Loading ...
Sorry, an error occurred while loading the content.

Re: [AAT] Re: 2-Ma evidence shows tool-making hominins inhabited grasslands

Expand Messages
  • Marc Verhaegen
    ... I don t see much surprising in it: aren t grasses more abundant along rivers than in forests? In fossils, features like pachyostosis, large brains (DHA?),
    Message 1 of 4 , Nov 30, 2009
    • 0 Attachment
      > Marc,
      > The findings are not all that surprising if you accept that early
      > Homo around two million years ago was moving inland, moving inland
      > after a long sojourn on the shore between three and two million
      > years ago ... --- Bill (m3d)

      I don't see much surprising in it: aren't grasses more abundant along rivers
      than in forests?
      In fossils, features like pachyostosis, large brains (DHA?), ext.noses etc.
      are only known from the Pleistocene, but of course, Pliocene Homo must have
      lived next to coasts (at first incl.coastal forests) & the inland branches
      next to rivers/lakes etc., but we don't know exactly how aquatic they or
      their ancestors were. It's possible that inland branches reduced aquatic
      features, eg, got smaller brains, lighter bones etc.

      --marc

      >> Plummer TW cs 2009 PLoS ONE 4(9):e7199 doi:10.1371/journal.pone.0007199
      >> Oldest Evidence of Toolmaking Hominins in a Grassland-Dominated Ecosystem
      >>
      >> Background
      >>
      >> Major biological and cultural innovations in late Pliocene hominin evolution
      >> are frequently linked to the spread or fluctuating presence of C4 grass in
      >> African ecosystems. Whereas the deep sea record of global climatic change
      >> provides indirect evidence for an increase in C4 vegetation with a shift
      >> towards a cooler, drier and more variable global climatic regime beginning c
      >> 3 Ma, evidence for grassland-dominated ecosystems in continental Africa and
      >> hominin activities within such ecosystems have been lacking.
      >>
      >> Methodology/Principal Findings
      >>
      >> We report stable isotopic analyses of pedogenic carbonates and ungulate
      >> enamel, as well as faunal data from ~2.0 Ma archeological occurrences at
      >> Kanjera South, Kenya. These document repeated hominin activities within a
      >> grassland-dominated ecosystem.
      >>
      >> Conclusions/Significance
      >>
      >> These data demonstrate what hitherto had been speculated based on indirect
      >> evidence: that grassland-dominated ecosystems did in fact exist during the
      >> Plio-Pleistocene, and that early Homo was active in open settings.
      >> Comparison with other Oldowan occurrences indicates that by 2.0 Ma hominins,
      >> almost certainly of the genus Homo, used a broad spectrum of habitats in
      >> East Africa, from open grassland to riparian forest. This strongly contrasts
      >> with the habitat usage of Australopithecus, and may signal an important
      >> shift in hominin landscape usage.
      >>
      >>
      >> _____
      >>
      >>
      >> Two-million-year-old evidence shows tool-making hominins inhabited grassland
      >> environments
      >>
      >> In an article published in the open-access, peer-reviewed journal PLoS ONE
      >> on October 21, 2009, Dr Thomas Plummer of Queens College at the City
      >> University of New York, Dr Richard Potts of the Smithsonian Institution
      >> National Museum of Natural History and colleagues report the oldest
      >> archeological evidence of early human activities in a grassland environment,
      >> dating to 2 million years ago. The article highlights new research and its
      >> implications concerning the environments in which human ancestors evolved.
      >>
      >> Scientists as far back as Charles Darwin have thought that adaptation to
      >> grassland environments profoundly influenced the course of human evolution.
      >> This idea has remained well-entrenched, even with recent recognition that
      >> hominin origins took place in a woodland environment and that the adaptive
      >> landscape in Africa fluctuated dramatically in response to short-term
      >> climatic shifts.
      >>
      >> During the critical time period between 3 and 1.5 million years ago, the
      >> origin of lithic technology and archeological sites, the evolution of Homo
      >> and Paranthropus, selection for endurance running, and novel
      >> thermoregulatory adaptations to hot, dry environments in H. erectus have all
