posted on Dec, 13 2012 @ 06:38 AM
A study published in the prestigious scientific journal Nature has some scientists up in arms. According to
the article suggests that life may have
emerged on land 100 million years earlier than previously thought.
The reason for this change in thinking? Meet Dickinsonia costata
, first thought to be an ancestor of a jellyfish-like creature or a sea pen.
The study, published today (Dec. 12) in the journal Nature, suggests that ancient fossilized creatures found in Southern Australian sediments actually
came from land, not from the ocean. If the findings are true, the fossils would have been lichenlike plants that first colonized land, not
ocean-dwelling ancestors of jellyfish.
Scientists first discovered the fossils in 1947 in the Ediacaran Hills of Southern Australia. The reddish rocks contained imprints from a strange,
striated creature called Dickinsonia, as well as other primeval creatures that lived around 550 million years ago. (Extreme Life on Earth: 8 Bizarre
Until now, scientists had long believed the rocks were made up of ocean sediments and that Dickinsonia and other primeval creatures fossilized in the
outcroppings were sea dwellers similar to jellyfish or sea pens that lived just before the Cambrian explosion began about 540 million years ago, when
all the major animal groups suddenly appeared.
But when Retallack first saw the fossils, he wondered whether they were formed on land. In particular, the fossils had a reddish hue that comes from
oxygen in the atmosphere reacting with iron to create rust -- a process that doesn't happen under the sea, he said. He also noticed that nodules
throughout the rock looked strikingly similar to the rootlike structures put out by primitive lichen or fungi found in other ancient soils.
To see if some of the Ediacaran fossils were land-dwellers, he tested the rock's composition and found it was characteristic of the very first stages
of soil formation on land, in which nutrients such as potassium and magnesium are depleted. A similar process doesn't happen in the ocean, he said.
Not everyone agrees with the idea, of course. And just because the article is published in Nature does not prove it, although it will be interesting
to see the peer reviews. But this is interesting, nevertheless, and I thought my friends at ATS might enjoy it as much as I did.
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edit on 13/12/2012 by ArMaP because: (no reason given)