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.
Humans did come out of Africa, says DNA. The DNA of living humans is revealing the secrets of our evolution, reports Jeremy Thomson. Archaeologists are still not sure when and where modern humans first appeared. Some believe that Homo sapiens evolved independently in several places around the globe.