Announcement

Collapse

Natural Science 301 Guidelines

This is an open forum area for all members for discussions on all issues of science and origins. This area will and does get volatile at times, but we ask that it be kept to a dull roar, and moderators will intervene to keep the peace if necessary. This means obvious trolling and flaming that becomes a problem will be dealt with, and you might find yourself in the doghouse.

As usual, Tweb rules apply. If you haven't read them now would be a good time.

Forum Rules: Here
See more
See less

Evolutionary Timeline of Homo Sapiens

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Evolutionary Timeline of Homo Sapiens

    Smithsonian Magazine has an excellent piece on their website called AN EVOLUTIONARY TIMELINE OF HOMO SAPIENS which is where "Scientists share the findings that helped them pinpoint key moments in the rise of our species."

    The article is broken down into six sections, and while being a brief article skipping a few things it is still remarkably thorough for it's brevity.

    The sections are
    • 550,000 to 750,000 Years Ago: The Beginning of the Homo sapiens Lineage
    • 300,000 Years Ago: Fossils Found of Oldest Homo sapiens
    • 300,000 Years Ago: Artifacts Show a Revolution in Tools
    • 100,000 to 210,000 Years Ago: Fossils Show Homo sapiens Lived Outside of Africa
    • 50,000 to 60,000 Years Ago: Genes and Climate Reconstructions Show a Migration Out of Africa
    • 15,000 to 40,000 Years Ago: Genetics and Fossils Show Homo sapiens Became the Only Surviving Human Species


    Each contains multiple hyperlinks providing more detail.

    To provide a taste here is the portion before each of the sections

    The long evolutionary journey that created modern humans began with a single step—or more accurately—with the ability to walk on two legs. One of our earliest-known ancestors, Sahelanthropus, began the slow transition from ape-like movement some six million years ago, but Homo sapiens wouldn’t show up for more than five million years. During that long interim, a menagerie of different human species lived, evolved and died out, intermingling and sometimes interbreeding along the way. As time went on, their bodies changed, as did their brains and their ability to think, as seen in their tools and technologies.

    To understand how Homo sapiens eventually evolved from these older lineages of hominins, the group including modern humans and our closest extinct relatives and ancestors, scientists are unearthing ancient bones and stone tools, digging into our genes and recreating the changing environments that helped shape our ancestors’ world and guide their evolution.

    These lines of evidence increasingly indicate that H. sapiens originated in Africa, although not necessarily in a single time and place. Instead it seems diverse groups of human ancestors lived in habitable regions around Africa, evolving physically and culturally in relative isolation, until climate driven changes to African landscapes spurred them to intermittently mix and swap everything from genes to tool techniques. Eventually, this process gave rise to the unique genetic makeup of modern humans.

    "East Africa was a setting in foment—one conducive to migrations across Africa during the period when Homo sapiens arose," says Rick Potts, director of the Smithsonian’s Human Origins Program. "It seems to have been an ideal setting for the mixing of genes from migrating populations widely spread across the continent. The implication is that the human genome arose in Africa. Everyone is African, and yet not from any one part of Africa."

    New discoveries are always adding key waypoints to the chart of our human journey. This timeline of Homo sapiens features some of the best evidence documenting how we evolved.


    As I said, it isn't long and I highly recommend it.

    I'm always still in trouble again

    "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
    "Overall I would rate the withdrawal from Afghanistan as by far the best thing Biden's done" --Starlight
    "Of course, human life begins at fertilization that’s not the argument." --Tassman

  • #2
    assumptions are embedded in our perceptions...a different assumption can change perspective....
    I found this interesting....
    from the linked article...

    But fragments of 300,000-year-old skulls, jaws, teeth and other fossils found at Jebel Irhoud, a rich site also home to advanced stone tools, are the oldest Homo sapiens remains yet found.

