Posted tagged ‘Ediacaran’

Grape-sized protists make tracks

November 20, 2008

 I think this is great, macroscopic single-celled organisms making tracks that can be confused with multicellular organisms:

DNA analysis confirmed that the giant protist found by Matz and his colleagues in the Bahamas is Gromia sphaerica, a species previously known only from the Arabian Sea.

They did not observe the giant protists in action, and Matz says they likely move very slowly. The sediments on the ocean floor at their particular location are very stable and there is no current—perfect conditions for the preservation of tracks.

Matz says the protists probably move by sending leg-like extensions, called pseudopodia, out of their cells in all directions. The pseudopodia then grab onto mud in one direction and the organism rolls that way, leaving a track.

He aims to return to the location in the future to observe their movement and investigate other tracks in the area.

Matz says the giant protists’ bubble-like body design is probably one of the planet’s oldest macroscopic body designs, which may have existed for 1.8 billion years.

“Our guys may be the ultimate living fossils of the macroscopic world,” he says.

Discovery Of Giant Roaming Deep Sea Protist Provides New Perspective On Animal Evolution

The above excerpt suggests that these organisms are not in fact entirely new, but I wasn’t aware of such huge protists before this. It does indicate that evolution has more than one way to make larger organisms, although it does not seem likely that they would ever evolve into the many forms that multi-celled animals have.

Other than that, it appears that at least many Precambrian tracks are put into doubt by this, since multicellular organisms aren’t necessary to leave tracks behind. What is confusing is that the article implies that there may have been no multicellularity, and then there was a “Cambrian explosion”–ignoring the fact that there was an “Ediacaran explosion” before the Cambrian began.

Still, it could mean that the Ediacaran (presumably) multicellular organisms have no known precursors, and it’s still a good question whether or not any Ediacaran organisms left descendents. The appearance of multicellular life is not as mysterious as the anti-evolutionists pretend, but it continues to leave a lot of questions to be answered.

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Ediacaran reef yields new organisms

September 22, 2008

This is more of a heads up, because the details have yet to be released.  Nonetheless, it is almost certainly one of the most important paleontological finds of recent years.  Here’s an excerpt:

The reef is about 650 million years old and is the only known reef complex of this age anywhere in the world. The next closest aged series of reefs found to-date are around 800 million years old and located in Arctic Canada.

And while they are yet to confirm it scientifically, the scientists – Mr Jonathan Giddings, Associate Professor Malcolm Wallace and Ms Estee Woon from the School of Earth Sciences at the University of Melbourne – believe that peculiar fossils of possible multi-cellular organisms found in the reef could be the earliest examples of primitive animal life discovered to-date.

And a bit further down:

It is a particularly intriguing period because it also coincided with the sudden and widespread appearance of very early primitive lifeforms.

“This reef is an internationally significant discovery because it provides a significant step forward in showing the extent of climate change in Earth’s past and the evolution of ancient reef complexes – and it also contains fossils which may be of the earliest known primitive animals” Mr Giddings said.

“There is a good chance that the new fossils and organisms found in the reef will provide significant insight into the evolution of early multi-cellular life. It could prove that life took more complex forms much earlier in history than we previously thought.

News source

Of course this will be significant primarily for the scientific knowledge it produces.  But it again emphasizes the fact that the Cambrian is not the “creation event” that the IDists want it to be. 

Anyway, we should know more on September 25, when the facts are presented.