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Earth Science

Ancestor of All Placental Mammals Revealed 123

Posted by samzenpus
from the back-in-the-day dept.
sciencehabit writes "The ancestor of all placental mammals—the diverse lineage that includes almost all species of mammals living today, including humans—was a tiny, furry-tailed creature that evolved shortly after the dinosaurs disappeared, a new study suggests. The hypothetical creature, not found in the fossil record but inferred from it, probably was a tree-climbing, insect-eating mammal that weighed between 6 and 245 grams—somewhere between a small shrew and a mid-sized rat. It was furry, had a long tail, gave birth to a single young, and had a complex brain with a large lobe for interpreting smells and a corpus callosum, the bundle of nerve fibers that connects the left and right hemispheres of the brain. The period following the dinosaur die-offs could be considered a 'big bang' of mammalian diversification, with species representing as many as 10 major groups of placentals appearing within a 200,000-year interval."
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Ancestor of All Placental Mammals Revealed

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  • by Anonymous Coward

    Just sayin'.

  • by Frosty Piss (770223) * on Thursday February 07, 2013 @08:28PM (#42827781)

    A *POSSIBLE* ancestor that a study suggests *MIGHT* be what they thing. Maybe. Possibly.

    In other words, the headline is, as usual, misleading.

    • by Anonymous Coward on Thursday February 07, 2013 @08:34PM (#42827823)

      Here's what may have happened [youtube.com] to the little guy...

      • That is fucking hilarious.
      • by DarkOx (621550)

        Well you gota look at it like this. The hawk has to eat too, and while things did not work out so well for the mouse his alternative like fate was not better for him. I mean he would have died slowly having one or more of his limbs crushed in trap. After which he would have been buried so deep in a landfill lack of oxygen would likely even prevent most microbes from making use of him for decades.

        It might not have gone how the guy hoped but he still better served nature.

    • by Theovon (109752) on Thursday February 07, 2013 @08:39PM (#42827857)

      I guess you might say they interpolated what a likely ancestor was probably like.

    • Re: (Score:2, Insightful)

      by gewalker (57809)

      How is the different than anything else in evolutionary theory. No actual observational science, a couple of fossils here and there, no soft tissue to examine. Then bang, an possible/probable ancestral relationship is declared by somebody -- often discarded later due to other discoveries. It is what it is and will always be unless you manage to make a time machine.

      • It's a single study stated as fact.

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          How does the phrase "..., a new study suggests." qualify as an assertion of fact?

        • by ByOhTek (1181381)

          "The hypothetical creature, not found in the fossil record but inferred from it, probably was " doesn't sound very much like 'stated as a fact' to me. TFT might be misleading but beyond that, the appropriate care in phrasing seems to be in use.

          • No, but it is designed to illicit recitation as fact later. In very short order, you will have "scientists" who state "All Mamals evolved from a single rodent" as a fact, and it will be place in Textbooks as a "fact" and so on. The fact that in the original source it is clearly hypothetical bullshit is irrelevant. Shit like this should NEVER be published as "science". It isn't "science" ... yet.

      • Re: (Score:3, Informative)

        by Anonymous Coward

        We're starting to sequence the genomes and map species after species at an accelerating rate. Within the century we'll have a gene-by-gene map of the ancestry of most of the biosphere.

      • by dudpixel (1429789) on Thursday February 07, 2013 @09:18PM (#42828153)

        The genome project offers a fair bit more credibility than this, and it's more than "a couple" of fossils here and there.

        No one's saying it is all indisputable fact (science doesn't deal with facts) but to date no other theory has been put forward that can offer a better explanation of all the known data.

        That's how science works...so until a more plausible theory shows up, evolution is where we are at.

        As for this study, yeah there's a bit too much uncertainty for it to be much more than an opinion piece.

        • by dbug78 (151961) on Thursday February 07, 2013 @09:29PM (#42828229)

          science doesn't deal with facts

          Uh, what? Facts are the foundation of science. If science has any issue with facts it's that Joe Sixpack thinks the hierarchy is...

          Hypothesis -> Theory -> Facts

          In actuality, it's...

          Facts -> Hypothesis -> Theory

          Hypotheses and theories are built on facts. Maybe you meant science doesn't deal with proof?

          • by Anonymous Coward

            The problem with calling observations "facts" is that it can obscure a good deal of observational bias and measurement error. Its more tenable all around to just go with "data" or "observations".

          • by dudpixel (1429789)

            Correct - but I was talking about the Joe Sixpack definition, which as you pointed out, equals 'proof'.

            Thanks for the correction :-)

          • Maybe you meant science doesn't deal with proof?

