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Anthropology

<OpenstaxParagraph>
	The term <OpenstaxTerm>hominin</OpenstaxTerm> refers to all species considered to be in direct lineage to humans, which include the genera <OpenstaxEm>Homo, Australopithecus</OpenstaxEm>, <OpenstaxEm>Paranthropus</OpenstaxEm>, and <OpenstaxEm>Ardipithecus</OpenstaxEm>. <OpenstaxTerm>Hominids</OpenstaxTerm> refers to all modern and extinct great apes, which include humans, gorillas, chimpanzees, and orangutans and their ancestors. These terms have been understood to represent different things over the years, but the definitions provided here are the most current. While all hominins may differ in varying ways from one another, they all share one anatomical behavioral complex: bipedal locomotion.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Scientists can hypothesize about how a creature moved by analyzing several aspects of its morphology. <OpenstaxTerm>Brachiators</OpenstaxTerm>, animals that move by swinging from branch to branch, generally have long arms, while <OpenstaxTerm>leapers</OpenstaxTerm>, animals that propel their bodies through the force of their lower limbs, have relatively long legs. Arboreal primates have arms and legs of equal length. In <OpenstaxTerm>bipedal locomotion</OpenstaxTerm>, one leg is called the stance leg, and the other is called the step leg. While the stance leg is on the ground, the step leg is off the ground and striding forward. During normal walking, both feet are on the ground only about 25 percent of the time. As speed of locomotion increases, the percentage of time that both feet are on the ground decreases. As a result, for most of the time that bipedal organisms are moving, their body is balanced on only one of their legs (the stance leg). To ensure that bipedal organisms do not fall over while balanced on their stance leg, they have undergone many anatomical changes since the earliest hominin ancestors.
</OpenstaxParagraph>
<OpenstaxParagraph>
	One of the most important anatomical changes that facilitate successful bipedalism is the angling of the femur (upper leg bone) inward at what is referred to as a <OpenstaxTerm>valgus angle</OpenstaxTerm>, which positions the knees and feet under the center of the pelvis. Bipedal hominins have also evolved spinal curves that make it possible for the hips to balance the weight of the upper body. The evolution of the arch in the foot as well as the realignment of the big toe so that it is parallel to the other toes is also instrumental in transmitting weight during the step phase of bipedal locomotion.
</OpenstaxParagraph>
<OpenstaxFigure id="fig-00001" src="https://openstax.org/apps/archive/20240226.174525/resources/c8d2c3e9d09051fecef1e32486cbd9bb2a0388c8" alt="Sketches of the hips and legs of two different species. On the left is a skeleton with long arms and short legs that extend straight down from the hips. A line traces the femur (upper leg bone) and the related text reads “Femur is angled straight in the gorilla.” On the right is a human skeleton. The femurs on this skeleton angle inward, with the knees closer together than the hip sockets. Text pointing to the hip reads “Femoral head is angled.” Text pointing to the femur reads “Femur angles in towards knees in humans.”" mediaType="image/png" width="1284" height="1065" />
<OpenstaxFigureText width="1284">
	<strong>Figure 4.30</strong> In humans, the femur bones angle inward. This adaptation, known as the valgus angle, makes bipedal locomotion (walking upright) more comfortable and more efficient. (attribution: Rice University, OpenStax, under CC BY 4.0 license)
</OpenstaxFigureText>
<OpenstaxParagraph>
	The most important evidence of early hominin bipedalism is provided by the work of English paleoanthropologist Mary <OpenstaxTerm>Leakey</OpenstaxTerm>. In the 1980s, Mary Leakey discovered a 75-foot trail of footprints made by three bipedal individuals who had crossed a thick bed of wet volcanic ash about 3.5 MYA. These footprints were found in East Africa at the site of <OpenstaxTerm>Laetoli</OpenstaxTerm>. Based on the date and the location, it is probable that these footprints were made by <OpenstaxTerm><OpenstaxEm>Australopithecus afarensis</OpenstaxEm></OpenstaxTerm>. Analysis of the Laetoli footprints indicates a modern striding gait.
</OpenstaxParagraph>
<OpenstaxFigure id="fig-00002" src="https://openstax.org/apps/archive/20240226.174525/resources/b429fdc016b581ade04ba72a842b1a3afc9a2a88" alt="Indistinct footprints in a dark substrate." mediaType="image/jpeg" width="800" height="472" />
<OpenstaxFigureText width="800">
	<strong>Figure 4.31</strong> These replicas of the 3.6-million-year-old hominin footprints found in Tanzania by Mary Leakey are on display at the National Museum of Nature and Science in Tokyo, Japan. (credit: “Australopithecus afarensis Fossil Hominid Footprints (Pliocene, 3.6–3.7 Ma; Laetoli Area, Northern Tanzania, Eastern Africa)” by James St. John/flickr, CC BY 2.0)
</OpenstaxFigureText>
<OpenstaxParagraph>
	The evolution of hominin bipedalism required complex anatomical reorganization. For natural selection to produce such a tremendous amount of change, the benefits of these changes must have been great. There have been dozens of hypotheses for these changes, ranging from freeing hands to carry tools, food, or offspring to increasing energy efficiency or thermoregulation (the ability to maintain the body’s temperature) by exposing more of the body’s surface. None of the hypotheses are testable, making it truly challenging to understand why humanity’s ancestors made such a huge behavioral shift. The next sections explore some of the key discoveries of early hominin fossils in which anthropologists see some of the earliest indications of the adaptation of bipedalism in the human story.
</OpenstaxParagraph>

