Human Evolution – Tree Climbing to Habitual Bipedalism

Why in News?

A new study provides evidence that archaic humans had largely shifted from regular tree climbing to habitual upright walking on the ground.

Key Finding

• Major evolutionary transition – Arboreal lifestyle to Terrestrial bipedalism
• Approximate period – 1.8 million years ago
• Evidence used – Internal strength of limb bones
• Fossils studied – Little Foot and Dmanisi Homo
• Researchers – University of the Witwatersrand + University of Southern California

• Methods Used by Scientists to Determine Findings
  • Previous research primarily analyzed the morphology and proportions of fossilized limbs.
  • The recent study concentrated on assessing the internal structural strength of bone shafts.
• Analytical Framework – Bone strength reflects the physical loads experienced, which in turn inform interpretations of locomotor behavior and habitat utilization.
  • Increased forelimb loading indicates greater use of the arms, including activities such as tree climbing.
  • Stronger adaptation of the lower limbs suggests a greater reliance on terrestrial locomotion.
• Researchers compared the strength ratios of fossil limb bones with those observed in the following extant species:
  • Modern humans
  • Chimpanzees
  • Gorillas
  • Orangutans

Reference

The Hindu | Human Evolution