            It's seems obvious to me that is what he meant, it also seems obvious to me you meant "observations" not "facts". A "fact" is an absolute truth only within an axiomatic system, science is not an axiomatic system. A "scientific fact" is a rigously tested theory that has no known conflict with observation.

            In actuality, it's...

            Observation -> Hypothesis -> Theory--> Test---> Scientific fact.
            - Feedback loops not shown.

            • Observation -> Hypothesis -> Theory--> Test---> Scientific fact.

              I'd only add:

              Observation -> Hypothesis -> Theory -> Predictions -> Test -> Scientific fact.

              • by guruevi (827432)

                It's really:

                Observation -> Hypothesis -> Predictions -> Test -> Observation -> Scientific Theory (-> Scientific Fact).

                Most things in science are Theories - they are the best possible explanation for what we have observed in a verifiable test. Scientific facts are either necessarily vague or very dependent on space and time. There is also the Mathematical Proof in exact sciences.

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          to date no other theory has been put forward that can offer a better explanation of all the known data.

          That's how science works...so until a more plausible theory shows up, evolution is where we are at.

          That's actually false. The Flying Spaghetti Monster and Catholic Christian religions both have equally good or better explanations, that amount to "God plays little tricks on ya, for yer own damn good!". If you posit that an omnipotent deity exists, then nothing else is really provable scientifically, unle

      • talkorigins.org

        Or if that's too hard for you, I'll just call you an ignoramus.

        Any other subjects you know fuck all about you want to make sweeping declarations about?

      • How is the different than anything else in evolutionary theory. No actual observational science, a couple of fossils here and there, no soft tissue to examine. Then bang, an possible/probable ancestral relationship is declared by somebody -- often discarded later due to other discoveries. It is what it is and will always be unless you manage to make a time machine.

        An enormous catalogue of fossil history, geo distribution of species also provides massive evidence especially in recently observable separators such as archipelagos, the bounty genetic evidence, the ability to recreate observable evolution in our timescale on the bacterial level and our ability to force changes through selective breeding all combine to provide an irrefutable level of evidence. Each of these fields could also be used to disprove evolution if not for the fact that no reliable evidence contr

        • by Empiric (675968)

          Depends on your definition of "evolution". If you mean "random mutation and natural selection", or a more-recent, nuanced version on that, there is not only extensive evidence against that as a sole causal factor, it is provably not the case.

          How do we know design is a factor when speaking to the scope of biological organisms, and provably so? Because we did it ourselves, through genetic engineering.

          I understand you likely don't accept that genetic engineering -also- happened previous to the 20'th century,

          • ..... your notion of "evolution" is not merely of an indeterminate scientific status, it is provably false.

            Interesting... so go ahead and disprove it. Please provide hard, testable or otherwise provable facts and not mere goofy wordplay. Are we talking proof such as finding large mammalian fossils in Ordovician or even pre Cambrian rock strata? That would do it. Or perhaps when you assert things like pre 20th century genetic engineering. Are you going to produce fingerprint signatures left behind by genetic engineers on existing modern animals? I'm eagerly awaiting the inevitable disappointment?

            • by Empiric (675968)

              As stated, if your notion of "evolution" is as a scientific theory explaining all physical characteristics of biology, a set which includes organisms after 1951, it is directly false as a theory.

              And regarding fingerprints and such, no, that would be a test of a -limited subset- of biology, irrelevant to a statement about evolution that is intended to apply (as most scientific theories attempt) to -all- biology, and I already stated my position on that subset is that it is untestable. We are at a point much

              • As stated, if your notion of "evolution" is as a scientific theory explaining all physical characteristics of biology, a set which includes organisms after 1951, it is directly false as a theory.

                Citation needed. So the overwhelming concensus of the worldwide community based on an undeniable array of evidence is false because of what... I'm still waiting for something with some form of refutation and not just gassy wordplay.

                .... I already stated my position on that subset is that it is untestable.

                With respect to your design argument for which you refuse to provide a shred of evidence.... “That which can be asserted without evidence, can be dismissed without evidence.” – Christopher Hitchens.

                We are at a point much like the situation regarding the Copenhagen and Everett interpretations of quantum mechanics--which is "true" is indeterminate as the same observables support either interpretation, and there is no presently test by which to demonstrate one correct "versus" the other.

                Using fancy words to try to describe the situation as an

      • by ByOhTek (1181381)

        Actually, it is, in a way, an observational science.

        You can observe changes of allele frequencies and phenotype frequencies in a population over time, and they do.

        Also, as the TFS (and I'm assuming TFA) says "The hypothetical creature", not theoretical, not definitive, hypothentical. Evolutionary science makes it clear that all cladograms are hypothesis, if you bother looking at it from more than a surface level.

