Earth’s Catastrophic Past: Teacher’s Guide
Grade Level: 6-8
Curriculum Focus: Earth Science
Lesson Duration: Two class periods
Program Description
Never has Earth been a more violent place than when the planet first formed. Brilliant graphics
depict the formation of the oceans, show how volcanoes played a major part in creating the first
life forms, bring dinosaurs to life and extinction, and re-create the continental collisions that
formed such geologic features as the massive Himalayas. Be there for the glory "in the beginning."
Onscreen Questions and Activities
Segment 1, Earth’s Catastrophic Past: Part One
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Pre-viewing questions:
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As a class, discuss what you already know about how Earth was formed. What types
of geologic events do you think led to the formation of the continents, the oceans,
and the atmosphere?
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As you watch the program, keep track of the evidence that scientists use to formulate
theories about what shaped our planet.
Post-viewing questions:
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Geology can be defined as the science dealing with the formation and the structure
of the Earth. Discuss how geology has increased our understanding of Earth’s
biological history. Use examples from the documentary to illustrate your points.
Activity: Research one aspect of the creation of Earth or its atmosphere. Then, create a
presentation using visual support materials such as maps, graphs, and sketches to illustrate
your data. Share your research in a classwide geologic conference.
Segment 2, Earth’s Catastrophic Past: Part Two
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Pre-viewing questions:
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Environmental scientists believe that the continents were once joined together in one
supercontinent. While you watch the documentary, keep track of the evidence that
supports this theory.
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What events might have led to the separation and the unique landscaping of Earth’s
lithosphere?
Earth’s Catastrophic Past: Teacher’s Guide
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Post-viewing questions:
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2
The documentary highlights several research efforts aimed at creating a picture of
Earth’s past. Choose one of these studies and make a list of supporting evidence
presented in the documentary. Is the evidence convincing to you?
Activity: Pretend that you are teaching a class on geology and must introduce the plate tectonic
theory. Prepare a lesson plan, gather visual aids, and compile a list of resources to teach your
students the basics of plate tectonics.
Lesson Plan
Student Objectives
Students will understand:
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Earth is believed to be approximately 4.6 billion years old.
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The first life, in the form of bacteria, appeared on Earth approximately 3.6 billion years ago.
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Primitive organisms inhabited Earth long before more advanced ones, such as fish, amphibians,
reptiles, and mammals.
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Human ancestors and modern-day humans are relatively recent arrivals on planet Earth.
Materials
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Earth’s Catastrophic Past video and VCR, or DVD and DVD player
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Research materials on the history of life on Earth
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Computer with Internet access
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A long, narrow sheet of paper to create a wall frieze going around all four walls of the room
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5" x 7" index cards
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Markers
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Tape
Procedures
1. Inform students that they are going to work as a class to create a time line of life on Earth.
2. Assign one of the following organisms to each student, or have students work with partners
and assign one organism to each pair: bacteria, cynobacteria, plants, invertebrates, fish,
amphibians, reptiles, birds, first mammals, Java man, Peking woman, Australopithecus boisei,
Neanderthal man, Cro-Magnon man, modern-day humans.
3. Instruct students to use the research materials you have provided or the Internet to answer the
question, “How many years ago did your organism first appear on Earth?”
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Earth’s Catastrophic Past: Teacher’s Guide
3
4. Distribute index cards to students, and have them use markers to write on the index cards the
names of their organisms and the approximate number of years ago they appeared on Earth (for
example, “bacteria—3.6 billion years ago,” or “birds—200 million years ago”). Instruct students
to include simple line drawings of their organisms on the cards. (They may draw microscopic
organisms, such as bacteria, as if seen under the lens of a microscope.)
5. Use narrow paper to create a frieze going around all four walls of your room, explaining that
students will use the frieze to create their time line. Ask students why the time line is so long
and explain that the Earth is estimated to be 4.6 billion years old.
6. Here is one way to divide the time line: use one wall to represent 4.6 billion to 3.6 billion years
ago; use the second wall to represent 3.6 billion to 2 billion years ago; use the third wall to
represent 2 billion to 1 billion years ago; use the fourth wall to represent the most recent billion
years. Divide the fourth wall into tenths, each tenth representing one hundred million years.
Explain to the students that the scale is not exactly correct, but the numbers are so large that it
will give them a good idea of relative time periods.
