تحياتي للجميع لقد قرأت اليوم أخر مقال علمي يتعلق بموضع النقاش وأردت اشراككم في قراءته.
Questions raised by the discovery of Homo Floresiensis
By Espe Espigares
Homo Floresiensis
The discovery of the remains of an unknown pre-historic human on a little island near Indonesia shook up the scientific community a few weeks ago. This has been considered the most important event in palaeoanthropology in decades. The bones of seven different individuals where found in the Liang Bua cave of Flores Island, with unique characteristics that classify it as a new species of human: Homo Floresiensis. This little hominid that lived between 85,000 and as close to our times as 13,000 years ago, was 3 feet tall [one metre], had a brain smaller than that of a chimp and was able to build quite sophisticated tools.
Many questions arise from this discovery. How did this hominid manage to get to this island? Who were its ancestors? How could it make tools having such a small brain?
It would appear that Homo Floresiensis is a descendant of Homo Erectus (which appeared some 1.8 million years ago) that dwarfed once it got to the island. This phenomenon, known as “island dwarfing”, has been seen several times. Species that become extremely isolated can dwarf due to a combination of lack of high calorie food with a lack of predators. A rabbit sized animal in such conditions would have the most efficient size in terms of energy saving, so big animals tend to dwarf and small animals tend to get bigger in order to adapt to this isolated environment. We have several well-documented cases of this, as for example the stegadons, which were primitive dwarfed elephants.
The question that follows is, as Homo Floresiensis is a descendant of Homo Erectus, how did Homo Erectus get to the island? There are a few theories that attempt to explain this: one of them is that Homo Erectus may have been able to build small rudimentary boats. There are other more fantastic – and less scientific – explanations, but the most logical and more likely answer to this question is that Homo Erectus got to the island on floating mats of vegetation. There may also have been small islands that do not exist any more which created a short-lived land bridge between Flores and the mainland. This scenario may seem unlikely and improbable, but whether they floated on vegetation or crossed over a land bridge, they only had to do so once, so over a long period of time Homo Erectus had several chances of wining this lottery.
The fact that Homo Floresiensis appeared some 85,000 years ago, and bones have been discovered dating from 13,000 years ago, confirms another interesting fact: that several species of humans have shared the planet at the same time. This is an idea now accepted in the scientific community, but articles on Homo Floresiensis in newspapers seem reluctant to accept it. It is proven without doubt that Homo Sapiens and Neanderthals lived in Europe at the same time. However, this is presented as an exception to the rule. In fact it is quite likely that several different species of hominids existed at the same time.
Evolution is not a linear and gradual matter. Evolution works in a dialectical way where for long periods of time nothing much seems to change. During these long periods there are quantitative changes taking place, and these quantitative changes accumulate. These longer periods are interspersed with shorter periods where quantity changes into quality, where the accumulated quantitative changes transform into apparently sudden and huge qualitative changes, shaking the old arrangement of the species. The late palaeontologist Steven Jay Gould termed this process “punctuated equilibria: “the history of life is not a continuum of development, but a record punctuated by brief, sometimes geologically instantaneous, episodes of mass extinctions and subsequent diversification.” (quoted in Alan Woods and Ted Grant “Reason in Revolt”)
Evolution does not function according to clear cut eras and periods, as seen on an ‘evolutionary tree’. It is not a linear process in which less developed species kindly disappear leaving room for the most advanced ones. It is not a step-by-step process of gradual evolution, but proceeds dialectically with periods of changes and development overlapping one another. Gould describes it in this way: “Evolution is a theory of organic change, but it does not imply, as many people assume, that ceaseless flux is the irreducible state of nature and that structure is but a temporary incarnation of the moment. Change is more often a rapid transition between stable states than a continuous transformation at slow and steady rates.” (Gould, Stephen Jay 1980. “A Quahog is a Quahog”, The Panda’s Thumb). For instance it would be absurd to think that Neanderthals simply disappeared over the course of one day or just a few years in order to clear the way for Homo Sapiens.
Scientists are puzzled by the fact that Home Floresiensis could make tools having such a small brain. This is another example of non-dialectical thinking. Size does not always matter. The proportion of brain size in relation to the body is more important than the size itself. Quality is more important than quantity. The fact that Home Floresiensis had the capacity to make tools should not be surprising at all. Its brain may have been smaller than that of other tool-making hominids but its structure is sophisticated enough to make tools. We have also to take into account that Homo Floresiensis is a descendant of Homo Erectus, who was able to make tools. That Homo Floresiensis evolved by reducing its body size to adapt to the environment of an isolated island, doesn’t mean that it lost brain capacity in the process. Even just taking the aspect of brain volume, where is the evidence that a Saint Bernard is cleverer or more intelligent than a Chiwawa?
