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Home , Java Man, Meave Leakey, Piltdown Man

THE SEARCH FOR OUR ANCESTORS

Adapted from Irwin Cohn, In Search of the Origins of Humanness , 2005. pathologist of the day pronounced the bones to be those of an idiot. Many other views were presented, but since it was impossible to accur- ately date the age of the find, the individuals who main- tained that the might be an extinct form of humanity, perhaps a Have you ever wondered what it is to be "?" What sets us different species, won little support. Later, these fossils were to become apart from other ? If you go back far enough in our ancestry, there known as Neanderthal Man who lived in Europe between 300,000 and was a time when we were not quite human. So when did we cross that 40,000 ago. "line" that separates the human from the non-human? Scientists did not It wasn't until 1859, the that published his begin posing this question from an evolutionary perspective until relatively famous book The Origin of Species , when a number of thoughtful recently. For much of the 19th century, Western scientists believed people began to suspect that the experts might be wrong about fossils had always been around, in our present form, and that the earth itself, and the idea of a mechanism that could explain evolutionary change judging from the Bible, was only about 4,000 years old. Evidence to the slowly developed. Darwin wrote that species had not always contrary, such as ancient fossils, were viewed as curious oddities or simply been physically the same as they are today--that present-day animals ignored. were the result of many thousands, perhaps millions, of years of In 1856, in the selective change. And he pointed to fossils as evidence of this change. Neander Valley in What a furor arose! Germany, a group of All over the world, anyone who could read a newspaper argued quarrymen discovered with his neighbor about who was right--the supporters of evolutionary what, at first, they thought change (the gradual, continuous transformations in the forms and were the remains of a cave behavior of living organisms resulting from adaptations made to changes bear. They had blasted in their environment) or the people who maintained the traditional view. open a small cave on the Darwin's "crime" was not that he believed man evolved from side of a mountain and (another scientist, Thomas Huxley, had already proposed that), but that were digging in the floor he was opposing the idea of progress as being inherent in evolutionary of the cave with pickaxes change. Darwin's natural selection (The process describing the inter- when they found a strange action between members of a species and their environment by which and set of bones. those individuals possessing advantageous characteristics are more likely These bones came to survive than individuals who do not possess them) was a mechanical quickly to the attention of process that did not need divine intervention and did not, by definition, scientists, immediately creating a controversy. Some scientists said they lead to progressively superior forms of life. were the bones of an ancient man, much more ancient than modern humans, Facts in favor of an evolutionary interpretation of human origins while others insisted that the individual was merely a deformed person of already existed. As developed, the gaps between one geological modern . Rudolph Virchow, a respected German anatomist, declared era and the next were becoming smaller, indicating the idea of a con- that the heavy brow ridges of the skull had developed from constant winc- tinuous transformation of the earth's surface. It was also evident by ing, caused by the life-long pain of rickets, and of a broken elbow and the Darwin's time that some living animals had useless, unexplainable rem- slightly bowed thigh bones of the creature had developed through years of nants of organs, such as the presence of undeveloped limbs in certain riding a horse. snakes and insects with small, functionless wings incapable of flight. He concluded that the bones were those of a Russian Mongolian All vertebrate limbs show an underlying identity of basic structure in Cossack who had died fighting Napoleon in 1814! Another well known creatures so diverse as the leg of a horse, the front limb of a mole, the wing of a bat and the arm of a human: there is also the resemblance shelter called Cro-Magnon in southwestern France, made a remarkable between human embryos and other embryos. Nineteenth century embry- discovery. ologists also understood, in a simplified form, the idea of recapitulation, They found five fairly intact skeletons in the floor of the shelter, that an organism passes through a series of embryonic stages resembling its accompanied by an assortment of stone tools and the bones of animals biological predecessors from which it was descended. known to have been extinct for thousands of years. This time there was no question that humans and extinct animals had lived at the same time and that the Cro-Magnon people had made and used the stone tools that were found with them. Unlike the earlier finds, these were human beings like ourselves. Cro- Magnon ( Sapiens) is a term often used not only to refer to these early modern representatives of humans in Europe, but to modem humans in other parts of the world as well. Particularly in Africa from where they are thought to have evolved about 120,000 BP (Before Presnt) before spreading out into the rest of the world. In the next two decades more fossil human bones, all of them like Cro-Magnon, were found. By this time, the study of archaeology had become more systematic. Archaeologists began peicing together the Darwin did not