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.
The term human denotes any creature belonging to the genus Homo. The first species of human was Homo habilis, which evolved in Sub-Saharan Africa ca. 2,500,000 BC. Since Homo habilis was a maker of stone tools, the evolution of this species marks the beginning of the stone age.56.