Stephen P. Broker
Man’s relationship with nature, his place in the universe, and the manner of his origin have been topics of speculation and controversy throughout recorded history. Religion, folklore, and science have dealt with these topics in a variety of ways, posing explanations and answers which are satisfying to some and inadequate to others. Accepting the premise that religion encompasses matters of faith, whereas science is the domain of that which is demonstrable, this unit provides methods for familiarizing the student with recent and contemporary scientific thinking about human origins.
From the discovery of the Taungs baby in South Africa in 1924 and its subsequent description by Raymond Dart, to the 1979 announcements of the new species
Australopithecus afarensis,
the new hybrid primate siabon, the discoveries of 3.8 millionyearold fossil hominid footprints, and of the earliest known fossil anthropoids, there has been a steady progression of major finds, new interpretations, and revisions of man’s thinking about his origins. Human evolution is a subject attracting as much attention and publicity today as at any time in the past. Our understanding of the last 15 million years of hominid evolution is vastly more complete than it was half a century ago. The term ‘hominid’ is used here to denote man and his immediate ancestors or nearancestors.
Biology textbooks frequently relegate topics in evolution to the last chapters of the book, much the way that organic chemistry used to be an addendum to chemistry textbooks. This is unfortunate when one considers that evolution is one of the most substantiated of theories in the biological sciences, and that it is also one of the major unifying theories of biology. Evolution introduces a fourth, temporal dimension to biology. It is that aspect of the science which reminds us that we presently represent a minuscule fraction of biological history.
The diverse forms of life on earth today—between one million and two million different species—exploit their surroundings in a multiplicity of ways, while at the same time being limited and partially fixed by their surroundings. Today’s forms of life are the products—and it must be emphasized, not the endproducts—of an extremely long evolutionary process. Despite our increased knowledge of the processes of evolution, teaching these processes is one of the most difficult aspects of any biology class. The suggestion that man has evolved from earlier, different forms of life is one which is easily misunderstood and frequently dismissed by our students as beyond belief. By presenting much of the evidence for human evolution and having the student participate in some of the activities of a paleontologist, it is hoped that the student will be in a better position to draw his own conclusions, Consequently, laboratory activities such as examining animal bones, preparing plaster casts, and working with photographs of important hominid fossils are a major part of this unit.
Among the objectives of the unit are the following:
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1. to present methods for better understanding the magnitude of geological time;
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2. to familiarize the student with basic characteristics of hominid forms;
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3. to consider some of the interdisciplinary methods for studying human origins;
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4. to consider the relationship between morphology (structure) and function, as applied to hominid characteristics;
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5. to familiarize the student with the modern consensus ideas of human evolution, including consideration of recognized species of hominids and their discovery sites;
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6. to present the idea that scientific data are frequently interpreted differently and that scientific models change.
The unit is intended for Biology, Advanced Biology, and Anthropology students who have had some background in the study of animal diversity and evolution. It can be adapted for use in other science classes.
