lab 3
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Dec 6, 2023
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Uploaded by mohamedabshira12
Abshira Abdi
Unit 3: Assignment (Lab Exercise
10/31/23
Part 1
On Earth, plate tectonics has been a dynamic process for hundreds of millions of years.
Take a look at the “plate tectonics movie” on the University of California, Berkeley,
Museum of Paleontology web page
(
http://www.ucmp.berkeley.edu/geology/tectonics.html
Links to an external site.
). Do this
by clicking on “animated GIFs” for the last 750 million years. Play the movie. As time
passes, the continents seem to move around. Why is this so? What is “pushing” the
continents around and why? Why do the continents appear to move around over time?
Plate tectonics is a fundamental geological theory that explains how the lithospheric plates of
Earth move and cause continents to continuously migrate during geological time periods. This
process has been reshaping the planet's surface for hundreds of millions of years, creating
mountains, lakes and rivers, and earthquakes.
Mantle Convection
The idea of mantle convection is fundamental to plate tectonics. Melted rock makes up the
Earth's mantle, a semi-fluid layer. The movement of this molten material is caused by currents
that upwell and down well, driven by heat produced by the Earth's interior. The movement of
tectonic plates is primarily propelled by this convective flow. Whereas colder, denser material
sinks in subduction zones—where one plate is thrust beneath another—hot, buoyant material
rises at mid-ocean ridges, forcing the plates apart.
Slab Pull and Ridge Push
Ridge push and slab pull are two other processes that contribute considerably to plate motion.
The raised ridge functions as a "ridge push" force that forces plates away from mid-ocean ridges,
where new oceanic crust is constantly created. The new crust pushes away from the ridge as it
cools and gets thicker, making room for the next generation of crust. At subduction zones, when
one plate is subducted beneath another, the sinking slab provides a "slab pull" force that aids in
plate motion. Because the denser oceanic plate dips into the asthenosphere, a significant
gravitational attraction is created.
Boundaries must be transformed.
Transform borders, where plates slide horizontally past each other, are also important in plate
tectonics. While friction and resistance at plate borders may not directly cause plate movement,
they do contribute to the overall process. Stress builds up along these limits and finally releases
itself, resulting in seismic occurrences like earthquakes.
Continental Drift
The continents themselves are not driven directly by mantle convection but are instead carried
along on the tectonic plates. The movement of these plates can result in the shifting positions of
continents. When two continental plates converge, they can form mountain ranges through the
process of orogenesis, and when they diverge, rift valleys can be created. The reason why
continents have shifted over millions of years in location is due to a phenomena called
continental drift.
Over millions of years, the cumulative effect of these forces causes the continents to move and
alter their positions on the surface of the Earth.
This process is responsible for the shifting locations of continents throughout geological time
periods, and it also explains phenomena such as continent breakup, mountain range construction,
and ocean basin formation.
Work cited.
Levin, H. L., & King, D. T., Jr. (2016). The Earth through time. John Wiley & Sons.
What is Tectonic Shift? (n.d.).
https://oceanservice.noaa.gov/facts/tectonics.html#:~:text=The%20heat%20from%20radioactive
%20pr
ocesses,plate%20motion%2C%20or%20tectonic%20shift.
Continental drift. (n.d.).
https://education.nationalgeographic.org/resource/continental-drift/
Part 3
Using web pages at the University of California’s Museum of
Paleontology
(
http://www.ucmp.berkeley.edu/paleo/fossilsarchive/molecu.html
Lin
ks to an external site.
), take a look at the description of molecular
fossils.
After reviewing what this web page has to offer, use the
resources there to answer briefly these questions.
What are the
four main organic compounds that form molecular fossils?
What
conditions are necessary for the formation and preservation of
molecular fossils?
What can we learn from molecular fossils?
Molecular fossils are old, tiny relics that can provide information about the past. They are
organic materials derived from long-dead species that have either become fossils or deteriorated
over time. These molecules are fragile and can break apart as a result of chemical reactions,
making preservation difficult.
Four main organic compounds that form molecular fossils:
Nucleic acids (e.g., DNA and RNA)
Proteins
Carbohydrates (e.g., starch and cellulose)
Lipids (e.g., cell membrane components)
What conditions are necessary for the formation and preservation of
molecular fossils?
Isolation from air and microbes, appropriate temperature and oxygen levels, and specialized
habitats such as fossil shells, organic-rich muds and shales, coal, and kerogens are required for
molecular fossil creation and preservation.
What can we learn from molecular fossils?
Evolutionary linkages and the history of life are explored.
Understanding of the interactions between various creatures.
Problems with contamination risk in analysis.
Technological advancements may disclose additional information from these ancient
biological remnants in the future.
Work cited.
K, M. (n.d.). Fossils - Window to the past.
https://ucmp.berkeley.edu/paleo/fossilsarchive/molecu.html
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