The Evolution of Humans

by fulltimestudent 8 Replies latest jw friends

• 

  fulltimestudent

  Tracing the evolutionary path of humans is complicated. Why? Simply because human and proto-human remains (including bones) are perishable. Remains from the distant past are usually only preserved when some unique features exist that assist preservation.

  For those who have an interest in the topic, I've collected some references from Nature* Journal. Your interest will need to be a bit deeper than casual as access to the journal (like most academic journals) must be purchased or accessed through a library. Many University libraries will permit public access for a fee. As an example, the University of Sydney allows public access for $40 (in 2015) a semester.

  Usually an Abstract (on the linked page) provides details of what each paper is about, and therefore can assist you to follow your own interests.

  There is, of course,.a huge range of published material on the topic, and these are only (personal) suggestions of published commentary that may be useful, as in this first link, in which the complexities of links between fossil finds are discussed.

  Nature 355, 783 - 790 (27 February 1992); doi:10.1038/355783a0

  Origin and evolution of the genus Homo
  BERNARD WOOD
  Bernard Wood is in the Hominid Palaeontology Research Group, Department of Human Anatomy and Cell Biology, University of Liverpool, PO Box 147, Liverpool 169 3BX, UK.
  It is remarkable that the taxonomy and phylogenetic relationships of the earliest known representatives of our own genus, Homo, remain obscure. Advances in techniques for absolute dating and reassessments of the fossils themselves have rendered untenable a simple unilineal model of human evolution, in which Homo habilis succeeded the australopithecines and then evolved via H. erectus into H. sapiens — but no clear alternative consensus has yet emerged.

  web-link: http://www.nature.com/nature/journal/v355/n6363/abs/355783a0.html -------------------------------------------------------------------------------------------------------------- * Nature; A description of the journal from Wikipedia: Nature is a British interdisciplinary scientific journal, first published on 4 November 1869.[1] It was ranked the world's most cited scientific journal by the Science Edition of the 2010 Journal Citation Reports, is ascribed an impact factor of approximately 42.4, and is widely regarded as one of the few remaining academic journals that publishes original research across a wide range of scientific fields.[2]Nature claims an online readership of about 3 million unique readers per month.[3] The journal has a weekly circulation of around 53,000 but studies have concluded that on average a single copy is shared by as many as eight people.[4] Research scientists are the primary audience for the journal, but summaries and accompanying articles are intended to make many of the most important papers understandable to scientists in other fields and the educated public. Towards the front of each issue are editorials, news and feature articles on issues of general interest to scientists, including current affairs, science funding, business, scientific ethics and research breakthroughs. There are also sections on books and arts. The remainder of the journal consists mostly of research papers (articles or letters), which are often dense and highly technical. Because of strict limits on the length of papers, often the printed text is actually a summary of the work in question with many details relegated to accompanying supplementary material on the journal's website. There are many fields of research in which important new advances and original research are published as either articles or letters in Nature. The papers that have been published in this journal are internationally acclaimed for maintaining high research standards.
• 

  Half banana

  FTS, the unilinear model i.e. a single evolving thread remains an idealistic notion which does not easily fit with the findings. Whereas 1992 is a long time ago in paleoanthropology, the phylogeny or positions in the family tree, are still constantly being reconsidered as new finds and new species are discovered. Since that date we have even had two completely new types of human species living simultaneously with our own namely the Denisovans in the Urals and the so called 'Hobbit', Homo floresiensis from Indonesia.

  Imagine the consequences of living with other species of humans...
• 

  Mephis

  Just away from Nature itself, a few other places which give you the ability to go to sources directly if you want to research something for yourself.

  JSTOR offers limited access to papers with a free account, for those without access to a decent library. It's only 3 articles every fortnight however. But better than a kick to the nether regions and it covers a crazy amount of academic journals.

  http://about.jstor.org/rr

  Plosone is becoming very fashionable to use. Open access, peer reviewed papers. The homo naledi papers were put up there, which caused quite a stir as usually one would expect it to take a few years from discovery to publication in a traditional journal.

  http://www.plosone.org/

  Academia.edu has a huge number of essays and articles put up by individual academics wanting to do open access. You may want to just create an account (free) to be able to browse through. Much goodness contained whether you're into science things or the humanities.

  https://www.academia.edu/
  
• 

  fulltimestudent

  Half banana : s ago
  FTS, the unilinear model i.e. a single evolving thread remains an idealistic notion which does not easily fit with the findings. Whereas 1992 is a long time ago in paleoanthropology, the phylogeny or positions in the family tree, are still constantly being reconsidered as new finds and new species are discovered. Since that date we have even had two completely new types of human species living simultaneously with our own namely the Denisovans in the Urals and the so called 'Hobbit', Homo floresiensis from Indonesia.

  We are in agreement, thanks for posting.

  Half Banana: Imagine the consequences of living with other species of humans.

  But (of course) its not what we may imagine, but what another proto-human species may have imagined. Currently, the evidence suggests that early humans did meet and intermingle (to an unknown extent) and even interbred, as we are reputed to carry some Neanderthal genetic material. Would they have 'thought' too much about another similar species? Would they have been able to communicate? Were they competing or co-operating? I doubt that we will ever be able to puzzle out answers to such questions.

