Friday, January 31, 2014

The Most Fascinating Human Evolution Discoveries of 2013 | Observations, Scientific American Blog Network

The Most Fascinating Human Evolution Discoveries of 2013 | Observations, Scientific American Blog Network

The Most Fascinating Human Evolution Discoveries of 2013

Curated by Rene Volpi.

Sahelanthropus tchadensis

Sahelanthropus tchadensis had a
tiny brain, but one that had nonetheless undergone some reorganization
toward the human condition. Image: Didier Descouens, via Wikimedia
Wow. I’ve just spent the last couple days going through the
paleoanthropology news that broke in 2013 and I must say it was a banner
year. There were so many exciting new findings that bear on scientists’
understanding of just about every chapter of humanity’s
seven-million-year saga—from our ancestors’ first upright steps to the
peopling of the Americas. But don’t take my word for it. Check out the
links below for highlights from our latest turn around the sun and see
for yourself just how very far we have come.

  • Analysis of the shape of the braincase of seven-million-year-old Sahelanthropus tchadensis from Chad supports the claim that it is the oldest human ancestor on record.
  • The femur of Orrorin tugenensis, a putative human ancestor
    that lived six million years ago in Kenya, has a shape that is
    intermediate between that of fossil apes and early members of the human
    lineage—a finding that confirms previous claims that the creature walked upright.
  • Tiny, rarely preserved middle-ear bones from two of our ancient
    relatives that lived millions of years ago exhibit modern features,
    which may indicate an early shift in hearing ability.
  • The latest round of studies of Australopithecus sediba, a
    nearly two-million-year-old relative of ours from South Africa, reveals
    a previously unknown form of upright walking and decidedly humanlike
    jaws and teeth. But is it the ancestor of our genus, Homo? Not so fast.
  • Spectacular skull from the site of Dmanisi
    in Georgia is the fifth skull to emerge from the site, which dates to
    1.77 million years ago. The specimens are quite diverse in size and
    shape, yet they all come from the same time and place, and thus surely
    belong to the same species. The discovery team argues that the variation
    seen in this one group suggests that several early human species that
    scientists have named may in fact belong to a single, variable species.
    Not everyone agrees. Either way, some of the variation evident in the
    lower jaw bones from Dmanisi may be the result of overuse of toothpicks.
  • A hand bone dating to nearly 1.5 million years ago, probably from H. erectus, shows
    that a key feature related to the dexterity and strength necessary for
    making and wielding complex tools evolved half a million years earlier
    than previously thought.
  • Researchers unearthed a treasure trove of fossils
    belonging to an as-yet-unidentified human relative from a cave in South
    Africa’s Cradle of Humankind—and invited the world to follow the
    adventure as it unfolded (not the usual way of doing things in
    paleoanthropology, which is notoriously secretive).
  • DNA from a 400,000-year-old fossil from Spain—the oldest human DNA yet by a long shot—unexpectedly resembles DNA from the mysterious Denisovan people who lived in Siberia 80,000 years ago.
  • Stone-tipped javelins from Ethiopia
    date to more than 279,000 years ago, making them nearly 200,000 years
    older than the previous record holders. Experts thought that H. sapiens
    was the first species to invent composite projectiles, but the new
    finds pre-date the origin of our kind and thus must be the handiwork of
    another species. It’s one more wrinkle in the surprisingly complex story
    of the evolution of human creativity.
  • The first high-quality genome of a Neandertal—a
    female who lived in Siberia around 50,000 years ago–shows that her
    parents were as closely related as half siblings and that her recent
    ancestors mated with close relatives, too. Comparison of her genome with
    genomes of other extinct humans suggests that both Neandertals and an
    unknown human species interbred with the mysterious Denisovans from
    Siberia—yet more evidence of interspecies boot-knocking among our ancestors.
  • Additional wrist bones
    of the wee human “hobbits” that lived in Indonesia as recently as
    17,000 years ago bolster the case for the remains representing a
    distinct species, H. floresiensis, and not diseased modern
    humans as critics have claimed. On a sad note, archaeologist Mike
    Morwood, co-discoverer of our little hobbit cousins, passed away.

About the Author: Kate Wong is an editor and writer
at Scientific American covering paleontology, archaeology and life
sciences. Follow on Twitter @katewong.

The views expressed are those of the author and are not necessarily those of Scientific American.
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