Skip to comments.Finding an answer to Darwin’s Dilemma
Posted on 12/10/2006 5:29:49 PM PST by shrinkermd
Oxygen may be the clue to first appearance of large animals, says Queens prof
The sudden appearance of large animal fossils more than 500 million years ago a problem that perplexed even Charles Darwin and is commonly known as Darwins Dilemma may be due to a huge increase of oxygen in the worlds oceans, says Queens paleontologist Guy Narbonne, an expert in the early evolution of animals and their ecosystems.
In 2002, Dr. Narbonne and his research team found the worlds oldest complex life forms between layers of sandstone on the southeastern coast of Newfoundland. This pushed back the age of Earths earliest known complex life to more than 575 million years ago, soon after the melting of the massive snowball glaciers. New findings reported today shed light on why, after three billion years of mostly single-celled evolution, these large animals suddenly appeared in the fossil record.
In a paper published on-line in Science Express, Dr. Narbonnes team argues that a huge increase in oxygen following the Gaskiers Glaciation 580 million years ago corresponds with the first appearance of large animal fossils on the Avalon Peninsula in Newfoundland.
Now for the first time, geochemical studies have determined the oxygen levels in the worlds oceans at the time these sediments accumulated in Avalon. 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 worlds oceans, says Dr. Narbonne. Immediately after this ice age there is evidence for a huge increase in atmospheric oxygento at least 15 per cent of modern levels, and these sediments also contain evidence of the oldest large animal fossils.
Also on the research team are Don Canfield (University of Southern Denmark) and Simon Poulton (Newcastle University, U.K.). Geochemical studies by Drs. Canfield and Poulton included measurements of iron speciation and sulphur isotopes to determine the oxygen levels in the worlds oceans at the time these sediments accumulated in Avalon.
The close connection between the first appearance of oxygenated conditions in the worlds 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 say. They hypothesize 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 mobile bilateral animals, and ultimately to the Cambrian explosion of skeletal animals 542 million years ago.
God created through His Word.
Now everyone can sleep.
I bet these scientists believe maggots come from rotting meat.
It didn't say that oxygen creates life. Think when you read.
That is a very fruity statement, and it doesn't explain anything.
Life is change.
Exactly. "Sudden appearance of large fossils." Gee, I wonder how that could have happenned??? Oxygen, yeah right.
They'll never admit to even wondering if God created those large animals. Their secular world would crumble!
I wish I could be a fly on the wall when they figure out nothing in this universe is older than 10,000 years. Parking at church is going to be much harder!
Miasma theory is indisputable!
So melting glaciers caused an explosion in complex animal life-forms. It seems we are melting the remaining glaciers right now. So what complex life-forms come next?
This is a very significant hypothesis to explain the "Cambrian explosion" of biodiversity.
It is naturally a bit confusing to the scientifically illiterate, as some of the foregoing posts indicate.
The mention of the "iceball" refers to the idea that the late Precambrian was a time of almost worldwide glaciation. Then the ice melted. Through global warming. And humans were not even around. Al Gore, take note!
Free oxygen can only exist when there is no active molecule to bind it. This accounts for the extended period in which there was only single celled anaerobic bacteria in the oceans--there was an incredible amount of atmospheric iron that had to be fixed as iron oxide by the waste product of the bacteria, before oxygen could accumulate.
This resulted in a huge geological band of rust in much of the world. And when the iron was finally fixed, the percentage of oxygen in the atmosphere multiplied. And once there was enough oxygen in the atmosphere, oxygen levels in the oceans increased so much that bacteria had to evolve to live around it.
Now, this took place long before the events discussed in the article, but it took a vast amount of time.
OK Darwins dilemna is "the sudden appearance of large animal fossils". Fine, dilemnas happen.
Now we have a hypothesis that states that the level of O2 and nutrients increased dramatically at some point for some reason. OK fine there as well.
Darwinian evolution, RM/NS/heritability, posits small changes over long periods of time. So, I'll need somebody to help me out with how increases in O2 and nutrient levels explains "the sudden appearance of large animal fossils".
dilemna with two m's dumdum.
To geologists and paleontologists that work in the Precambrian, "sudden" means "over several million years."
It's even more confusing when you have the scientifically illiterate reading very short press releases about something that possibly took a decade of work and likely resulted in a 20 page detailed article in a scientific journal.
It's impossible to summarize these things and the work done by the scientists in these brief press releases, but there's a lot of people who have never read an actual scientific paper in their lives and get the impression that this is all there is.
I will get flamed by the Darwiniacs soon. Nothing heats them up more than when I saw, "I believe this because of the Word."
That said, the whole universe makes a lot more sense. Dinosaurs did not disappear. Some are still in the ocean. Stories of dragons from all over the world may just be the sightings of those leftover flying dinosaurs. Coast to Coast AM thinks the dinosaurs are still around in very remote parts.
I wonder where all that fossil fuel came from. Billions of animals died all at once. I wonder how. Maybe the global Flood which never happened? And all that coal.
I am struck by the disconnect between the physical data, what they call it, and how this data came into being. How could we have a 90 foot seam of coal when it takes 10 feet of leafy matter to make a 1 foot seam?
Rehwinkel's The Flood is good on this. Concordia Publishing House.
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