Final answer:
Several different human species, including Homo erectus and Neanderthals, existed prior to Homo sapiens up to around 200,000 years ago. Homo sapiens evolved in Africa and later expanded to replace other human species. Debates on human origins continue based on new archaeological and genetic evidence.
Step-by-step explanation:
Prior to Homo sapiens, evidence suggests there were as many as several different human species existing at the same time. Around 200,000 years ago, Homo sapiens evolved in Africa, and approximately 100,000 years ago began expanding out of Africa, which led to the decline of other human species. This period saw the rise and fall of species such as Homo erectus, who lived approximately 500,000 years ago, and Neanderthals, who thrived between about 200,000 and 40,000 years ago. The discussion about early human species and their origins is ongoing and complex, fueled by new fossil finds and genetic data. The commonly accepted "out of Africa" model prescribes a single-origin for modern humans in Africa, which then spread out and replaced other species. In contrast, the "multiregional evolution model" suggests simultaneous evolution in multiple regions from Homo erectus. Nonetheless, only Homo sapiens survived to present day, diversifying and adapting to numerous environments, including the harsh conditions of ice ages and mastering tools and fire for survival.