discuss the subject of human origins in Origins of past using the idea of site stratigraphy (the gradual layering of deposits the Species . He may have wanted to avoid entering into conflict with the and artifacts on top of each other, over time—the lowest layers proponents of Special Creation (God created the universe and everything in representing the oldest deposits). It gradually became possible to sort it exactly as it now appears) . They now had cleverly shifted their reliance the prehistory of France into consecutive segments of time represented on biblical faith, in their battle against the evolutionists, to enlisting the by different kinds of tools found in various regions and strata of earth, findings of science, itself. Such things as fins, feathers, hearts, lungs and but there were too few human bones. While tools were found that were eyes were too well adapted to the functions they served to have developed very much earlier than those found with the Cro-Magnon bones, there solely by chance. Wasn't this a "rational" explanation in the favor of was no way of telling just what the people who made them looked liked. Special Creation, demonstrating the existence of a Divine Intelligence? The situation continued until 1886, when two more skeletons Darwin did enter the fray, however, in his next book, The Descent of Man , like that of Neanderthal were found in the mouth of a Belgian cave. published in 1871. Near them were stone tools, which were very different from those found In The Descent of Man , Darwin concluded that man was descended with the Cro-Magnon skeletons that proved they were definitely very from an ancient "lower" and extinct form. Because Darwin wrote about the much older than Cro-Magnon tools. similarities between man and the great apes, many people misunderstood This new evidence made it difficult for people to go on arguing him and thought he meant that modern apes are human ancestors. It was that earlier kinds of prehistoric men were just like us. Of course, some primarily the influence of Darwin's book that made fossils, especially scientists declared that these were not really human ances- human fossils, really worth looking for. Even though most scientists were tors but primitive "offshoot cousins" who had become extinct long ago. very cautious about their interpretation of Neanderthal bones, people had By then, discoveries of fossil bones were occurring more begun to pay attention. Old bones were no longer thought of as something frequently, primarily because more people were interested in looking for to be thrown away. them. The people who considered Neanderthals ancient were in for a Before long, a new discovery was made, one that scientists could surprise. In 1887, a young Dutch doctor named Eugene Dubois, who really get excited about. In 1868 a group of workmen digging in a rock believed that man might have originated in tropical Asia, obtained a job as a health officer in in order to look for the remains of earliest them under his dining room floor where they remained for nearly twenty humans. He finally reached , where he succeeded in convincing his years. It wasn't until the 1920s that the bones reappeared along with government employers that he could do more good by digging up fossil and other and bones that Dubois had not mentioned earlier. Dubois geological specimens than by looking after the health of the Javanese had by then completely changed his mind about Pithecanthropus (Homo natives. In 1891, Dubois found a very important piece of skull on the erectus). It was indeed a giant , he said. He banks of the in . did not change his mind again, even though, Later, he found several teeth and a thigh bone in the same by the time of his death in 1940, the rest of area. At first, he thought the bones were those of a large, prehistoric the scientific world had fully accepted Homo . But the shape of the skull cap showed that the brain erectus as a human ancestor. must have been twice the size of the biggest . The forehead In the 1930s more bones of Java Man sloped backward from the huge, heavy, bony browridge that had been were discovered and several scientists the eyebrow. The thigh bone showed that this creature, whatever it uncovered bones of another example of Homo was, must have walked upright on its hind legs, erect in a way that no erectus, this time in China, which they called living ape walks. . By the 1940s scientists had Was it a "man-ape" or an "ape-man?" After long, careful found many bones of hominids that seemed to study, Dubois decided that this creature was an ancient precursor of fit some-where between and early humans, and he named this "Java Man", Pithecanthropus Homo sapiens (modern humans). These erectus , ("erect apeman"). The term "Pithecanthropus" is no discoveries presented many questions. One longer used. The current scientific name for Java Man, and others like problem was that if Java/Peking Man were a him, is Homo erectus . While Dubois’ Java Man specimens dated to form between apes and modern humans, then about 1.8 million years old, earlier what was the form between apes and specimens of H. erectus Africa have Java/Peking Man? Who was this ancestor? since been dated as old as 2 million years. One imaginative Englishman, , whose name BP. Dubois' creature immediately became will go down in anthropological infamy, chose a novel way of providing both famous and highly controversial. such an ancestor. He buried parts of the braincase of a modem human Some scientists agreed with and the carefully doctored jaw of an . Then he asked a Dubois, while others, holding tenaciously to scientist from the to help him dig up some ancient their much shaken anti-evolutionary beliefs, bones. A