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Big Bang from 10-15 billion years ago

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Title: Slide 1 Author: David Bray Last modified by: David Bray Created Date: 1/18/2005 6:14:46 PM Document presentation format: On-screen Show Company – PowerPoint PPT presentation

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Title: Big Bang from 10-15 billion years ago


1
A Short History of the Universe and Planet Earth
  • Big Bang from 10-15 billion years ago

2
About 5 billion years ago Earth formed out of
gases and dust We are stardust. We are golden.
We are billion year old carbon Joni Mitchell

3
First life forms about 4 billion years ago-single
celled organism
4
Pleistocene-emergence of first human lineage
Australophithcus 5 million years ago
5
First modern humans homo sapiens about 50,000
years ago, differentiated from Neanderthals.
6
Evolution of Human Society
  • For the first 30,000-40,000 years or so human
    beings lived exclusively in hunting and gathering
    societies or bands.
  • Bands- depend on hunting, fishing, or the
    gathering of wild plants to provide basic food
    needs. The hunting and gathering economy demands
    extensive land, permanent settlements rarely
    possible.
  • people have to keep moving whenever the local
    food supply becomes depleted.

7
  • Possessions are limited to what can be carried,
    and dwellings are very simple huts and tents.

8
Hunting and Gathering Societies
  • They are egalitarian.
  • Little specialized knowledge
  • Children socialised in all roles involved in
    everything
  • Gathering is done more frequently/ hunting is
    sporadic (depends on availability of game)
  • Completely dependent on environment.
  • original affluent society - all need were met,
    lots of leisure time.

9
Did Early Human Beings or Indigenous Peoples in
more recent times, live in harmony with the
environment?
  • Human Beings-in-Nature vs Human
    Beings-above-Nature.
  • Pleistocene Overkill.
  • Use of Fire

10
Pleistocene Overkill
  • Pleistocene (1.8 million-10,000 years ago)
  • Mammoths and their cousins the mastodons,
    longhorned bison, sabre-toothed cats, giant
    ground sloths, and many other large mammals in
    North America.
  • Native horses and camels galloped across the
    plains of North America. Great teratorn birds
    with 25-foot wingspans stalked prey.
  • Around the end of the Pleistocene, all these
    creatures went extinct (the horses living in
    North America today are all descendants of
    animals brought from Europe in historic times).

11
Pleistocene Overkill II
The Pleistocene also saw the evolution and
expansion of our own species, Homo sapiens, and
by the close of the Pleistocene, humans had
spread through most of the world. According to a
controversial theory, first proposed in the
1960s, human hunting around the close of the
Pleistocene caused or contributed to the
extinction of many of the Pleistocene large
mammals
12
Pleistocene Overkill III The Evidence
  • 1)Large animals, over 100 lbs,suffered far more
    than small ones. If climate, you would expect
    small animals to suffer as much.
  • 2) extinctions occurred in each particular
    location soon after the arrival of human beings.
  • 3) The large mammals that survived and are still
    with us span 12 genera moose, white-tailed and
    mule deer. among hoofed animals. But North
    America had 45 genera of large animals. We lost
    four types of giant sloths .
  • Large mammals that survived were largely of
    Eurasian origin and were accustomed to human
    beings. Survivors like moose are solitary, or
    like bison have unpredictable migrations.

13
19th Century Evidence
  • .capable of abusing their environments by, for
    example, driving great numbers of large game
    animals off cliffs and using only a few. And
    given more powerful technological means, such as
    guns, they were not necessarily better stewards
    of nature than people in industrial societies
    p. 41 Harper

14
HOWEVER
  • Native peoples lived much closer to nature and
    depended directly on nature for their
    livelihoods.
  • There are important lessons on respect and
    reverence for nature in many indigenous religions
    and traditions.

15
Indigenous Peoples and Fire
  • Villages moved every 15 years-20 years, when
    local resources were exhaustedshifting
    agriculture /slash and burn. Created a mosaic of
    secondary succession.
  • 10-20 of forests in clearing or secondary
    succession.
  • Tallahassee means old fields ie secondary
    succession areas.

16
Ancient Civilization The Rise of Agriculture
  • Neolithic- beginning of agriculture 10,000 bp.
    domestication of plants and animals. Change, via
    ARTIFICIAL selection, from wild forms to a more
    useful form, such as wolf to dog, grasses to
    wheat, etc.
  • Catal Huyuk, Turkey, 9000 bp. A town of 10,000
    people.. Not quite a city, no division of labor,
    occupied by farmers, decentralized. Individual
    residential structures with ovens, benches,
    storage areas. But had painted murals showing
    vultures attacking headless men, volcanoes,
    hunting. A rich symbolic life.

17
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18
Mesopotamia Babylonians, Sumerians
Environmental Degradation
  • In Mesopotamia, irrigation was essential for crop
    production.
  • Rivers were higher than the surrounding plain
    because of built-up silt in the river beds, so
    water for irrigation flowed into the fields by
    gravity. Once the water was on the fields, it
    could not readily drain away because the fields
    were lower than the river. As water evaporated,
    left its dissolved mineral salts behind. Over
    time, soil became toxic and no longer supported
    crops.
  • By about 2300 B.C., agricultural production in
    Mesopotamia was reduced to a tiny fraction of
    what it had been. Many fields were abandoned as
    essentially useless. Mesopotamian cuneiform
    tablets tell of crop damage due to salts.

19
  • As late as 7000 BC, the Tigris and Euphrates
    valleys were covered with productive forests and
    grasslands. But increased salt buildup in the
    soil from irrigation evaporation in a hot climate
    caused food production to decline an estimated
    42 per hectare between 2400 and 2100 BC.
    Environmental degradation was clearly one of the
    factors, with climate change, invading armies.
    (p. 43 Harper)

20
Chaco Canyon-New Mexico (800-1100 AD)
21
During the middle and late 800s, the great houses
of Pueblo Bonito, Una Vida, and Peñasco Blanco
were constructed. These structures were often
oriented to solar, lunar, and cardinal
directions. Sophisticated astronomical markers,
communication features, water control devices,
and formal earthen mounds surrounded them
22
By 1050, Chaco had become the ceremonial,
administrative, and economic center of the San
Juan Basin. Dozens of great houses in Chaco
Canyon were connected by roads to over 150 great
houses built throughout the region.
23
"public architecture" that were used periodically
during times of ceremony, commerce, and trading
24
But it CollapsedDisappeared. Why????
  • A very arid environment, totally dependent on
    rain (but had overcome with careful irrigation).
  • Probably overpopulation for available resources,
    combined with drought, very fragile environment.

25
Mayan Civilization (400 BC-1150 AD)
26
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27
Collapse of the Mayan Civilization
  • Theories
  • over-population
  • extensive warfare
  • revolt of the farmer/laborer class
  • drought

28
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29
Environmental Stress probably one of several
causes
  • Now known that Maya region suffered extensive
    deforestation during the Classic Maya period.
  • Many soils in region marginal.
  • Also known there was a severe drought late in the
    Classic Mayan period.

30
World Views in Agricultural Societies
  • Cognized environments of hunter-gathers was a
    natural living wilderness. Man-in-nature.
  • Cognized environment in agricultural societies is
    a garden. Human beings begin to push the
    wilderness away

31
All of these civilizations lasted hundreds of
years before collapsing. Are we immune from this
history? Are we stressing our environment in the
same way they did? Could a change in the
environment like global warming cause widespread
failures of agriculture?
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