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PHYSICAL ANTHROPOLOGY (Unit 1 (The Field of Anthropology (The Four Main…

- - - - Darwin: Natural Selection
        
        Context for Darwin's Theory
        
        Influences:
        
        James Hutton
        
        Uniformitarianism
        
        Developed by James Hutton, the theory postulates that the processes of the geological past are still in effect today.
        
        Calculated Earth's age as millions of years old (1788) & Provided geologic evidence necessary for calculating time span of evolution
        
        John Ray
        
        Pioneered taxonomy based on physical appearance (1660). Created the first scientific classification of plants and animals
        
        Carolus Linnaeus
        
        Systems of Nature
        
        Presented the binomial nomenclature taxonomy of
        plants and animals
        
        Georges Cuvier
        
        Catastrophism
        
        Revealed much variation in the fossil record
        
        Thomas Malthus
        
        Founded demography: only some will find enough food to survive (1798). Provided the concept of characteristics advantageous for survival
        
        Observations on variation
        
        Robert Hooke
        
        Proved that fossils are organisms’ remains, Revealed that fossils would provide the history of past life
        
        Jean-Baptise de Lamarck
        
        Theory of Acquired Characteristics
        
        Provided the first serious model of physical traits
        passing from parents to offspring
        
        Charles Lyell
        
        Rediscovered and reinforced Hutton’s
        ideas
        
        Erasmus Darwin
        
        Also posited characteristics (determined by wants and needs) acquired via inheritance (1794). Advanced the notion that physical changes occurred in the past
        
        His theory drew from these fields:
        
        Taxonomy
        
        Systematics
        
        Paleontology
        
        Demography
        
        Geology
        
        How did variation appear? What would happen to a species when humans weren't around to select traits?
        
        Darwin began to figure out solution when he stumbled upon Malthus' work
        
        Malthus suggested that selection is the natural result of competition (who did and did not survive)
        
        "Nature Selects"
        
        Adapting is adjusting to changing environmental circumstances
        
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        Species
        
        Darwin did NOT come up with evolution. His theory proposed that natural selection was the prime mechanism of evolution
        
        What remained at issue for Darwin, was the possibility that whole new distinct species could evolve. What was then unknown, was how this might take place in nature. Darwin's theory, "natural selection," explains this.
        
        While natural selection explains what happens as new variations are expressed within a population, Darwin had no idea where the variations come from to begin with. He simply noted that in any progeny there are variations between siblings and between children and their parents. Natural selection operates on these variations but does not explain their origins.
    - - Population
        
        Bell Curves
        
        What is the relationship between a bell curve and diversity?
        
        Bell curves illustrate variation within a data set. The curve of the bell represents how much variation occurs or is dispersed.
        
        Thin curve= little variation
        
        Thick curve= large variation
        
        The curve of the bell is the central pattern in which variation gathers around
      - Three elements that result in evolution
        
        Variation
        
        Not all copies are exact. Descent with modification
        
        VARIATIONS BUILD ON EXISTING FORMS
        
        Competition
        
        Not all copies survive. Some are more successful than others
        
        Adaptation describes changes in copies that help it survive
        
        Replication
        
        Making copies, reproductions, duplication
        
        Think of memes. Memes are copied. Format? Or think of babies lol
      - Mechanisms of Evolution
        
        Mutation
        
        spontaneous change in an existing gene. This creates new genetic material
        
        Gene flow
        
        the spread of new genetic material from one population to another of the same species
        
        Natural Selection
        
        Variation
        
        Variation in the context of natural selection is synonymous with adaptation, which is understood as characteristics that are advantageous to an organisms survival reproduction
        
        Variation comes from genetic differences and differences in their expression within a species.
        
        Mendel contributed from his experiments that "discrete physical units" are the cause for specific characteristics which are passed from parent to offspring. Combined with Darwin's theory this lead to more questions about variation and laid groundwork for understanding genes
        
        "Individuals having variation that is advantageous for survival to reproductive age produce more offspring (and more offspring that survive) than do individuals lacking this variation." (35)
        
        "...biological characteristics that enhance survival increase in frequency from generation to generation" (p. 26)
        
        Competition
        
        The role of competition in natural selection- the competition for resources and reproduction, as there are limited resources. Those with the most advantageous traits have more access to these resources, go on to reproduce more successfully, and pass on these advantageous traits
        
        adaptive radiation: out of one species branch multiple closely related species.
        