world-renowned expert on human fossils fitted the pieces maintained that this creature was no proper together, not knowing that a trick had been played. The usual argument ancestor of ours. Dubois packed up his ensued, but most of the world accepted "Piltdown Man" at face value. precious bones and returned to Europe, A prominent American scientist, however, warned that this was where for several years arguments raged very conceivably a hoax, but he remained in a minority, with no one around him. willing to seriously consider his objections We now know that brains Tired of the incessant controversy and jaws did not evolve together. from which he found no relief, Dubois In the early 19th century the prevailing theory was that early removed himself and his collection from hominids were essentially apes with large brains. Piltdown fit this public view. His mind had apparently begun preconceived picture. (Today we have many fossils to wander and, believing that someone which show that early hominids had fairly modern-like dentition (teeth) wished to steal the bones, Dubois buried and were erect bipeds, walking erect on two feet. Yet the brain did not increase in size for quite some time). one paid any further attention to it. Just as the scientists were wrong It was confusing to many--this combination of an ape's jaw and a about Piltdown Man, so were they wrong about modern human braincase. Other fossils seemed to indicate that brains and africanus . jaws had evolved together, so scientists had great difficulty deciding where The gaps in the story of human between Homo this mixed-up creature belonged. It did not seem to fit in any of the known erectus and ourselves were slowly being filled in as an increasing gaps (at the time) of . number of human bones were discovered. In China, more and more Hundreds of thousands of words were written about "Piltdown bones of Peking Man were found. Stone tools and fireplaces where Man," all in deadly earnest, for forty-two years. It was not until 1953 that animals had been cut up and cooked, all dating back to more than half- scientists found out what a tragically wasteful hoax had been perpetrated. million years, were also dug up, providing proof that " Pithecanthropus " Then, by means of chemical and microscopic tests, it was proven beyond (Homo erectus ) was human. Cousins of Neanderthals were also found in all doubt that the braincase and jaw were not the same age and that China and Java. They lived much later than Homo erectus , and their "Piltdown Man" was a fake. large skulls and stone tools suggest that they had led more complicated lives than originally thought. Anthropologists took another look at Africa when, in 1936 an Australopithecus' lone dusty skull was joined by that of a robust (heavy, strong, muscular) relative. There was enough of this newly found skull, as well as a piece of thigh bone, to prove that this creature, too, had walked erect. Dr. Robert Broom, who made the discovery, found another one two years later, in 1938. Less reserved than Dart, Broom called his second find ("like a man") robustus . Recent dating suggests that Australopithecus africanus is older (2.75 mya) than (1.8 mya). Anthropologists are not in agreement as to whether or not Paranthropus robustus is a separate species, as Broom thought, or just another kind of Australopithecine. When the war ended, Broom, who was then in his irascible eighties, was determined not to let anything, not even solid rock, stand in the way of his search for more ancestors. For almost three million But the question still remained: What was the ancestor of Java Man years the bones of had been sealed in rock. Pickaxes (Homo erectus )? One such candidate, Australopithecus africanus , had were discarded in favor of dynamite, and after each blast the rubble was actually been discovered in as long ago as 1924. Almost no carted away and carefully examined. Many bones were found, and teeth one knew about it at that time because the man who discovered it, Professor as well. The Australopithecine teeth were more like a human's than an , did not wish to become involved in scientific controversy ape's. A hip bone that was found was nearly human, not ape-like at all. and cautiously suggested that it was a very superior ape. Among all the contradictory statements on human evolution, Despite Dart's caution Australopithecus africanus ("Austra" means who was to determine what was ape and what was human? By 1947 the "south," referring to South Africa. The second part of these names is always tide of thought had changed. Sir , long considered to be the written in lower case letters) was soundly rejected as an important find. greatest expert on fossil man, declared that he himself had been wrong Since Professor Dart lived far from the center of scientific opinion, he and that Dart's Australopithecus had indeed more human characteristics scarcely knew a controversy was raging. Presently, scientists concluded than most scientists had been willing to believe. that Australopithecus africanus was an ape, and for more than ten years, no The following year, Broom found more Paranthropus bones at yet another site. More and more Australopithecine finds were made in the being the first hominid to have manufactured tools. What sets Homo late 1940s and early 1950s. The colorful Broom died, and his colleague, habilis off from the rest of the pack is a different dental pattern, a larger John Robinson, carried on his work. During the 1950s human fossils were cranial capacity, and a more delicate and rounded head. Still, if you discovered in many parts of the world. The new finds included were to put in a suit or dress, there would be no trouble in Australopitecines, Java, Neanderthal