        As for observation and predictability - it's hard to make predictions with evolution, but it has

    • There is this video from discovery channel which shows the hypothetical furry creature as one of evolutionary steps to mankind, I personally find it interesting:

      http://www.youtube.com/watch?v=HwxCnV2PL2k [youtube.com]

    • by kwyjibo87 (2792329) on Thursday February 07, 2013 @10:28PM (#42828607)

      Well, yes, the headline is misleading, but it's also a bit more than a "possible" ancestor.

      The researchers in the study wanted to create a better phylogenetic reconstruction of the evolution of mammals than had been previously accomplished, to resolve whether divergence of placental mammals from non-plancental mammals (egg-laying / marsupials) occurred before or after the extinction of the Dinosaurs (the K-T boundary), and also to make predictions of the biology of that last common ancestor. Previous phylogenetic reconstructions had been done with molecular data (DNA or protein sequences), but molecular data is limited to extant species and makes a lot of assumptions about the rates of changes in DNA that get more unreliable the further back in time you go. This study combined molecular data with character traits they call 'phenomic' characters - from the paper: "4541 phenomic characters de novo for 86 fossil and living species." The resulting matrix of traits, both molecular and character, was used to generate a tree based on maximum parsimony [wikipedia.org] - a method which minimizes the number of trait changes over time when building a tree. This resulted in a single, highest scoring tree predicting the evolution of these species and the changes in their traits over time. The resulting tree is then "clocked" (called 'time-calibration in the paper) to known rates of evolution for the molecular data (good for recent divergence of species) and by fossil data to give time ranges for the deeper sections of the tree. This last part is key, as you cannot get molecular data from fossils, and fossils allow you to map the existence of certain traits within a group to a certain point in the history of these organisms.

      The result is a time-range in which the last common ancestor between placental and NON-placental mammals must have lived, given the data provided and the parsimony criterion. As the tree makes claims about when the phenomic characters evolved or were lost, it also predicts which phenomic characters the last common ancestor had.

      • by Vreejack (68778) on Friday February 08, 2013 @01:38AM (#42829491)

        The characteristics of the first placental are not really controversial. The real news here is that a lot of the work on placentals and eutherians is wrong and must be re-evaluated. Granted, a lot of the placental work was already merely tentative. Molecular phylogenetics estimates had placentals appearing about 105 Mya, This new work ignores the molecular results and comes up with a later date. From what I can see, dating of the relevant available fossils is equivocal.

        Also curious is that according to this interpretation, the ancestral afrotherian (elephants, aardvarks, manatees, etc.) originated in South America and somehow migrated across the then 1000-mile ocean to Africa. Prepare for further revision.

    • by linatux (63153)

      photos, or it didn't happen!

    • by six025 (714064)

      A *POSSIBLE* ancestor that a study suggests *MIGHT* be what they thing. Maybe. Possibly.

      In other words, the headline is, as usual, misleading.

      Worse, this crap gives the creationists plenty of reasons to laugh and point at science.

      Basically, headlines and (extremely) speculative articles like this do a lot of undermine the real work and value of science.

      Peace,
      Andy.

      • No it doesn't. You think you are actually able to reason with creationists but this is not the case. Creationist operate on the belief level, outside of reason, thus it does not matter how good the scientific facts are. Write creationists off and go on with your life.

    • Today's education system even impacts /. when a "hypothetical" creature "not found" in the fossil record, but "inferred" by it, is now put forth as a revelation as to the origin of all mamals, including humans.

      By not being found in the fossil record, we have no concrete evidence. By being inferred, we have reasoned it's existence. That makes the use of the term "revealed" quite correct, as that is exactly the same process early man used to determine their various deities.

      I don't doubt the scientific method

  • by Anonymous Coward
    in this [imgur.com].
  • by decora (1710862) on Thursday February 07, 2013 @09:12PM (#42828089) Journal

    The rough group of placentals from the wrong side of the tracks has a young placental who falls in love with a nice placental from the meadow.. but their parents disapprove...

  • Damn them whacky scientists. Me and my girl didn't come out some squirrel's butthole !
  • ...it turned out to be Betty White.

  • The Ornithorhynchus [wikipedia.org] is a mamall but lay eggs. How does it relates?
    • by Myopic (18616) *

      If it lays eggs then it's not a placental mammal (is that right? I think that's right). That would make it a more distant ancestor to this creature, a placental mammal.

      • by manu0601 (2221348)

        If it lays eggs then it's not a placental mammal (is that right? I think that's right).

        It is difficult to be sure about anything for this odd creature. It has venom (for males only), electric field sensitivity, 5 pair of sexual chromosomes... If nature proceeds from an intelligent design, then the creating intelligence was probably intoxicated the day it created ornithorhynchus

        • by OakDragon (885217)

          It is difficult to be sure about anything for this odd creature. It has venom (for males only)...

