Final answer:
Hominoid diversity declined between 40,000 and 15,000 years ago, with the remaining species being Homo sapiens. This decline is explained by two theories, the more widely accepted 'out of Africa' model and the 'multiregional evolution' model. Pivotal changes in culture and technology during this period are attributed to Homo sapiens, who achieved a global distribution.
Step-by-step explanation:
Hominoid Diversity Decline
The decline in hominoid diversity occurred between 40,000 and 15,000 years ago, during which time the various human species were reduced to only Homo sapiens. This reduction in diversity is explained by two prevailing models: the "out of Africa" model and the "multiregional evolution" model. The "out of Africa" model is the most accepted and posits that Homo sapiens first emerged in Africa around 200,000 years ago and later expanded out of the continent about 100,000 years ago, replacing other human species. Conversely, the "multiregional evolution" model suggests that Homo sapiens evolved from Homo erectus in various places around the same time.
The Pliocene epoch was pivotal in the evolution of bipedal hominins, and despite sparse fossil evidence from the late Miocene, ongoing discoveries continue to enrich our understanding of human evolution. The emergence of the genus Homo, which includes species such as Homo habilis and the potentially older Homo gautengensis, marks a significant step in this evolutionary journey, showcasing development of traits more aligned with modern humans.
Culture and technology saw radical transformations approximately 40,000 years ago, across multiple regions, often referred to as "the human revolution." This was also a time when homo sapiens achieved a global distribution, completing massive migrations across different continents. The eventual arrival of modern humans led to new challenges and interactions with existing species, including the possibility of competition and pressure leading to the decline of other hominin species.