and modern-types of humans. identifying him or her as not quite human. For almost sixty years the Leakey family has played a prominent It is not easy to get to Hadar in role in the search for human ancestors. and his wife Mary had the Afar region of north-central Ethiopia. begun searching for fossils in Olduvai Gorge in Tanzania in the early The area is remote, accessible only by 1930s. More than twenty years of patient searching would pass before Mary four-wheel drive vehicles, and dangerous. Leakey, in 1959, found an almost complete skull. It took 19 days to free the The government, never fully in control face and teeth. The Leakeys named it " Zinjanthropus " (East African Man). there, has been constantly in conflict with It now generally bears the name of Paranthropus boisei . Although revolutionary movements seeking their Paranthropus boisei had about the same sized brain as Paranthropus independence. Because of its particular robustus , it was even larger in other respects, having a massive face and geography, at the top of Africa's Great teeth. Paranthropus boisei is dated at around 2.5 million years B.P. Rift Valley, Hadar is a treasure ground of fossil remains. It is a place of almost continuous earthquake activity, where the meeting of two massive tectonic plates-- the African and Arabian--has been grinding and shifting for the past 30 million years, creating a huge "scar" that extends from Mozambique, in the South, to Israel in the North. It is also an area of great volcanic activity, as well. Old lava flows (basalt) and layers of old volcanic ash (tuffs) permit the use of radiometric dating methods (based on the decay of radioactive materials) which has revolutionized the dating of early hominid fossils. Because of all this violent, constant action, fossils are sometimes forced up near or to the surface of the Earth, where they lie In 1960 Dr. Leakey found the remains of yet another ancestor in exposed to the erosion of wind and water. Since the area is sparsely Olduvai Gorge, which he named Homo habilis , often translated as "handy populated and devoid of dense vegetation, the Afar region of Ethiopia man." For the first time, we have an example of the "Homo" which is provides an excellent environment for the sharp-eyed, persistent the Latin word for "human being". Australopithecines and Homo are both anthropologist to go fossil hunting. referred to as hominids, human ancestors. Scientists studying human Donald Johanson is a paleoanthropologist, an anthropologist origins prefer to use this term, rather than "human." Hominid comes from who studies the fossil remains of humans and their immediate ancestors. the term , which is the family designation in biological One day in 1973, Johanson was walking in what he refers to as his . The family Hominidae includes the genera , "paleontologist's slouch." He had spent an uneventful day searching for Australopithecus, Paranthropus and Homo, so these are all hominids. fossils and was at the point of returning to his base camp when he Remains of Homo habilis (dated about 2 million years BP) were noticed a bone sticking up in the sand. Kicking it loose, he discovered found with stone implements and therefore have the distinction, so far, of that the bone was part of the right tibia (shinbone) of a (the order of part of her body, especially the skull (not 's, but a member of her that includes man, apes and monkeys). Johanson had picked up the bone species which Johanson found on a much later dig in 1990) and and was writing a description of it in his notebook, when he noticed another fragments, indicate that her kind was somewhat ape-like as well. bone on the ground a few yards away. This turned out to be part of a thighbone that seemed to match in color and size the tibia. When he tried to place the two bones together, Johanson found that they didn't fit as he would have expected of ape leg bones. Ape leg bones form a straight line in the body across the knee joint. Re- arranging the two bones at different angles, Johanson found that they did fit, indicating that instead of belonging to a ape, the bones must have belonged to a hominid. A human thighbone extends downward and inward from the hip, forming a distinct angle with the straight shinbone. Donald Johanson had just made what was to become one the great paleontological discoveries of the past forty years. He had found a new In 1992, not more than fifty miles south of the site in which hominid ancestor, quite possibly older than any other previous discovery. Lucy was discovered, paleonathropologists Gen Suwa and Timothy Eagerly, he returned to Hadar the following year, in November, 1974, to White discovered the bones of a species that had lived earlier than Lucy. find a cornucopia of fossils, all belonging to this same individual. As The new find, Ardipithecus ramidus, has been dated to be 4.5 million Johanson tells us, returning to camp, "the find launched a celebration in years old. Scientists believe that the two species, Australopithecus afar- camp that lasted into the next morning. We must have been a curious sight ensis and Ardipithecus ramidus , may not be related, although Ardi- to the nomads of the desert, our work tent aglow with butane lamps and the pithecus may have walked upright. One clue is a tiny piece of bone that music of the [Beatle's song] 'Lucy in the Sky with Diamonds' blasting from belonging to what is known as the foramen magnum, the opening at the a cassette player. Inspired by the song, we affectionately named the partial base of the skull where the spinal cord joins the brain: Its location indi- skeleton "Lucy." It was not until 1978 that Johanson was to make the cates an upright stance. Its teeth are