Final answer:
The argument that modern Homo sapiens emerged as a new species in Africa around 200,000 years ago is called the 'Out of Africa' model. This model, supported by genetic evidence, suggests a single origin of modern humans in Africa, with subsequent migration and replacement of other human species across the world.
Step-by-step explanation:
The argument that modern Homo sapiens appeared as a new species in Africa about 200,000 years ago is most commonly known as the "Out of Africa" model. It proposes that modern humans emerged first in Africa and then spread throughout the world, replacing other human species. This model is widely accepted and is supported by genetic data, which confirms a single origin of modern humans in Africa before they began colonizing other continents.
Conversely, the "multiregional evolution model" suggests that modern Homo sapiens evolved in various regions concurrently, a theory that arose to explain the diversity in human traits across different populations. However, the genetic evidence supports a single African origin, thereby reinforcing the Out of Africa model as the more viable explanation for human evolution. Additionally, early humans lived in small nomadic groups as hunters and gatherers before eventually spreading across different continents.