Fossil of Unusual Human Ancestor Discovered

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Researchers have identified a nearly complete skeleton of an unusual, tree-dwelling ancestor of humans that lived 55 million years ago, a discovery that illuminates one of the earliest stages of our evolution.


Unearthed in China, the mouse-sized creature has a mix of anatomical features that make it quite unlike any other primate—living or extinct—known to science. The discovery was published Wednesday in the journal Nature.

 

By about 55 million years ago, the earliest primate ancestors of humans had split into two branches. One branch gave rise to lemurs, lorises and bush babies. The other led to tarsiers, whose enormous-eyed, tree-dwelling descendants still live in Southeast Asia. The second branch also gave rise to anthropoids, including monkeys, apes and humans.

The animal described in the study is a primitive tarsier relative. It is of interest to scientists because it lived at a crucial period, fairly soon after the two branches split.

The discovery gives new insight into very early ancestors of humans: How big they were, what they looked like, what their anatomy was like, what they ate and how they moved.

For example, many scientists believed that the specialized anatomy of a monkey's foot developed much later. But some of that anatomy can be seen in the unearthed skeleton—far, far earlier in evolution.

"It has a monkey-like foot but a body more or less like a tarsier's," said Daniel Gebo, co-author of the paper and anthropologist at Northern Illinois University. "It's the first time we've seen this combination."

The finding also is striking because of the completeness of the skeleton. Until now, scientists only had seen fragmentary remains of these ancient primates, such as teeth, jaws or skulls.

"It's rare because most of the important parts of this skeleton are there," said Jerry Hooker, a paleontologist at London's Natural History Museum, who wasn't involved in the study. "It's only lacking hands and wrists, which is a pity."

Written By: Gautam Naik
continue to source article at online.wsj.com

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  1. One question – size. The illustration suggests a creature of relatively diminutive stature – what are the basic facts concerning this skeleton?

    I ask because later fossils are somewhat larger – why should this be?

    • In reply to #1 by TanyaK:

      One question – size. The illustration suggests a creature of relatively diminutive stature – what are the basic facts concerning this skeleton?

      I ask because later fossils are somewhat larger – why should this be?

      It’s under the source link -

      “…mouse-sized creature…”

      “Researchers who studied the skeleton say the animal weighed less than an ounce and was small enough to fit in the palm of a human hand.” with some other interesting comments and speculations.

      • In reply to #2 by Geoff 21:

        In reply to #1 by TanyaK:

        One question – size. The illustration suggests a creature of relatively diminutive stature – what are the basic facts concerning this skeleton?

        It’s under the source link -

        “…mouse-sized creature……

        Yes quite – so why are later variants so large? We are somewhat larger than a mouse, so where is the logic for an increase in size of such magnitude?

        • In reply to #3 by TanyaK:

          In reply to #2 by Geoff 21:

          In reply to #1 by TanyaK:

          One question – size. The illustration suggests a creature of relatively diminutive stature – what are the basic facts concerning this skeleton?

          It’s under the source link -

          “…mouse-sized creature……

          Yes quite – so why are later variants…

          The logic is natural selection. If variants of larger size have an advantage in reproduction(which implies better access to food, shelter, protection from predators) leaving behind more offspring than a smaller variant, the logic predicts that those with more offspring will take over a given ecosystem.

          • In reply to #4 by kraut:

            Yes – but Natural Selection is merely an effect. Science really needs to be concentrating upon how the precise anatomical structures are established and survive relative increase of scale of the organism, with functional integrity and relationship to other relevant systems maintained, via the proposed means of undirected mutations. There is always great excitement over these new links in the chain, but the actual processes seem to be glossed over.

          • In reply to #5 by TanyaK:

            In reply to #4 by kraut:

            Yes – but Natural Selection is merely an effect. Science really needs to be concentrating upon how the precise anatomical structures are established and survive relative increase of scale of the organism, with functional integrity and relationship to other relevant systems…

            There is no glossing over. The mechanisms are well understood of changes in the genetic material, changes in the genetic switches that control for gene expression of phenotypical features.
            You asked for the logic of increases in body size. The logic behind that is mutation and natural selection.
            It seems you are lacking basic concepts in biology, and you should remedy that.

          • In reply to #9 by kraut:

            In reply to #5 by TanyaK:

            In reply to #4 by kraut:

            Yes – but Natural Selection is merely an effect. Science really needs to be concentrating upon how the precise anatomical structures are established and survive relative increase of scale of the organism, with functional integrity and relationship…

            Quote by kraut: “There is no glossing over. The mechanisms are well understood of changes in the genetic material, changes in the genetic switches that control for gene expression of phenotypical features. You asked for the logic of increases in body size. The logic behind that is mutation and natural selection. It seems you are lacking basic concepts in biology, and you should remedy that.”

