Final answer:
The sole survival of Homo sapiens as the remaining hominin species is explained by hypotheses, notably the 'out of Africa' model, suggesting H. sapiens emerged first in Africa and then spread, replacing other species. Their distinct brain size, tool use, mastery of fire, and facial features such as a projecting chin, likely gave them an adaptive edge over other hominin species.
Step-by-step explanation:
The survival of Homo sapiens as the sole hominin species is subject to several hypotheses. Initially, the genus Homo included at least eight different species in human lineage, but today only H. sapiens prevail. One crucial hypothesis is the “out of Africa” model, suggesting that H. sapiens first emerged in Africa around 200,000 years ago. These anatomically modern humans subsequently expanded out of Africa about 100,000 years ago, outcompeting or replacing other human species. Alternatively, the “multiregional evolution model” proposes that H. sapiens evolved from Homo erectus in multiple regions simultaneously, a theory that explains the diversity of human traits but lacks robust genetic data support.
The unique characteristics of the genus Homo include an increased brain size compared to predecessors like Australopithecus and the development of sophisticated tools, the mastery of fire, and a projecting chin associated with speech capabilities. Overlapping existence among hominin species and a variety of evolutionary dead-ends characterizes hominin evolution, complicating the understanding of H. sapiens’ sole survival.
Predation and climate change impact, coupled with competition for resources, might have favored H. sapiens’ adaptive traits, leading to the extinction of other homo species. The evolutionary success of H. sapiens might also be attributed to their advanced tool-making skills, use of fire, refined social structures, and ultimately, a greater ability for cultural and technological innovation.