        Artificial Selection
        
        Similar to nat. in that selective traits are passed down. Not necessarily advantageous to resources or reproduction however. Humans are the ones guiding the selection of traits
        
        Basically, humans choose the traits they want expressed in offspring
        
        Selective Pressure
        
        “Selective pressure is any phenomena which alters the behavior and fitness of living organisms within a given environment. It is the driving force of evolution and natural selection, and it can be divided into two types of pressure: biotic or abiotic.
        
        Biotic- Biotic pressure affecting an organism are living organisms within the same ecosystem that interact with the affected organism
        
        Abiotic- Abiotic pressure is created by non-living factors within the organism's environment, such as light, wind, and soil.
        
        When anthropologists are trying to understand the evolutionary history of a species or a particular trait, they are often looking for evidence of the kinds of selective pressures that were active at the time of interest.
        
        For example, when the climate gets colder, there is pressure for mammals to increase layers of fur and body fat, and become shorter and stockier to conserve heat. The climate is the selective pressure. The body changes are adaptations to that pressure.
        
        Genetic drift
        
        Random change in the frequency of alleles. This effects smaller populations more than larger populations. Ex: two populations lose a red fish every month. The ration of red to yellow fish will be different in a larger pop and a smaller pop. Smaller pop will sooner have no red fish than the larger pop
      - The Six Big Events of Human Evolution
        
        3.3 million years ago- Material culture and tools
        
        2.5 million years ago- Speech
        
        5.5 million years ago- nonhoning chewing (no projecting canines)
        
        1 million years ago- Hunting
        
        6 million years ago- Bipedalism
        
        11,000 years ago- Domesticated foods
      - Our Species is dependent on culture
        
        Culture: a complex human characteristic that facilitates our survival by enabling us to adapt to different settings
        
        Material Culture: part of culture that is expressed as objects humans can use to manipulate their environments
        
        No society functions without any form of technology
      - Taxonomy
        
        Taxonomy is the classification of past and living life-forms. This discipline laid the foundation for systematics, the study of biological relationships over time.
        
        "As late as the seventeenth century, scientists generally believed that species were immutable. In their view, life had changed very little, or not at all, since the time of the single Creation. Thus, early taxonomists were not motivated by an interest in evolution. Rather, they were motivated by their desire to present the fullest and most accurate picture of the Creator’s intentions for His newly created world. "
        
        "Linnaeus presented the first version of his taxonomy in his book Systema Naturae (1735), or System of Nature. As he revised the taxonomy—his book would eventually go through 10 editions—he added more and more levels to the hierarchy. He classified groups of genera into orders and groups of orders into classes."
      - Evolution = Replication + Variation + Competition
    - - Cladogenisis
        
        Cladogenisis refers to speciation that is due to isolation across space. Ex: Darwin's finches. They lived simultaneously but were separated by space. They evolved from isolation.
      - Anogenesis
        
        sometimes used to describe this process of evolution that is the result of isolation across time. Notice that in contrast to cladogenesis, where there are two new species that exist simultaneously, anogenesis refers to two species that exist sequentially.
      - It is important to realize that cladogenesis and anogenesis are actually interrelated processes. They occur simultaneously in evolving populations. The value of these concepts is that they help us to think about how we are defining new species. This is particularly relevant to the challenge of defining species by their fossil remains.
  - - - Cultural/Social Anthropology
        
        The study of human thought and behavior from a broad comparative perspective.
        
        Study current cultures and thir very recent past
        
        Interested in how diverse worldviews influence social behavior
        
        Typically in a "non-western" setting
      - Linguistics
        
        Explores human behavior from the perspective of our use of symbols to order society and influence experience.
        