            I lack nothing. You are almost embarrassingly over-optimistic in stating that ‘The mechanisms of changes in the genetic material are well understood……etc’ – the more sub-cellular biochemistry is refined, the more complex it becomes. My point is that – for example – if an eye were to increase in size, then so too would the surrounding skeletal structure, etc, to accommodate it. Living systems are not mechanical, but are dynamic and co-operative systemically, to the extent that a change in one area necessitates changes in many others to a precise degree and simultaneously if the change is to result in anything other than disaster. Answers such as in post number 4 are typical, and come across as rather ‘pat’.

        • In reply to #3 by TanyaK:

          Yes quite – so why are later variants so large? We are somewhat larger than a mouse, so where is the logic for an increase in size of such magnitude?

          If you are asking if there is some general law that organisms get bigger (or smaller) as they evolve I’m pretty sure there isn’t. Things like that are driven by the specific factors of the environment and how they effect that organism. Some times its advantageous to the organism to increase in size sometimes though it could be just the opposite, the increased requirements for food to satisfy a bigger (or faster, stronger) body aren’t worth it, it might be more beneficial to evolve in the other direction.

          • In reply to #11 by Red Dog:

            In reply to #3 by TanyaK:

            Yes quite – so why are later variants so large? We are somewhat larger than a mouse, so where is the logic for an increase in size of such magnitude?

            If you are asking if there is some general law that organisms get bigger (or smaller) as they evolve I’m pretty sure there…

            Actually, what I am asking is as I said in post 9 above – how is this up/down scale adaptation of a highly complex organism achieved with all functionality intact, when the relative scale of systemic elements is controlled by separate factors yet must of necessity remain proportionate?

          • In reply to #12 by TanyaK:

            Actually, what I am asking is as I said in post 9 above – how is this up/down scale adaptation of a highly complex organism achieved with all functionality intact, when the relative scale of systemic elements is controlled by separate factors yet must of necessity remain proportionate?

            Sizing up an animal takes many more generations than sizing down to a smaller version.
            Here is an article which explains it.

            http://monash.edu/monashmag/articles/small-winners-in-the-mammalian-race-to-evolve.html#.UbN1tdih7PU

            It takes at least 10 times as many generations for a mouse to reach elephantine proportions as for the reverse transition, reveals a vast study of mammalian evolution over the past 70 million years.

            Just before dinosaurs became extinct about 65 million years ago, the largest mammals were tiny, with the biggest discovered fossils from the time indicating a weight of just three kilograms, the size of a house cat.

            “Believe it or not, the ancestors of elephants were once as small as mice,” Dr Evans says. “So we were curious to find out how long it would take a 20-gram mouse to evolve into a two-million-gram elephant … and vice versa.”

            The researchers pieced together the lineages of nine families of large mammals – including those that contain elephants, apes, deer and whales – from the often-fragmentary traces left in the fossil record (the diminutive rodent family was included because of its gargantuan guinea pig relative). By calculating the body mass of each family, they could show how the animals have grown or shrunk over the years. They found that it can take 24 million generations to build an elephant-sized creature out of a mouse, but perhaps only two million generations to create a mouse-sized animal from an elephantine beast.

            ▬▬▬▬▬▬▬▬ ▬▬▬▬▬▬▬▬ ▬▬▬▬▬▬▬▬

            The emerging picture is one of steady increases in maximum mammal size after the dinosaurs quit the scene, until the peak was reached with the largest mammal ever to walk the Earth: Indricotherium, a 15-tonne cross between a giraffe and a rhinoceros that clomped across the Central Asian grasslands 20 to 30 million years ago.

            Since then, things have become more erratic. Broadly speaking, whales have continued to grow up to the present day, while land mammals have tended to stabilise or shrink.

          • In reply to #15 by Alan4discussion:

            In reply to #12 by TanyaK:

            Actually, what I am asking is as I said in post 9 above – how is this up/down scale adaptation of a highly complex organism achieved with all functionality intact, when the relative scale of systemic elements is controlled by separate factors yet must of necessity remain…

            Quote by Alan:”Sizing up an animal takes many more generations than sizing down to a smaller version.
            Here is an article which explains it.”

            I am not disputing that animals may ‘size up’ – I am asking how the effect is achieved with all systemic elements remaining in proportion with respect to timing. Maybe I should elaborate the point, because I feel it is a valid one, and has never once had a proper answer from a biologist, and I’ve asked a few.

