CONTINENTAL DRIFT THEORY | SCIENCE 10 - Week 8 Part I

00:06:51
https://www.youtube.com/watch?v=mg9FrfYnPZY

Sintesi

TLDRThe video discusses the theory of continental drift, initially proposed by Alfred Wegener. He suggested that all continents were once part of a single large landmass called Pangaea, which started to break apart around 200 million years ago into smaller supercontinents, Laurasia and Gondwanaland, and gradually drifted to their current positions. Wegener's idea was supported by various evidence, including the fit of continental shapes like a jigsaw puzzle, fossil distribution of plants and animals across continents now separated by oceans, alignment of rock formations, glacial striations indicating past polar positions, and coal deposits showing past tropical climates in now-polar regions. Although initially not widely accepted due to the lack of explanation for the driving forces, the theory of plate tectonics later provided a mechanism and helped validate Wegener's observations.

Punti di forza

  • 🌍 Alfred Wegener proposed the continental drift theory.
  • 🧩 Continental jigsaw puzzle evidence shows matching coastlines.
  • 🦖 Fossil distribution patterns support past continent connections.
  • ⛰️ Rock formations suggest a continuous range across now separate continents.
  • ❄️ Glacial striations found in tropical regions indicate previous polar positions.
  • ⛏️ Coal deposits reveal past tropical climates in regions like Antarctica.
  • 📜 Pangaea was a supercontinent that began to break apart during the Jurassic period.
  • 🔍 The theory of plate tectonics provided a mechanism for Wegener’s observations.

Linea temporale

  • 00:00:00 - 00:06:51

    The discussion focuses on the learning competency related to plate movement, specifically the Continental Drift Theory proposed by Alfred Wegener. The theory suggests that continents were once a single large landmass called Pangaea. Wegener cited evidence such as the continental jigsaw puzzle, fossil evidence across different continents, matching rock formations, glacial striations in now-tropical regions, and coal deposits in Antarctica to support his theory. However, it wasn't accepted until the advent of plate tectonics theory in 1965.

Mappa mentale

Mind Map

Domande frequenti

  • Who proposed the continental drift theory?

    Alfred Wegener proposed the continental drift theory.

  • What does the supercontinent Pangaea mean?

    Pangaea means 'all Earth.'

  • What type of evidence supports the idea of continental drift?

    Evidence includes the continental jigsaw puzzle, fossil distribution, rock formations, glacial striations, and coal deposits.

  • How do glacial striations support continental drift?

    Glacial striations in current tropical areas indicate these regions were once colder and potentially located towards the poles.

  • What era did the supercontinent Pangaea begin to break apart?

    Pangaea began to break apart around 200 million years ago during the Jurassic period.

  • What evidence is provided by fossils in supporting the continental drift theory?

    Fossils of similar species found on different continents suggest those continents were once connected.

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Sottotitoli
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Scorrimento automatico:
  • 00:00:16
    [Music]
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    our discussion will focus on the
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    learning competency
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    enumerate the lines of evidence that
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    support plate movement
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    at the end of the lesson you should be
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    able to one
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    describe continental drift theory number
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    two trace the geologic formation of
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    continents in the continental drift
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    theory
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    and number three explain evidences that
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    support continental
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    drift theory everybody have seen the map
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    of the world
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    but if you will take a closer look at
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    the shapes of each landmass
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    you will notice that they seem to fit
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    together like a puzzle
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    that if you are going to put each
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    continents close to each other
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    you will actually create a giant
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    landmass
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    let's say for example the continents of
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    south america
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    may seem to fit together with africa
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    can you see it
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    this observation actually led to one of
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    the theories that
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    explained earth movement known as the
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    continental drift theory
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    this theory was proposed by alfred
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    budgener
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    he laid out his case in his book the
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    origin of continents and ocean
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    he proposed a theory that about 200
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    million years ago
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    the continents were once one large
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    landmass
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    however wedgener could not explain what
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    force was driving the motion of the
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    continents
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    his theory was not accepted by the
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    scientific community until 1965 when the
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    theory of blade tectonics was published
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    according to wedgener all continents
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    formed a single continental mass
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    this supercontinent was named panjaya or
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    panjei
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    which means all earth this was
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    surrounded by a mega ocean
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    called pantalasa meaning
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    all water wagener argued that around 200
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    million years ago
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    this supercontinent pangea started to
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    break into two smaller super continents
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    called laurasia in the north and
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    gondwanaland
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    in the south during the jurassic period
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    these smaller supercontinents broke into
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    the continents and this continent
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    separated and drifted apart
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    since then the illustration shows how
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    the landmasses drifted in the last 250
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    million years
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    to support his claim wagener cited
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    evidences of continental drifting
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    first is the continental jigsaw puzzle
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    the most visible and fascinating
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    evidence
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    that these continents were once one in
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    their shapes
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    if you will cut out pictures of each
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    continent and bring them close together
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    you will see that the edge of continent
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    surprisingly matches the edge of another
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    south america and africa fit together
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    india antarctica and australia match one
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    another
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    and eurasia and north america complete
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    the whole continental puzzle in the
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    north
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    next is the evidence from fossils
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    fossils are preserved remains or traces
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    of organisms from the remote past
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    fossils have unique distribution
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    patterns in some parts of the world
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    mesosoros cynonatus listosaurus and
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    glossopteries are the notable ones
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    fossilized leaves of an extinct plant
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    gloss of terrace were found in 250
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    million years old rocks
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    these fossils were located in the
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    continents of south africa
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    australia india and antarctica which are
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    now separated from each other by
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    wide oceans the large seeds of this
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    plant could not possibly travel a long
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    journey
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    by the wind or survive a rough ride
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    through the ocean waves
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    fossils of mesosoros a freshwater
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    reptile was found in the eastern coast
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    of south america
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    and western coast of africa according to
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    wedgener
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    while mesosaurus roamed the land these
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    continents were connected
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    but after they become extinct the
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    continents were torn apart
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    rocks also provide evidence that
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    continents drifted apart
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    rock formations in africa lined up with
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    that in south
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    america as if it was a long mountain
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    range
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    folded cape mountains of south america
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    and africa
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    line up perfectly as if they were once a
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    long mountain range
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    another evidence is the glacial
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    striations
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    glaciers can only be found in cold
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    places of the earth
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    like the north and south pole of the
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    earth something interesting about
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    glaciers
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    is that they move and when they move
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    over the rock beneath
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    they leave evidence in the form of
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    scratch called
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    glacial striation in the present day
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    tropical rainforests of south america
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    and africa
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    have glacial striations
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    this means that this place were not
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    always in their warm equatorial regions
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    like they are
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    now they were once down in the south
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    pole where they have been cold enough to
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    form glaciers
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    and we have the coal deposits coal beds
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    were formed from the compaction in the
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    composition of swamp plants that
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    lived millions of years ago this were
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    discovered in south america
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    africa indian subcontinent south east
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    asia and even in antarctica
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    the current location of antarctica could
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    not sustain substantial amount of life
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    if there is substantial quantity of coal
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    in it
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    it only means that antarctica must have
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    been positioned in a part of the earth
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    where it once supported large quantities
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    of life
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    this leads to the idea that antarctica
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    once experienced a tropical climate
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    thus it might have been closer before to
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    the equator
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    and that ends our lesson i hope you
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    learned something today
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    thank you for watching
Tag
  • continental drift
  • Alfred Wegener
  • Pangaea
  • fossil evidence
  • rock formations
  • glacial striations
  • coal deposits
  • plate tectonics