Scientific Facts in Lucy's Child: The Discovery of a Human Ancestor by Johanson - Book Report/Review Example

A Giant of a Child: Evidence for Links in Human Evolution Co-authors of Lucy’s Child: The Discovery of a Human Ancestor, Donald Johanson and James Shreeve, construct a very useful network of theories around Johanson’s second hominid fossil discovery in the Olduvai Ranges. Coming in the wide wake of the unearthing of the first, Lucy, in 1973, this dig in Tanzania and its contents were to arouse a number of things: firstly, and possibly the most neglected among commentators, was the necessity to make new observations and hypotheses. Then, the old controversies were once more posited, and although the arguments were not in the main new, it summoned to the debate a few different and more eager observers. Neo-Darwinism was shown to have merit, and everyone noted that the discipline of paleoanthropology had come some way since the days of Lucy’s discovery. But even this archaeo-palaeontological discipline needed a spring-clean and a detailed examination of how things were to be done, and how they were to be funded. Reluctantly, it seemed. The authors make much of the practical and physical difficulties at the Olduvai dig, and also go into great detail about the petty - and some of the more serious - feuds, misunderstandings and arguments that took place among the archaeologists and paleoanthropologists present at the site, involved in the data gathering, charged with forensic investigations, involved in writing, and responsible for the various laboratory tests that followed. Woven through are some splendid descriptions of the landscape. Here, the personal and practical debacles will only be mentioned if deemed important enough to interrupt the review of the main points of this interesting book, such as the surprising fact that Mary Leakey, in whose territory Johanson and his scientist collaborators were accused of trespassing, sent congratulations for the find. Seeing that the events were rehashed in some detail, what rises as being vital about this book can be condensed into much less than was previously supposed on first examination. The focus gathers around the party, backed by the Institute of Human Origins, a non-profit organization founded by Donald Johanson himself, accompanied by Lewis Binford, writer/researcher James Shreeve, and Tim White, who after some fruitless scavenging comes upon a partial fossilized skeleton. It is tiny: but it is possible to ascertain, with a number of behests to avoid making assumptions, that it belongs to the species Australopithecus afarensis (Johanson and Shreeve, 1989). Johanson used a set of identifiers and markers peculiar to the dig and his personal choices, mainly because it is somewhat difficult to come up with a definite set for this species, since a conglomeration of features have been listed by several scientists and have been used, in differing sub-sets, depending on the scientist in question and the aim of the particular study (Johanson and Shreeve, ibid). On this particular dig, the size and proportions of the cranium and the pincer-like positioning of finger and thumb, which suggested the fine manual ability necessary for the species to endure successfully, and of course its relationship to other extant Australopithecus afarensis and Homo habilis skeletons, were the main indicators. The molars indicated a move away from vegetarianism. The basic ‘Homo’ type was definitely there: of that there was no question. A proficient climber, Homo habilis has certain skeletal proportions that led Johanson to confirm his measurements met with his hopes. With a skull very similar to what one finds in the world’s baboons, Homo habilis has a very distinctive ear canal system, which to the Olduvai scientists meant that this newly found skeleton was of the species, related to the previous Olduvai find, Lucy, and was naturally capable of terrestrial bipedalism (Johanson and Shreeve, ibid). That is, when it was alive - an exciting 200,000 years previous to Homo erectus - this creature was doing some serious climbing and walking upright. The gradual ability to stand erect and walk on two legs has always been an issue considered fundamental in the study of adaptations linked with deviation of the column of hominids away from a common ancestor that the human lineage has with the apes of Africa. The most persuasive of Johansen’s strengths in this book is his ability to link findings with empirical data, and his way of regarding his findings and hypotheses as additions to an already impressive bank of details and studies by other scientists. He does not make grand dramatic announcements. He manages, using half a femur, three bones from the radius and humerus, small pieces of a brain case, a fragment of tibia, a couple of molars and a palate, to conjure a reasonable explanation. The fragments were taken from the dig and jig sawed together during the space of about four weeks. Although tenuous to some reviewers, it feels wholly plausible that these scientists could calculate the length of a thigh from the comparatively tiny part of it that was found; and that the femur originated from the same skeleton as the rest of the fragments. With measurements, dating, time-line and still steadfastly avoiding the temptation to