Fundamentals of Genetics, Evolution, and Human Anthropology

Cellular and Genetic Foundations

• Cells: The fundamental unit of life.
• Prokaryotes: Lack a nucleus; typically single-celled organisms.
• Eukaryotes: Possess a nucleus and organelles; can be multi- or single-celled.

Genetics is the study of heredity. DNA structure was revealed in 1953, based on the work of Rosalind Franklin.

• DNA: A double helix structure composed of four bases (Adenine–Thymine, Cytosine–Guanine).
• DNA organizes sequentially into histones, forming chromatin, which condenses into chromosomes (humans have 23 pairs).

DNA Replication and Mutational Forces

• Replication Process: Involves initiation (using helicase), elongation (using polymerase), and termination.
• Mutations: Errors during replication are the only source of new genetic variation. Mutations can be harmful, neutral, or beneficial.
• Somatic Cells: Body repair occurs via mitosis.
• Gametes: Reproduction occurs via meiosis, leading to recombination and genetic diversity.

Protein Synthesis: From DNA to Protein

The central dogma of molecular biology:

1. DNA is converted to RNA (transcription).
2. RNA is converted to protein (translation).

The ribosome reads mRNA codons, and tRNA brings corresponding amino acids to build the protein chain.

Principles of Mendelian Genetics

Gregor Mendel established the concepts of dominant versus recessive traits.

• Genotype (the specific alleles) determines the Phenotype (the observable trait).
• Punnett squares are used to predict inheritance patterns.
• Codominance: Both alleles are expressed equally (e.g., AB blood type, where both A and B antigens are present).
• Polygenic Traits: Influenced by multiple genes plus environmental factors (e.g., height, eye color).

Microevolution: The Four Forces of Change

• 1. Mutation: Introduces new variation.
• 2. Natural Selection (NS): Allele frequencies change based on survival and reproductive advantage (e.g., the peppered moth).
• Fitness: Defined as reproductive success.
• 3. Genetic Drift: Random changes in allele frequencies, particularly impactful in small populations.
  • Bottlenecks: Population size is drastically reduced (e.g., mass extinction events).
  • Founder Effect: A small group separates to form a new population (e.g., the Amish community and Ellis-van Creveld syndrome).
• 4. Gene Flow: Allele exchange between populations (in humans, often referred to as admixture).

Epigenetics: Gene Expression and Environment

• Genes can be turned "on" or "off" through mechanisms like methylation.
• The environment can significantly alter gene expression (e.g., famine leading to activation of fat-storage genes).
• This mechanism suggests that Lamarck's idea that acquired traits can be passed on is partially correct.

Biological Adaptations in Humans

• Melanogenesis (Skin Color): Dark skin protects folic acid (important for fertility). Light skin aids Vitamin D synthesis (essential for bone growth). The Inuit population exhibits darker skin combined with a Vitamin D-rich diet and high UV reflection from snow.
• Body Shape (Allen’s Rule): Tall and thin body shapes are favored in hot climates; short and stocky shapes are favored in cold climates.
• Disease Resistance: Sickle cell anemia is codominant. The heterozygous genotype (NS) provides protection against malaria.

Coevolutionary Examples

Lactase persistence (the ability to digest milk sugar into adulthood) coevolved with cattle domestication, providing a significant survival advantage.

Phenotypic Plasticity (Non-Genetic Adjustments)

These are temporary or developmental adjustments made by an organism that are not encoded genetically.

• Behavioral: Cultural practices (e.g., using spices to prevent food spoilage).
• Acclamatory: Temporary and reversible physiological changes (e.g., shivering, vasoconstriction).
• Developmental: Changes occurring early in life that persist (e.g., high-altitude natives growing slower and maturing later).

Foundations of Anthropology

Holism: The study of all aspects of society. Factors (family, law, religion, economy) interconnect like organs in a body.

Comparative Methods: Comparing groups across time and space (e.g., Homo sapiens versus archaic humans, or different gender roles globally).

Fieldwork: Data gathered via travel, surveys, interviews, excavation, shadowing, and other methods.

Dynamism: Humans change biologically and culturally over short- and long-term periods (e.g., globalization, hybridity).

Cultural Anthropology: Methods and Themes

• Ethnography: Focuses on people, not just data. Uses participant observation to identify cultural patterns.
• Malinowski: Studied the Trobriand Islands, noting the kula ring exchange system, which established social prestige and alliances.
• Preparation: Requires permissions (community, government, IRB) and ensures anonymity.
• Data: Includes quantitative data (demographics, mortality) and qualitative data (stories, interviews).
• Research Themes: Identifying shared cultural meanings. Research sites can be physical or virtual.
• Researcher Role: The researcher is initially an outsider who needs language and background knowledge; their identity influences the research process.
• Collaboration: Participants are viewed as interlocutors, which helps decolonize research practices.
• Reflexivity: Acknowledging the researcher's bias and identity effects on the results.
• Mead: Studied Samoa, concluding that adolescence was shaped more by nurture than biology; this finding was later disputed.
• Positionality: The researcher’s social and political context shapes the research results.

