Humans, specifically anatomically modern Homo sapiens, have been on Earth for approximately 300,000 years. This estimate is based on fossil evidence such as skulls and other remains found in Africa, including the oldest known fossils from sites like Jebel Irhoud in Morocco

. The broader genus Homo, which includes earlier human ancestors like Homo habilis and Homo erectus, appeared around 2 to 2.8 million years ago

. Even earlier, hominins-species more closely related to humans than to chimpanzees-emerged about 7 million years ago

. In summary:

• Anatomically modern humans (Homo sapiens): ~300,000 years ago
• Genus Homo (early humans): ~2 to 2.8 million years ago
• Hominins (human lineage ancestors): ~7 million years ago

Thus, modern humans have existed for a relatively short time compared to the entire history of life on Earth, representing only a tiny fraction of Earth's 4.5 billion-year history