What is clear is that this hominid is not an aberration or an exception to the rule, but something that could be quite common, which may result in the discovery that yet more different species of hominids shared the earth at the same time and we do not yet have knowledge of their existence.
A lot has been made of legends in remote villages on Flores Island about small human-like monkeys that would come from the forest to the villages, eat and spoil crops and even take away babies. Scientists have been very surprised by the similarities between the descriptions from villagers of this “Ebu Gogos” (meaning he who eats anything) with Homo Floresiensis. In fact the nickname of the most well preserved specimen of Homo Floresiensis, Ebu, comes from these legends. The possibility has even been raised of finding these hominids still living somewhere on the remote islands. Although this is quite unlikely, what is certain is that in the remote case that these legends originally had any basis in truth, mixed with fantasy, they have now been conditioned by present day reality, and this will colour the attempts of scientists to find clues about Homo Floresiensis.
What makes as human?
Even so, there are hypothetical questions being raised about how we would treat them in the case that they still existed. They are from the same species as we are so... what makes as human?
Homo Floresiensis alongside Homo Sapiens
This seems like a very tricky question and it can only be answered correctly from a dialectical point of view. There are two main theories that attempt to answer this question. On the one hand there is one school of thought that describes Homo Sapiens as the most intelligent and cleverest species of hominid, distinct from all of the other species, who are all put in the same bag, and are described as less intelligent. The abilities of early Homo Sapiens are often over-estimated and exaggerated while the abilities and intelligence of all other hominids are often under-estimated. On the other extreme you have scientists who exaggerate the abilities of primates. It is true that the study of apes is very useful in order to understand human development. That we are cousins of the monkeys and we have 98% of genetic code in common is not a small detail. But that obviously has its limitations.
Language is an important difference. But is it exclusive to humans? Studies show that not only monkeys, but also other animals more distant in evolution from us can use sounds to communicate to each other and with the pack. Animals have very sophisticated ways of sharing information. Bees for example can communicate to each other the exact position of where flowers are to collect pollen. But they are unable to compare this information with the location of flowers on previous days. Monkeys use different sounds to warn each other about dangers. The sounds can be quite specific, being different when danger comes from above (i.e. an eagle, to which monkeys will react by looking up and hiding) or from below (i.e. a snake, to which they will react by climbing and hiding in the trees). But this cannot be considered a language of monkeys because other animals from completely different species that live nearby can “understand” these sounds and act accordingly in order to protect themselves. This, although interesting enough, is not language. It is certainly a method of communication, but not language.
Monkeys cannot learn to speak. Firstly their brain is not developed enough. Language requires a level of abstract thought that they do not possess, and secondly but much more importantly, it is physically impossible, because they lack the vocal apparatus to be able to speak. Our ancestors were able to develop language by the lowering of the larynx in a way that enlarges the resonance chamber in the throat and mouth, enabling us to produce a range of sounds that is well beyond the capabilities of apes. We are not born with this apparatus fully developed. Babies are born with high larynxes which drop as they grow, enabling them to speak. In fact that is quite useful for babies because it allows them to swallow and breathe at the same time avoiding the danger of choking when feeding.
Learning is also an important characteristic that makes us human. Most animals can also learn, so we must put the question in a different way: can animals teach? No, they cannot. They cannot teach and they learn mostly by imitation. Animals can facilitate learning to their offspring, for example slowing down what they are doing so it is easier for their young to pick up the technique. A cat will bring a half dead mouse to its kittens so they can practice their hunting techniques. This is not teaching but facilitating learning.
Culture is another aspect that must be taken into account. For example, some monkeys use wood to break nuts while other groups use stones. This has been considered by some to be a rough embryonic culture but what it really shows is that monkeys learn by a lot of trials and a lot of errors, and by imitation.
Making tools
The most important aspect is the ability to create tools. There are some examples of alleged tool making by monkeys. Some monkeys chew leaves to create a sponge to get to hard in order to reach areas to soak water to drink. There are also cases of monkeys that use sticks to get ants in a safe way from dangerous columns of deadly ants or from the inside of trees. As curious and exciting as this may be, these tools are so rudimentary that they cannot be considered as such. Even if one were to consider these as tools, they are very different from the tools made by hominids. Chimps do not have the capacity for abstract thought that would allow them to make something more sophisticated, and using a stone to crack a nut cannot be considered as making a tool. They are bound by the limits of their natural surroundings and are “using tools”, not “making tools”. Even if you consider chewing a leaf to use as a sponge a tool, what is clear is that these are never built before the moment in which they need them, and they forget about them the moment that they finish with the particular task. This can be more accurately described as using the environment than as creating tools.
