Becoming humans

Becoming humans

This documentary explains us the evolution of the human specie during 4 million years.
First of all, we knew the doctor Donald C. Johansson who is a researcher that wants to discover the evidences of the human’s origins and this is the starting of amazing articles, photos, definitions, dialogues of many specialists and his knowledge of the evolution.
We all know that the story of our antecessors began in Africa where a complex culture was developed by animals and their adaptation. By doing researches in areas like Ethiopia we have found partials skeletons of animals that seem to walk on two legs and this was the first evidences for the human’s origins. The knowledge of the experts everyday is bigger and the studies of the footprints, the environmental impacts (like the cool and dry period that was the exiction of some species), and also the fantastic Darwin have made our knowledge of the evolution and adaptation something very important.

This is what I have learnt from the documentary but with the chat of Maria del Mar I have learnt more. I have enjoyed so much her meeting and her explanations because she reflected her love for her job and this made the talk much more interesting. I think our class has made so many questions and she was very pleased to be with us.

Now I want to add to my blog this article of Homo Floresiensis because this point of the chat has woken up my curiosity and I would like to share with yours my searching about this hominid full of mysteries.
Homo floresiensis: the Hobbit
Homo floresiensis is a species of dwarf human discovered at the Liang Bua cave on the Indonesian island of Flores in 2003. H. floresienses was only about 1 meter in height and fully bipedal, with a very small brain size of 417cc. The skull has human-like teeth with a receding forehead and no chin. floresiensis fossils have been discovered from 38,000 to 18,000 years ago, though archeological evidence suggests it lived at Liang Bua between at least 95,000 and 13,000 years ago. It used stone tools and fire, and hunted pygmy elephants (mostly juvenile ones), Komodo dragons, and the giant rats found on Flores. Its discoverers believe that floresiensis is a dwarf form of Homo erectus - it is not uncommon for dwarf forms of large mammals to evolve on islands.
The most complete floresiensis fossil, consists of an almost complete skull and a partial skeleton consisting of leg bones, parts of the pelvis, hands and feet, and some other fragments. The skeleton found was probably an adult of about 30, probably female judging by the pelvis. Males could have been larger, though the other fossils found so far indicate only individuals about the same size as floresciensis . Because of the damp condition and young age, the bones have not fossilized (i.e. had not turned to stone), and reportedly had the consistency of mashed potatoes.
The brain size of the floresiensis skull is extraordinarily small, at 380cc. This is as small as any australopithecine ever discovered, and fairly typical for a chimpanzee. (Chimps range from about 300 to 500cc, averaging about 400cc, but are physically bigger than floresiensis.) This is smaller than would be expected even for a dwarf form of Homo erectus, and suggests there was active selection for a small brain size for some reason. (Human pygmies, incidentally, are nothing like H. floresiensis; their brains are almost as large as those of normal-sized humans)
There has been some speculation that the stone tools found with it were actually made by Homo sapiens, mainly because it is hard to believe a creature with such a small brain could make such sophisticated stone tools. There is no other evidence in support of this, however, and if it were not for the small brain size, there would be no hesitation about assuming floresiensis made the tools because of the close association between the tools and the fossils. The same tools are found through the entire deposit (from 90,000 to 13,000 years ago) and, interestingly, they are not like any stone tools made by Homo erectus.
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.
Modern humans arrived on Flores between 55,000 and 35,000 years ago, and presumably interacted with floresiensis, though there is no evidence of this at Liang Bua. However Indonesian folklore tells of creatures called Ebu Gogo which were small, inarticulate, and walked with an odd gait. This sounds remarkably suggestive of floresiensis, but it could easily be coincidence - if floresiensis had been found in Ireland, we'd possibly be wondering if they were leprechauns.
The discovery of H. floresiensis does not change the broad picture of human evolution, including our lineage - it was certainly not ancestral to us. But since it is the most extreme example of human adaptation ever found, it suggests that humans are more subject to evolutionary forces than we tend to think. And the fact that floresiensis lived so recently and yet has been unknown until now suggests that there could be other surprises waiting in the human family tree.