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.
Other scientists have argued that human beings originated in Africa before moving to other regions 150,000 to 200,000 years ago. Homo sapiens discovered in Middle Awash, Ethiopia, from 160,000 years ago were believed to be the oldest 'modern' human beings. Other remains previously found in Israeli caves are thought to have been more recent and 80,000 to 100,000 years old.