evolution of life and earth (historical geology)
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Evolution of Life and Evolution of Life and EarthEarth
(Historical Geology)(Historical Geology)
Physical vs. Historical Physical vs. Historical GeologyGeology
► Physical Geology-Physical Geology- Origin, classification, Origin, classification, and composition of Earth materials and and composition of Earth materials and internal and surficial processesinternal and surficial processes
► Historical Geology-Historical Geology- Earth evolution, Earth evolution, changes in lands and seas, mountain changes in lands and seas, mountain building and destruction, fossil succession building and destruction, fossil succession through time, and history of the solar through time, and history of the solar systemsystem
Scientific MethodScientific Method
QuestionsQuestions Collection of DataCollection of Data Development of HypothesisDevelopment of Hypothesis Testing of HypothesisTesting of Hypothesis
The beginningThe beginning
►The Big BangThe Big Bang Most scientist believe that the universe Most scientist believe that the universe
was created in a single event known as was created in a single event known as the the Big BangBig Bang►This occurred ~15 billion years agoThis occurred ~15 billion years ago
Some studies suggest 22 byaSome studies suggest 22 bya
Our Solar System started to form about 5 Our Solar System started to form about 5 byabya
Our Solar SystemOur Solar System
► Solar Nebula HypothesisSolar Nebula Hypothesis Cold, Rarified cloud of gas and Cold, Rarified cloud of gas and
dust particlesdust particles Dust cloud starts Dust cloud starts
counterclockwise rotation counterclockwise rotation around proto-sunaround proto-sun
Eddies in dust cloud begin Eddies in dust cloud begin planetary development: cold planetary development: cold homogeneous accretionhomogeneous accretion
Final Phase of FormationFinal Phase of Formation
► Eventually, gravitational collapse at Eventually, gravitational collapse at core of rotating disc forms the Suncore of rotating disc forms the Sun
Solar wind drives out lighter elements Solar wind drives out lighter elements Leaving heavy elements in inner solar Leaving heavy elements in inner solar
system and lighter elements in outer system and lighter elements in outer systemsystem
EarthEarth
► Formative IntervalFormative Interval Hadean Eon: 4.6-3.9 byaHadean Eon: 4.6-3.9 bya
► Accretion and DifferentiationAccretion and Differentiation Heating, partial melting and solid Heating, partial melting and solid
diffusiondiffusion Ni and Fe migration to coreNi and Fe migration to core Mantle separation forming lighter crustMantle separation forming lighter crust
Differentiation Differentiation
►Source of Internal heatSource of Internal heat Accretionary heatAccretionary heat Heat caused during bombardmentHeat caused during bombardment Radioactive decayRadioactive decay
►Development of Magnetic FieldDevelopment of Magnetic Field Caused by movement of liquid coreCaused by movement of liquid core
Crustal DevelomentCrustal Develoment
► Crust formed by cooling magma Crust formed by cooling magma oceanocean► KomatititesKomatitites formed early in Earth’s crust formed early in Earth’s crust► Continental Crust and Water present as early Continental Crust and Water present as early
as 4.4 byaas 4.4 bya
Evolution of the Atmosphere Evolution of the Atmosphere and Hydrosphereand Hydrosphere
► Primitive atmosphere before 3.8byaPrimitive atmosphere before 3.8bya
The OceansThe Oceans
► Origin of Oceans (After 4.4bya)Origin of Oceans (After 4.4bya)
Tied to the onset of the Hydrologic cycleTied to the onset of the Hydrologic cycle Salinity due to chemical weatheringSalinity due to chemical weathering
Standard Geologic Time Standard Geologic Time ScaleScale
► Divisions of TimeDivisions of Time Eons (largest): Hadean, Archean, Eons (largest): Hadean, Archean,
Proterozoic, and PhanerozoicProterozoic, and Phanerozoic Eras- units within eons: Eras within the Eras- units within eons: Eras within the
Phanerozoic are the Paleozoic, the Phanerozoic are the Paleozoic, the Mesozoic, and the Cenozoic.Mesozoic, and the Cenozoic.
Periods, Epochs and Ages: decreasing Periods, Epochs and Ages: decreasing order subdivisions of geologic timeorder subdivisions of geologic time
Understanding Earth’s Understanding Earth’s ChangesChanges
► CatastrophismCatastrophism - - Earth surface changes through Earth surface changes through large scale eventslarge scale events
► UniformitarianismUniformitarianism James HuttonJames Hutton
► Dynamic/Cyclic Concept of Earth HistoryDynamic/Cyclic Concept of Earth History► Used principle of actualism (uniformitarianism)Used principle of actualism (uniformitarianism)► Wrote first great Geology text ( Theory of the Wrote first great Geology text ( Theory of the
Earth)Earth)