EVOLUTION OF THE HOMO GENUS As mentioned, the earliest human and the first to have used tools was Homo habilis, who was the prototypical caveman”, using stone tools. The Homo habilis brain wasn t very big but it was believed to have been wired more efficiently. Encephalization occurred soon after this, which resulted in Homo erectus and Homo ergaster. In fact, the cranial capacity doubled in size at the time of their arrival. These early humans were likely the first to make use of fire and more complex tools. These were the first also to leave Africa to all parts in the Northern Hemisphere in Eurasia. Modern humans probably evolved from Homo rhodesiensis, Homo heidelbergensis, or Homo antecessor, migrating out of Africa the last time about 55,000 years ago, although some believe it could have been as early as 100,000 years ago. These replaced the local populations in Eurasia of the Denisovans, Neanderthals, Homo floresiensis, and Homo luzonensis. Archaic Homo sapiens were the original prototype of modern man. At some point, there was the evolution to more modern cultures, language, and complex stone tools, which may have occurred about 50,000 years ago, although there is disagreement as to whether this happened all at once or gradually over time. Eventually, all of the Homo genuses died out and became extinct except for Homo sapiens. We cannot underestimate the impact of the environment on human evolution. There was, for example, the super-eruption of Lake Toba in Indonesia about 70,000 years ago that had global implications on evolution. It is believed that most humans were killed and the population dwindled before taking off again over time. This phenomenon is referred to as a population bottleneck. Homo habilis directly diverged from Australopithecus in South and East Africa about 2.5 million years ago. Stone and animal bones were used as tools by this primitive form of man. There are some who believe this species should be moved back to the Australopithecus genus because they were adapted to living in trees and did not move easily as bipedal primates. Homo erectus was first identified in Indonesia. It was originally called a form of Anthropopithecus rather than one of the Homo genera. The skeleton, called Java man, was compared to Peking man at a later date and it was determined that both were the same and they were renamed to become Homo erectus. They were likely wiped out by the Toba catastrophe because of their proximity to Indonesia during the super-eruption. Homo ergaster is either a separate species or a subspecies of Homo erectus.
115
