Homo Erectus: Who Was the Earliest Modern

Homo Erectus: Who was the earliest modern ancestor of today's homo sapiens?

Homo Erectus was a species of mammal that was, in form and function, a modern foreshadower of today's human being. Homo Erectus lived from about 1,900,000 years to about 400,000 years ago. "The Latin word Homo means human being. The term erectus means upright and refers to the creature's upright posture. Homo erectus differed from modern human beings in having a large, projecting face; a low, sloping forehead; and a large brow ridge, a raised strip of bone across the lower forehead. Homo erectus also possessed a large jaw that lacked a chin." (Mann, 2005) The brain of Homo erectus was smaller than the brain of modern human beings, even though this species was able to manipulate simple tools, contain fire, walk in migrating tribes over long distances, and engage in other, modern humanlike behaviors.

Homo erectus is commonly characterized as "an accomplished tool maker and tool user." It is assumed he or she used "hand-axes" and sharp-edged flints to make fire. The tools of Homo erectus are the first in the fossil record to show conscious design of any complexity. Wooden tools and weapons are also assumed to be present in the tool kit of this species. However, "none has been preserved in the fossil record." Thus there is no conclusive archeological proof such tools were used, even if the species could technically manipulate such tools unlike its earlier ancestors. (Long Foreground: Species Timeline, p.2) Controversial claims have also been made about cannibalism in some species, given the fossil and archeological evidence, another difficult judgment to make, given the imperfect nature of the surviving skeletal record.

Fossils of Homo erectus usually assumed about 1,800,000 years old have been found at a site called Dmanisi in the country of Georgia, which lies at the eastern end of the Black Sea. Fossil remains show that Homo erectus migrated as far as the island of Java in Southeast Asia before spreading into southern Europe and northern China. Recent dating techniques applied to earlier finds in Java and the Caucasus Mountains indicate dates much earlier than that and would place Homo erectus in Asia over 2 million years ago. Such early dates would, if proven accurate, dramatically overturn the currently accepted chronology of early human development. (Long Foreground: Species Timeline, p.4)

Thus, two different hypotheses exist as to when Homo erectus first arose. The first, most traditional model is called "The Multi-regional Evolutionary Model and used to be by far the most popular until recent genetic evidence was brought to light. "This model believes that roughly 1 million years ago, Homo erectus expanded its range beyond Africa, first into Asia and then into Europe, developing geographically variable populations. Homo erectus then became the direct ancestor of Homo sapiens by a gradual worldwide (excluding the Americas and Australia) evolutionary transformation of all populations of Homo erectus." ("Homo Erectus," 2005)

At this date, however, the earliest claimed dates for Homo erectus outside of Africa are still highly controversial. Long Foreground: Species Timeline, p.4) Most anthropologists using conventional dating techniques believe that Homo erectus originated in Africa and soon after migrated to these other continents because, geographically, the land masses of the earth were connected in areas that they are not connected today. "In 1984, a nearly complete fossil skeleton of an adolescent Homo erectus boy was found near Lake Turkana in Kenya. The fossil is about 1,600,000 years old. The skeleton indicated that he had died at about 11 or 12 years of age. The fossil is the most complete skeleton of an early human ancestor ever found." (Mann, 2005) "This boy stood more than 5 feet tall when he died, and would have exceeded 6 feet -- had he lived to maturity. His cranial capacity was 880 cc and his body stature (tall, thin, long arms and legs) are typical of humans adapted to open, tropical environments." ("Homo Erectus," 2005)

But although the fossil and environmental evidence is convincing regarding the "Multi-regional" hypothesis, it is not conclusive. Some anthropologists think that the earliest Homo erectus fossils from Africa should be called by another name, Homo ergaster. These anthropologists point out that these earlier African fossils have thinner skull bones than those of later Homo erectus fossils found in Asia. They believe that Homo ergaster migrated out of Africa to Asia and that Homo erectus developed from this earlier species. But there is a great statistical unlikelihood of such an evolutionary development occurring in parallel over wide areas. (Long Foreground: Species Timeline, p.1)