      >> been linked to increasingly open environments in Africa.
      >>
      >> However, ecosystems in which grassland prevails have not been documented in
      >> the geological record of Pliocene hominin evolution, so it has been unclear
      >> whether open habitats were even available to hominins, and, if so, whether
      >> hominins utilized them. In their new study, Plummer and colleagues provide
      >> the first documentation of both at the 2-million-year-old Oldowan
      >> archeological site of Kanjera South, Kenya, which has yielded both Oldowan
      >> artifacts and well-preserved faunal remains, allowing researchers to
      >> reconstruct past ecosystems.
      >>
      >> The researchers report chemical analyses of ancient soils and mammalian
      >> teeth, as well as other faunal data, from the ~2.0-million-year-old
      >> archeological sites at Kanjera South, located in western Kenya. The
      >> principal collaborating institutions of the Kanjera project are
      >> QueensCollege of the City University of New York, the Smithsonian
      >> Institution's Human Origins Program, and the NationalMuseums of Kenya. The
      >> findings demonstrate that the recently excavated archeological sites that
      >> preserve Oldowan tools, the oldest-known type of stone technolog y, were
      >> located in a grassland-dominated ecosystem during the crucial time period.
      >>
      >> The study documents what was previously speculated based on indirect
      >> evidence - that grassland-dominated ecosystems did, in fact, exist during
      >> the Plio-Pleistocene (ca. 2.5-1.5 million years ago) and that early human
      >> tool-makers were active in open settings. Other recent research shows that
      >> the Kanjera hominins obtained meat and bone marrow from a variety of animals
      >> and that they carried stone raw materials over surprisingly long distances
      >> in this grassland setting. A comparison with other Oldowan sites shows that
      >> by 2.0 million years ago, hominins, almost certainly of the genus Homo,
      >> lived in a wide range of habitats in East Africa, from open grassland to
      >> woodland and dry forest.
      >>
      >> Plummer and colleagues conclude that early Homo was flexible in its habitat
      >> use and that the ability to find resources in both open and wooded habitats
      >> was a key part of its adaptation. This strongly contrasts with the habitat
      >> usage of older species of Australopithecus and appears to signify an
      >> important shift in early humans' use of the landscape.
      >>
      >> More information: Plummer TW, Ditchfield PW, Bishop LC, Kingston JD, Ferraro
      >> JV, et al. (2009) Oldest Evidence of Toolmaking Hominins in a
      >> Grassland-Dominated Ecosystem. PLoS ONE
      >> <http://www.physorg.com/tags/plos+one/> 4(9): e7199.
      >> doi:10.1371/journal.pone.0007199
      >> <http://dx.doi.org/10.1371/journal.pone.0007199>
      >>
      >> Source: Public Library of Science (news
      >> <http://www.physorg.com/partners/public-library-of-science/> : web
      >> <http://www.plos.org/> )
      >> http://www.physorg.com/news175330627.html
      >>
      >> Posted by
      >> Robert Karl Stonjek
      >>
      >>
      >>
      >>
      >>
      >> ------ Einde van doorgestuurd bericht
      >>
      >
      >
      >
      >
      >
    • m3dodds
      ... Marc, Would depend on the type of forest. Grasses and trees are in competition for the available light, nutrients and moisture. With dense tree coverage
      Message 2 of 4 , Dec 1, 2009
      • 0 Attachment
        --- In AAT@yahoogroups.com, Marc Verhaegen <m_verhaegen@...> wrote:
        >
        >
        > > Marc,
        > > The findings are not all that surprising if you accept that early
        > > Homo around two million years ago was moving inland, moving inland
        > > after a long sojourn on the shore between three and two million
        > > years ago ... --- Bill (m3d)
        >
        > I don't see much surprising in it: aren't grasses more
        > abundant along rivers than in forests?



        Marc,

        Would depend on the type of forest.
        Grasses and trees are in competition for the available
        light, nutrients and moisture. With dense tree coverage
        you would get little in the way of grasses in the
        forest, as grasses would be in competition too with
        the forest undergrowth for what little
        light there was.

