New Ediacaran research (Introduction)

by David Turell , Monday, June 26, 2017, 23:43 (2498 days ago) @ David Turell

Very simple organisms not related to any organisms we know about. Could they possibly be mobile? No proof:

https://www.scientificamerican.com/article/reverse-engineering-mysterious-500-million-y...

"When large, complex fossils were discovered in the Ediacaran, researchers naturally expected that many of them would represent early relatives of the same animal groups that had been recognized in the Cambrian. But these Ediacarans seem completely distinct from modern animals.

"For instance, the rangeomorphs were a collection of leaf- and mat-like organisms with a unique fractal architecture, constructed from a series of branching “frond” elements, each a few centimeters long, each of which is itself composed of smaller, identical frond elements.

"Another – Tribrachidium – was a small hemispherical organism possessing three raised branches that meet at the top of the organism and which curved toward the margin in a counterclockwise direction.

"So how do oddballs like these fit in with what came before and what came after? We just haven’t been able to place them on any evolutionary tree.

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"We’ve abandoned all assumptions about what they might be related to, and instead tried to answer more fundamental questions. For instance, did they move? How did they feed? How did they reproduce? By answering these questions, we can begin to understand their biology and ecology, which in turn may provide hints as to how these organisms are related to other multicellular lifeforms.

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"With modern species, researchers can study fluid flows around living animals. But for organisms that have been extinct for over half a billion years—such as the Ediacara biota—virtual simulations using CFD are the only approach.

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"Our recent work with the enigmatic Ediacaran fossil Parvancorina is an example of this approach. Parvancorina is a simple-looking, shield-shaped organism typically 1-2 centimeters in length, with an anchor-like series of ridges on its top surface. Although it’s been interpreted in a variety of ways, most scientists have assumed that it was fixed on the seafloor—what we call sessile. No one has seen any limbs preserved withParvancorina and it’s never been found in association with fossilized tracks or trails.

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"We also used these simulations to calculate drag in different orientations. Although talking about front and back ends in Parvancorina is slightly problematic (because we can’t even tell whether it had anything resembling a head and tail), we usually think of the shield end as the front. We showed that the drag experienced by Parvancorina was typically lower when it was placed front-on to current, compared to when it was placed side-on. This is also bad news if you’re a sessile organism, because it leaves you open to being ripped from the sediment in strong currents.

"The inference from these two observations is clear: Parvancorina was better adapted to life as a mobile, rather than a sessile, organism.

One of the most important techniques at our disposal is computational fluid dynamics (CFD), a method for virtually simulating fluid flows around objects using computers.

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"The knowledge that it was mobile will help us work out where this fossil fits in the tree of life.

"Second, the inference that Parvancorina was mobile, but nonetheless left no trace of its movement, is important—it means that many other Ediacaran fossils that we’ve assumed were sessile may actually have been mobile as well. This may require us to reimagine Ediacaran ecosystems as much more dynamic and, by extension, much more complex than we previously thought."

Comment: Hope always springs eternal with Darwinist scientists. Make The very simple Ediacarans seem more complex and shrink the Cambrian Explosion Gap, the major point which is totally against the Darwin interpretation of gradual evolution. What this study shows is that the animal may prefer a specific orientation in relation to water flow, and settle on the bottom that way, nothing more. What the article makes quite clear is the Cambrians have no precursor.