            A basic premise of evolution by natural selection is that an unsolicited change in part of a chromosomal sequence/the transcripted version of that sequence/the protein product of that sequence results in an alteration to the output/the control of the output of proteins which provide the means via which a cell may act in accordance with its purpose in context, resulting in a phenotypical change which environmental factors then act to allow to continue to exist, or not, as a factor in the makeup of that organism and its offspring, correct?
            The question I ask is this… an overall increase/decrease in organism scale requires the co-operative simultaneous alteration in the scale of all the systemic elements of that organism, at least in so far as they are relevant to each other directly in terms of essential support/function, yet many such elements are seemingly under the control of separate supposed developmental factors. How is it always allowed for, by ‘Natural Selection’, that such systemic relevance is maintained so the organism functions adequately?

          • In reply to #16 by TanyaK:

            The question I ask is this… an overall increase/decrease in organism scale requires the co-operative simultaneous alteration in the scale of all the systemic elements of that organism, at least in so far as they are relevant to each other directly in terms of essential support/function, yet many such elements are seemingly under the control of separate supposed developmental factors.

            That is why natural selection has to take so many generations to select appropriate adjustments to the many different factors from the natural variations and any mutations which occur.

            How is it always allowed for, by ‘Natural Selection’, that such systemic relevance is maintained so the organism functions adequately?

            Within any population, there will be a range of variation in numerous characteristics.

            Where the over-all change of size is beneficial, these things can only happen in small increments, with the individuals displaying the poorer end of the range of adaptations to the new size, dying out under selection pressure, while the better suited ones reproduce passing on their traits.

            A whole range of parts and organs have to be retuned to the new scale over millions of generations, as it explains on the link.

            The absence of large dinosaurs would have made niches for larger mammals available.

          • In reply to #17 by Alan4discussion:

            In reply to #16 by TanyaK:

            The question I ask is this… an overall increase/decrease in organism scale requires the co-operative simultaneous alteration in the scale of all the systemic elements of that organism, at least in so far as they are relevant to each other directly in terms of essential…

            Quote from Alan:”That is why natural selection has to take so many generations to select appropriate adjustments to the many different factors from the natural variations and any mutations which occur.”

            Alan – you do see, I hope, that unless the changes result in a functionally able and notable effect, that Natural Selection would have nothing upon which to operate? It is only upon such changes that evolution can possibly occur as stated.

          • In reply to #18 by TanyaK:

            Alan – you do see, I hope, that unless the changes result in a functionally able and notable effect, that Natural Selection would have nothing upon which to operate? It is only upon such changes that evolution can possibly occur as stated.

            There is normally a considerable variation both in the genetics and the phenotype of species, so even within existing forms there is great potential for adjustments in size, even though some of these may have some detrimental effects. (It is a common misconception that there is a genetic homogeneity in species, when in fact there is usually variation and diversity.)

            (There is for example a considerable variation in height, leg length, foot-size, etc in modern humans – With pygmy bushmen found in some areas where large westerners are too heavy to climb the trees.)

            You only have to look at the artificial selection of the range of sizes and shapes in domestic dogs to see this. The original wolves were kept within tight parameters by their demanding environment and the fitness arms-race with their prey, but once dogs were protected by humans and selected for their novelty rather than their ability to survive in the wild, a whole rage of diversity was released.

            Particular environments mould species to their local conditions. That is why you get strange and unusual creatures on remote, inaccessible isolated islands, where they are protected from predation and competition. Once a population of larger (or smaller) individuals has been selected, further refinements and adjustments take place as the generations of new offspring compete with each other for survival.

            Many animals have large litters of young, with only a few surviving, so selection pressure can be very strong.

            Evolution and natural selection have no “objectives”. Diversity explores the possibilities, and natural selection wipes out the unsuccessful attempts to fit in, and picks out the best adaptations for survival and reproduction – concentrating the genes which best fit the current environment!

  2. One of the difficulties with accepting the theory of evolution as the means of our creation is the inexplicable complexity of our design which is routinely ignored. An example of this is our ability to view the world in three dimensions.

    We perceive the world visually in three dimensions. You will never mistake a person, house, tree or any object for a life-size, two dimensional photograph of the object placed next to it. Why is that?

    Light waves, like all waves, are defined by their amplitude, frequency, and phase. If you have a life-size photograph of an object next to the object, the light reflecting off each and entering your eye is the same, isn’t it? The amplitude of the light waves, meaning their brightness, may be the same. The frequency of the light waves, meaning its color, may also be the same. That just leaves phase. The phase of a wave refers to the position on the wave, its peak, its trough, or somewhere in between. That is going to be the difference between the light reflected by the three dimensional object and the two dimensional image. And that is why you need a coherent light source, like a laser, to create a three dimensional image, a hologram, because you can control the phase of the light. A coherent light source emits light waves with the same phase.