        Grasses excel in open spaces, being fast growing they
        take the available nutrients and moisture making it
        difficult for trees to get established.

        Possibly open forest, woodland, which Ardi is said to
        have favored some four million years ago ... you would
        see a mixture of trees open spaces and grasses.




        > In fossils, features like pachyostosis, large brains (DHA?),
        > ext.noses etc. are only known from the Pleistocene, but of
        > course, Pliocene Homo must have lived next to coasts (at first
        > incl.coastal forests) & the inland branches next to rivers/lakes
        > etc., but we don't know exactly how aquatic they or their
        > ancestors were. It's possible that inland branches reduced
        > aquatic features, eg, got smaller brains, lighter bones etc.
        >
        > --marc
        >



        The Pliestocene began around 2.5 million years ago, so our more
        aquatic ancestor could have been on the shore at that date - as
        features like smaller jaws and larger brains have their origins
        in the period between three and two million years ago ... so by
        the time emerged H.erectus in north Africa some 1.8 million
        years ago, these features would have been part and
        parcel of H.erectus ... an genus Homo.

        Over the next two million years a succession of Homo species
        adapted to life away from the shore, moved inland, resulting
        today in the more gracile, lighter built form of modern Man.

        The H.erectus brain was not all that large, compared to that
        seen in the later species such as ... H.heidelbergensis ...
        H.neanderthal an H.sapiens (an H.ss - modern Man - today).

        Of the two - H.erectus and H.heidelbergensis - it was the
        latter that had a significant increase in the size of
        the human brain ... (1100-1400 cm³)


        --- Bill (m3d)

















