Prehistory of NA Test 1 Lecture 2 (Pleistocene)

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Prehistory of NA Test 1 Lecture 2 (Pleistocene)
2015-02-16 23:47:28

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  1. There have been a number of migration
    events over the course of human evolution and several radiations of human
    populations out of _____.

    Humans have been moving around as soon as genus_____ evolves.
    • Africa
    • Genus Homo
  2. First People in the Americas:
    Where did they come from?

    Friar José de Acosta
    • started to speculate about where people came from
    • involved in missionary activities
    • had a publication regarding the Natural and Moral History of the East and West Indies that states people can only come to the New World via land bc crossing the ocean was difficult requiring advanced technology
    • he believed only europeans were equipped to travel by maritime technology
    • therefore, the only way to come to the new world was from the Bering strait between siberia and Alaska (this is one common theory most logical)
  3. obstacles and other theories of how people came to the new world
    Bering strait is an obstacle that has an extremely inhospitable environment that needs to be traveled by boat or land

    - Coastal Hypothesis - coming by kayak, canoe, raft.

    - Pacific Hypothesis - people in pacific islands continued east across the pacific and reached the new world. The idea that people are coming by sea.

    - Solutrean hypothesis - recent hypothesis people from late Pleistocene traveled west and followed the ice sheets arriving in eastern coast of america
  4. Human Migration: people moving around is not new

    Early human ancestors such as Australopithecus ______ and Australopithecus______ evolved in ______ and never left; dont have expansive habitats
    • Afarensis
    • Garhi (east africa)
    • Africa
  5. ______ million years ago the _____ evolves from ______
    • 2.5 mya
    • genus homo
    • Australopithecine
  6. _____ is the first human ancestor to migrate out of Africa almost as soon as it evolves _____ MYA.

    By _____ the species is in China.
    • Homo Erectus
    • 1.8-2.0million years ago
    • 1.8 mya
  7. our species, homo ____ is built for movement and evolved around ___ mya. by 1.8 million years ago the species is found in Asia
    • erectus
    • 2 MYA
  8. homo erectus vs. Australopithecus
    • homo erectus much more lean, more upright and more suited for long range movement and other activities
    • but their habitat was limited even though they were found throughout the land because environmental constraints (susceptible to radiation and harsh climates)
  9. So why did homo erectus not venture into some areas?
    environemental constraints make it difficult for survival
  10. So why did early humans not make it to the Americas?
    afflicted with disease like rickets and lack of UV exposure that affect migration
  11. Rickets
    • disease caused by dietary deficiency
    • impaired metabolism of vitamin D
    • leads to calcification of bone
    • in immature individuals, before epiphyseal closure, the disease leads to deformity due to abnormal bone growth
    • can be fatal
  12. epiphysis
    growth plates in long bones that closes as a person matures
  13. ____ is the primary means of Vitamin D
    synthesis for humans

    where does it occur?
    • UV exposure
    • in the dermis
  14. Why can UV radiation also be harmful?
    • epidermis produce melanocytes that in turn Produce melanin
    • 2 types of melanin produced by melanocytes: red and yellow
    • increased number of melanin causes thickening of the epidermis and can cause decreased UV penetration and vitamin D production in dermis
    • skin needs enough melanin to protect against harmful UV radiation, but also enough radiation for vitamin D production.
  15. Prior to _______ ago humans did not venture north of ____ Latitude.
    • 25,000 years
    • 50 degrees
  16. why did humans not venture north of 50 degrees latitude 25,000 years ago?
    • harsh environment not suitable for human survival
    • regardless of pigmentation humans cannot survive north of 50 degrees latitiude
    • there is not enough sunlight to produce vitamin D in the dermis of the skin
    • therefore another source of vitamin D must be obtained
    • Vitamin D can be obtained by continuously and consistently exploiting marine resources, lichens, and animals that eat lichen (such as reindeer and caribou).
  17. when do we see people cross the 50 degree boundary?
    • at about 35,000 years ago when humans developed specialized subsistence strategies in dietary exploitation, technology and ecological knowledge
    • Vitamin D can be obtained by continuously and consistently exploiting marine resources, lichens, and animals that eat lichen (such as reindeer and caribou).
    • this does not mean that humans have not tried to cross the boundary
  18. in order to cross berengia into the new world what must people do?
    • adopt specialized strategies
    • dietary exploitation - marine mammals, lichen
    • to obtain vitamin D and avoid diseases such as rickets
    • must have technological and ecological knowledge because of the harsh environment
  19. If another pathway to the American continents is explored, such as the Pacific hypothesis then:
    ☀the people must be very specialized in technology and subsistence strategies technology