    There is a significant difference, though, between a hologram and our three dimensional vision. We do not have the technology to detect the phase of individual light waves as our eyes apparently do. Instead, to create a hologram, you record an interference pattern on film, the interference pattern created by mixing the coherent light source with other coherent light after it is reflected from the object you are filming. This requires a special optical table that is large and heavy with shock absorbers that dampen vibrations that are near the size of a wavelength of light. Your eyes do not have the advantage of an optical table. Instead, they are collecting the phase information in an unknown way. If your eye was not detecting the phase information of light, you would not perceive a hologram as a three dimensional image. The information recorded by a hologram is a phase map of the light reflected from the object you are recording. Our eyes not only detect this information constantly, our brain interprets it constantly in a manner such that we perceive the world in three dimensions.

    Many assume we see in three dimensions via a stereoscopic effect resulting from having two eyes. However, if you close one eye, you continue to perceive the world in three dimensions.

    Evolution theory asserts that a lengthy series of chance mutations occurred over time with each mutation having a benefit sufficient for it to dominate within the species long enough for another beneficial mutation. Eventually, this lead to the design of the human eye with its ability to capture light wave phase information. As difficult as this is to accept, Evolution Theory also asserts it happened twice; once for vertebrates and once for invertebrates which supposedly evolved separately. In addition, Evolution Theory asserts that the lengthy series of mutations occurred identically in both the vertebrates and invertebrates as exhibited by the octopus, an invertebrate which has an eye essentially identical to the human eye.

    • In reply to #7 by Brighthouse01:

      One of the difficulties with accepting the theory of evolution as the means of our creation is the inexplicable complexity of our design which is routinely ignored. An example of this is our ability to view the world in three dimensions.

      We perceive the world visually in three dimensions. You wil…

      Bollocks. Our 3d vision is due to stereopsis. If you don’t believe me wear an eye-patch for a month, and count how many visual errors you make.

    • In reply to #7 by Brighthouse01:

      Eventually, this lead to the design of the human eye with its ability to capture light wave phase information. As difficult as this is to accept,

      You really should study biology rather than listening to scientific illiterates or making stuff up!

      Evolution Theory also asserts it happened twice;

      No it doesn’t. BUT – Actually eyes and various forms of photo-sensitivity evolved many times separately.

      once for vertebrates and once for invertebrates which supposedly evolved separately.

      Vertebrates evolved separately after vertebrates branched from invertebrates on the evolutionary tree of life.

      In addition, Evolution Theory asserts that the lengthy series of mutations occurred identically in both the vertebrates and invertebrates

      No it doesn’t! The mutations were different.

      as exhibited by the octopus, an invertebrate which has an eye essentially identical to the human eye.

      The invertebrate eyes are nothing like human eyes. You really should get some proper academic sources of information. If you had actually studied Mollusc eyes, you would know that they beautifully illustrate a whole series of evolutionary stages of eyes from light sensitive patches, to pin-hole “camera” pits, pits with simple lenses, compound eyes – right through to the complex colour vision of an octopus.

      There is a huge range of different forms and structures of eyes. Some creatures like spiders have more than one type of eye.

      Most spiders have eight eyes. Some have no eyes and others have as many as 12 eyes. Most can detect only between light and dark, while others have well-developed vision. Experiments have demonstrated that some spiders can recognize and respond to specific shapes on television monitors. However they’re equipped to see, all spiders have highly evolved systems to detect prey and danger.

  3. It is worth noting, that present-day PRIMATES vary in size from Mouse Lemurs up to Gorillas.

    Mouse lemur – Microcebus

    The taxonomy of the genus Microcebus is extremely fluid, with ten new species described since 2000 (Rylands 2007). Groves (2005) lists 8 species in the genus, however since his publication, seven new species have been described and are all here included as full species (Kappeler et al. 2005; Andriantompohavana et al. 2006; Louis et al. 2006; Olivieri et al. 2007).

    As I discussed @ 20 there is considerable variation leading to speciation. Small animals with short life-cycles can have more generations in a short time-span.

    @link- Mouse lemurs have a combined head, body and tail length of less than 27 cm (10.6 in) making them the most diminutive of the primates (Mittermeier et al. 2006; Ankel-Simons 2007). Among the mouse lemurs, the superlative goes to M. berthae, which is the world’s smallest primate

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