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Africa provides a comprehensive and contigious time line of human
development going back at least 7 million years. Africa, which developed the world's oldest human civilization, gave humanity
the use of fire a million and half to two million years ago. It
is the home of the first tools, astronomy, jewelry, fishing, mathematics,
crops, art, use of pigments, cutting and other pointed instruments
and animal domestication. In short Africa gave the world human civilization.
Ishango
Bone
World's First Abacus |
Millions of years ago human life started in Africa, Australopithecus
aphaeresis and Australopithecus africanus and Australopithecus
robustus were all key rungs in the development of humanity.
These fossils were found in East and South Africa (Azania). Some
of the fossils may be as old as 5 million years. For example Australopithecus
robustus fossils found in an East Turkana Kenya site were at
least 4 million year old.
It is generally accepted that the Homo habilis were the
first full fledge tool makingancestor of humans. The earliest archaeological
evidence of toolmaking comes from the Koobi Fora section of East
Turkana. These Homo habilis are believed to be at
least 2.5 million years old. The name Homo habilis comes
from the Leakeys. They found what they believed to be conclusive
fossil evidence of the first humans in the Olduvai Gorge in Tanzania
and gave these ancestors that name called Homo habilis..
The Olduvai Gorge Homo habilis existed at least a million
and quarter years ago
More important than tool making in human evolution is the mastery
of fire. Nearly 2 million years ago early East Africans had mastered
the use of fire. This was a revolutionary step in the development
of humanity. This critical innovation insured the survival and spread
of the species around the planet. It gave us an advantage over animal
predators such as the big cats, hyenas and allowed human settlements
in less accommodating climates. These people have been named Homo
erectus by archaeologists. It is generally accepted that the
final leap from Homo erectus to Homo sapiens sapiens
as having occurred in Africa over two hundreds thousand years ago.
The Encyclopedia of World History describes the use of mtDNA found
in fossils as a means of revealing the processes involved in this
final leap. (The acronym mtDNA stands for mitochondrial DNA*.)
Molecular biologists like Alan Wilson and Rebecca Cann have studied
the human family tree using this form of DNA, which is inherited
through the female line without being diluted with paternal DNA.
Thus, they argue, it provides a unique tool for studying ancestral
populations. They compared mtDNA from Africans, Asians, Europeans,
and Southeast Asians and found that the differences between them
were small. They formed two groups: one was the Africans, the other
the remainder. Wilson and Cann concluded that all modern humans
derive from a primordial African population, from which populations
migrated to the rest of the Old World with little or no interbreeding
with existing archaic human groups. By calculating the rate of mtDNA
mutations, they argue that archaic Homo sapiens evolved from Homo
erectus in Africa by about 200,000 years ago. Then Homo sapiens
sapiens, anatomically modern humans, appeared some 140,000 years
ago. Mitochondrial DNA is still controversial, but there is some
archaeological evidence from Africa that supports the biologists'
scenario. Highly varied, early Homo sapiens populations flourished
in sub-Saharan Africa between 200,000 and 150,000 years ago, some
of them displaying some anatomically modern features. At the Klasies
River Caves on the Indian Ocean coast of South Africa, anatomically
modern human remains date to between 125,000 and 95,000 years ago.
They are associated with sophisticated, versatile tool kits that
were, if anything, superior to those used by the Neanderthals in
Europe at the time.
Many scientists believe that Homo sapiens sapiens, modern humans,
did indeed evolve in tropical Africa sometime after 150,000 years
ago, as the geneticists argue. Ecologist Robert Foley has theorized
that modern humans evolved in a mosaic of constantly changing tropical
environments, which tended to isolate evolving human populations
for considerable periods of time. Some groups living in exceptionally
rich areas may have developed unusual hunting and foraging skills,
using a new technology so effective that they could prey on animals
from a distance with finely made projectiles. With efficient technology,
more planning, and better organization of both hunting and foraging,
our ancestors could have reduced the risks of living in unpredictable
environments in dramatic ways.
source: http://www.bartleby.com/67/24.html
*Mitochondrial is defined as: 1. A spherical or elongated organelle
in the cytoplasm of nearly all eukaryotic cells, containing genetic
material and many enzymes important for cell metabolism, including
those responsible for the conversion of food to usable energy. It
consists of two membranes: an outer smooth membrane and an inner
membrane arranged to form cristae. 2. The cell organelle where much
of cellular respiration takes place; the "power plant" of the cell.
Mitochondria probably entered eukaryotes by an act of endosymbiosis,
in which one simple cell was absorbed by another. Mitochondria contain
their own DNA. It is by tracing the mitochondrial DNA, which individuals
inherit only from their mothers, that genetic linkages are often
traced (Sources: the Houghton Mifflin Company Medical and Science
Dictionaries)
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