Encyclopedia of Evolution.pdf - Online Reading Center

Although Homo ergaster, the presumed ancestors of H.
erectus, made advanced stone tools of the Acheulean industry,
H. erectus tools represented only the most primitive stone
tool technology, the Oldowan. A diagonal line from England
to India, called the Movius line, separates the old and
new industries. This pattern could be explained either of two
ways. First, H. erectus may have evolved from very early H.
ergaster, or even from populations that could be called H.
habilis, before the Acheulean tool culture had developed.
Second, the H. erectus migrants may have lost the ability or
desire to produce Acheulean tools and reverted to the simpler
Oldowan style.
Homo erectus constitutes evidence that human evolution
consisted of several or many parallel lineages, all of which
except one ultimately became extinct.
Further Reading
Boaz, Noel T., and Russell L. Ciochon. Dragon Bone Hill: An Ice-
Age Saga of Homo erectus. New York: Oxford University Press,
2005.
Fischman, Josh. “Family ties.” National Geographic, April 2005,
16–27.
Tattersall, Ian, and Jeffrey Schwartz. Fossil Humans. New York:
Westview, 2000.
Homo ergaster Homo ergaster (“worker man”) refers to
the “erectus” humans who lived in Africa from about two
million to about one and a half million years ago, and who
were the ancestors of modern humans. “Erectus” humans
were transitional between Homo Habilis and later human
species (see Neandertals; Homo sapiens). They were
anatomically nearly modern in all respects except that their
brains were smaller than those of Neandertals and modern
humans. “Erectus” humans lived in Africa, then spread
throughout Europe and Asia. Most anthropologists consider
the African, European, and Asian “erectus” specimens to represent
distinct species. African “erectus” humans, H. ergaster,
that remained in Africa evolved into modern humans (H.
sapiens); H. ergaster that migrated into Europe (see Homo
HeiDelbergensis) evolved into Neandertals; H. ergaster that
migrated into Asia became the Asian “erectus” species (see
Homo erectus; Flores Island people). Since the name H.
erectus was first defined from southeast Asian “Java man”
specimens, which are considered to be the same species as
“Peking man” specimens, the Asian “erectus” species retains
the original name.
Numerous specimens of H. ergaster have been found.
The most complete is the Nariokotome skeleton, also called
the Turkana boy (see figure on page 189), found by Kenyan
anthropologist Kamoya Kimeu and associates (see Leakey,
Richard). Some molars were still erupting at the time of
death, therefore the Nariokotome boy was less than 10 years
of age when he died. He was already five feet three inches
(160 cm) tall when he died, and probably would have grown
to six feet one inch (185 cm) by adulthood. The tall, skinny
body form of this species, like that of modern tribes of the
African savanna, appears well adapted to dispersing body
Homo ergaster
The Nariokotome or “Turkana boy” skeleton, excavated and reconstructed
by Alan Walker and Richard Leakey, was about nine years of age when
he died. He was over five feet (almost m) tall but had the brain of a
modern one-year-old child. He represents an almost perfect “missing link”
in human evolution. (Courtesy of Kenneth Garrett/National Geographic
Society)
heat. The skeleton is complete enough that almost nothing is
left to the scientific imagination. H. ergaster, as represented
by this specimen, had a fully modern anatomy except that the
brain was the size of a modern one-year-old child. Because
of the fact that there are no obvious structural abnormalities,
and that the boy lived to be almost a teenager, the small brain
cannot be considered to represent a deformed microcephalic
individual. The Nariokotome boy was normal for his species.
H. ergaster in general, and the Nariokotome skeleton in
particular, represent one of the almost perfect missing links
between earlier hominins and modern humans.
H. ergaster differed from earlier H. habilis by making
more advanced stone tools, having larger brains and more
complex cultures, making fire, and possibly by having the
first languages: