Chapter Two Human Evolution
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CHAPTER TWO
HUMAN EVOLUTION
CHAPTER OUTLINE
theories of evolution
Origin Myths
The Darwinian Revolution
Principles of Inheritance
The Evolution of Life
Critical Perspectives: Creationism and Evolution
Hominid evolution
Australopithecus
Homo
Homo erectus
An Ancient Hobbit?
“Premodern” or Archaic Homo sapiens
Modern Homo sapiens
modern homo sapiens culture: the upper paleolithic
Upper Paleolithic Tools
Variation in Upper Paleolithic Technologies
Upper Paleolithic Subsistence and Social Organization
The Upper Paleolithic in Africa and Europe
Migration of Upper Paleolithic Humans
human variation
Skin Color
Summary
CHAPTER OBJECTIVES
Based on thorough reading and careful consideration of Chapter Two, students should be able to:
1.Define cosmology and origin myth, using examples from Navajo, Greek, and personal origin myths.
2.Identify the contributions to evolutionary theory of Charles Darwin and Gregor Mendel.
3.Describe the process and provide an example of natural selection.
4.Define the characteristics of a primate and describe the relationship between humans and primates.
5.Explain the major trends in hominid evolution; describe the characteristics which hominids have in common.
6.Define bipedalism and the importance of bipedalism and cranial capacity in hominid development.
7.Describe, compare, and contrast the origins, technological and social innovations, adaptation to climatic and resource conditions, and subsistence patterns of the following: Australopithecus, Homo habilis, Homo erectus, archaic Homo sapiens, and modern Homo sapiens.
8.Compare and contrast the multiregional evolutionary model and the replacement model (the Eve hypothesis).
9.Describe the Upper Paleolithic, emphasizing the changes in technology and migration patterns during this period.
10.Describe the Upper Paleolithic hunters in the Americas; explain their origins, and how and when humans entered the Americas.
11.Describe how skin color functions to protect humans from variations in environmental conditions.
12.Discuss the newest hominid discovery on the island of Flores (Homo floresiensis).
LECTURE AND DISCUSSION TOPICS
Each of these topics is intended to generate ideas for either a lecture/recitation format or discussion in the classroom. For most topics, students should be able to respond and participate in discussions based solely on reading the text. For others, you may need to provide further reading or other forms of information so that students can develop some personal perspective and become equipped to make independent decisions about the topics.
1.Lecture on origin myths that you are familiar with; explain their internal logic and how they fit within a particular cultural context.
2.Lecture on evolution. Be sure to talk about both the special theory of evolution (individual variation and microevolution) and the general theory of evolution (macroevolution). You could comment on both the monophyletic and polyphyletic schools of thought in macroevolution.
You might also include a discussion of the scientific method in this chapter, including its procedures and limitations. It can only deal with questions that are potentially or actually repeatable. Its steps are: (1) observation; (2) question or problem; (3) hypothesis/null hypothesis; (4) gathering data/methodology; and (5) formation of a conclusion. Stress the equal importance of honest and effective methodology and conclusion formation. Describe the process of theory formation, a hypothesis supported by a large body of observations confirmed by many independent investigators.
As part of this lecture, describe how good theory formation (1) explains or shows relationships among facts; (2) simplifies; (3) clarifies; (4) grows to relate additional facts which means it is always tentative in scope; (5) predicts new facts and relationships; and (6) does not explain too much.
Theory becomes a scientific law if it possesses a high degree of certainty and is widely accepted within the scientific community. Stress to students that science is never finished; scientific fact is an accurate description of an object or event based on what we know and what we know how to do. It is not an absolute finality.
You may also take the opportunity to discuss patterns of deductive and inductive logic. Talk about proof and rigor of proof in science. Be sure to emphasize that when we extrapolate from proven scientific theory, it is only supposition, not scientific fact. An interesting book on the uses of science and pseudoscience within the context of archaeology is Kenneth L. Feder's Frauds, Myths, and Mysteries: Science and Pseudoscience in Archaeology.
3.A lecture on problem solving would follow naturally from one on the scientific method. Present it as a methodology we can use when the scientific method is not appropriate. One problem-solving strategy is to: (1) identify the problem; (2) state the goal; (3) list the constraints and assumptions; (4) suggest possible solutions; (5) judge suggested solutions and decide which one to test; and (6) test and implement your best solution. Use this model to analyze some current local, state, or national problem.
4.Discuss the material on population genetics and evolution, using early humans (Lower, Middle, and Upper Paleolithic) as an example. Emphasize the small population size and group size during that time period. With proper debriefing, you could show the film Quest for Fire. It can provide a vivid visual impression for student understanding of this material.
5.Lecture on the primates, including details on taxonomy, major types, physical characteristics, nonhuman primate similarities to humans, and behavioral characteristics. Explain how we use primate models of human behavior to understand the past.
6.Lecture on phylogeny, and place the hominids within a phylogenetic tree to provide an overview for the material in this chapter. Be sure to deal with the various controversies in phylogeny (e.g., place of A.afarensis and other australopithecines, the place of Neandertal) and the personalities involved (explain that egos are involved as well as "disinterested science"). Roger Lewin's Bones of Contention isa good resource.
7.Lecture on the process of how we interpret the fossil record. Stress how tentative it is, being based only on what has been found and on what we know. Emphasize that we do our work based on assumptions that might not always be made explicit.
8.Lecture on definitions of hominids and each of the trends in hominid evolution.
9.Use slides or an opaque projector to show figures in the text that illustrate artistic representations of early humans. Lead your students to observe the ways in which skin color, body hair (its configuration, heaviness, etc.), and other physical characteristics create a general perception of how "civilized" a form is.
10.Lecture on the transition from Homo erectus to Homo sapiens. Discuss the concept of transitional forms and how they may fit into several taxa. You could discuss the idea that small breeding populations, such as those observed by Mendel, serve as a model for early human populations.
11.Lecture on both the multiregional evolutionary model and the replacement model. Discuss the pros and cons of each. Compare and contrast them. Share with the students your own views, which you support, and why. When you discuss the replacement model, include the Eve hypothesis and its underlying assumptions. Show how radio-carbon dating and other forms of radioactive dating facilitate our research in human origins and evolution.
12.Lecture on the tools of both the Middle and Upper Paleolithic. When appropriate, discuss geographical variation of tools. Introduce the diverse processes of tool making and how each allowed for a more efficient use of resources. For example, talk about how much material could be chipped from a core if you were making a pebble tool, a hand axe, or a blade.
13.Lecture on Homo sapiens neanderthalensis. Discuss both the classic (robust) (e.g., Spy, La Chapelle aux Sainte, La Quina, Shanidar, Tabun, Gibraltar, Circeo, Le Moustier, Le Ferrassie) and the progressive (gracile) (e.g., Saccopastore, Ehringsdorf, Skhul, Krapina, Rhunda, Florisbad) forms. Discuss the likely explanations for the origins of the classic form. Discuss the possible relationships of Homo sapiens neanderthalensis to Homo sapiens. Be sure to discuss the rituals associated with cave bears at Petershohle and Drachenloch and the burials at places such as Mt. Circeo, Crimea, Mt. Carmel, Le Moustier, La Ferrasse, and Teshik-Tash. Discuss the general Middle Paleolithic tool technology and also specific assemblages from a variety of geographical locations. An introduction of home bases (maintenance tools) and work camps (extraction tools) would be appropriate at this point. Discuss some of the hypotheses concerning the evolutionary and cultural relationships between Homo sapiens neanderthalensis and Homo sapiens, emphasizing the Neandertal as a complex human being rather than the popularized image of a brute.
14.Because this chapter discusses hominid lifestyles, you might want to introduce some of the basic questions of ethnography and archaeology to get students thinking about translating the data in the text into a picture of a people's lifestyle. Three basic questions of ethnography are:
(a)What do these people do?
(b)How do they do it?
(c)Why do they do it that way?
Some basic goals of archaeology are:
(a)Study of cultural history
(b)Reconstruction of ancient lifestyles
(c)Investigation of the ways in which human cultures changed in prehistory and history
In archaeology we ask:
(a)Who produced these remains?
(b)Where and when did the producers live?
(c)What were they like (e.g., culture, society, values)?
(d)How and why did they become that way?
Be sure to emphasize the importance of sociocultural and archaeological patterns, and question whether patterns are due to choice or chance.
15.Lecture on how we discern a people's lifestyle from the paleoanthropological and archaeological records. Lecture on use-wear studies and experimental studies in archaeology and how they shed light on early hominids.
16.Lecture on the advent of Homo sapiens (e.g., Cro Magnon, Chancelade, Premost, Brunn, Afalon, Oldoway, Boskop, Hotu, Choukoutien, Wadjak, Keilor, and Grimaldi). Discuss the physical variations among these different populations. Try to dispel the idea that they all tended to look alike.
17.Lecture on the peopling of the Americas, emphasizing the differing points of view on the topic. There are a variety of sources which you may choose to illustrate this subject (see Resources).
18.Lecture on race and racism. Discuss the various schemes of racial classification, explaining what they really measure. Discuss the validity of race as a population classification system. Talk about racism from all areas of the world (e.g., China seeing itself as the middle kingdom and every one else being barbarian) so that students do not just get examples of white racism. Talk about the racism of majority and minority groups (e.g., Louis Farrakhan). Try to stress that most groups in the world have had their times of racism, slavery, and being oppressive when in power. Many students have unrealistic notions of other groups being too good or too pure to engage in such negative behaviors. Such notions reflect their lack of information about the world's history.
