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.
Itâs one of my favorite stories in the history of paleoanthropologyâone that involves an anatomist youâve probably never heard of and an infant who was attacked by an eagle and dropped into a hole almost three million years ago. The idea that humans evolved in Africa can be traced to Charles Darwin. In his 1871 book The Descent of Man, Darwin speculated that it was âprobableâ that Africa was the cradle of humans because our two closest living relativesâchimpanzees and gorillasâlive there.