section_path: Anatomical changes
section_name: Anatomical changes
paragraph_text: Anatomical changes
  
  Since Homo sapiens separated from its last common ancestor shared with chimpanzees, human evolution is characterized by a number of morphological, developmental, physiological, behavioral, and environmental changes. Environmental (cultural) evolution discovered much later during the Pleistocene played a significant role in human evolution observed via human transitions between subsistence systems. The most significant of these adaptations are bipedalism, increased brain size, lengthened ontogeny (gestation and infancy), and decreased sexual dimorphism. The relationship between these changes is the subject of ongoing debate. Other significant morphological changes included the evolution of a power and precision grip, a change first occurring in H. erectus.