Biological Anthropology Subfields and Hadza film .Some Biological Anthropology Subfields ... how

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  • Biological Anthropology Subfields

    and Hadza film Notes

  • Some Biological Anthropology Subfields Population genetics: the study of gene frequencies and changes in them over evolutionary

    time; also in biology departments Primatology: the study of the order to which we belong (morphology, phylogeny, ecology, and

    behavior); also in zoology departments Paleoanthropology: the study of ancient humans as found in fossil hominid evidence such as

    petrified bones and footprintsuses many archaeological methods Bioarchaeology: a subfield of both archaeology and biological anthropology (includes

    forensics); the film The Perfect Corpse in the Archaeology portion of our class involves bioarchaeology

    Human variation: the study of ways in which different populations express different physiological properties (e.g., skin color variation by region, lactose tolerance)

    Human evolutionary biology: how do the human bodys physiological adaptations work, and why do we have them? (for example, do fevers have a beneficial function which can explain why they evolved?)

    Behavior genetics: can inter-individual differences in morphology and behavior be attributed to inter-individual differences in ones genetic makeup?; emphasizes differences

    Evolution of behavior and mental processes: Human behavioral ecology: how do ecological variables impact human behavior and reproduction? Evolutionary psychology: how did natural selection shape the minds adaptations in ancestral

    populations, and how are those mental adaptations expressed in measurable behaviors?; emphasizes a universal human nature,

    Both fields examine inter-individual differences in terms of responses to different environments, experiences, and cultures

  • Subfields

    Not all BioAnthro subfields look specifically at how evolutionary processes shaped humans and their relatives, BUT, all agree that evolution DID shape us

    For example, a bioarchaeologist might study the chemical components of Bronze Age teeth to infer the dietary differences of a wealthy individual vs. a poor individual, without necessarily having a hypothesis related to the evolution of human diets or the evolution of the shapes of the teeth

    Not all BioAnthro subfields look specifically at how genes affect humans and their relatives, BUT, all agree that genes do build proteins--the stuff we are made of

    For example, we do not know what genes build the proteins that make upthe heart, but we do know that evolution (specifically, evolution by natural selection) shaped an organ that was sufficient to pump blood through the body and lungs, with the effect of delivering oxygen and nutrients to various body structures

    Some subfields are subfields in disciplines other than anthropology

  • The Hadza The Hadza are an ethnic group in central Tanzania, living around Lake

    Eyasi in the central Rift Valley and in the neighboring Serengeti Plateau. The Hadza number under 1000. Some 300-400 Hadza live as, hunter-gatherers much as they have for thousands, or even tens of thousands, of years; according to some anthropologists, they are of the last few functioning hunter-gatherers in Africa.

    The Hadza are not closely related to any other people. While traditionally considered an East African branch of the Khoisan peoples, primarily because their language has clicks (see Pinker 167-168). The Hadza language appears to be an isolate, unrelated to or very distantly related to any other language. (e.g., 8 noun classes).

    The Hadza still subsist by hunting and gathering-foragingwhich is what hominids (including our ancestors) did for millions of years during and prior to the evolution of anatomically modern humans (us)

    The lifestyle of the Hadza may be one of the worlds current best indicators of what life was like when humans evolved

    Film (39 mins.) and how to take notes during a film

  • Hand Notes on The Hadza

  • Some notes on The Hadza Huts put up by women They are hunter-gatherers (HGs) Men hunt alone Women gather plant foods Hunt many impala Men gamble in downtime, winning and losing mainly arrows but also bees, honey; gambling losses do not cause significant

    hardships ad arrows can be replaced by making new ones within hours to days No territoriality--people HG anywhere they want, unlike in most other HGs studied to the time the film was made All hunting by adult men is with bow and arrow; no traps, snares, or nets; the force require to pull a bow is strong--throws

    off accuracy but implants arrow more deeply; 90% misses in hunting (often due to inaccuracy point above) Arrows with metal heads traded with other groups (for, e.g., honey) Majority of food from wild berries and roots/tubers, though they consider themselves meat-eaters Berries are abundant and many are eaten on the spot; food not stored past a days worth of eating (some seasonal

    variation) Women about 2 hrs a day gathering all the food they need Baobob trees have tasty fruits (ground and cooked to a porridge); some trees better than others; berries are not like sweet

    wildberries--harder to eat; roots and tubers cooked; water from underground sources and water trapped in tree hollows that are scarce during the dry season

