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.
Out of Africa. Modern Human beings evolved in Africa from a variety of hominid species over a few million years. The first humans to leave the African continent were Homo erectus (upright man), who migrated northeast about 2 million years ago when present day deserts were grassland.