Ancient humans evolved to walk on two legs in two steps , Pg13

Key Highlights:

• Research published in Nature on August 28 reveals the developmental origins of bipedalism in humans.
• The study identifies two key innovations in pelvic development: horizontal expansion of the iliac cartilage and delayed bone formation.
• These shifts are linked to a network of developmental regulators influenced by changes in human DNA.
• Findings clarify how human embryos developed a pelvis suitable for upright walking and childbirth.

Detailed Insights:

• Traditional explanations of bipedalism focused on fossil anatomy and biomechanics, failing to reveal underlying molecular processes.
• Researchers compared human embryonic pelves with those of mice, chimpanzees, and gibbons using histology, micro-CT scanning, and molecular analysis.
• The growth plate of the iliac cartilage in humans expands horizontally, unlike the vertical elongation seen in apes and mice.
• Delayed bone formation in humans allows the pelvis to expand in width before hardening, accommodating upright walking.
• Understanding these developmental pathways may provide insights into the origins of pelvic malformation and the evolution of hominins like Australopithecus.

Scientific/Technical Concepts Involved:

• Bipedalism: The ability to walk upright on two legs, a defining trait of humans.
• Ilium: The broad, upper bone of the pelvis, crucial for understanding the evolution of bipedalism.
• Histology: The study of the microscopic structure of tissues.
• Micro-CT scanning: A high-resolution imaging technique used to visualize bone formation.