Early Homosapiens  
Between 200,000 and 300,000 years ago, H. ergaster evolved into H. sapiens. Because of the gradual nature of human evolution at this time, it is difficult to identify precisely when this evolutionary transition occurred, and certain fossils from this period are classified as late H. erectus by some scientists and as early H. sapiens by others.

Although placed in the same genus and species, these early H. sapiens are not identical in appearance with modern humans. New fossil evidence suggests that modern man, H. sapiens sapiens, first appeared more than 90,000 years ago. There is some disagreement among scientists on whether the hominine fossil record shows a continuous evolutionary development from the first appearance of H. sapiens to modern humans. This disagreement has especially focused on the place of Neandertals (or Neandertals), often classified as H. sapiens neanderthalensis, in the chain of human evolution. Fossil evidence indicates that the Neandertals (named for the Neander Valley in Germany, where one of the earliest skulls was found) occupied parts of Europe and the Middle East as early as 120,000 years ago until about 30,000 years ago, when they disappeared from the fossil record.

The dispute over the Neandertals also involves the question of the evolutionary origins of modern human populations, or races. Although a precise definition of the term race is not possible (because modern humans show continuous variation from one geographic area to another), widely separate human populations are marked by a number of physical differences. The majority of these differences represent adaptations to local environmental conditions, a process that some scientists believe began with the spread of H. erectus to all parts of the Old World. In their view, human development since H. erectus has been one continuous, in-position evolution; that is, local populations have remained, changing in appearance over time. The Neandertals and other early H. sapiens are seen as descending from H. erectus and are ancestral to modern humans.

Other scientists view racial differentiation as a relatively recent phenomenon. In their opinion, the features of the Neandertals—a low, sloping forehead, large brow ridge, and a large face without a chin—are too primitive for them to be considered the ancestors of modern humans. They place the Neandertals on a side branch of the human evolutionary tree that became extinct. In 1997 a team of scientists added strong evidence to support this view. They managed for the first time to analyze mitochondrial DNA—a DNA form inherited only from the mother and particularly useful for determining ancient ancestral relations—from a Neandertal skull. The analysis showed that the lines leading to Neandertals and modern Homo sapiens began to diverge over 500,000 years ago and that Neandertals and modern humans did not interbreed.

Also according to this theory, the origins of modern humans can be found in southern Africa or the Middle East. Evolving perhaps 90,000 to 200,000 years ago, these humans are thought to have spread to all parts of the world, supplanting the local, earlier H. sapiens populations. In addition to some fragmentary fossil finds from southern Africa, support for this theory comes from comparisons of mitochondrial DNA taken from women around the world, representing a worldwide distribution of ancestors. These studies suggest that humans derived from a single generation in sub-Saharan Africa or southeastern Asia. Because of the tracing through the material line, this work has come to be called the "Eve" hypothesis; its results are not accepted by most anthropologists, who consider the human race to be much older. See also Race, Human.

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