7. Have students tape their index cards to the appropriate part of the time line.
8. Ask the students what observations they can make about the history of life on Earth based on
the time line. They should note that, during Earth’s first billion years, no life existed at all. They
should also recognize that most of the cards have been placed at the very end of the time line.
What does this show us about the history of human beings as residents of our planet? (Students
should conclude that we are relative newcomers, the earliest humans having appeared on Earth a mere
two million years ago.) Students may also be interested to note that dinosaurs, mammals, and
birds appeared on Earth around the same time (dinosaurs 240 million years ago, first mammals
225 million years ago, and first birds 200 million years ago).
Discussion Questions
1. Piece by piece, geologists put together evidence to begin to tell a story of what happened and is
happening to create our dynamic Earth. Discuss how a geologist is like a detective.
2. List several ways tectonic forces have changed the face of the Earth.
3. Absolute geologic dating and relative geologic dating are two methods by which scientists try
to determine the age of geologic evidence. Carbon-14 dating is an example of absolute dating,
and the law of superposition is an example of relative dating. Discuss the differences between
absolute and relative geologic dating methods and how they can be used together.
4. The Earth has endured a great deal of weathering and erosion. Coastlines are impacted greatly
by erosion. Discuss the forces of nature that cause this erosion. Now describe the methods
coastal cities have instituted to reduce the erosion of their beaches.
5. How could you prove to a friend who doesn’t have a scientific background that the continents
are still in motion and that they were once all joined together as the super continent Pangaea?
6. What theory explains why catastrophes occur every 30 million years?
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Earth’s Catastrophic Past: Teacher’s Guide
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7. During the history of the Earth there have been five mass extinctions. One of those mass
extinctions eliminated the dinosaurs. Discuss what catastrophic events occurred to cause such a
mass extinction.
Assessment
Use the following three-point rubric to evaluate students' work during this lesson.
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3 points: Students’ findings included accurate dating of organism, careful drawing of organism,
correct placement of index card on time line.
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2 points: Students’ findings included accurate dating of organism, no drawing of organism,
correct placement on time line.
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1 point: Students’ findings included accurate dating of organism, no drawing, incorrect
placement on time line.
Vocabulary
asteroid
Definition: One of a group of planetlike bodies whose general orbit around the sun is between
Mars and Jupiter.
Context: Asteroids are found between Mars and Jupiter; these celestial bodies probably
originated from meteorites.
basalt
Definition: A dark gray to black, dense to fine-grained igneous rock that consists of basic
plagioclase, augite, and usually magnetite.
Context: Basalt, an igneous rock found in remnants of lava flows has been used by geologists to
determine the relationships of land masses and rock formations.
lithosphere
Definition: The crust and upper part of the mantle of Earth.
Context: Our lithosphere continues to change as new landforms are created due to the
movement of crustal plates.
meteorite
Definition: Matter that has fallen on the Earth from outer space.
Context: Meteorites provided the rock material necessary for the Earth to grow.
stalactites
Definition: Deposits of calcium carbonate hanging from the roof of a cave.
Context: The scientists investigated the stalactites hanging from the roof of the cave because they
felt it would give them the age of the cave.
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Earth’s Catastrophic Past: Teacher’s Guide
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stalagmites
Definition: Deposits of calcium carbonate standing as pillars on the floors of caves.
Context: The stalagmites in the cave formed as calcium carbonate dissolved in water, permeated
through the Earth’s surface, and was gradually deposited on the cave’s floor.
stromatolites
Definition: Laminated sedimentary fossils formed from layers of blue-green algae.
Context: As geologists analyze core samples, they look for stromatolites to assist them in
determining the ages of different rock layers.
Academic Standards
Mid-continent Research for Education and Learning (McREL)
McREL's Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education
addresses 14 content areas. To view the standards and benchmarks, visit http://www.mcrel.org/.
This lesson plan addresses the following national standards:
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Science—Earth Science: Understands basic Earth processes.
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Science—Nature of Science: Understands the nature of scientific inquiry.
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Geography—Physical Systems: Knows the physical processes that shape patterns on Earth’s
surface.
National Academy of Sciences
The National Science Education Standards provide guidelines for teaching science as well as a coherent
vision of what it means to be scientifically literate for students in grades K-12. To view the standards,
visit http://books.nap.edu.
This lesson plan addresses the following science standards:
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Earth Science: Structure of the Earth system
Published by Discovery Education. © 2005. All rights reserved.