalon, on the coast of Newfoundland, were laid down.

"Our studies show that the oldest sediments on the Avalon Peninsula, which completely lack animal fossils, were deposited during a time when there was little or no free oxygen in the world's oceans," says Narbonne. "Immediately after this ice age there is evidence for a huge increase in atmospheric oxygen to at least 15 per cent of modern levels, and these sediments also contain evidence of the oldest large animal fossils."

The research analysed sediments found in 2002 by Narbonne and his research team that contained fossilised 575 million-year-old complex life forms sandwiched between layers of sandstone. Their find pushed back the age of Earth's earliest known complex life to soon after the melting of the "snowball" glaciers of the massive Gaskiers Glaciation 580 million years ago.

In a paper published online in Science Express, Narbonne's team argued that the huge increase in oxygen following the Gaskiers Glaciation corresponds with the first appearance of large animal fossils on the Avalon Peninsula in Newfoundland.

The findings shed light on why, after three billion years of mostly single-celled evolution, these large animals suddenly appeared in the fossil record.

Geochemical studies by the team included measurements of iron and sulphur to determine the oxygen levels in the world's oceans at the time these sediments accumulated in Avalon.

The close connection between the first appearance of oxygenated conditions in the world's oceans and the first appearance of large animal fossils confirms the importance of oxygen as a trigger for the early evolution of animals, the researchers said.

They suggested that melting glaciers increased the amount of nutrients in the ocean and led to a proliferation of single-celled organisms that liberated oxygen through photosynthesis. This began an evolutionary radiation that led to complex communities of filter-feeding animals, then complex mobile animals, and ultimately to the Cambrian 'explosion' of skeletal animals 542 million years ago.

http://www.cosmosmagazine.com/news/915/darwin...

Neat...

And I'm no chemist, but a change in ocean chemistry at about the same time may have allowed the evolution of calcium carbonate "hard parts"... sea shells:)

FossilBob wrote:

Neat...
And I'm no chemist, but a change in ocean chemistry at about the same time may have allowed the evolution of calcium carbonate "hard parts"... sea shells:)

Thanks, Bob.

My post (above) was actually meant to refute that which was being suggested in the headline story.

But yeah, it IS a neat story! Thanks!

Kong_ wrote:

<quoted text>
Thanks, Bob.
My post (above) was actually meant to refute that which was being suggested in the headline story.
But yeah, it IS a neat story! Thanks!

Yes... and I was referring to YOUR post, but forgot to hit the reply button:)

It just goes to show you: hillbilly is a state of mind.

The Sam Nobel Museum is opening its doors to the public for free the day of the movie showing, and will be featuring its evolution exhibits. It is also giving a free lecture on the Cambrian Explosion following the movie.

Also Abbie Smith (aka ERV) is going to be at the museum to answer questions. She is particularly disgusted with Jonathan Wells, who denies both aspects of her graduate studies...HIV evolution.

From ERV's blog...

http://scienceblogs.com/erv/2009/09/no_but_it...

Darwins Stepchild wrote:

The Sam Nobel Museum is opening its doors to the public for free the day of the movie showing, and will be featuring its evolution exhibits. It is also giving a free lecture on the Cambrian Explosion following the movie.
Also Abbie Smith (aka ERV) is going to be at the museum to answer questions. She is particularly disgusted with Jonathan Wells, who denies both aspects of her graduate studies...HIV evolution.

I could 'ride the dog' for one third the airfare and three hours quicker but would have to spend two nights in OKC.
Maybe DI has some hotel discounts for the curious .