Linguistic Anthropology

• Origin: Began with cataloging Indigenous North American languages.
• Studies: Focuses on language change, migration, how language shapes worldview, and the meanings of slang.
• Methods: Participant observation and transcription (of both speech and gestures).
• Data: Interviews, media, graffiti, and sign language.

Archaeology: Record, Methods, and Shifts

• Focus: The archaeological record (material remains plus their context).
• Survey: Mapping sites using ground surveys, aerial photography, and LiDAR.
• Excavation: Systematic exposure of artifacts and ecofacts (e.g., coprolites, seeds).
• Superposition: Lower layers are generally older, unless the context has been disturbed. Context provides meaning.
• Preservation: Depends on the material, environment, and human activity.
• Dating:
  • Absolute Dating: Provides calendar years (e.g., radiocarbon dating, volcanic dating, dendrochronology).
  • Relative Dating: Determines if something is older or younger than another item.
• Theoretical Shifts:
  • Processual (1960s): Scientific approach focusing on how and why change occurs.
  • Postprocessual (1980s): Focuses on subjectivity and multiple truths.

Biological Anthropology Subfields

• Focus: Human biology and behavior within an evolutionary framework. Evidence includes bones, DNA, and fossils.
• Paleoanthropology: The study of hominin evolution.
• Primatology: Studying primates to find human parallels and focusing on conservation.
• Living Humans: Studying growth, disease, stress, and lifespan. Often uses ethnographic analogy.

Ethics and Modern Issues in Anthropology

• Decolonizing Anthropology: Centering local knowledge and rejecting colonial research practices.
• Decanonization: Recovering overlooked scholars (e.g., Al-Jahiz, who preceded Darwin in discussing natural selection).
• Community Control: Descendant communities must decide how human remains and artifacts are used.
• Biological Samples: Often considered sacred; using them without consent is unethical (e.g., the case of HeLa cells).
• Data Sovereignty: Communities govern the collection, storage, and use of their data. Samples must be returned if requested.
• Diversity: The field, historically rooted in studying "Others," now requires diverse voices and community-based participatory research (CBPR).

Defining Anthropology and Its Subfields

Anthropology is the study of humans. It explores human similarities and differences, and biological and cultural complexity (past and present).

The four main subfields are Cultural, Linguistic, Archaeology, and Biological (with Applied Anthropology sometimes considered a fifth).

Cultural Anthropology Revisited

Uses cultural relativism (suspending judgment) to counter ethnocentrism.

Uses participant observation to study emotions, behaviors, movement, and cultural hybridization.

Linguistic Anthropology Revisited

Language is unique to humans, symbolic, and allows for abstract thought.

Studies origins, change, dialects, adaptation, identity, and worldview.

Historically began with documenting dying Indigenous languages.

Archaeology Revisited

Studies material remains (tools, bones, seeds, pottery, etc.).

Uses excavation carefully, as it is a destructive process.

Studies societies' size, environment, agriculture, cities, and even modern garbage (garbology).

Biological Anthropology Revisited

Studies human evolution and variation, fossil hominins (paleoanthropology), and primates.

Examines modern populations regarding physiology, health, and traits.

Applied Anthropology

Applies anthropological theory and methods to real-world problems.

It is controversial because it rejects full objectivity and often advocates for social change.

Anthropology and the Scientific Method

Science requires testable, empirical, and peer-reviewed evidence.

Some branches are more "scientific" (Biological Anthropology, Archaeology).

Anthropology values multiple truths, ethics, and humanities aspects.

Understanding Knowledge Systems

There are many ways of knowing: science (evidence), religion (faith), and culture.

Both scientific and non-scientific systems are valid, recognizing that multiple realities can exist.

Core Anthropological Practices

1. Fieldwork
2. Comparison
3. Multidisciplinary approaches
4. Positive change advocacy
5. Ethical standards

Ethical Standards and Debates

Core principles include informed consent and prioritizing participants.

The American Anthropological Association (AAA) Principles emphasize: do no harm, avoid plagiarism, harassment, and withholding results.

Ethical debates include the role of anthropologists in war zones (e.g., the Human Terrain System) and the use of data derived from unethical sources (e.g., Nazi hypothermia data).

The Teeth Example: Four Subfield Perspectives

• Cultural: Studies social meanings associated with teeth (e.g., modification, aesthetics).
• Linguistic: Studies the sounds produced by teeth and their role in identity.
• Archaeology: Studies teeth to infer past conditions and social hierarchy (e.g., diet, wear patterns).
• Biological: Studies teeth in the context of human and primate evolution.