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.
There is general agreement that Homo erectus, the precursor to modern humans, evolved in Africa and gradually expanded to Eurasia beginning about 1.7 million years ago. Anatomically modern humanshumans that more or less looked like usarose in Africa at least 130,000 years ago.y 100,000 years ago, several species of hominids populated the Earth. H. sapiens uslived in Africa, H. erectus in Southeast Asia and China, and Neandertals in Europe.