    • ☀In any case, the first people to come to
    • the New World will have been specialists either in terms of dietary exploitation, technological, or ecological knowledge.
  20. describe the Pleistocene
    • a geological epoch dating from 2.5 mya to 11,700 years ago
    • climate characterized by a series of ice-ages with several glaciation events and low temperatures
    • Pleistocene fauna embodied by large mammals (the megafauna) such as mammoths, mastodons, sabretooth cats, but also other sized animals existed then too
  21. pleistocene climate in depth
    • 30% of earth covered by massive glaciers
    • very dry climate bc of little percipitation bc moisture is bound up in the ice sheets
    • avg. temp is 4 degrees centigrade lower than today
    • 1st half of pleistocene with glaciation events followed by interglacial events (melting - causing warmer climate) that lasts about 41,000 years
    • 800,000 years ago climate gets more extreme, more colder. ice sheets grow
    • extinction events begin to happen at different intervals of the pleistocene
    • unpredictable environment
    • away from the glaciers environment is tundra and permafrost that only animals that can live off of grass would survive
  22. holocene
    what we are living in now (began at end of Pleistocene until present)
  23. what do glaciers do?
    melt, freeze, melt again etc and move deposits around causing mixture amongst other deposits
  24. 4 Major Pleistocene Glacial Cycles in North America
    • 1)Nebraskan        
    • 2) Kansan  530-270 kya?  
    • 3) Illinoian 190-130kya   
    • 4) Wisconsin
  25. Which glaciation event in North America are we most concerned with? WHY?
    • Wisconsin Glaciation
    • last glaciation that lasts roughly 90-11.5 kya.  Includes the Cordilleran, Inuitian, and
    • Laurentide ice
    • sheets. 
    • Last Glacial Maximum (LAST TIME IT GOT EXTREMELY COLD) - 18,500 BC or 20,500 years ago (1 big glacier blocking with no where to go)
    • laurentide and cordilleron also glacial blockage
  26. why is the 11.5 kya boundary important in the wisconsin glaciation?
    after 11.5 kya boundary we have a lot of evidence of people here. before that people are here but we are uncertain of where they are coming from and how.
  27. what is NAMLA?
    what is it based off of?
    • North American Land Mammal Ages
    • different geological strata that respond to different species
    • based on chronostratigraphic system
  28. what is a chronostratigraphic system
    • relative chronology based on the presence of different genera of mammals in geological deposits and strata.
    • As species go extinct, their remains, and those of species that coexisted with them, become associated with specific geological strata and sequences.
  29. what does land mammal age establish
    geologic timescale for prehistoric North American fauna
  30. true or false?
    Land Mammal Ages are geographically discrete
  31. Irvingtonian (1.8mya-240kya)
    There has never been an instance where human remains or artifacts have been found in undisturbed Irvingtonian contexts.
  32. All human remains are associated with the _____ land mammal age
  33. Rancholabrean fauna characteristic:  Most were herbivores feeding on
    grasses.  Hooves were on average smaller
    than today.  The later stages of the Rancholabrean is
    witness to the gradual replacement of xeric* feeders
    • unusually large and more diverse compared to Holocene Fauna
    • most were herbivores
    • hooves were smaller than today (less trecherous environment)
    • In later stages, gradual replacement of xeric (extremely dry habitat; horses, bovids feeder eats grass and shrubs) feeders by cerid-mesic adapted species like (those that feed on leaves flowering plants, lichens, and twig-tips - deer).
  34. difference between xeric feeder and xeric environment
    • feeder: eats grass and shrubs (horses bovids)
    • environment: extremely dry habitat
  35. when is the last glacial maximum?
    18.5 thousand years ago
  36. what happened after the last glacial maximum?
    • the ice sheets begin to melt
    • gradual warming until about 12,000 years ago
    • then we get global event called the younger dryas cold snap
    • temperatures fluctuate from really cold to warm which is disastrous for ecosystems and animals.
  37. Extinction of the Megafauna dates:
    Last Glacial Maximum-
    • Last Glacial Maximum- 22,000-18,000 BP
    • Younger-Dryas– ca 12,000 BP
  38. RCYBP
    • radio carbon years before present
    • before present
    • around/about/approximately
  39. In the wake of the Younger-Dryas coldsnap what happens?
    ☀vast majority megafauna goes extinct

    ☀extinction affects humans who relied on large mammals for prey

    ☀humans now needed to exploit other resources

    ☀Archaeological evidence indicates that humans adapted by pursuing smaller game such as birds, small deer, antelope, and rabbits.

    ☀New subsistence strategies included exploiting wild plants and seeds. 

    • ☀archaeological evidence shows prevalence for sedentism, (living in the same locale for extended periods of time) seasonal
    • residency, and co-habitation by various groups.

    ☀These changes are accompanied by new technology such as ceramic vessels.