Even so, in decades studying monkeys we have only found a few examples of monkeys using “tools”. These examples are so scarce that they are anecdotal, while we have thousands of examples and ample evidence of tools made by hominids of all kinds and shapes, usefulness and sophistication. We also have to take into account that many of the tools made by our ancestors were built with materials that were less durable than stone. They may have built tools that we will never have the chance to see, made for example from wood, leaves, skin of animals, etc...We tend to find mostly the ones that were left in caves, not because all hominids lived in caves, but because conditions there are better for their preservation.
It is the combination of all these things that make us human – language, the ability to teach, culture, and tool making. Some animals have what is a very embryonic or primitive version of some of these abilities, but the qualitative difference is more than relevant. What made us human, what made language, culture and complex learning a necessity was labour. Labour is a unique characteristic that we do not share with any other animal on the planet and this is the crucial difference that separates us from them. Through labour we are the only species that has been able to transform the environment and use it consciously for our own benefit. In the words of Engels: “the animal merely uses its environment, and brings about changes in it simply by its presence; man by his changes makes it serve his ends, masters it. This is the final, essential distinction between man and other animals, and once again it is labour that brings about this distinction.” (The Part played by Labour in the Transition from Ape to Man)
The climate was the most important factor that forced life to evolve. From the very beginning evolution is a race to adapt to the environment. We do now know quite accurately what the temperature of the earth was in pre-historic times. Measuring the layers of oxygen (which is more scarce and lighter in ice) at the bottom of the oceans has given us an accurate pre-historic temperature history of the earth. The retreat of glaciers created a dramatic change in climate which transformed the jungles of Africa (the cradle of humans) into savannas. All natural life had to adapt to this new environment and for the early apes this meant they had to leave the trees and forests. In an open space an upright position was much more advantageous allowing hominids to see danger from a distance. This was the first stage in freeing the hands for labour, and the whole body had to adapt to this change.
The upright position also had another major advantage: they lost speed but gained in being able to walk longer distances. Again it was necessary to adapt the centre of gravity nearer the trunk of the body. Freeing the hands was a major breakthrough because it allowed hominids to start building the tools needed to adapt to harsher environmental conditions. At the same time this labour developed the brain, which allowed us to build even more complicated tools. As the complexity of the tools grew, collaboration between different individuals and language became a necessity. Engels brilliantly describes this process: “the development of labour necessarily helped to bring the members of society closer together by increasing cases of mutual support and joint activity, and by making clear the advantage of this joint activity to each individual. In short, men in the making arrived at the point where they had something to say to each other.” (Ibid) This led us to our mastering of nature.
Oppression of women
Going back to Homo Floresiensis. Of the bones from the seven individuals, the best preserved is of a female know as LB1 or by the nickname of “Ebu”. We know that it was a female because of the shape of the pelvis. The bones are not fossilized so it may be possible to extract DNA. This is surely going to be of key importance if we are to know more about this species of hominid and about our own origins.
What is really surprising is that although the main object of study discovered was a female, in all the newspapers hardly without exception the graphic representation was of a male. This is a very common practice in palaeoanthropology. Books, textbooks, museums, etc, tend to represent human ancestors as males. This is wrong from a scientific point of view and it shows that science and scientists are not immune from the prejudices dominant in society.
We also have to remember that scientific theories are also shaped by the society we live in – modern-day class divided society and capitalism. In the textbooks we have pictures of Homo Sapiens, our closest ancestors, with white skin, fair hair and looking very agile and sophisticated, while the Neanderthals are depicted as hairy beasts with dark skin and looking very similar to apes. These images presented to us by “science” are quite unlikely to represent the true picture. Homo Sapiens had just arrived from Africa and Neanderthals had been the first ones to colonise the north of Europe. So it is actually much more likely that Sapiens had dark skin and hair and that Neanderthals were the fair-haired ones with blue eyes! These prejudices are not always so obvious and palpable as in the drawings but they still affect theories, and sometimes in a very disturbing way.
