Sunday, 16 December 2012

The Origins of Homo floresiensis

A dwarf is an extremely short adult who is less than 58 inches tall. The word midget is considered derogatory and offensive. Both words describe a short person, but refer to different physical characteristics and genetic conditions. "Midget" refers to a person who is very short, but normally proportioned. The term midget is now rarely used and is considered offensive. But its usage was very common until the end of the twentieth century. It has given way to "Short person" or "little person". Several varieties of a specific genetic condition called dwarfism. A dwarf has disproportion of body parts.This is generally caused by a genetic or nutritional disability. Any adult human below the height of 4'10" (147 cm) is considered a dwarf. With reference to legends or folklore, a dwarf is considered a legendary creature resembling a tiny old man, who lives in the depths of the earth and guards buried treasure.
But while a genetic mutations, may create dwarfism, a discovery of a new human species was found in a cave on the Indonesian island of Flores in 2003. Flores is one of the Lesser Sunda Islands, an island arc with an estimated area of 14,300 km² extending east from the Java island of Indonesia. Its unique location with deep underwater trenches have dangerous currents that have cut of Fores and other neighboring islands from the mainland. Its isolation has brought about some unique changes spawning creatures like the kimono dragon. While evidence of modern man never reaching the islands until 1200 years, the compelling mystery of stone tools found dates back 3 quarters of a million years ago. Archaeologist Mike Morwood and colleagues tracked a cave called Liang Bua, while reading the techniques of deep excavation of sand before any work was done.
Because evolving from erectus to floresiensis is such a drastic reduction in body size, there has been some speculation that floresiensis might actually have evolved from something smaller, such as the Dmanisi hominids found in Georgia, some of which have brain sizes between 600 and 700 cc, smaller than the 800-900cc typical of early erectus.
Flores was also in the news in 1998, when Mike Morwood (who is also involved with this new find) announced the discovery of stone tools at another site on Flores dated at 840,000 years many many years before homo sapiens. It was assumed at the time that this was evidence of Homo erectus, since erectus was the only pre-sapiens hominid known to have existed in Indonesia.

Indonesia's most prominent paleoanthropologist Teuku Jacob has also been reported in newspapers as claiming that LB1 was not a member of a new species, but a member of the "Australomelanesid race" of modern humans, and only 1,300 to 1,800 years old. Other septics mentioned Microcephaly has caused the specimen to be small.
The disorder may stem from a wide variety of conditions that cause abnormal growth of the brain, or from syndromes associated with chromosomal abnormalities. But common brain shapes of microcephaly brains differ to the H. floresiensis.
The diseased modern human theory couldn't explain the growing evidence that a jaw bone and a skull at different chronologies probably thousands years apart. The teeth shared a similar size and shape suggest it was either had the same disease or in fact they were normal for that species. While experts explain that evolutionary causes for the shorten teeth, other specialists found that the bones of the hand and feet are similar to early hominids.
This conclusion was challenged by Robert Martin, since Jacob's death the leading proponent of the microcephaly hypothesis, and Alan Thorne. Martin noted that no research has been done on wrists of microcephalic people. Thorne maintained that the differences were small and that similar variation could occur with living modern humans. He also pointed out that the carpal bones had been found scattered in the cave and it was not certain that they all belonged to the same individual. Project leader Morwood countered that there were also other features, such as the stature, body proportions, brain size, shoulder, pelvis, jaw, and teeth which suggested that H. floresiensis is a separate species that evolved in isolation on the island.
Another explanation is the theory of island biogeography proposes that the number of species found on an undisturbed island is determined by immigration and extinction. And further, that the isolated populations may follow different evolutionary routes, as shown by Darwin's observation of finches in the Galapagos Islands. Immigration and emigration are affected by the distance of an island from a source of colonists (distance effect). Usually this source is the mainland, but it can also be other islands. Islands that are more isolated are less likely to receive immigrants than islands that are less isolated. The absence of natural predators and mainland creatures would create a unique evolutionary pathway, whereby small animals with evolve large and large elephants become small.
The final evidence of Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct 2 million years ago. The bones of Australopithecus matched up to the bone configuration of Homo floresiensis.
Early human fossils, dubbed Homo georgicus, or Homo erectus georgicus, were found at Dmanisi between 1991 and 2005. Soon after evidence of Australopithecus and Homo erectus have been dated at 1.8 million years, showed how it could be possible that Homo floresiensis might be part of the lineage. The compelling evidence that early man as far back as 1.8 million years exiting Africa reaching Dmanisi, could go further to Asia and possibly Flores island. Despite skeptics thinking the bones at Flores is a genetic mutation similar to a pygmy or disease that stunts grown, the original discoverer Mike Morwood will return back to the cave to uncover more evidence. While it is uncertain if Homo floresiensis will be accepted species of human, people are still researching to uncover hard evidence.  Meanwhile modern forensics have reconstructed the archaeological remains of the Homo floresiensis skull to uncover a surprisingly human face...

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