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Researchers ask, Was early animal evolution co-operative?

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File:DickinsoniaCostata.jpg
Dickinsonia (approx 635 to 542 mya)/Verisimilus

Re the Ediacaran period (before the Cambrian, 635–541 million years ago), from :

But what are these peculiar organisms? Their very strange morphology has made relating them to modern organisms very difficult, and they have been suggested to be related to anything from plants, fungi and lichens through to recognisable animals such as worms and arthropods.

In a major review of the Ediacaran fossils recently published in Biological Reviews, Graham Budd, professor of palaeobiology in Uppsala University, Sweden, and Sören Jensen, researcher at Badajoz University, Spain, suggest that most of the Ediacarans are very basal representatives of animal lineages, and as such are likely to reveal the hitherto very obscure pathways taken by animal evolution. This goes some way to explain why they happen to appear just before clearly recognisable animals do in the fossil record, and raises the question of what the ecological relationship between the two biotas is.

It’s been assumed that the mostly rather static Ediacarans block our view of mobile life forms that probably hid much of the time.

The new thesis suggests that the typical Ediacaran animals created an environment around them that enabled the more mobile creatures to evolve.

Rather than the Ediacarans and later animals being direct competitors then, the Ediacarans themselves created a permissive environment that was ideal for higher animals to evolve in. This idea fits well into a modern view of evolution, called “ecosytem engineering” whereby key species (such as beavers) influence the environment in order to create new evolutionary and diversity opportunities for other species. Perhaps then, the Ediacaran taxa weren’t impediments but the drivers of the evolution that was eventually to lead to all the rich animal diversity we see today. More.

A promising suggestion, though there are lots of questions it doesn’t answer.

See also: Animal with muscles found from 560 mya (Ediacaran period)

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Here’s the abstract:

The earliest evolution of the animals remains a taxing biological problem, as all extant clades are highly derived and the fossil record is not usually considered to be helpful. The rise of the bilaterian animals recorded in the fossil record, commonly known as the ‘Cambrian explosion’, is one of the most significant moments in evolutionary history, and was an event that transformed first marine and then terrestrial environments. We review the phylogeny of early animals and other opisthokonts, and the affinities of the earliest large complex fossils, the so-called ‘Ediacaran’ taxa. We conclude, based on a variety of lines of evidence, that their affinities most likely lie in various stem groups to large metazoan groupings; a new grouping, the Apoikozoa, is erected to encompass Metazoa and Choanoflagellata. The earliest reasonable fossil evidence for total-group bilaterians comes from undisputed complex trace fossils that are younger than about 560?Ma, and these diversify greatly as the Ediacaran–Cambrian boundary is crossed a few million years later. It is generally considered that as the bilaterians diversified after this time, their burrowing behaviour destroyed the cyanobacterial mat-dominated substrates that the enigmatic Ediacaran taxa were associated with, the so-called ‘Cambrian substrate revolution’, leading to the loss of almost all Ediacara-aspect diversity in the Cambrian. Why, though, did the energetically expensive and functionally complex burrowing mode of life so typical of later bilaterians arise? Here we propose a much more positive relationship between late-Ediacaran ecologies and the rise of the bilaterians, with the largely static Ediacaran taxa acting as points of concentration of organic matter both above and below the sediment surface. The breaking of the uniformity of organic carbon availability would have signalled a decisive shift away from the essentially static and monotonous earlier Ediacaran world into the dynamic and burrowing world of the Cambrian. The Ediacaran biota thus played an enabling role in bilaterian evolution similar to that proposed for the Savannah environment for human evolution and bipedality. Rather than being obliterated by the rise of the bilaterians, the subtle remnants of Ediacara-style taxa within the Cambrian suggest that they remained significant components of Phanerozoic communities, even though at some point their enabling role for bilaterian evolution was presumably taken over by bilaterians or other metazoans. Bilaterian evolution was thus an essentially benthic event that only later impacted the planktonic environment and the style of organic export to the sea floor. (Public access) – Graham E. Budd, Sören Jensen. The origin of the animals and a ‘Savannah’ hypothesis for early bilaterian evolution. Biological Reviews, 2015; DOI: 10.1111/brv.12239

5 Replies to “Researchers ask, Was early animal evolution co-operative?

  1. 1
    Mung says:

    some people believe that all evolution is cooperative because all life is cooperative.