        Social and cultural contexts of language
        
        language- a set of written or spoken symbols that refer to things other than themselves
        
        Sociolinguistics- investigation of language's social contexts
      - Physical/Biological Anthropology
        
        The study of human biological evolution and human bio-cultural variation
        
        Five primary areas
        
        Forensic anthropology- analyze patterns/conditions of human remains
        
        Medical anthropology- contemp. issues in health. How cultural beliefs affect health
        
        Primatology- biology and behavior of non-human primates. Provides insight to humans
        
        Comparative biological anthropology (human diversity)- patterns in diversity. Similarities/differences
        
        Paleoanthropology- study fossil record for human evolution
        
        Key Concepts
        
        each individual is the result of evolution and its history, all the bio changes that have brought humanity to its current form
        
        We are the products of our own life history
        
        Biological makeup is influenced by the environment
        
        Franz Boas
      - Archaeology
        
        Study from persp. of objects left behind. The study of past societies through objects left behind
      - These 4 sub-fields encompass the range of human existence/experience: biological, social, cultural, symbolic, historic, prehistoric
    - - Central to all sub-fields
    - - what are these connections?
  - - - Experiments
        
        "These plants enabled him to identify and carefully observe seven characteristics, or traits, that were especially informative about breeding and its outcome over generations (Figure 2.17). From his results, Mendel inferred that a discrete physical unit was responsible for each characteristic. This unit passed from parent to offspring, and in this way the characteristic was inherited. In fact, the discrete unit could be traced through generations, and its passage (the inheritance) was determined by mathematical laws."
        
        Mendel spend years cross-breeding varieties of peas. Think of the punnet square
        
        By carefully tracking generations of artificially mated pea plants, Gregor Mendel began to discover the operation of genes in populations. It would be decades before scientists would identify the molecular process that explained Mendel's observations and the emergence of endless variation that puzzled Darwin.
        
        "Mendel also discovered that the garden peas’ traits did not blend. For example, plants and their offspring were either tall or short. Over time, the short plants diminished in frequency and eventually disappeared".
        
        Later scientists discovered....
      - Father of genetics
      - ANSWER: what is the genetic basis, observations as well as the origins of biological variation.
    - - DNA & Genes
        
        DNA (deoxyribonucleic acid) ...
        
        Allels
        
        the physical unit of inheritance—now known as a gene—has two subunits, one from the father and one from the mother, each called an allele. Each allele is either dominant or recessive.
        
        Dominant
        
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        Recessive
        
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        The page 43 Danish botanist Wilhelm Ludvig Johannsen (1857–1927) called the pair of alleles (for example, TT, Tt, tt) the genotype and the actual physical appearance (tall, short) the phenotype.
        
        Genotype
        
        Phenotype
        
        More on Chromosomes...
        
        The Geneticist Thomas Hunt Morgan bred the common fruit fly in experiments based off of Mendel's peas. They discovered that all genes are passed from parents to offspring in the ratios proposed by Mendel. These genes are on chromosomes
        
        "In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure....DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division."
        
        It is found in the nucleus of the cell, usually in a loose noodle form, however it has a different , condensed form when it is being used for reproduction. Looks like an x with spools of thread wound inside
        
        Chromosomes contain genetic information
        
        it is important because the genes that are passed from parent to offspring are located on the chromosome. This is the "discrete unit"
        
        DNA is the chemical that makes up each chromosome
        
        Chromosomal DNA is contained in the nucleus of the cell, thus nDNA
        
        nDNA is homoplasmic; it is the same in EVERY cell (except red blood cells which have no nuclei). Skin cell mathces DNA in a bone cell. Think of it as certain parts of the DNA being switched on or off for each type of cell
        
        A small but sig. amount of DNA is found in the mitochondria (use oxygen to turn food molecules into ATP). mt DNA is heteroplasmic which means that it differs depending on the parts of the body or parts of the cell that it's in.
        
        “the most important, most wondrous map ever produced by mankind.” The Human Genome
        
        Within each chromosome, DNA molecules form sequences, or codes, that are templates for the production of proteins or parts of proteins in the body
        
        Each DNA sequence, each protein-generating code, is a gene; and the complete set of genes is the genome.
        
        PRODUCING PROTEINS | DNA FUNCTION
        
        DNA serves as the template for protein synthesis. Proteins are the complex chemicals that make up tissues and bring about the functions, repair, and growth of tissues
        
        Proteins are made up of amino acids, of which there are 20. Body makes 12, the essential 8 are obtained through diet.
        
