Introduction to Planet Earth

The World Ocean

• The most prominent feature of our planet, covering approximately 71% of the Earth's surface.

• The location where life originated on our planet.

• Human body chemistry is very similar to seawater.

• Has been around for billions of years and dominates the Earth's surface.

• Largest habitat and contains the largest number of living organisms.

• 97.2% of the surface water found on Earth is ocean water.

Principal Oceans

• One world ocean, with interconnected ocean basins.

• Four principal oceans:

  • Pacific Ocean

  • Atlantic Ocean

  • Indian Ocean

  • Arctic Ocean

• The Southern Ocean (or Antarctic Ocean): Anything south of approximately 50 degrees South latitude.

  • Distinct due to major shifts in global wind belts and ocean circulation.

Earth's Coverage

• 70% of the Earth's surface is covered by the ocean and 30% is land.

• Pacific Ocean: Makes up about half of the ocean coverage.

Ocean Size Comparison

• Atlantic Ocean: About half the size of the Pacific.

• Indian Ocean: Slightly smaller than the Atlantic.

• Arctic Ocean: Very small, only about 3.4% of all ocean water.

Average Ocean Depth

• Pacific Ocean: Largest and deepest ocean. Average depth around four kilometers.

• Atlantic Ocean: Slightly shallower than the Pacific.

• Indian Ocean: Similar depth to the Atlantic.

• Arctic Ocean: Very shallow in comparison to other major oceans.

Elevation Comparison

• Sea Level: Baseline for elevation measurements (e.g., Florida).

• Mount Everest: Tallest mountain on Earth, approximately 29,000 feet in elevation.

• Continents: Average elevation around 800 feet above sea level.

• Marianas Trench: Deepest part of the ocean in the Pacific Ocean, approximately 36,000 feet deep.

• Average Ocean Depth: Approximately four kilometers below sea surface.

• Ferdinand Magellan named the Pacific Ocean.

Individual Oceans

• Pacific Ocean named for its calm waters in 1520.

• Atlantic Ocean: About half the size of the Pacific and separates the Old World from the New World.

• Indian Ocean: As deep as the Atlantic and mostly in the Southern Hemisphere.

• Arctic Ocean: Smallest and shallowest, with a permanent layer of sea ice a few meters thick.

• Southern Ocean: Circumnavigates Antarctica, comprising parts of the Atlantic, Pacific, and Indian Oceans (50 degrees South Latitude).

The Seven Seas

• Large bodies of water smaller and shallower than the oceans, enclosed by land with a direct connection to the ocean.

• Sargasso Sea: East of the United States Eastern Seaboard, named after the sargassum algae.

• Historically (before the 15th century), the Seven Seas were:

  • Red Sea

  • Persian Gulf

  • Black Sea

  • Adriatic Sea

  • Caspian Sea: A salty lake due to high evaporation rates and erosion from the land.

  • Indian Ocean

  • Mediterranean Sea

• Named based on where civilizations with written history and navigation existed.

Depths and Altitudes

• Average ocean depth: 3,600 kilometers (about 12,000 feet).

• Average continental elevation: 840 meters (2,756 feet).

• Marianas Trench depth: 36,000 feet.

• Airplane cruising altitude: Between 30,000 and 35,000 feet.

• Mount Everest height: 29,000 feet.

Oceans and Human History

• Civilizations settled near oceans for food (oysters, fish, lobsters, whale blubber) and trade/movement.

• Oceans facilitated trade and interaction between cultures. Vessels took advantage of currents/wind patterns.

Early Navigators

• Pacific Navigators: Earliest and best navigators as evidenced by genetic studies.

• Voyagers from Southeast Asia settled islands in Micronesia, Melanesia, and Polynesia.

• Micronesia had humans 4000 years BCE. Fiji was colonized by 1000 years BCE.

• New Zealand, 800 AD, French Polynesia,30 AD.

• Hawaiian Islands were colonized by 300 years AD, and Easter Island by 1200 AD.

Navigation Techniques

• Ocean guidelines made of palm twigs indicate patterns of open ocean waves.

• Skilled navigators interpreted wave diffraction patterns to find land masses.

• Voyaging cultures colonized new islands due to population growth exceeding island capacity.

Genetic Studies

• Scientist's genetic studies showed: populations of islands in New Zealand, Australia, New Guinea, Fiji, and Hawaii, are descendants from people who originated in Southeast Asia, Taiwan.

