Copyright © 1998 by McGraw-Hill, Inc. All rights reserved. Printed in the United States of America. The entire contents or parts of this Update may be reproduced for use with Physical Anthropology, Sixth Edition, or Physical Anthropology: The Core, second edition, by Philip L. Stein and Bruce M. Rowe, provided each reproduction bears the copyright notice. The publisher's written permission must be obtained for other use.
See Physical Anthropology, 6th edition, Chapter 14, page 363; Physical Anthropology: The Core, 2nd edition, Chapter 9, page 227.
The origin of animal life predates 540 million years ago. At that time, all basic forms of life known today appeared in an event that has been labeled the "Cambrian explosion." Few rocks dated earlier than 540 million years ago have yielded antecedent fossils of the Cambrian explosion organisms.
Until recently the earliest animals were dated to about 565 million years ago. Now, fossil sponges (Porifera) from South China have been identified as dating to about 580 million years ago. They push back the date for the first known animals by about 15 million years.
References: R. A. Kerr, "Pushing Back the Origins of Animals," Science, 279 (February 6, 1998) 803; C. W. Li, J-Y. Chen, and T-E. Hua, "Precambrian Sponges with Cellular Structures," Science, 276 (February 6, 1998), 879-882.
See Physical Anthropology, 6th edition, Chapter 16, pages 406-416; Physical Anthropology: The Core, 2nd edition, Chapter 11, pages 257-270.
Meave Leakey and her team recently reported on continuing work at Kanapoi, including new fossils of Australopithecus anamensis recovered during the 1995-97 field season. There has been a refinement and confirmation of the antiquity of the Kanapoi australopithecine fossils. All but one of the fossils falls below the Kanapoi Tuff that has now been dated by single crystal 40Ar-39Ar radiometric dating method to 4.070±0.023 million years ago. This places all but one of the fossils to the interval between 4.17 and 4.07 million B.P. The exception is the mandible KNM-KP 29287 that was found in a deposit immediately above the Kanapoi Tuffs and may be just slightly younger than 4.07 million years.
Reference: M. G. Leakey et al., "New Specimens and Confirmation of an Early Age for Australopithecus anamensis," Nature, 393 (7 May 1998), 62-66.
See Physical Anthropology, 6th edition, Chapter 19, pages 495-497; Physical Anthropology: The Core, 2nd edition, Chapter 13, pages 330-331.
In a previous issue of Physical Anthropology Update we reported an extremely early date for the peopling of Australia at Jinmium Rock Shelter in northern Australia. Thermoluminescence dating gave dates of 75,000 to 50,000 B.P. for quartz sands associated with buried engravings and 176,000 to 116,000 B.P. for the underlying artifact-containing layers.
New dates have been obtained for this site. The first were determined through accelerator mass spectrometry radiocarbon dating based on charcoal samples carefully collected from the site. The new analysis suggests that the site is less than 10,000 years old.
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Reference: R. Robert et al., " Optical and Radiocarbon Dating at Jinmium Rock Shelter in Northern Australia," Nature, 393 (28 May 1998), 358-362.
See Physical Anthropology, 6th edition, Chapter 18, pages 482-486; Physical Anthropology: The Core, 2nd edition, Chapter 12, page 319.
In 1996 a group of investigators suggested that an ancient bear femur pierced by four complete or partial holes was in fact a Neandertal flute dated to around 43,000 years ago. A new investigation of the bone has led to the conclusion that the object it not a musical instrument but a product of carnivore chewing.
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Reference: B. Bower, "Doubts Aired over Neandertal Bone 'Flute'," Science News, 153 (April 4, 1998), 215.
See Physical Anthropology, 6th edition, Chapter 19, page 505; Physical Anthropology: The Core, 2nd edition, Chapter 13, page 339.
The use of domesticated plants as a staple part of the diet in the American Southwest was thought to date to perhaps 700 A.D. Before that time the people of this area were assumed to be nomadic hunter-gatherers. Now, the results of a salvage archeological project along a portion of Interstate Highway 10 near Tucson, Arizona, point to significant domestication and settled village life in the Southwest more than 1000 years earlier than previously thought.
A people, perhaps ancestral to the Hohokam culture, had built a large community and had made pottery, beads, and ceremonial structures. They also cultivated maize, may have used tobacco and cotton, and used bow and arrows long before 700 A.D. At one site along the interstate highway, 730 dwelling and other structures were uncovered. The evidence from this research will force a rethinking of the settlement pattern, technological development, and ancestral relations of groups in the American Southwest.
