Sci pre-final

• The structure of the earth is divided into four major components

  • the crust
  • the mantle
  • the outer core
  • the inner core
• Each layer


  • Has a unique chemical composition
  • Has a unique physical state
  • Can impact life on Earth's surface
• How scientists inferred the earth's structure

  1. Study of seismic waves

  2. Seismic waves are caused by sudden movement of materials within the Earth

  3. Seismic waves are refracted as they travel through the earth

  4. Seismic wave speed gave vital information on the composition of the different layers of earth
• Seismic Tomography


  A technique of inverting seismological data to retrieve a 3D image of the anomalies in seismic wave velocity within a media
• Seismic tomography has revolutionized our understanding of tectonics
• The structure of the earth can be defined as

  • Mechanically
  • Chemically
• Mechanically, earth can be divided into five layers

  • Lithosphere
  • Asthenosphere
  • Mesospheric mantle
  • Outer core
  • Inner core
• Chemically, the earth layers are as follows

  • Crust
  • Upper mantle
  • Lower mantle
  • Outer core
  • Inner core
• Lithosphere


  The outer solid part of the planet, underlain by asthenosphere
• Asthenosphere


  A highly viscous, hotter, and ductile region of the mantle that is involved in plate tectonic movement and isostatic
• Crust

  The outermost layer of the earth, making up only about 1% of earth
• Thickness of the crust

  Dependent on its age - the thicker the layer the older the crust
• Three types of Plate Boundaries

  • Divergent boundary - plates move away from each other
  • Convergent boundary - plates move towards each other
  • Transform boundary - plates slide past each other
• Plate tectonics


  Massive, irregular slab of solid rocks that envelope the surface of Earth
• Earthquake


  What happens when two blocks of the earth suddenly slip past one another
• Faults


  Breaks in Earth's crust where rocks have slipped past each other
• Tsunami


  A very high, large waves or seismic sea waves caused by the sudden movement of the ocean floor
• Intensity

  A quantitative measurement based on instruments that relies on the data from seismic records along with other techniques to estimate the amount of energy released
• PHIVOLCS

  Philippine Institute of Volcanology and Seismology, a Philippine national institution dedicated to provide information on the activities of volcanoes, earthquakes, and tsunamis
• PAG ASA

  Philippine Atmospheric, Geophysical and Astronomical Services Administration, the government agency that provides information on meteorological, astronomical, and climatological activities in the Philippines territory
• Tectonic plates


  Also known as lithospheric plates, the earth's outermost layer that is fragmented into a dozen or more larger and small solid plates
• Asthenosphere


  More mobile material known to allow the movement of tectonic plates, ranging from less than one to more than 15 centimeters per year
• The plate tectonics theory was first proposed


  1918
• The first world Atlas Theatrum Orbis Terrarum was published by Abraham Ortelius on January 1, 1569
• Alfred Wagner, a German climatologist, proposed the continental drift theory in his book 'the origins of continents and oceans' in 1915
• Pangea (all earth) had really existed during the Permian period
• Around 1100 Mya, there was a continent named Rodinia which predated Pangea
• In the Late Triassic Period, Pangea broke up into 2 supercontinents called Laurasia and Gondwanaland
• Two types of lithospheric plates

  • Continental Crust - lighter than the oceanic crust, composed of lower density, granitic rocks
  • Oceanic Crust - made of heavier basalt and gabbro rocks
• The other human species besides Homo sapiens were extinct
• Mechanism of plate tectonics

  1. Mantel convection theory - fluid expand and become less dense when heated

  2. Slab pull theory - responsible for the tectonic through subduction process
• Plate boundaries

  • Convergent (colliding) - also called as destructive plate boundary
  • Divergent spreading - also called as constructive boundary
  • Transform boundaries/fault+ (lateral) - also called as conservative boundary
• Different landforms and processes are involved in plate tectonics
• Homeostasis


  Stimulates or inhibits the activities of other systems
• Mental activities

  • Consciousness
  • Memory
  • Thinking
• Nervous system cells

  • Neurons (conducting cells)
  • Neuroglia (supportive cells, 40% of brain bulk)
• Neurons


  Receive stimuli and transmit impulses to other neurons or body organs such as muscles
• Neuron

  • Structural and functional unit of the nervous system
  • Specialized for transmitting, processing, and conducting impulses/information
• Neuron components

  • Cell body (perikaryon)
  • Dendrites (receive stimuli, conduct towards cell body)
  • Axons (conduct impulses away from cell body)
• Axons


  • Covered by lipid-rich membrane called myelin sheath
  • Conduct impulses away from nerve cells