Chapter 1 Clickers Chapter 1 Lecture Essentials Of .

ChapterChapter11ClickersLectureEssentials of OceanographyEleventh EditionIntroduction toPlanet “Earth”Alan P. TrujilloHarold V. Thurman 2014 Pearson Education, Inc.

Overview The world ocean is the most prominentfeature on Earth. Oceans cover 70.8% of Earth’s surface. The origin and development of life on Earthare connected to the ocean. The oceans have a long history on Earth. 2014 Pearson Education, Inc.

Earth’s Oceans Earth has one ocean. It is divided into fourprinciple oceans andone other.–––––Pacific OceanAtlantic OceanIndian OceanArctic OceanSouthern, or Antarctic,Ocean 2014 Pearson Education, Inc.

Ocean Size and Depth 2014 Pearson Education, Inc.

Earth’s Oceans Pacific Ocean– World’s largest ocean Accounts for more than half of Earth’s oceanspace– World’s deepest ocean– Earth’s largest geographic feature– Named in 1520 by Ferdinand Magellan 2014 Pearson Education, Inc.

Earth’s Oceans Atlantic Ocean– Half the size of the Pacific Ocean– Shallower than the Pacific Ocean– Separates the Old World from the New World Indian Ocean– Smaller than the Atlantic Ocean– Similar depth as the Atlantic Ocean– Primarily in the Southern Hemisphere 2014 Pearson Education, Inc.

Earth’s Oceans Arctic Ocean– Seven percent the size of the Pacific Ocean– Shallowest world ocean– Permanent layer of sea ice a few meters thick Southern Ocean or Antarctic Ocean– Circumnavigates Antarctica– Is really the parts of the Pacific, Atlantic, andIndian Oceans that lie south of 50 S latitude 2014 Pearson Education, Inc.

The Seven Seas Smaller and shallower than oceans Salt water Usually enclosed by land– Sargasso Sea defined by surrounding oceancurrents Directly connected to the ocean 2014 Pearson Education, Inc.

The Seven Seas Before the 15th century, Europeansconsidered the seven seas to be thefollowing:1.2.3.4.5.6.7.Red SeaMediterranean SeaPersian GulfBlack SeaAdriatic SeaCaspian SeaIndian Ocean 2014 Pearson Education, Inc.

Comparing Oceans to Continents Average ocean depth is 3682meters (12, 080 feet) Average continental elevation is840 meters (2756 feet) Deepest ocean trench is theMariana Trench at 11,022 meters(36,161 feet) Highest continental mountain isMt. Everest at 8850 meters(29,035 feet) 2014 Pearson Education, Inc.

Early Exploration of the Oceans Early “explorers” used boats to seek newfishing grounds for food. The ocean facilitated trade and interactionbetween cultures. 2014 Pearson Education, Inc.

Pacific Navigators The peopling of thePacific Islandsrequired extensivetravel in open boatsand exceptionalnavigation skills. It was difficultbecause islands arewidely scattered. 2014 Pearson Education, Inc.

Pacific People No written records exist of Pacific humanhistory before the 16th century. Archeological evidence suggests islandoccupation by people from New Guinea asearly as 4000–5000 B.C. Thor Heyerdahl sailed on a balsa raft – theKon Tiki – to demonstrate migration of SouthAmericans to Pacific Ocean islands. 2014 Pearson Education, Inc.

European Navigators Phoenecians – first from WesternHemisphere to develop navigation arts– Navigated circa 2000 B.C.– Explored Mediterranean Sea, Red Sea, andIndian Ocean– First circumnavigation of Africa– Reached the British Isles 2014 Pearson Education, Inc.

European Navigators Greek Pytheas– Sailed northward using a simple method todetermine latitude in 325 B.C.– Navigated using the North Star Eratosthenes determined Earth’scircumference fairly accurately. 2014 Pearson Education, Inc.

Europeans Herodotus producedinaccurate world maparound 450 B.C. Claudius Ptolemyproduced fairlyaccurate world maparound 150 A.D.– Erroneously updatedEratosthenes’ originalcircumferenceestimation, latercausing ChristopherColumbusto believe he hadreached Asia 2014 Pearson Education, Inc.