  2. 2
    bornagain says:

    semi OT:

    Cooperating bacteria isolate cheaters – December 8, 2015
    Summary: Bacteria, which reciprocally exchange amino acids, stabilize their partnership on two-dimensional surfaces and limit the access of non-cooperating bacteria to exchanged nutrients. Scientists have shown that bacteria that do not contribute to metabolite production are excluded from the cooperative benefits. The researchers demonstrated that cooperative cross-feeders that grow on two-dimensional surfaces are protected from being exploited by non-cooperating bacteria.
    http://www.sciencedaily.com/re.....133443.htm

  3. 3
    bornagain says:

    OT:

    Quantum physics problem proved unsolvable: Godel and Turing enter quantum physics – December 9, 2015
    Excerpt: A mathematical problem underlying fundamental questions in particle and quantum physics is provably unsolvable,,,
    It is the first major problem in physics for which such a fundamental limitation could be proven. The findings are important because they show that even a perfect and complete description of the microscopic properties of a material is not enough to predict its macroscopic behaviour.,,,
    A small spectral gap – the energy needed to transfer an electron from a low-energy state to an excited state – is the central property of semiconductors. In a similar way, the spectral gap plays an important role for many other materials.,,,
    Using sophisticated mathematics, the authors proved that, even with a complete microscopic description of a quantum material, determining whether it has a spectral gap is, in fact, an undecidable question.,,,
    “We knew about the possibility of problems that are undecidable in principle since the works of Turing and Gödel in the 1930s,” added Co-author Professor Michael Wolf from Technical University of Munich. “So far, however, this only concerned the very abstract corners of theoretical computer science and mathematical logic. No one had seriously contemplated this as a possibility right in the heart of theoretical physics before. But our results change this picture. From a more philosophical perspective, they also challenge the reductionists’ point of view, as the insurmountable difficulty lies precisely in the derivation of macroscopic properties from a microscopic description.”
    http://phys.org/news/2015-12-q.....godel.html

  4. 4
    bornagain says:

    OT:

    Darwin’s Origin Is Voted Most “Influential,” but Here’s the Rest of the Story – Sarah Chaffee – December 9, 2015
    Excerpt: Asking whether a book has enabled further scientific discoveries seems like a reasonable criterion. Measured that way, contrary to what some have asserted, On the Origin of Species falls short. Judged for its heuristic value, evolutionary theory has had little impact on biology research or medical advancement. Even Jerry Coyne admits as much, writing in Nature:
    “If truth be told, evolution hasn’t yielded many practical or commercial benefits. Yes, bacteria evolve drug resistance, and yes, we must take countermeasures, but beyond that there is not much to say. Evolution cannot help us predict what new vaccines to manufacture because microbes evolve unpredictably. But hasn’t evolution helped guide animal and plant breeding? Not very much. Most improvement in crop plants and animals occurred long before we knew anything about evolution, and came about by people following the genetic principle of “like begets like.”
    http://www.evolutionnews.org/2.....01501.html

  5. 5
    mahuna says:

    Smells like Design to me: critters who later disappear without ANY descendants existed SOLELY to prep the landscape (and seascape)for the REAL lifeforms that would appear during the Cambrian Explosion?

    This would also tend to suggest that there was a fundamental DIFFERENCE between Early Life on Earth, and “Sustained” Life on Earth. That is, it reduces the likelihood that later life DESCENDED from the failed originals. Kinda like the Edsel…

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