• Thor Heyerdahl theorized native cultures from South America may also have made it to Easter Island.

  • He built a balsa raft to demonstrate his theory, sailing from South America to Easter Island.

  • Genetics proved that the native people from South America are not related to the Polynesians

European Explorers

• Phoenicians: First explorers in Europe/Western Hemisphere. Credited because had written history.

  • Explored Mediterranean Sea, Red Sea, Indian Ocean.

  • First to circumnavigate Africa and reached British Isles.

  • Developed the alphabet to communicate and trade.

  • Egypt, Jordan, Israel region

• Greeks: built on Phoenician's discoveries with rise in scientific thought and constructed institutions.

  • Determine latitude using the North Star.

    • The angle between the horizon and Polaris indicates latitude.

  • Aristoscenes - determined the Earth was round and calulated its circumference.

  • Calculated Earth's circumference: 42,000 kilometers.

  • Actual circumference: 42,032 kilometers.

  • Later scientists updated world map, drawing longitude and latitude lines.

  • January - Ptolemy updated the the circumference estimation.

  • Christopher Columbus used Ptolemy's update because he thought that the Earth was smaller. This is why he thought he could sail to Asia.

Middle Ages

• Library of Alexandria burned down, Western Hemisphere in the dark ages causing information and precious information to be lost.

• Arab: Copied a lot of information, becoming the dominant navigators in the Mediterranean Sea trading with East Africa, India, and Southeast Asia

  • Dominant Navigators took advantage of Monsoon winds.

• Vikings: Explored Iceland and Greenland in the 9th and 10th centuries AD.

  • Leif Erikson made it down to Canada. Vinland, in Newfoundland

  • (Bjarne Herjolfsson) developed settlements, but there was bad weather. Settlements kind of died out

  • Actual cultures to settle in America. Not Christopher Columbus

Age of Discovery

• Constantinople, and major town in Mesopotamia had a major shift in power, which cut off trade routes.

• Europe needed a new way to trade. They needed good navigation and good sailors.

• Portuguese started training explorers. Prince Henry the Navigator.

• Prince Henry the Navigator trained explorers: Christopher Columbus
  * Set to explore trade routes. Most time was to circumnavigate Africa.
  * Queen of Spain, finance his trip to find a new route and landed in Hispaniola.

Ferdinand Magellan

• First to circumnavigate the globe with 3 ships and 250 sailors.

• Took 3 years to do it, but he was killed on a Pacific Island.

• Juan Sebastian de Cano completed circumnavigation.

• Voyages allowed Spanish to rule the Seas exploited, exploited all the resources, committing atrocities in Central and South America.

England's Dominance

• English & Dutch became the most maneuverable

• England defeated the Spanish Armada in 1588

• England became colonial powers.

Voyages of Columbus,

• Voyages that went down, made one stop, came back. Three times.

• Magellan took the long way around the globe.

Captain James Cook

• One of the best navigator.

• The English wanted to maintain their maritime superiority.

• Strict with going on the voyages for scientific purposes rather than settlements.

• Voyages to find passes and new islands.

• Captained the HMS Endeavor Resolution and Adventure.

• Measured ocean character. (surface temperature)

• New Technology: Chronograph developed by a cabinet maker in England. Enabled them to tell time independently.

• English found the latitudes through Captain James Cook's help.

• Cook encountered people in the Pacific who have never met anybody ever before.

• Died in a skirmish with native people.

• Cook figured out that his sailors suffered from scurvy (Vitamin C deficiency). Pirates of the Caribbean. Scurvy was pretty bad, caused teeth to turn black and immune system to die.

• Improved sailors diets through Sauerkraut, which is loaded with vitamin C and store for a prolonged time.

Oceanography Today

• Today we have sonar, robots, satellites, and computers.

• National Oceanographic and atmospheric administration, helps predict ocean conditions and tracks hurricanes.

Oceanography

• Interdisciplinary science that includes all types of science together: Geology, Biology, Chemistry, Physics, and Astronomy.

• Scientific inquiry: to try to understand the physical processes on earth, being to predict what'll happen because of understanding.

• The physical properties that we witness today, processes that we witnessed today, are similar than ones we've seen in the past

• Science tries to discover and make predictions.

Scientific Method

• A logical method

• Observation

• Hypotheses are made and then have been tested rigorously

• Theory

• Comes up with a whale breaching theory.