The Middle Ages Arabs dominant navigators in theMediterranean Sea Traded extensively with East Africa, India,and Southeast Asia Learned to use Indian Ocean monsoon windsfor travel 2014 Pearson Education, Inc.

The Middle Ages Vikings explored North Atlantic Ocean– Settled Iceland and Greenland in 9th and 10thcenturies A.D.– Leif Eriksson designated part of easternCanada Vinland (now Newfoundland) in 995 A.D.– Greenland, Vinland settlements abandoned by1450 A.D. due to climatic cooling 2014 Pearson Education, Inc.

Viking Routes and Colonies 2014 Pearson Education, Inc.

The Age of Discovery in Europe1492–1522 Search for new Eastern trade routes by sea– Prince Henry the Navigator of Portugal soughttrade routes around Africa.– Europeans explore North and South America. Christopher Columbus was financed bythe Spanish to find new trade routes toAsia. Englishman John Cabot arrived innortheast North America in 1497. 2014 Pearson Education, Inc.

The Age of Discovery in Europe1492–1522 Spaniard Ferdinand Magellancircumnavigated the globe.– Was killed on a Pacific Island in 1521 Juan Sebastian del Caño completed thecircumnavigation in 1522. Voyages paved the way for the Spanish totake gold from the Incas and Mayas. Spain’s maritime dominance ended whenEngland defeated the Spanish Armada in1588. 2014 Pearson Education, Inc.

Voyages of Columbus and Magellan 2014 Pearson Education, Inc.

Voyaging for Science The English wanted to retain maritimesuperiority. Captain James Cook (1728–1779) undertookthree scientific voyages.– Ships HMS Endeavour, Resolution,Adventure– Mapped many islands in Pacific– Systematically measured oceancharacteristics– Marine chronograph (longitude) 2014 Pearson Education, Inc.

Cook’s Voyages 2014 Pearson Education, Inc.

Oceanography Continues More high-technology tools available today– Sonar– Robotics– Computers– Satellites 2014 Pearson Education, Inc.

Nature of Scientific Inquiry Natural phenomena governed by physicalprocesses Physical processes similar today as in thepast Scientists discover these processes andmake predictions. Called the scientific method 2014 Pearson Education, Inc.

The Scientific Method 2014 Pearson Education, Inc.

Theories and Truth Science never reaches absolute truth. Truth is probable and based on availableobservations. New observations yield scientific progress. In reality, scientists have no formal method. 2014 Pearson Education, Inc.

Formation of Earth and the Solar System Nebular hypothesis– all bodies in thesolar systemformed from nebula– Nebula cloud ofgases and spacedust Mainly hydrogenand helium 2014 Pearson Education, Inc.

Nebular Hypothesis Gravity concentrates material at centerof cloud (Sun). Protoplanets form from smallerconcentrations of matter (eddies). 2014 Pearson Education, Inc.

Protoearth Larger than Earthtoday Homogeneouscomposition Bombarded bymeteorites– Moon formedfrom collisionwith largeasteroid. 2014 Pearson Education, Inc.

Protoearth Radioactive heat– Spontaneous disintegration of atoms– Fusion reactions Heat from contraction (protoplanet shrinks dueto gravity) Protoearth partially melts Density stratification (layered Earth) 2014 Pearson Education, Inc.

Density Stratification High density heavy for its size Early Earth experienced gravitationalseparation.– High-density materials (iron and nickel)settled in core.– Less dense materials formed concentricspheres around core. 2014 Pearson Education, Inc.

Earth’s Internal StructureLayers defined by Chemical composition Physical properties 2014 Pearson Education, Inc.

Layers by Chemical Composition Crust– Low-density, mainly silicate minerals Mantle– Mainly iron (Fe) and magnesium (Mg)silicate minerals Core– High-density, mainly iron (Fe) andnickel (Ni) 2014 Pearson Education, Inc.

Layers by Physical Properties LithosphereAsthenosphereMesosphereOuter coreInner core 2014 Pearson Education, Inc.