        > >> Plummer TW cs 2009 PLoS ONE 4(9):e7199 doi:10.1371/journal.pone.0007199
        > >> Oldest Evidence of Toolmaking Hominins in a Grassland-Dominated Ecosystem
        > >>
        > >> Background
        > >>
        > >> Major biological and cultural innovations in late Pliocene hominin evolution
        > >> are frequently linked to the spread or fluctuating presence of C4 grass in
        > >> African ecosystems. Whereas the deep sea record of global climatic change
        > >> provides indirect evidence for an increase in C4 vegetation with a shift
        > >> towards a cooler, drier and more variable global climatic regime beginning c
        > >> 3 Ma, evidence for grassland-dominated ecosystems in continental Africa and
        > >> hominin activities within such ecosystems have been lacking.
        > >>
        > >> Methodology/Principal Findings
        > >>
        > >> We report stable isotopic analyses of pedogenic carbonates and ungulate
        > >> enamel, as well as faunal data from ~2.0 Ma archeological occurrences at
        > >> Kanjera South, Kenya. These document repeated hominin activities within a
        > >> grassland-dominated ecosystem.
        > >>
        > >> Conclusions/Significance
        > >>
        > >> These data demonstrate what hitherto had been speculated based on indirect
        > >> evidence: that grassland-dominated ecosystems did in fact exist during the
        > >> Plio-Pleistocene, and that early Homo was active in open settings.
        > >> Comparison with other Oldowan occurrences indicates that by 2.0 Ma hominins,
        > >> almost certainly of the genus Homo, used a broad spectrum of habitats in
        > >> East Africa, from open grassland to riparian forest. This strongly contrasts
        > >> with the habitat usage of Australopithecus, and may signal an important
        > >> shift in hominin landscape usage.
        > >>
        > >>
        > >> _____
        > >>
        > >>
        > >> Two-million-year-old evidence shows tool-making hominins inhabited grassland
        > >> environments
        > >>
        > >> In an article published in the open-access, peer-reviewed journal PLoS ONE
        > >> on October 21, 2009, Dr Thomas Plummer of Queens College at the City
        > >> University of New York, Dr Richard Potts of the Smithsonian Institution
        > >> National Museum of Natural History and colleagues report the oldest
        > >> archeological evidence of early human activities in a grassland environment,
        > >> dating to 2 million years ago. The article highlights new research and its
        > >> implications concerning the environments in which human ancestors evolved.
        > >>
        > >> Scientists as far back as Charles Darwin have thought that adaptation to
        > >> grassland environments profoundly influenced the course of human evolution.
        > >> This idea has remained well-entrenched, even with recent recognition that
        > >> hominin origins took place in a woodland environment and that the adaptive
        > >> landscape in Africa fluctuated dramatically in response to short-term
        > >> climatic shifts.
        > >>
        > >> During the critical time period between 3 and 1.5 million years ago, the
        > >> origin of lithic technology and archeological sites, the evolution of Homo
        > >> and Paranthropus, selection for endurance running, and novel
        > >> thermoregulatory adaptations to hot, dry environments in H. erectus have all
        > >> been linked to increasingly open environments in Africa.
        > >>
        > >> However, ecosystems in which grassland prevails have not been documented in
        > >> the geological record of Pliocene hominin evolution, so it has been unclear
        > >> whether open habitats were even available to hominins, and, if so, whether
        > >> hominins utilized them. In their new study, Plummer and colleagues provide
        > >> the first documentation of both at the 2-million-year-old Oldowan
        > >> archeological site of Kanjera South, Kenya, which has yielded both Oldowan
        > >> artifacts and well-preserved faunal remains, allowing researchers to
        > >> reconstruct past ecosystems.
        > >>
        > >> The researchers report chemical analyses of ancient soils and mammalian
        > >> teeth, as well as other faunal data, from the ~2.0-million-year-old
        > >> archeological sites at Kanjera South, located in western Kenya. The
        > >> principal collaborating institutions of the Kanjera project are
        > >> QueensCollege of the City University of New York, the Smithsonian
        > >> Institution's Human Origins Program, and the NationalMuseums of Kenya. The
        > >> findings demonstrate that the recently excavated archeological sites that
        > >> preserve Oldowan tools, the oldest-known type of stone technolog y, were
        > >> located in a grassland-dominated ecosystem during the crucial time period.
        > >>
        > >> The study documents what was previously speculated based on indirect
        > >> evidence - that grassland-dominated ecosystems did, in fact, exist during
        > >> the Plio-Pleistocene (ca. 2.5-1.5 million years ago) and that early human
        > >> tool-makers were active in open settings. Other recent research shows that
        > >> the Kanjera hominins obtained meat and bone marrow from a variety of animals
        > >> and that they carried stone raw materials over surprisingly long distances
        > >> in this grassland setting. A comparison with other Oldowan sites shows that
        > >> by 2.0 million years ago, hominins, almost certainly of the genus Homo,
        > >> lived in a wide range of habitats in East Africa, from open grassland to
        > >> woodland and dry forest.
        > >>
        > >> Plummer and colleagues conclude that early Homo was flexible in its habitat
        > >> use and that the ability to find resources in both open and wooded habitats
        > >> was a key part of its adaptation. This strongly contrasts with the habitat
        > >> usage of older species of Australopithecus and appears to signify an
        > >> important shift in early humans' use of the landscape.
        > >>
        > >> More information: Plummer TW, Ditchfield PW, Bishop LC, Kingston JD, Ferraro
        > >> JV, et al. (2009) Oldest Evidence of Toolmaking Hominins in a
        > >> Grassland-Dominated Ecosystem. PLoS ONE
        > >> <http://www.physorg.com/tags/plos+one/> 4(9): e7199.
        > >> doi:10.1371/journal.pone.0007199
        > >> <http://dx.doi.org/10.1371/journal.pone.0007199>
        > >>
        > >> Source: Public Library of Science (news
        > >> <http://www.physorg.com/partners/public-library-of-science/> : web
        > >> <http://www.plos.org/> )
        > >> http://www.physorg.com/news175330627.html
        > >>
        > >> Posted by
        > >> Robert Karl Stonjek
        > >>
        > >>
        > >>
        > >>
        > >>
        > >> ------ Einde van doorgestuurd bericht
        > >>
        > >
        > >
        > >
        > >
        > >
        >
      Your message has been successfully submitted and would be delivered to recipients shortly.