    The remains of five individuals at Jebel Irhoud exhibit traits of a face that looks compellingly modern, mixed with other traits like an elongated brain case reminiscent of more archaic humans. The remains’ presence in the northwestern corner of Africa isn’t evidence of our origin point, but rather of how widely spread humans were across Africa even at this early date.

    Other very old fossils often classified as early Homo sapiens come from Florisbad, South Africa (around 260,000 years old), and the Kibish Formation along Ethiopia’s Omo River (around 195,000 years old).

    The 160,000-year-old skulls of two adults and a child at Herto, Ethiopia, were classified as the subspecies Homo sapiens idaltu because of slight morphological differences including larger size. But they are otherwise so similar to modern humans that some argue they aren’t a subspecies at all. A skull discovered at Ngaloba, Tanzania, also considered Homo sapiens, represents a 120,000-year-old individual with a mix of archaic traits and more modern aspects like smaller facial features and a further reduced brow.

    Debate over the definition of which fossil remains represent modern humans, given these disparities, is common among experts. So much so that some seek to simplify the characterization by considering them part of a single, diverse group.

    “The fact of the matter is that all fossils before about 40,000 to 100,000 years ago contain different combinations of so called archaic and modern features. It’s therefore impossible to pick and choose which of the older fossils are members of our lineage or evolutionary dead ends,” Scerri suggests. “The best model is currently one in which they are all early Homo sapiens, as their material culture also indicates.”


    I have previously encountered a similar argument among those studying dinosaur fossils...that morphological (and/or genetic) differences may be within the range of a species and not necessarily a different species. We modern humans have a very narrow--almost non-existent "range" of differentiation---but this might actually be unusual---rather than the norm....especially when we consider ancient evolution in relative isolation from others of the same species....?....

    Also---what is with the dark skin in these pics? About 700,000 (?) to about 6,000 years ago---Africa was tropical---Lots of rain and plants and shade....humans might have been more light skinned---perhaps brown tones than depicted?....
    https://www.sciencedaily.com/release...1130141053.htm

    Comment


    • #3
      Originally posted by siam View Post



      Also---what is with the dark skin in these pics? About 700,000 (?) to about 6,000 years ago---Africa was tropical---Lots of rain and plants and shade....humans might have been more light skinned---perhaps brown tones than depicted?....
      https://www.sciencedaily.com/release...1130141053.htm
      As your link indicates the region was tropical and it is believed that lighter pigmented skin evolved as people began moving away from tropics into other regions. Interestingly, pale skin appears to be a relatively recent development and further that most Europeans today may have had darker skin than seen today just some 8000 or so years ago.

      Apparently DNA study of the remains of hunter-gatherers in Spain, Luxembourg, and Hungary from 8500 years ago had darker skin, lacking versions of two genes -- SLC24A5 and SLC45A2 -- that lead to depigmentation and, therefore, pale skin in Europeans today. Some feel that the predominantly pale skin we see today might be largely due to a massive influx of people from the Russian steppes north of the Black Sea around 4500 years ago, but the data is far from conclusive.

      Still, research also shows that Human skin color diversity is highest in sub-Saharan African populations so it might be better to stop depicting all early humans as having the exact same dark complexion we've seen in recreations in recent decades.


      I'm always still in trouble again

      "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
      "Overall I would rate the withdrawal from Afghanistan as by far the best thing Biden's done" --Starlight
      "Of course, human life begins at fertilization that’s not the argument." --Tassman

      Comment

      Related Threads

      Collapse

      Topics Statistics Last Post
      Started by Hypatia_Alexandria, 03-18-2024, 12:15 PM
      48 responses
      135 views
      0 likes
      Last Post Sparko
      by Sparko
       
      Started by Sparko, 03-07-2024, 08:52 AM
      16 responses
      74 views
      0 likes
      Last Post shunyadragon  
      Started by rogue06, 02-28-2024, 11:06 AM
      6 responses
      47 views
      0 likes
      Last Post shunyadragon  
      Working...
      X