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Oldest ancestor of all animals found

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  • Oldest ancestor of all animals found

    I do not believe this is the oldest ancestor of all animals, but it is the oldest found so far.

    Source: https://scitechdaily.com/ancestor-of-all-animals-including-humans-identified-in-australian-fossils/



    Ancestor of All Animals – Including Humans – Identified in Australian Fossils

    By UNIVERSITY OF CALIFORNIA - RIVERSIDE MARCH 23, 2020

    A wormlike creature that lived more than 555 million years ago is the earliest bilaterian.

    A team led by UC Riverside geologists has discovered the first ancestor on the family tree that contains most familiar animals today, including humans.

    The tiny, wormlike creature, named Ikaria wariootia, is the earliest bilaterian, or organism with a front and back, two symmetrical sides, and openings at either end connected by a gut. The paper is published today (March 23, 2020) in Proceedings of the National Academy of Sciences.

    The earliest multicellular organisms, such as sponges and algal mats, had variable shapes. Collectively known as the Ediacaran Biota, this group contains the oldest fossils of complex, multicellular organisms. However, most of these are not directly related to animals around today, including lily pad-shaped creatures known as Dickinsonia that lack basic features of most animals, such as a mouth or gut.

    Ikaria Impressions
    These are Ikaria wariootia impressions in stone. Credit: Droser Lab/UCR

    The development of bilateral symmetry was a critical step in the evolution of animal life, giving organisms the ability to move purposefully and a common, yet successful way to organize their bodies. A multitude of animals, from worms to insects to dinosaurs to humans, are organized around this same basic bilaterian body plan.

    Evolutionary biologists studying the genetics of modern animals predicted the oldest ancestor of all bilaterians would have been simple and small, with rudimentary sensory organs. Preserving and identifying the fossilized remains of such an animal was thought to be difficult, if not impossible.

    For 15 years, scientists agreed that fossilized burrows found in 555 million-year-old Ediacaran Period deposits in Nilpena, South Australia, were made by bilaterians. But there was no sign of the creature that made the burrows, leaving scientists with nothing but speculation.

    Scott Evans, a recent doctoral graduate from UC Riverside; and Mary Droser, a professor of geology, noticed miniscule, oval impressions near some of these burrows. With funding from a NASA exobiology grant, they used a three-dimensional laser scanner that revealed the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. The animal ranged between 2-7 millimeters long and about 1-2.5 millimeters wide, with the largest the size and shape of a grain of rice — just the right size to have made the burrows.

    Ikaria Laser Scan
    A 3D laser scan that showing the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. Credit: Droser Lab/UCR

    “We thought these animals should have existed during this interval, but always understood they would be difficult to recognize,” Evans said. “Once we had the 3D scans, we knew that we had made an important discovery.”

    The researchers, who include Ian Hughes of UC San Diego and James Gehling of the South Australia Museum, describe Ikaria wariootia, named to acknowledge the original custodians of the land. The genus name comes from Ikara, which means “meeting place” in the Adnyamathanha language. It’s the Adnyamathanha name for a grouping of mountains known in English as Wilpena Pound. The species name comes from Warioota Creek, which runs from the Flinders Ranges to Nilpena Station.

    “Burrows of Ikaria occur lower than anything else. It’s the oldest fossil we get with this type of complexity,” Droser said. “Dickinsonia and other big things were probably evolutionary dead ends. We knew that we also had lots of little things and thought these might have been the early bilaterians that we were looking for.”

    In spite of its relatively simple shape, Ikaria was complex compared to other fossils from this period. It burrowed in thin layers of well-oxygenated sand on the ocean floor in search of organic matter, indicating rudimentary sensory abilities. The depth and curvature of Ikaria represent clearly distinct front and rear ends, supporting the directed movement found in the burrows.

    The burrows also preserve crosswise, “V”-shaped ridges, suggesting Ikaria moved by contracting muscles across its body like a worm, known as peristaltic locomotion. Evidence of sediment displacement in the burrows and signs the organism fed on buried organic matter reveal Ikaria probably had a mouth, anus, and gut.