leap to persuasive conclusions, Johanson, with Binford keeping him on the straight and empirical pathway, started to think differently about the commonly-held perspective of human evolution. That is, he looked with a new eye at what is believed among scientists to be the time-line from basic hominids to Homo erectus. This last user of tools and torches is commonly, and without much controversy, understood to be the immediate previous springboard for Australopithecus afarensis and then Modern humans. (Binford 1981) But Johanson was thinking about the length of time it took for the branch to occur: he came to the conclusion that it was much faster than scientists generally supposed. Binford’s methodologies, (Binford, 1981) which he formalized and published previously, came to the fore on Johanson’s dig and the investigations that came up with what came to be known as Lucy’s Child. This nickname had less to do with the age of the creature when it met its death, than with the probability in the scientists’ minds that what they had found was a descendent of Leakey’s Lucy. In this book, moreover, the reader has no doubt that it is definitely Johanson’s Lucy. Of course, the age of the individual at time of death was also a consideration that had to be weighed and measured carefully, in all senses, literal and metaphorical. It was established after many tests, including scans, that the individual was not a juvenile when it died, but an ‘old-ish’ female. Since Lucy was established to be a female adult individual, the nickname was coined The partial early skeleton, dated as being from nearly 2 million years ago, looks rather human. So far, only skulls of this genus had been unearthed, and this particular one, incomplete as it seems from its description, indicates that the female hominid was three and a half feet tall, with arms very nearly as long as the legs. Smaller than the early 1970s Lucy, and appearing similarly ape-like, readers of this book have no reason to doubt Johanson’s eagerness to treat her as Lucy’s child, in the sense already mentioned above. These bones were not retrieved and studied in isolation: Johansen mentions a great deal of bones, how they were meticulously disinterred, how exact and complex measurements and other data was collected, and how they also discovered other non-fossil finds such as stone tools. Remembering that Johanson is not a scientist who is a close and faithful follower of the Leakey theories, which is pursued at length in this book, the finding of this skeleton, which is scientifically identified as OH 62, is followed by statements and observations that are not as dramatic as the Leakeys’, except for the fact that Johanson points out his ‘acceleration’ theory: that is, that human evolution underwent a sudden spurt. In his view, the transition periods that brought hominids from the Homo habilis stage to the present were much more rapid, condensed and dramatic than previously thought (Johanson and Shreeve ibid). Lucy, the earlier find, was established as being Australopithecus afarensis, a common ancestor to humans that scientists had been seeking for generations. In an interview, Johanson has said, ‘She is a mother to all the various branches, some which went extinct, and one which ultimately evolved into ourselves.’ (Academy of Achievement, 1991) This makes the reader, on analysis of what appears in Lucy’s Child: The Discovery of a Human Ancestor, that Johanson, Binford and White - and later also Shreeve - have an agenda that brings about the name. It also brings about the satisfaction they must have felt in being able to propound the significance of the find and its very clear relationship with the previous discovery, despite the early obstacles to the project. The assertion is made in a very conclusive and persuasive way. No reader can have any doubt that this book carries forward and substantiates a number of evolutionary hypotheses and that this empirical trove of actual bones with actual weights and measurements comes a long way to confirming that there can be no doubt of two things. One: that there were substantial and subtle changes discernable in the different remains of hominids discovered through the ages. These changes can scientifically be dated and placed in some order of record. Although there are gaps, there is a visible column of advancement - Johanson never calls it ‘progress’ - and a definite connection, between one shape and the one that proceeds from it. Two: that the weaknesses of Johanson’s writings lie not in the compilation of scientific facts, or errors of putting data together, but in the enumeration of the opinions of others, and the sometimes long-winded accounts of agreements and disagreements. So it is not the Johanson the scientist that is at fault, but Donald Johanson the narrator. This collaboration with James Shreeve, who shows himself to be an excellent scientific reporter, reads like an absorbing detective story. Sources Cited Binford Lewis , Bones: Ancient Men and Modern Myths Academic Press: 1981 Johanson, Donald and Shreeve, James Lucy's Child: The Discovery of a Human Ancestor William Morrow Co 1989 Academy of Achievement Discovering our Human Origins Interview with Donald Johanson, PhD 1991 < http://www.achievement.org/autodoc/page/joh1int-7> Accessed 12/30/2009 Read More