19.Lecture on the art of the Upper Paleolithic, using slides, if possible, to illustrate cave paintings, clay figures, hairpins, engravings, and other forms. Be sure to mention the development of art styles throughout the Upper Paleolithic and the spatial distribution of art subjects within the cave systems of France and Spain.
CLASSROOM ACTIVITIES
1.Have students share their cosmologies and origin myths. Talk about similarities and differences in the ones expressed. As always with such discussions, it is necessary to establish a neutral atmosphere, with acceptance and patience for hearing others' ideas.
2.Invite a biologist into class to lecture about a biological understanding of evolution. Check your library or rental catalogs for films on evolution and natural selection. Such films can often provide visual explanations that are clearer and more complete than simple lecture or text information.
3.Invite a philosopher to discuss the philosophy of science, with emphasis on the discussion of the scientific revolution brought about by Darwin and Mendel.
4.Arrange students into groups of four or five and have them use the problem-solving method (outlined in Lecture and Discussion topic #3) to analyze a problem or issue facing their community. Then have the groups come together and share their results.
5.View the film Quest for Fire and use it as a basis for discussion about genetics, evolution, and sociocultural complexity. After correcting its obvious inaccuracies, you can continue to use the visual images from the film for discussion of other anthropological topics.
6.Display fossil skull casts for the class to examine. Put them in chronological order, or have students try to arrange them in order: australopithecines, Homo habilis, Homo erectus, Homo sapiens neanderthalensis, and modern Homo sapiens. Askthe students to describe what they see. What are the differences and similarities among the skulls? What developmental changes do they see as they look from the earliest skulls to more recent ones? Direct their attention to the brow ridges, cranial capacity, prognathism, and other features you believe to be significant. By arranging the skulls in rough chronological order, you could point out that this fossil record supports both the gradualist and the punctuated views of evolution. If you have several specimens within each taxon, you could ask your students where and why they would draw taxonomic lines. The Mystery Fossil simulation from Mayfield Press (Macintosh, Hypercard) is an interesting and accessible resource that allows independent student work with taxonomic classification. Use slides or transparencies if skulls or casts are unavailable.
7.Discuss the student’s various religious and nonreligious beliefs about the origins of life. Emphasize again the importance for tolerance in listening to other students' points of view.
8.Members of the order Primates exhibit a great deal of variation, but they share certain general characteristics, including a generalized skeleton and a high degree of manual dexterity. Have students describe what they see in a picture of primates, either in the text, or provided by you. Have students describe the animal they see, its posture, configuration of arms and legs. Provide the context for the picture and explain what the students missed. Discuss primate brachiation, brachiating and nonbrachiating posture, and relative arm and leg lengths. This could also be a research/paper topic.
9.Encourage students to visit a local zoo. Have each student observe one primate's behavior for fifteen minutes or longer, taking field notes. Have students do a write-up which describes what was seen and then makes conclusions based on the observations. Or you may show a film on primates and have students describe the behaviors which were demonstrated on film.
10.Invite a biologist, physical anthropologist, sereologist, or zoologist to discuss and evaluate the Eve hypothesis.
11.Show an archaeological site map and have the students analyze it. Describe what they have missed. Make and display a site map of your own home and yard, or of an area of the building grounds you teach in. Have the students draw a site map of their school or home.
12.If you have access to tool casts, slides, and transparencies, ask your students to describe the tool style and function based on a visual inspection. If you are able to get the proper materials, introduce your students to the process of making stone tools. You might also demonstrate tool making or give them the materials (along with a safety lecture) and let them try to make one.
13.Develop worksheets on hominid evolution and the Upper Paleolithic that describe animal bones, tools, and other archaeological data. Have the students use that information to construct a general overview of the Middle Paleolithic or Upper Paleolithic lifestyle.
RESEARCH AND WRITING TOPICS (Research Navigator)
Encourage your students to utilize the free tool OneSearch with Research Navigator, included with this textbook as a supplement. They will have to register to use this service. Once registered, students can use this tool to research the Internet to find valid sources for research papers, saving them much time in their efforts to identify relevant sources.
1.Have students research an origin myth that is not their own, using library sources and/or interviewing. Have them compare and contrast this myth with their own and explain how they reconcile competing claims of truth. This may be presented in written or oral form.
2.Have students complete written or oral biographical reports on Charles Darwin or Gregor Mendel and how their scientific ideas contributed to Western thought.
3.Have students replicate some of the genetics experiments of Mendel using quick growing plants or quick breeding animals (e.g., fruit flies).
4.Do a research project on the concept of hominids and humans.
5.Analyze one of the major controversies or outline the trends in the field of hominid evolution. Roger Lewin's Bones of Contention can provide a perspective from which to begin.