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.
After decades of debate, paleoanthropologists now agree the genetic and fossil evidence suggests that the modern human species -- Homo sapiens -- evolved in Africa between 100,000 and 200,000 years ago. Yet, archaeological sites during that time period are rare in Africa.