4.7.1 Walking on Two Feet

1 What Is Anthropology?

1.1 The Study of Humanity, or "Anthropology Is Vast"

1.1.1 The Heart of Anthropology: Central Narrative and Commitments

1.1.2 Central Commitment #1: Exploring Sociocultural Diversity

1.1.3 Central Commitment #2: Understanding How Societies Hold Together

1.1.4 Central Commitment #3: Examining the Interdependence of Humans and Nature

1.2 The Four-Field Approach: Four Approaches within the Guiding Narrative

1.2.1 Biological Anthropology

1.2.2 Archaeology

1.2.3 Cultural Anthropology

1.2.4 Linguistic Anthropology

1.2.5 How the Four Fields Work Together: The Example of Race

1.3 Overcoming Ethnocentrism

1.3.1 Enculturation and Ethnocentrism

1.3.2 Primitivism and Orientalism

1.4 Western Bias in Our Assumptions about Humanity

1.4.1 Primitivism and Orientalism in Popular Culture

1.4.2 The Bias of Backwardness

1.5 Holism, Anthropology’s Distinctive Approach

1.5.1 Society as an Integrated Whole

1.5.2 Sources of Contradiction, Conflict, and Change

1.6 Cross-Cultural Comparison and Cultural Relativism

1.6.1 Relativism Is Not “Anything Goes”

1.6.2 Morality, Activism, and Cultural Relativism

1.7 Reaching for an Insider’s Point of View

1.7.1 The Challenge of Representing Others

1.7.2 Collaborative Methods of Representation

1.7.3 Working across Cultures toward Common Goals

1.7.4 Suggested Readings

2 Methods: Cultural and Archaeological

2.1 Archaeological Research Methods

2.1.1 Archaeological Techniques

2.1.2 Archaeological Dating Methods

2.2 Conservation and Naturalism

2.2.1 Early Efforts

2.2.2 Salvage Anthropology

2.2.3 Museum Collections

2.2.4 Interpretation and Voice

2.3 Ethnography and Ethnology

2.3.1 The Development of Ethnography and Ethnology

2.3.2 Perspective and Interpretation in Ethnography

2.4 Participant Observation and Interviewing

2.4.1 Participant Observation

2.4.2 Interviewing Informants

2.4.3 Ethical Considerations

2.5 Quantitative and Qualitative Analysis

2.5.1 Differences between Quantitative and Qualitative Information

2.5.2 Modeling

2.5.3 The Science of Anthropology

2.6 Collections

2.6.1 Archives

2.6.2 Three-Dimensional Collections

2.6.3 Ownership

2.6.4 Suggested Readings

3 Culture Concept Theory: Theories of Cultural Change

3.1 The Homeyness of Culture

3.2 The Winkiness of Culture

3.3 The Elements of Culture

3.3.1 Culture Is What We Make

3.3.2 Culture Is What We Do

3.3.3 Culture Is What We Think

3.4 The Aggregates of Culture

3.4.1 Symbols

3.4.2 Ritual

3.4.3 Social Structure

3.5 Modes of Cultural Analysis

3.5.1 Evolution, Adaptation, and Historical Particularism

3.5.2 Functionalism

3.5.3 Structuralism

3.5.4 Ontology

3.6 The Paradoxes of Culture

3.6.1 Paradox 1: Culture Is Continuous, but It Changes

3.6.2 Paradox 2: Culture Is Bounded but Mobile

3.6.3 Paradox 3: Culture Is Consensual but Contested

3.6.4 Paradox 4: Culture Is Shared, but It Varies

3.6.5 Suggested Readings

4 Biological Evolution and Early Human Evidence

4.1 What Is Biological Anthropology?

4.1.1 Looking to the Deep Past

4.1.2 Exploring What It Means to Be Human

4.2 What’s in a Name? The Science of Taxonomy

4.2.1 Defining the Science of Taxonomy

4.2.2 Defining a Species

4.3 It’s All in the Genes! The Foundation of Evolution

4.3.1 The Units of Life

4.3.2 Gregor Mendel and the Laws of Heredity

4.3.3 Mendelian Inheritance in Humans

4.4 Evolution in Action: Past and Present

4.4.1 Early Evolutionists and the Fixity of Species

4.4.2 Charles Darwin’s Role in Changing Views of the Natural World

4.4.3 Understanding Darwin’s Theory of Natural Selection

4.5 What Is a Primate?

4.5.1 What Is a Primate?

4.5.2 Primate Behavioral Variation

4.5.3 Explaining Primate Success

4.5.4 Primate Classification and Taxonomy

4.6 Origin of and Classification of Primates

4.6.1 Understanding Concepts of Time

4.6.2 Fossils and Dating Methods