Lithosphere Cool, rigid shell Includes crust andupper mantle About 100 km(60 miles) thick 2014 Pearson Education, Inc.

Continental vs. Oceanic Crust 2014 Pearson Education, Inc.

Asthenosphere Relatively hot, plastic Flows with high viscosity– Important for movement of lithospheric plates Base of lithosphere to about 700 km(430 miles) deep 2014 Pearson Education, Inc.

Isostatic Adjustment Vertical movement of Earth’s crust Buoyancy of lithosphere on asthenosphere– Less dense continental crust floats higherthan denser oceanic crust. Isostatic rebound – rising of crust formerlyweighed down by glacier ice 2014 Pearson Education, Inc.

Isostatic Adjustment 2014 Pearson Education, Inc.

Origin of Earth’s Atmosphere Outgassing – occurred during densitystratification– Water vapor– Carbon dioxide– Hydrogen– Other gases Earth’s early atmosphere different from today 2014 Pearson Education, Inc.

Origin of Earth’s Oceans Outgassed water vapor fell as rain. The first permanent oceans formed 4 billionyears ago. Salinity developed from dissolved rockelements.– Early acidic rain dissolved more crustal mineralsthan today. 2014 Pearson Education, Inc.

Development of Earth’s Oceans 2014 Pearson Education, Inc.

Life’s Possible Ocean Origins Earth’s earliest known life forms are3.5-billion-year-old bacteria fossilized inocean rocks. These are the building blocks for life on earlyEarth. There is no direct evidence of early Earth’senvironment. 2014 Pearson Education, Inc.

Oxygen Humans require O2.Ozone (O3) protects from ultraviolet radiation.Early Earth had little free oxygen.The lack of ozone may have helpedoriginate life. 2014 Pearson Education, Inc.

Stanley Miller’s Experiment Organic molecules formed by ultraviolet light,electrical spark (lightning), and a mixture ofwater, carbon dioxide, hydrogen, methane,and ammonia 2014 Pearson Education, Inc.

Stanley Miller and His Experiment 2014 Pearson Education, Inc.

Evolution and Natural Selection Organisms adapt and change through time.Advantageous traits are naturally selected.Traits are passed to the next generation.Organisms adapt to environments.Organisms can modify environments. 2014 Pearson Education, Inc.

Plants and Animals Evolve Heterotrophs– Very earliest life– Require external food supply Autotrophs– Evolved later– Manufacture own food supply 2014 Pearson Education, Inc.

First Autotrophs Probably similar to modern anaerobicbacteria– Survive without oxygen Chemosynthesis from chemicals at deephydrothermal vents Supports idea of life’s origins on deep oceanfloor in absence of light 2014 Pearson Education, Inc.

Photosynthesis and Respiration Complex autotrophs developed chlorophyll. This allowed the use of the Sun forphotosynthesis. Cellular respiration 2014 Pearson Education, Inc.

Photosynthesis and Respiration 2014 Pearson Education, Inc.

Great Oxidation Event 2.45 billion years ago Increased oxygen and ozone eliminated theanaerobe food supply. Light and oxygen kill anaerobes. Cyanobacteria adapted and thrived. 2014 Pearson Education, Inc.

Changes to Earth’s Atmosphere Photosyntheticorganisms areresponsible for life aswe know it today. Reduce CO2,increase O2 to 21% High oxygen biodiversity increase Low oxygenassociated withextinction events 2014 Pearson Education, Inc.

Plants and Earth’s Environment 2014 Pearson Education, Inc.

Age of Earth Radiometric age dating– Spontaneous change/decay– Half-life Earth is about 4.6 billion years old. 2014 Pearson Education, Inc.

Radioactive Decay 2014 Pearson Education, Inc.

Geologic Time Scale 2014 Pearson Education, Inc.

End of CHAPTER 1Introduction to Planet “Earth” 2014 Pearson Education, Inc.

Voyaging for Science The English wanted to retain maritime superiority. Captain James Cook (1728–1779) undertook three scientific voyages. –Ships HMS Endeavour, Resolution, Adventure –Mapped many islands in Pacific –Systematically measured ocean characteristics –Marine chronograph (longitude)