        The Seven Types (table on p. 72)
        
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        Protein synthesis is 2-step:
        
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        Composition and Structure
        
        RIght-twisted double helix structure
        
        Each side of the ladder= phosphate, sugar, and nitrogen base which forms a single nucleotide
        
        Phosphate and sugar stay the same, but the the base can be adenine, thymine, guanine, or cytosine
        
        A & T are complementary base pairs
        
        G & C are complementary base pairs
        
        Anthropologists and geneticists investigate the many thousands of single DNA base pairings that produce genetic differences between individuals. These pairings are known as single nucleotide polymorphs
        
        Replication
        
        One function of DNA is replication, which takes place of the nucleus and is part of cell division, leading to production of new somatic cells (mitosis) or the production of new gametes (meiosis)
        
        Replication = identical copies
        
        Chromosome types
        
        Homologous- chromosomes occurring in matching pairs in a somatic cell. A pair = father's contribution + mothers contribution. The nonsex chromosomes are called autosomes
        
        Karyotype (complete set of chromosomes) = all autosomes + 1 pair of sex chromosomes (they determine biological sex)
        
        Females- 2 X chromosomes
        
        Males- 1 X & 1 Y chromosome
        
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      - Genetics
        
        The Cell
        
        Prokaryote: organisms with cells that have no internal compartments
        
        Eukaryote- organisms with cells that have internal compartments separated by membranes
        
        There are 2 types of euk. cells:
        
        Somatic cells (body cells) compose most tissue (bone, muscle, fat, etc.)
        
        DIPLOID: 46 chromosomes
        
        Gametes sex cells, sperm and ove/eggs
        
        HAPLOID: 23 chromosomes
        
        MITOSIS
        
        The production of IDENTICAL SOMATIC CELLS
        
        An organism starts life as a single cell, the zygote, which then produces identical copies of itself many, many times.
        
        In this process of cell division, a diploid cell divides to produce 2 cells which each have a full set of chromosomes
        
        (makes body cells)
        
        Mitosis Starts:
        
        Diploid (2n)
        
        Goes through PMAT
        
        Cell splits into 2
        
        END RESULT: 2 Identical diploid cells
        
        MEIOSIS
        
        The production of UN-IDENTICAL GAMETES
        
        "Unlike mitosis, the production of these cells—meiosis—does not result in identical copies of the parent cell and the parent cell’s DNA. Meiosis involves one DNA replication followed by two cell divisions"
        
        "Because each gamete contains just one chromosome from a homologous pair and just one sex chromosome, during reproduction each parent contributes only half of his or her genetic material"
        
        (makes gametes / sex cells (sperm or egg))
        
        Meiosis Starts:
        
        Diploid (2n)
        
        Goes through PMAT. Here there is a cross-over of chromosomes in prophase which results in new genetic combos / genetic variants / "recombination"
        
        END RESULT: 4 unidentical haploid gametes (sperm or egg)
        
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        Goes through PMAT II
    - - Gemmules
  - - - If you're not familiar with both the objects or ideas AND the relationships, you don't have knowledge
      - This formula applies to everything you study
      - Cultural Systems Diagram
      - Every child is encultured in three categories of relationship: self, society, and environment
    - - Science is a way of knowing
      - epistemology- the study of knowledge systems
      - "Almost everything that you know is the result of you believing what someone else told you..."
      - There are two ways of knowing:
        
        Authority
        
        Authority has limitations- some beliefs are wrong.
        
        We act in accordance with our beliefs which can have powerful consequences
        
        We chose our beliefs but at the same time are dependent on authority to different degrees (some people are more or less dependent on religious authority. More so historically
        
        Discovery
        
        Methods of discovery
        
        Skepticism
        
        Question authority. Questioning without providing better option is not skepticism but rebellion
        
        Question Source
        
        Consider potential bias. Human nature is biased
        
        Weigh the evidence
        
        proof in observable form; "research"
        
        Science is a way of knowing that uses all of these. Science actively tries to disprove its own beliefs. The scientific method helps us overcome bias. Don't confuse science with its applications.
        
        Scientists search for patterns.Variation exists around a central pattern. Patterns exist between things and relationships
        
        "Science is concerned with discovering which explanations are most accurate. In other words, which one reliably describe patterns in nature"
        
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    - - According to the Pew Research Center, most major religions and Christian denominations, many accept evolution as the mechanism by which God created life and all its diversity
      - There is the perception that Science and Religion are at odds, but that is not the reality. Even many scientists are religious.
      - Where is there conflict?
        
        Specific descriptions about the material world. Religion can make claims (ex: descriptions of material world in the bible) that don't make an argument about god. Science can test evidence from observable material world to discover truth.
        
        Not all beliefs are accurate.
        
        There are many questions that are beyond science or that science has yet to figure out