Stromatolites

1
Stromatolites
whole mounds
Shark Bay Western Australia
section view
Living fossil stromatolite reefs (made by
cyanobacteria) of Shark Bay Australia
Paleozoic stromatolite fossils (ARP)
www-cyanosite.bio.purdue.edu/images/images.html
2
Voyaging Ocean Exploration
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Early Voyaging Pacific Islanders Polynesians
Text pg. 14
A bamboo stick chart of the Marshall Islands
shows islands (shells at junctions), regular
ocean wave direction (straight strips), and waves
that bend around islands (curved strips).
Similar stick charts were used by early
Polynesians
Text pg. 13
Pacific islanders (Lapita people) were present
in New Ireland 5000 4000 BC and reached Fiji,
Tonga, and Samoa by 1100 BC. By 500 AD they
had reached Hawaii and begun regular trade across
3,500 km of open ocean!
4
Early Voyaging Mediterranean Mapping
Herodotus (450 BC)
Eratosthenes (200 BC)
Text pg. 9

• Greeks Phoenecians trade widely in
  Mediterranean by 1200 BC extensive records kept
  at the great library in Alexandria (Egypt)
  founded by Alexander the Great in 307 BC
• Herodotus (450 BC)- map with no ref. lines
• Eratosthenes (200 BC)- reference lines tied to
  geographical features
• Hipparchus (145 BC)- regular latitude
  longitude lines (degrees no copies known)
• Ptolemy (150 AD)- divided degrees of latitude
  longitude into minutes seconds
• Library in Alexandria burned (415 AD)

Ptolemy (150 AD)
Text pg. 17
librarians or scholars at Alexandria
5
Eratosthenes estimated earths circumference
200BC
Three observations 1) sunlight reached the
bottom of a vertical well at Syene at noon on the
longest day of the year 2) a vertical flagpole in
Alexandria cast a shadow of 7.2 degrees 3) the
distance between these sites was 800 km
Two assumptions 1) earth was a sphere 2) sun was
very far away so that rays of sunlight were
parallel
Text pg. 16
Eratosthenes (2nd chief librarian in Alexandria)
computed the earths circumference to within 8!
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Early Voyaging Vikings
Some notable events

• 62 ships raid Morocco in 859 AD
• colonize Iceland by 860 AD
• colonize Newfoundland by 985 AD

Text pg. 18
7
Early Voyaging Europeans
Text pg. 19
Some notable events

• Columbus reaches New World in 1492
• Ferdinand Magellan (actually his boat) is first
  to circumnavigate the globe (1519-1522)
• Cooks three voyages around the world (1768,
  1772, 1776)

Text pg. 20
8
The problem
of Longitude
Finding latitude is easy, finding longitude is
hard

• Most early navigators would run the latitude
• Determining longitude became a high priority to
  the British navy in early 1700s
• In 1707, 2000 British sailors died on return from
  a successful battle with the French
• After two weeks of travel in the fog the
  admirals navigator said land was still far off
• One sailor objected. His own records showed they
  should be nearing shore. He was hung for
  insubordination!
• In 1714 Parliament offered a 20,000 pound prize
  to find longitude to 0.5 degree (50 km)
• John Harrison (a clockmaker) made a chronometer
  that passed this test in 1759 but was denied the
  prize by the astronomers who ran the British
  Board of Longitude until 1773

Text pg. 8
John Harrisons first chronometer
David Sobels book on the story
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Important marine science voyages

• Cooks voyages (1768, 1772, 1776) were first to
  include many biological and scientific studies
• Darwins voyage on the Beagle (1831-36)
  revolutionized thinking about coral reefs and
  evolution
• Challenger Expedition (1872-76) defines Birth of
  Oceanography
• Prompted by a great debate over whether life
  existed in the deep sea
• Research on ocean chemistry benthic plankton
  biology was published in 50 volumes a total of
  4,717 new species were described
• Probably greatest oceanographic expedition of all
  time

Text pg. 23
Text pg. 22
10
The Scientific Method
The Scientific Method is much misunderstood

• What is its most valuable contribution? -
  does it yield more or better facts?
  - is it a better source of new
  hypotheses? - does it yield
  longer-lasting hypotheses?
• It provides a set of rules whereby two people who
  disagree about causes effects can agree on a
  test to decide who is right it is really a
  dispute-resolution method observation,
  hypothesis, test
• Two common misconceptions are
  - tests require experiments (in reality,
  crucial observations also provide tests)
  - hypotheses are proven (in reality, they are
  simply not yet rejected the choice is always
  between alternative hypotheses)
• It Makes the mystical discussable (E.
  E. Ruppert)

Text pg. 6
The texts summary of the scientific method
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