The genus Homo and The Evolution of Modern Humans from Australopithecines

genus Homo and The Evolution of Modern Humans from Australopithecines
The genus homo
The African environment became
considerably cooler between three and 2.5mya. Forest became smaller in size,
and the range of grasslands was extended.The genus homo, which includes living
and extinct humans, first appeared during these years and although the fossil
records is lacking vital fossils, many scientists infer that they evolved from an
ancestor of the australopithecines.

species had bigger brains, lighter skeletons, flatter faces, and smaller teeth
than their australopithecine ancestors.They are also the first species known to
control fire and to modify stones for tool use. As they evolved, they developed
language and culture Homo habilis used stone tools; the earliest known species
that is generally accepted as a member of the genus homo is Homo habilis,
called ‘handy man’ because of its association with primitive stone tools. This
species lived in Africa between about 2.4 and 1.4mya. 

Homo habilis possesses a
brain averaging 650cm, about 20% larger than that of the australopithecines. It
also had other homo species traits, including a smaller brow; reduce jaw,
flatter face, and more humanlike teeth. Like australopithecines, it was small,
long-armed, and it seems to have retained the ability to climb trees. Other
homo species might have coexisted with Homo habilis, among them a species
called Homo rudolfensis. Because few
fossils of homo rudolfensis have been found, it exact relationship to the rest
of the homo line is uncertain.   

The genus Homo and The Evolution of Modern Humans from Australopithecines
Homo ergaster migrated. Within about 500,000 years of the appearance
of homo habilis, another homo species, homo ergaster, emerged with an even
larger brain. Assertively, Homo ergaster, appeared only momentarily in the
fossil record, from about 1.8 to 1.3 mya. Homo ergaster commonly known as the working man, was taller and lighter
than Homo habilis, and had longer legs and shorter arms. Its brain average
1000 cm, and it had a rounded skull, reduced teeth, and what many scientists
think is the first human nose (with the nostrils facing downward) tools carefully
made and axes and other tools associated with homo ergaster fossils suggest to
some scientist that homo ergaster was a hunter, but others think that homo
ergaster was primarily a scavenger and used the tools to scrape the meat off to
scavenged bones. Displaying African Homo erectus features.
 Migration coupled with  both scavenging and hunting are associated with
migratory lifestyle, and homo ergaster appears to have been the first African
homo species to migrate in large numbers to Asia and possibly Europe, perhaps
following the trail of migrating animals. The later Eurasian forms of homo
ergaster are called Homo erectus. Because homo ergaster shares features with
modern humans, scientist hypothesize that homoergaster is an ancestor of modern humans.
The genus Homo and The Evolution of Modern Humans from Australopithecines
Homo erectus
used fire, homo erectus lived between 1.8 million and 400,000 years ago and
appeared to have evolved from homo ergaster as it migrated out of African. While some scientist consider homo ergaster and homo erectus as a single
species, homo erectus appear to have evolved traits that the early African homo
ergaster species did not have. Members of this species seem to have been more
versatile than their predecessors, and they adapted successfully to variety of
environment. Homo erectus includes ‘java man’, discovered in Indonesia in
1890s, and “peking man”, discovered in china in the 1920s.          
In general, homo erectus was larger
than homo habilis and had a bigger brain. It also had teeth that were no
humanlike. Brain capacity range from about 900cm in early specimens to about
1100cm in later ones. It was as tall as homo sapiens but it had longer skull,
lower forehead and ticker facial bones that either homo ergaster or homo
sapiens. It also had more prominent browridge. Evidence indicates that homo
erectus made sophisticated tools, used fire, and sometimes lived in caves.
The genus Homo and The Evolution of Modern Humans from Australopithecines
Homo floresiensisThe hobbit-In 2004, a curious set of fossils
discovered on the Indonesian island of Flores. This fossils which are about
18000 years old, are heavily debated in the scientific community. Some scientist
thinks they might represent specie called Homo Floresiensis. Others think that the fossils belong to the early
human dwarfs and do not warrant classification as separate specie. H.floresiensis, nicknamed; ‘The Hobbit’’,
was only 1m tall when fully grown. While it had brain and body proportions like
all the australopithecines, primitive stone tools were found with its fossils. In
2007 a study showed that H. floresiensis
had apelike wrist bones­­-further support for its status as a separate species.You
can compare H.floresiensis and
H.sapiens skulls.
The genus Homo and The Evolution of Modern Humans from Australopithecines
What are the evolutionary relationships among H.habilis, H.ergaster and
Homo heidelbergensis- The transition from H.ergaster to modern
appears to have occurred gradually. Numerous transitional fossils have
been found that display a mixture of H.ergaster and H.sapiens traits.These
fossils are often categorized as Homo heidelbergensis,but others
put them in category Homo sapiens.These humans generally had
larger brains and thinner bones than H.ergaster,but they still had browridges
and receding chins.
QUESTION: Relate H.heidelbergensis to
H.sapiens. and comment with your response
Homo neanderthalensis built shelter- A distinct human species called Homo neanderthalensis
or the Neanderthals, evolved exclusively in Europe and Asia about 200,000 years
ago, likely from H.erectus or a Homo intermediary. Neanderthals were shorter
but hd more muscle mass than more modern humans. Their brains were sometimes
even larger than the brains of modern humans, though the brains might have been
organized in different ways. Neanderthals had thick skulls, bony browridges,
and large noses. They also had a heavy muscled, bust stature. Evidence of heavy
musculature appears in the extremely large muscles attachments and the bowing
of the long bones   
The genus Homo and The Evolution of Modern Humans from Australopithecines
Neanderthals lived near the end of the Pleistocene ice age, a time of
bitter cold. Their skeletons reflect life of hardship; bones fracture and
arthritis seem to have been common. There is evidence that they used fire and
constructed complex shelters. They hunted and skinned animals, and it is
possible that they had basic language. There is also some evidence that they
cared for their sick and buried their dead.
Are Neanderthals our ancestors?-
In some areas of their range, particularly
in the middle East and Southern Europe, Neanderthals and modern humans
overlapped for as long as 10,000 years. Some scientists suggest that the two
species interbred. However, DNA test on fossils bones suggests that
Neanderthals were a distinct species that did not contribute to the modern
human gene pool. Neanderthals were extinct about 30,000 years ago.
Written and compiled by : Johnson O. Joseph, CHIEF Editor and defender at Jaysciencetech.