          Of course it has venom, it's from Australia.

          Am I right, people!?

    • by ichthus (72442) on Friday February 08, 2013 @01:18AM (#42829399) Homepage
      You know, you could have just said "platypus." You didn't have to get all pretentious and shit.
      • by manu0601 (2221348)
        I was not sure about the common name. In my native language, which happens to be french, the common name is Ornithorynque. Now you can troll french speakers for being natively pretentious :-)
    • from the wiki on platypus :
      "The platypus and other monotremes were very poorly understood, and some of the 19th century myths that grew up around themâ"for example, that the monotremes were "inferior" or quasireptilianâ"still endure.[60] In 1947, William King Gregory theorised that placental mammals and marsupials may have diverged earlier, and a subsequent branching divided the monotremes and marsupials, but later research and fossil discoveries have suggested this is incorrect.[60][61] In fact,
  • Placentals are so mainstream when there exist monotremes [blogspot.com].
  • I hate them, with their long tails and their stupid twitchy noses.
    • I don't have a clue why you find this so difficult to imagine.. you've spent so much of your life in pursuit of a nut, and if you're merely average, probably without the long tail.
    • As they say, squirrels are rats with a better PR department.
  • uh..."revealed"? (Score:2, Insightful)

    by Theolojin (102108)

    "The hypothetical creature, not found in the fossil record but inferred from it..." I know this is /., but c'mon.

    • by Myopic (18616) * on Thursday February 07, 2013 @10:02PM (#42828429)

      This is what we mean when we say that science makes predictions. Remember tiktaalik? Based on the rest of the fossil record and based on geology, scientists predicted that a certain fossil of a certain creature would be found in a certain kind of rock at a certain depth. It took them several years of digging but they found that fossil at that depth in that rock. Science made a specific prediction and it came true.

      Likewise, based on the rest of the fossil record we believe this creature must have existed. We might be able to predict where we would find fossils for it.

      • by drinkypoo (153816)

        Likewise, based on the rest of the fossil record we believe this creature must have existed. We might be able to predict where we would find fossils for it.

        None of which justifies the use of the word "revealed". The word you want is "predicted". This is also the word Slashdot should have wanted, but they went for sensationalism instead.

        • by Myopic (18616) *

          Oh, is that your complaint? That this new information provided to people doesn't meet your definition of "reveal"? What does it mean to you to "reveal" something? Here's what my dictionary says:

          make (previously unknown or secret information) known to others

          That's pretty much dead center what this study does: it makes previously unknown information known to others. What do you think the word means?

          • by drinkypoo (153816)

            That's pretty much dead center what this study does: it makes previously unknown information known to others

            Well, not really. It makes previously unspeculated speculation available to others.

    • "The hypothetical creature, not found in the fossil record but inferred from it..." I know this is /., but c'mon.

      Perhaps if you actually read the study. They examined, among many other things, the size and shape of all mammals as changed over time. By examining the emergence of genes, traits and other patterns and their geographical distribution allowed them to build a new family tree of placental mammals. They then just followed all the clues back up the tree of species until they found all the common traits converging on a single creature. It was previously believed to be a type of vole. The article is more abou

  • had a complex brain with a large lobe for interpreting smells and a corpus callosum, the bundle of ... etc

    Somehow my brain kept interpreting this akin to the concerto for smells and a corpus callosum, interpreted by the brain rather than a large lobe, to interpret the smells, and a corpus callosum; the later is the bundle of... I reckon its something to do with commas and the mixed nature of details: purpose (for smell) with details of structure (the bundle etc).

  • 1. Scientists describe new evolutionary theory to assembled dignitaries from across the universe
    2. Leading Anti-Evolutionist looks really pissed.
    3. Cut to scene of Anti-Evolutionist ships massing over a lush, green planet
    4. Lens flare
    5. Anti-Evolutionist soldiers shoot all sorts of ray gun zappers at the scientists below, shouting "Die, wasters of money!"
    6. Lens flare
    7. After wicked battle, scientists are rescued by Yoda-trained hero.
    8. Lens flare

  • Uh.... I though the placental lineages extended well within the Cretaceous (????).
  • SlashDot puts its reputation at risk when it claims "fact revealed" when only "one study suggests".
    • by cusco (717999)
      its reputation at risk

      Hee, hee, what reputation? As the originator of the goatse troll, or what?
  • Actually I have inferred that the Garden of Eden was in a coal mine in my back yard here in Coal Township, PA
  • We all know the Earth is only 6000 years old and that humans were created by God in his image. At least that's what Fox News and the 700 Club tell me. Why should I believe science when I have Fox News to tell me the truth?

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