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Reference: M. Muro, "New Finds Explore Old Views of American Southwest," Science, 279 (January 30, 1998), 653-654.
See Physical Anthropology, 6th edition, Chapter 7, page 154; Physical Anthropology: The Core, 2nd edition, Chapter 4, pages 80-84.
The cells of most tissue can only undergo a finite number of miotic divisions before they enter a nondividing stage called senescence. The consequence of senescence is the death of the tissue and therefore the death of the organism. On the other hand, in some tissues, the failure of cells to age may lead to the growth of too many cells, that is, a tumor.
Over a decade ago, Howard Cooke noted that the ends of chromosomes, areas referred to as telomeres, got shorter with each cell division. When these chromosomal "caps" got to a certain length, the cells entered senescence. However, this observation was not seen as proof that telomere shortening was directly related to cell senescence until now.
Andrea G. Bodnar and her associates have provided convincing evidence that this telomere shortening indeed is related to cell senescence. The consequence of the research might ultimately be the development of drugs that can stop cell division in cancer tissue and other drugs that can prevent or slowdown aging in normal tissue.
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References: A. B. Bodnar, "Extension of Life-Span by Introduction of Telomerase into Normal Human Cells," Science, 279 (January 16, 1998), 349-352; T. DeLange, "Telomeres and Senescence: Ending the Debate," Science, 279 (January 16, 1998), 334-335.
See Physical Anthropology, 6th edition, Chapter 7, page 154; Physical Anthropology: The Core, 2nd edition, Chapter 4, pages 80-84.
August 4, 1997, marked the death of Jeanne Calment. Her age at death was the longest ever documented for a human-122 years and 164 days. This is 21/2 years longer than what is generally considered today to be the ultimate human life span.
Members of Jeanne Calment's family were compared to a control population, and relatives in both groups were studied back to the 18th and 19th centuries. There appears to be a concentration of long-lived individuals among Calment's ancestors. It is very possible that her longevity was due to genetic factors, but such factors would certainly not consist of anything as simple as a single gene.
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Reference: J-M. Robine and M. Allard, "The Oldest Human," Science, 279 (20 March 1998), 1834-1835.
See Physical Anthropology, 6th edition, Chapter 17, pages 442-448; Physical Anthropology: The Core, 2nd edition, Chapter 12, pages 292-296.
On January 23, 1998, paleoanthropologist Richard Leakey was elected to a five-year term in Kenya's Parliament. Leakey has discovered numerous hominid fossils and artifacts in the Lake Turkana region of Kenya, including the most complete specimen of Homo habilis (ER 1470). Leakey has been the director of Kenya's National Museums and the Kenya Wildlife Service. He plans to push for constitutional reform, increased support for Kenyan science, and better conditioning for disabled persons. (Leakey lost both of his legs as a result of a 1993 plane crash.)
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Reference: "From Paleontologist to Parliamentarian," Science, 279 (February 6, 1998), 811.
See Physical Anthropology, 6th edition, Chapter 4, page 87; Physical Anthropology: The Core, 2nd edition, Chapter 2, page 51.
Dolly, the first mammal to be cloned from a nonfetal cell, has been featured in previous issues of Physical Anthropology Update. Initially some scientists doubted that the ewe was actually cloned from differentiated adult cells, but today Dolly, who became a mother of a normal noncloned offspring this year, has been firmly established as a true clone: one derived from an adult cell.
In the issue of Nature that validates Dolly's origin a report on the cloning of 22 female mice also exists. As we head into the 21st century, it appears that cloning will be a major activity of biological science. Although the fears about the misuse of all biological engineering techniques may put a brake on such research, many biologists see cloning as a method to explore basic biological mechanisms, such as still unknown principles of genetics. Biologists also see numerous practical applications of cloning and other genetic engineering techniques. These applications include cures for genetic diseases, the production of new tissue for victims of accidents and disease and of stocks of farm animals, crops, and plants used for medicine that are superior to nonengineered stocks.
Of course, the ethical, philosophical, and political problems that apply to cloning, especially human cloning, are considerable. These concerns will certainly be in the headlines for years to come.
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References: D. Solter, "Dolly is a Clone-and No Longer Alone," Nature, 394 (23 July 1998), 315-316; D. Ashworth, et al., "DNA Microsatellite Analysis of Dolly," Nature, 397 (23 July 1998), 329; E. N. Signer, et al., "DNA Fingerprinting Dolly," Nature, 397 (23 July 1998), 329-330; T. Wakayama et al., "Full-Term Development of Mice from Enucleated Oocytes Injected with Cumulus Nuclei," Nature, 397 (23 July 1998), 369-374.