6 How do atoms absorb & emit light? â¢ Key idea: Energy â¢ A photon carries energyâ¢ Electron in orbit has energy because it is moving and it is pulled by nucleus. â¢ When atom absorbs photon, energy of photon promotes electron to higher energy.
Until now, researchers believed that homo sapiens, the direct descendants of modern man, evolved in Africa about 200,000 years ago and gradually migrated north, through the Middle East, to Europe and Asia.
During a time of dramatic climate change 200,000 years ago, Homo sapiens evolved in Africa. Like other early humans that were living at this time, they gathered and hunted food, and evolved behaviors that helped them respond to the challenges of survival in unstable environments. Anatomically, modern humans can generally be characterized by the lighter build of their skeletons compared to earlier humans.