  A 2004 letter printed in Nature discusses it, and I'm sure later material can be found in that Journal

  Here's some of that letter and the link:

  The genomic landscape of Neanderthal ancestry in present-day humans
  The genomic landscape of Neanderthal ancestry in present-day humans

  • Sriram Sankararaman,
  • Swapan Mallick,
  • Michael Dannemann,
  • Kay Prüfer,
  • Janet Kelso,
  • Svante Pääbo,
  • Nick Patterson
  • & David Reich

  Genomic studies have shown that Neanderthals interbred with modern humans, and that non-Africans today are the products of this mixture1, 2. The antiquity of Neanderthal gene flow into modern humans means that genomic regions that derive from Neanderthals in any one human today are usually less than a hundred kilobases in size. However, Neanderthal haplotypes are also distinctive enough that several studies have been able to detect Neanderthal ancestry at specific loci1, 3, 4, 5, 6, 7, 8. We systematically infer Neanderthal haplotypes in the genomes of 1,004 present-day humans9. Regions that harbour a high frequency of Neanderthal alleles are enriched for genes affecting keratin filaments, suggesting that Neanderthal alleles may have helped modern humans to adapt to non-African environments. We identify multiple Neanderthal-derived alleles that confer risk for disease, suggesting that Neanderthal alleles continue to shape human biology. An unexpected finding is that regions with reduced Neanderthal ancestry are enriched in genes, implying selection to remove genetic material derived from Neanderthals. Genes that are more highly expressed in testes than in any other tissue are especially reduced in Neanderthal ancestry, and there is an approximately fivefold reduction of Neanderthal ancestry on the X chromosome, which is known from studies of diverse species to be especially dense in male hybrid sterility genes10, 11, 12. These results suggest that part of the explanation for genomic regions of reduced Neanderthal ancestry is Neanderthal alleles that caused decreased fertility in males when moved to a modern human genetic background.

  05 September 2013

  Accepted

  18 December 2013

  Published online

  29 January 2014

  507,

  354–357

  (20 March 2014)

  doi:10.1038/nature12961

  Reference: http://www.nature.com/nature/journal/v507/n7492/full/nature12961.html
  
• 

  fulltimestudent

  • Mephis : Just away from Nature itself, a few other places which give you the ability to go to sources directly if you want to research something for yourself.
    JSTOR offers limited access to papers with a free account, for those without access to a decent library. It's only 3 articles every fortnight however. But better than a kick to the nether regions and it covers a crazy amount of academic journals.
    http://about.jstor.org/rr
    Plosone is becoming very fashionable to use. Open access, peer reviewed papers. Thehomo naledi papers were put up there, which caused quite a stir as usually one would expect it to take a few years from discovery to publication in a traditional journal.
    http://www.plosone.org/
    Academia.edu has a huge number of essays and articles put up by individual academics wanting to do open access. You may want to just create an account (free) to be able to browse through. Much goodness contained whether you're into science things or the humanities.
    https://www.academia.edu/

    Thanks for your very useful suggestions, Mephis. I'm sure other interested folk will find them useful.
• 

  fulltimestudent

  A BBC overview covering evidence of early human and Neanderthal inter-breeding can be found at:

  http://www.bbc.com/news/science-environment-33226416
  
• 

  fulltimestudent

  This next article from Nature discusses:

  New evidence on the earliest human presence at high northern latitudes in northeast Asia

  Nature 431, 559-562 (30 September 2004) | doi:10.1038/nature02829;
  

  In it the authors describe the finding of a range of stone tools in layers of sediment at Majuangou in north China. The stone tools are considered to be evidence of human activity.

  An interesting side point is the level of international co-operation in conducting this research.

  The researchers are listed as: R. X. Zhu1, R. Potts2, F. Xie3, K. A. Hoffman4, C. L. Deng1, C. D. Shi1, Y. X. Pan1, H. Q. Wang1, R. P. Shi1, Y. C. Wang1, G. H. Shi1 & N. Q. Wu1

  And the co-operating Institutions are:

  1. Paleomagnetism Laboratory, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
  2. Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0112, USA
  3. Hebei Province Institute of Cultural Relics, Shijiazhuang 050000, China
  4. Physics Department, California Polytechnic State University, San Luis Obispo, California 93410, USA

  The Abstract reads:

  The timing of early human dispersal to Asia is a central issue in the study of human evolution. Excavations in predominantly lacustrine sediments at Majuangou, Nihewan basin, north China, uncovered four layers of indisputable hominin stone tools. Here we report magnetostratigraphic results that constrain the age of the four artefact layers to an interval of nearly 340,000 yr between the Olduvai subchron and the Cobb Mountain event. The lowest layer, about 1.66 million years old (Myr), provides the oldest record of stone-tool processing of animal tissues in east Asia. The highest layer, at about 1.32 Myr, correlates with the stone tool layer at Xiaochangliang1, previously considered the oldest archaeological site in this region. The findings at Majuangou indicate that the oldest known human presence in northeast Asia at 40° N is only slightly younger than that in western Asia2, 3. This result implies that a long yet rapid migration from Africa, possibly initiated during a phase of warm climate, enabled early human populations to inhabit northern latitudes of east Asia over a prolonged period.

  Weblink: http://www.nature.com/nature/journal/v431/n7008/full/nature02829.html
  
  

  If early humans (or, even proto-humans) were in existence at the times indicated by the layers of sediment, how do we explain the ignorance of the author of Genesis?

  
  
  
• 

  Half banana

  If early humans (or, even proto-humans) were in existence at the times indicated by the layers of sediment, how do we explain the ignorance of the author of Genesis?

  Perhaps...they were ordinary humans, uninspired by gods or spirits and lived at a time when religious superstition regulated their every move. Apart from that they were not aware of the human pedigree and therefore could not claim the paleolithic as a god story...

  I get the feeling that due to its size and the (normally improving) economic situation in China, we are likely to hear more from there in the way of significant hominin finds in the future. It holds out hope of explaining early Homo erectus movement in the "out of Africa" scenario. There is the possibility that China holds a second species diffusion focus after the Great Rift Valley.
  
  
• 

  Saintbertholdt

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