more ape-like than Lucy's. It may announcement that his discovery, Lucy, was a new species with the name well be that Ardipithecus was neither a two-legged walker, nor a four- Australopithecus afarensis , and was given date of 3.2 million years BP legged one, but had developed a gait somewhere in between. Lucy almost certainly walked upon two legs, rather than four, but the upper Fossil hunter Meave Leakey (daughter-in-law of pioneer African fossil hunters Louis and Mary Leakey) may have found another known hominid. Whether or not Sagelantropus was bipedal with the link in the chain of human development. Searching in the scorched hillsides ability to walk on two legs is still undetermined. Although its small near 's , she spotted several patches of bluish tooth is considered an apelike trait, the relatively reduced brow enamel embedded in a piece of stone. Her discovery, consisting of ridge and small canine teeth characterize Sagelantropus as a hominid. complete upper and lower jaws, teeth from several individuals, a piece of Sagelantropus is dated between 6-7 million years old. skull, arm bones and shinbone, belonged to a creature weighing about 120 The reason we mention Sageltropus tchdensis is to show that the pounds. This new find has been given the name Australopithecus history of the hominid species is in constant flux: new fossil finds are anamensis . That Austra-lopithecus anamensis probably walked upright is continuously being unearthed. Often in (the study of indicated by fragments of the tibia which narrows at the top where it would ancient life forms) controversy may surround a new fossil discovery. be attached to the knee, suggesting that it could bear more weight than the For example, in 2003, a very strange fossil found on the Indonesian leg bone of an ape. The ape tibia doesn't need to be as strong as a human's island of Flores caused quite a stir among anthropologists. Homo flores- because the weights of these animals falls heavily on the front limbs as they iensis , as the fossil was named, was identified as a female who stands "knuckle walk". Australopithecus anamensis , therefore, probably walked about three feet tall with a brain size of 380 cc. Floresiensis , at first was upright. The date assigned to the discovery is 4.4 million years BP Some thought to be a "miniature" Neanderthal; next, she was thought to be a scientists feel that we have gotten very close to the hypothesized time of the separate species and finally, she was classified as a "dwarf" Homo splitting of ape and human lineages from a common ancestor. erectus that evolved in isolation on the island, along with other dwarf The major issue that faces us now is which species survived to forms of larger mammals (elephants, for example). At the writing of this eventually give rise to modern human beings? Are the new species our own article (March, 2005), researchers are still not in agreement as to ancestors, or quite possibly, ancestors of the great contemporary apes of whether is a genuine fossil, or just an individual who Africa (for which fossil remains have never been identified)? Do the fossil suffered from a sickness characterized by dwarfism. Remains from fragments of any of these sites contain the bones, mixed together, of more Homo floresiensis have been found in strata dating from 94,000 to than one species? Are all the three last discoveries related, as part of the 13,000 years ago. same lineage, or are they just distant relatives? Probably the most exciting discovery in recent years was one During the next few years, scientists will certainly be searching for that was made in the Tugen Hills in Kenya, October of 2000 by a answers to these questions and others, as they attempt to put together the combined team of French and Kenyan paleontologists led by Brigitte riddle of our past, while trying, at the same time, to chart our navigation Senut and Martin Pickford. Based on only thirteen fossil bones from six through life into the unknown waters of humankind's future development. individuals, the new genus, dubbed "Millennium Man," has been given Is our final destination extinction (when we look at the past, we see that all the name of tugenesis and may be the oldest hominid ancestor, species eventually die out), or will we be able to evade a similar fate? dated at 6.2 million years, 1.5 million years older than Ardipithecus The question that always remains in the background whenever a ramidus, previously recognized as the oldest hominid. Orrorin tugenesis decision has to be made regarding which hominid species to include in an probably stood at about four feet five inches tall and weighed about 110 introductory text in physical , is are the selections from the pounds. According to researchers, Orrorin tugenesis is probably more hominid fossil evidence relevant to an understanding of human evolution? human than Lucy, but not as ape-like as the great apes. Another hypo- Often there is very little fossil evidence to represent a species. For example, thesis is that Orrorin may be a true pre-human ancestor, whereas the Sagelantropus tchadensis discovered by Ahounta Djimdoumalbaye in the Australopithecines, may be a dead end and not related to us at all. southern Sahara desert in Chad, Africa in 2002, is represented by a nearly According to DNA molecular studies, the split of humans and apes from complete cranium and a number of fragmentary lower teeth and jaws. The a common ancestor may have occurred sometime between 8 and 5 skull is 350 cc. (compared to modern human skulls which average 1350 cc.) million years ago, making Orrorin tugenesis a possible first step on the Some anthropologists consider Sagelantropus tchdensis as the oldest road to humanness.