    ☀in here somewhere after the last glacial maximum and in the wake of the younger dryas humans come to the new world coming either from the bering land bridge, along the coast, or across the sea
  40. The Earliest Presence of Humans in the New World Is based on ____, not _____
    • rocks
    • humans
  41. humans are messy creatures and they like to leave traces of their technology behind and just like land mammal ages this stuff can be used to tell ______
  42. earliest stone tool user is?
    autralopithicus ghari
  43. homo eructus 1.8 million to 200,000 years bp produced what kind of tool?
    • acheulian (a sort of hand axe)
    • they used the same tool making for about a million years in just a see and do production
  44. homo erectus and h. habilis is a part of which lithic industry period
    lower paleolithic
  45. neanderthals (200,000 - 35,000 years bp) produced what kind of tool or lithic technology?
    • mousterian
    • doesnt change much
  46. neanderthal is a part of which lithic industry period?
    middle paleolithic
  47. homo sapiens sapiens (anatomically modern humans) produced what kind of lithic technology?
    • 18,000-10,000  BP       Magdalenian
    • 22.000-17,000  BP       Solutrean
    • 36,000-27,000  BP       Aurignacian
    • 32,000-22,000  BP       Perigordian/Gravettian
    • 45,000-33,000  BP       Chatelperronian
  48. homo sapiens sapiens is a part of which lithic industry period?
    • upper paleolithic
    • which changes
    • tool industry doesnt change much until about 70,000 years ago and after that theres an explosion of technological change and symbolic thinking
  49. when did anatomically modern humans in the genus homo sapiens sapiens evolve?
    about 160,000 years ago
  50. description of AURIGNACIAN 36,000-27,000 BP

    •Blade Tradition

    • Refined manufacture of blades struck off conical cores. used for scraping

    •found throughout Europe. France and Middle East depending on whom you ask
  51. Solutrean description

    • another blade tradition

    • Distinctive use of pressure flaking retouched to make finely formed thin and light projectile points.

    •they are really fine blades called Laurel Leaf point that are bifacial (worked on both sides)

    • also has Pins, Ornamental beads that are dug and scooped and smoothed out

    • found in europe
  52. description of MAGDALENEAN 18,000-10,000ya

    • Microlithic Tradition (small blade technology)

    • •Blade technology: burins, star shaped borers
    • (drilling), raclettes (scraping).

    •Microliths:Small blades. Composite tools.
  53. true or false? you dont necissarily have to find the tool itself to know what time period they came from. you can just find the flakes and easily identify it.
  54. conundrum with early prehistory is that we have tools, but we dont have humans, but
    we know people are here because we have their tools, but we have very little evidence of humans.
  55. For the last ______ years humans and human ancestors have been using _______ as their subsistence strategy.  This lifestyle has a
    number of demands and consequences.
    • 2 million
    • foragers (hunter gatherers)
  56. In order to be a forager they need:
    • steady source of protein bc of high activity
    • hunter-gatherers only spend about 20 hours a week procuring food (this may vary depending on what type of environment you’re in). 
    • certain population size is needed bc you cant have too many people to feed and wont be effective. to be effective a minimum of 10-15 people is needed. their groups were no larger than 20-50 people.
  57. Overall, population densities were extremely ___. Genetic evidence suggests that all modern genetic material derives from
    a population no larger than _____ people. Therefore it was difficult to accurately attain mortality and life expectency range. it is rare to find individuals over ___ years of age
    • low
    • 10,000
    • 35
  58. why is living in small groups beneficial?
    • More individuals to help procure food , but it also means they will consume resources quickly

    • more individuals helps to protect against predators and other humans

    • Less people mean less exposure to communicable diseases. Small populations buffer against microbial parasites. For example, human children develop anti-bodies to measles in about two weeks. This means that in order to be maintained in a population the measles virus needs to find a new host every two weeks; in other words, for the virus to survive in a population for only one year there must be a pool of 26 new children available over the course of that year. This is possible in large agricultural populations, but virtually impossible in small hunter-gatherer populations.
  59. all of this work will require a great amount of labor and mechanical stress. what kind of body type did these people have?
    • Skeletons prior to 10,000 years ago are heavier with denser bone.  This is not surprising given that humans would have been much more active than people are today. 
    • they suffered from less arthritis and degenerative bone disease than more recent populations (remember this when we talk about domestication).
  60. What can we say about the first settlers of the New World?
    - global change brings them to the new world

    • -They originate from a small population of
    • people who left Africa some 70,000 years ago

    -They live and move in small groups

    -Regardless of origin, they are specialists

    -adapted to cold and adept at exploiting marginal environments

    -technological assemblages derive from their predecessors

    • -They are inhabiting and moving through a
    • formidable ice-age environment.  An
    • environment that is changing rapidly and in which numerous species are going
    • extinct.

    -They are changing too. Their very migration into new spaces is part of ongoing change on a large scale.