    “This is what evolutionary biologists predicted,” Droser said. “It’s really exciting that what we have found lines up so neatly with their prediction.”

    Reference: “Discovery of the oldest bilaterian from the Ediacaranof South Australia” by Scott D. Evans, Ian V. Hughes, James G. Gehlingc and Mary L. Drosera, March 2020, Proceedings of the National Academy of Sciences.

    © Copyright Original Source

    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  • #2
    Though Evolution News claims they are overstating their case:

    Source: Evolution News

    This does not mean that Ikaria could not be a potential bilaterian worm, but the case is far from established. Even if the attribution should turn out to be correct, the headlines — “Ancestor of all animals identified” — would be nonsense. Such hyperbole might be excused coming from ignorant popular science journalists, but that it was used in the official press release by the University of California is a shame. Nothing in this fossil discovery allows an identification as ancestor of any other group of animals or of all animals. Even being the oldest fossil record for Bilateria would not imply at all that it is ancestral to all animals. It could be an extinct side branch or only ancestral to a single phylum of worm-like animals. Evans et al. (2020) mention recent research that “suggests that the bilaterian LCA was a simple, small, mobile organism with anterior/posterior differentiation and limited sensory abilities (44–49). Remarkably, these predictions agree closely with the characters identified here for Ikaria.” However, such a simple worm-like habitus would fit with the ancestor of Bilateria, the ancestor of Xenacoelomorpha, the ancestor of Nephrozoa, the ancestors of Deuterostomia and of Protostomia, the ancestors of Lophotrochozoa and of Ecdysozoa, as well as the ancestors of several worm-like phyla like Platyhelminthes.

    Source

    © Copyright Original Source



    Blessings,
    Lee
    "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

    Comment


    • #3
      Originally posted by lee_merrill View Post
      Though Evolution News claims they are overstating their case:

      Source: Evolution News

      This does not mean that Ikaria could not be a potential bilaterian worm, but the case is far from established. Even if the attribution should turn out to be correct, the headlines — “Ancestor of all animals identified” — would be nonsense. Such hyperbole might be excused coming from ignorant popular science journalists, but that it was used in the official press release by the University of California is a shame. Nothing in this fossil discovery allows an identification as ancestor of any other group of animals or of all animals. Even being the oldest fossil record for Bilateria would not imply at all that it is ancestral to all animals. It could be an extinct side branch or only ancestral to a single phylum of worm-like animals. Evans et al. (2020) mention recent research that “suggests that the bilaterian LCA was a simple, small, mobile organism with anterior/posterior differentiation and limited sensory abilities (44–49). Remarkably, these predictions agree closely with the characters identified here for Ikaria.” However, such a simple worm-like habitus would fit with the ancestor of Bilateria, the ancestor of Xenacoelomorpha, the ancestor of Nephrozoa, the ancestors of Deuterostomia and of Protostomia, the ancestors of Lophotrochozoa and of Ecdysozoa, as well as the ancestors of several worm-like phyla like Platyhelminthes.

      Source

      © Copyright Original Source



      Blessings,
      Lee
      Typical of this Creationist rag no actual research nor peer reviewed literature supporting their claims. Actually it is using actual possible scenarios without understanding the basis of the evolution of early bilaterian worms as the root of the evolutionary diversification of the different diverse animals. This not the only evidence of the evolution of the diversification of later animals from early bilaterians,

      As I stated earlier in a post: "This is not necessarily the oldest bilaterian animal, but it is the oldest one presently found." The evidence does indicate that animals evolved and diversified from early bilaterians. The fossil evidence demonstrates the progressive increasing complexity and diversification of animal life from early bilaterian animals.
      Last edited by shunyadragon; 04-01-2020, 03:57 PM.
      Glendower: I can call spirits from the vasty deep.
      Hotspur: Why, so can I, or so can any man;
      But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

      go with the flow the river knows . . .

      Frank

      I do not know, therefore everything is in pencil.

      Comment

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