    Baobob and other locations have bees with honey and grubs Honey can be traded to other groups for western items like pots, tobacco, cloth, axes, iron/aluminum, beads One male duo did not find sufficient honey in one tree to walked a few miles to another known bee source Only collect enough food to last until the next day Dry months = more berries; wet months = more roots/tubers which are then more succulent Grandmas collect large tubers and share them with everyone in the camp--not just their specific families Hadza are nomads who only live in a particular camp for up to a few weeks Sometimes live on rock shelters--important returned-to shelters are on hills which provide a good vantage point of

    surrounding areas An impala is killed; hidden from scavengers like vultures and hyenas until the hunter comes back with others to help carry

    the carcass to camp The fat, not so much the meat, is what is prized in the impala--most hunted foods are high in protein but low in fat Boys practice hunting at young ages with wooden-tipped bows and arrows Boys catch a hyrax and use it to procure additional hyraxes, than kill & eat them all (no waste and yet no saving food)

  • Parental Investment and Sexual Selection

    Trivers 1972

  • Assumption Assumption: Every organism has adaptations that

    function to facilitate reproduction Members of a population/species live in the same

    environment, so why do some animals have different adaptations than others?

    Morphs: age, sex, others SEX: male and female adaptations are different WHY?

  • Parental Investment

    Any investment by the parent in an individual offspring that increases the offsprings chance of surviving (and hence reproductive success) at the cost of the parents ability to invest in other offspring (Trivers 1972)

  • Sperm vs. Egg

    In sexually-reproducing species, the relative size of gametes define who is male and who is female.

  • Nurturant Females

    In most animals, and almost all mammals, females provide far more parental investment than just the egg

    Internal fertilization protects, but at a cost

    Cod vs. gorillas Humans (mammals):

    Prolonged internal gestation (pregnancy)

    Placentation Lactation

  • Competitive Males Males are fighting with each other to mate with as

    many females as possible More females = more offspring (sharp contrast to


  • Sexual Selection and Parental Investment Theory

    For members of the sex that invests more in offspring, reproductive success is limited by the amount of resources an individual can secure for itself and its offspring

    For members of the sex that invests less in offspring, reproductive success is limited by the number of mates one can acquire

  • Sexual Selection and Parental Investment Theory

    What of it? Selection acted on males differently than it acted on females Specifically, differences in parenting strategies cause differences in

    adaptations Sex that invests more: adaptations to survive and get resources for

    offspring Sex that invests less: adaptations to help them get as many mates

    as possible It explains why, in many species, males look and behave differently

    than femalesWhen the sexes have different adaptations, they are sexually dimorphic

  • Intrasexual selection:weaponry/size differentiation

    Sexual Selection and Parental Investment Theory

  • Intrasexual selection: lack of differentiation

    Sexual Selection and Parental Investment Theory

  • Intersexual selection: ornaments in one sex and not the other

    Sexual Selection and Parental Investment Theory

  • Intersexual selection: why ornaments? Arbitrary (you just know you want your

    offspring to inherit those traits) Good genes Low parasite load Handicap principle Combination

    Sexual Selection and Parental Investment Theory

  • Sexual Selection and Parental Investment Theory

    Why not just say females are limited by resources and males are limited by access to females?

    The exceptions that prove the rule



  • Paternal confidence is typically less than maternal confidence

    If fathers invest, as they do in humans, the father needs to be sure he is, in fact, the father

    Sexual jealousy Acut