We live in a class divided, male-dominated society. Science is affected by this and often today’s standards, today’s models, are superimposed on prehistoric society. But human society has not always been male dominated and has not always been divided into classes. In fact for most of human existence this was not the case. The oppression of women arose with the appearance of private property. In this respect some very interesting conclusions emerge from a study of our ancestors.
The upright position which freed the hands for labour and the growth of the brain that resulted from this, created a physical contradiction for the procreation of humans. In nature, there is not much growth of the brain once an animal is born, so we could say that animals are born when their brain reaches maturity. If this were the case with humans the period of pregnancy would have to be 21 months. This would have deadly consequences for the mother and the baby because our brains and heads have evolved to become too large for passage out of the womb during birth.
So evolution solved the problem for our ancestors: giving birth prematurely. Even so it is a very tight squeeze and the bodies both of women and babies had to adapt. The mother’s pubic bone becomes more elastic during late pregnancy allowing the two halves of the pelvis to separate slightly during birth and the plates of the baby’s skull, which in adults are welded together, slide over each other at the edges as the head forces its way through the birth canal, making the skull slightly smaller. In fact, we are born on the edge of survival. We are just about able to make it. This is why premature birth is so dangerous for humans, while with other animals it is not such a problem. Humans are helpless when born and their underdevelopment demands even more need of attention and care from their parents.
If we look at apes, they are much more agile when born and they can easily jump onto their mother’s back and grip her in a way that allows her to carry on more or less with her normal everyday life, climbing trees, looking for food and grooming. An animal that is born underdeveloped is more dependent and demands more work from the mother. Originally this did not led to a disadvantage for women because raising the offspring was done in a collective manner in primitive human society. Unlike what we commonly see in drawings of pre-historic communities, in which we are shown a nuclear family composed of one mother, one father and one child, the primitive family was a much larger group of relatives helping and supporting each other.
There was division of labour between male and female, but this did not mean discrimination because all tasks were considered equally important. In fact the role of women in primitive society was extremely valued by society. Women’s responsibility for raising children became only a “disadvantage” with the development of class society. With the development of technology, agriculture and cattle breeding a surplus was created. This surplus was very modest. It was not enough to share with everybody in the clan, so only a small minority benefited from it. The division of labour, that previously had not mean any disadvantage for women, now became precisely that because of the role that man had in production. Engels described this change as “the world historic defeat of the female sex”:
“To him, therefore belonged the cattle, and to him the commodities and the slaves received in exchange for cattle. All the surplus which the acquisition of the necessities of life now yielded fell to the man; the women shared in its enjoyment, but had no part in its ownership.” (Origins of the Family, Private Property, and the State)
It was not so called “human nature” or some kind of male conspiracy that led to the development of class society and the oppression of women. The material conditions changed and these created the basis for class society and with it the oppression of women. This is the basis of Marxist philosophy: Materialism. In the study of the origins of humans and evolution this means that we have to analyse the objective conditions to understand the course of events. Humans evolved in a very sophisticated way, not because they had been given the gift of reason, but because the material conditions demanded it. Reason and the capacity of abstract thought evolved from these material conditions.
The application of the method of Marxism, dialectical materialism, allowed Engels to draw the general lines of the evolution of man as early as in 1856 when there was very little fossil evidence to support it. In those days the most important trend in evolutionary theory was idealistic. Reason was considered as the crucial aspect of being human, instead of considering it as something that we have acquired with the development of evolution and as a result of the needs created by labour.
Today most scientists disregard philosophy in general, and Marxism in particular. However, consciously or unconsciously, we all have a philosophy which we use constantly when we observe and analyse the world around us. If we do not consciously use a philosophy, we use the one of the dominant capitalist class, which is permeated by all kinds of prejudices and idealism. This philosophy looks at events from the point of view of a class divided society and aims to justify the status quo. The most recent discoveries in all fields of scientific research have confirmed that nature works in a dialectical way. Marxist philosophy, dialectical materialism, is the most advanced method of analysis available to us. It is a vital tool for workers and youth, not only to understand where we are and where we want to go and how, but also where we come from.
December 2005
See also:
The Demonic Ape By Alan Woods (January 2004)
What is Historical materialism By Mick Brooks (November 2002)
A tribute to a great scientist: Stephen Jay Gould By Fred Weston (May 23, 2002)
Engels and Human Development By John Pickard (June 1984)
Historical Materialism By Mick Brooks (September 1998)
Reason in Revolt, Marxism and Modern Science By Alan Woods and Ted Grant
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المصدر :
http://www.marxist.com/scienceandtech/homo...loresiensis.htm
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