Nebular Hypothesis

• Hypothesis that all bodies inform our solar system for nebula, a cloud of gases and space dust. Space dust (silica material, rock material, metals and gas.

• Composition of this nebula was mostly hydrogen and helium.

Proto Sun

• The gravity concentrates a lot of the material at the center of the nebula, and the cloud starts to collapse in the form of a disc and then begins to rotate, and it induces more collisions of this material.

• Proto Planets: Mercury, Venus, Earth, and Mars

• Exterior Protoplanets: Gas Giants, (Jupiter, Saturn, Neptune and Uranus).

Proto Earth

• Rocky Earth (Silicate).

• Composition: Homogeneous

• Bombarded with meteorites heating up Earth.

• Origin of Moon: collision with another planet (Boom!).

Density Stratification

• Lighter Elements: oxygen, silicon, potassium float to the outer edges.

• Denser elements: Iron and Nickel sink to the center.

• Layers formed distinct chemicals known as Density Stratification on Earth. Because of gravitational separation.

Earth's Layers Today

• Layers based on chemical composition: Crust, mantle, core

• Layers based on physical properties (how the material behaves): Lithosphere, asthenosphere, upper mantle, lower mantle, core

Layers Based on Chemical Composition

• Crust: Outermost, thinnest layer. Very low density. Lightest materials

• Mantle contains Silicate rock. More iron and magnesium. Heavior than crust

• Core is high density of iron and nickel.

Layers Based on Physical Properties

• Lithosphere: Outermost, rigid, brittle layer. The region experiences earthquakes.

• Asthenosphere: Hot, weak, plastic layer

Mesosphere

*Rigid from increase in pressure.

• Outer core contains Liquid iron and convex with it.

• Inner Sphere contains solid iron.

Ocean Crust

*Basalts.

Continental Crust

*Granite. Countertops

• Ocean crust - 5 miles thick

• Continental crust 22 miles thick. Differences in density.

• Gasses are expelled from fumaroles (volcanic vents, and hydro thermal activity at the bottom of the ocean.

• Atmosphere trap by Gravity, then caused our permanent Oceans.
  Ocean is Salty because rainwater dissolved rocks, made water salty. Caused weathered rocks had dissolved solids.

• Life: Showed up, earth formation approximately 4,500,000 years old. Oldest evidenced shows stromatolites made of bacteria, living in shallow parts of ocean, building mounds, single celled bacteria. Found in present day Australia today.

• Before, it was also suggested that earlier organisms and inhospitable environments (hydrothermal vends at bottom of the ocean that was starting place for all organisms.

• Oxygen appeared last. Major organisms event Photosynthesizing organism pump, oxygen. The organism deposits a lot of oxygen and all of the free in the ocean, deposited a deposition and started to form. But as soon as enough was being used and no deposit.

Stanley Miller

• Scientist who as a graduate student that came up with the experiment where he similarated Earth's early atmosphere.

• Created conditions for life to begin on Earth mimic each other to be prokaryotes. They reproduce evolves and changed. Lacked much change in daily temperatures. Allowed organisms to proliferate
  Eventually, once the organization's become successful organisms a modify environment.
  Evolution and Natural Selection. All of the organisms are adaptable, will continue natural selection. Those traits are passed and successful

Autotroph Forms of Life

• Later on. Autotrophs evolved. Organisms manufacture their own food. Those stromatolites build of those mounds building their own food supply. They don't need anybody else, right?

• First autotrophs to form with very similar to anaerobic bacteria.

• Today'S day in age in even deep environments exist 4 billion years ago.

• ChemoSynthesis - use chemical from volcanic and hydrothermal vents to create Sugars.

Later on. Kind of evolved eukaryotes showed up. Selby showed up nucleus and a bunch of different Oregon eels to perform functions that evolved the most cellular organisms develop chlorophylls. They allowed the use of sun for photosynthesis create sugar. I'm gonna put the dissolved oxygen to water to allow further organisms to respirated
Banded - Iron Formations are deposity that can no longer exist today, and because of a long, a lot of what can Earth the changed is that the environment changes (mass extinctions)(90 %).
46,000,000 old know to get spontaneous decay of radioactive elements. Half of elements decay into daughter istope which is what creates the half life through atomis
Entire geologoic time, scale, 46,000,000

Fossil Records

Shows the major mass of extinctions, organisms change, adapt to these conditions.