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Content Benchmark E.12.C.1
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Earth Science
Atmospheric Process and Water Cycle
Solar System and Universe
Earths Composition and Structure
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Nature of Science (NOS)
Life Science
Earth Science
Physical Science

Students know how successive rock strata and fossils can be used to confirm the age, history, and changing life forms of the Earth, including how this evidence is affected by the folding, breaking, and uplifting of layers. E/S

Imagine that your favorite author has just released a book and you were able to attain an advanced copy. You set aside some time to begin this much anticipated adventure only to find out that the book is incomplete. Upon turning to the first chapter, all that is written is the title followed by 30 pages of blank paper; worse still this pattern repeats for the next several chapters. Eventually a single word appears, followed by mainly blank pages in which only a few single words are scattered. An appreciable way into the book you discover short phrases, eventually followed by longer phrases, and finally complete sentences. From this point the remaining portion of the story is captivating, and you experience a robust story of life, death, and change with fully developed characters and an intriguing narrative. At the end of the book you are left with many questions as to how this story began and to the characters’ origins and early experiences. Just like the above scenario, the story of Earth and the life it supports has changed throughout time. The charge of the geoscientist is to piece together the parts of the story that are incomplete.

One of the challenges facing geoscientists is to determine the exact age and history of Earth that has brought it to its current situation. Earth is a dynamic planet that has evolved over time. As a result, continents have been moved, mountains created and leveled (eroded), meteors impacted, volcanoes erupted, earthquakes jolted, and rocks recycled and destroyed by the process plate tectonics. Earth’s biologic diversity and evolution have also been critical players in our changing planet. To help piece together the story of Earth an understanding of the rock cycle, importance of fossils, geologic timescale, and age dating techniques – both relative and absolute - need to be explored.

Rock Cycle
Rocks are naturally occurring aggregates of one or more minerals. All rocks are composed of material that has been present on Earth since it first formed – excluding that material which has been delivered by meteorites. Although the constituent material used to create rocks has not changed appreciably over time, their arrangements have. The rock cycle (Figure 1) is a model that illustrates the changes to rocks that have taken place through time. Rocks are recycled into other rocks through processes which occur in mainly two locations; at or near Earth’s surface such as weathering, erosion, and deposition; and deep below the surface such as melting and increased heat and pressure. Most rocks are formed from other rocks and a “rock” may take more than one path through the rock cycle. The arrows on the rock cycle diagram shows various processes one rock type (i.e. metamorphic) could advance through in order to become a different rock type (i.e. sedimentary).

Using the rock cycle diagram, let’s examine the processes a metamorphic rock passes through to become a different rock type. Starting at metamorphic rock and following the outside arrows clockwise our metamorphic rock would need to experience an increase in temperature to the point of melting it, creating magma. Eventually this magma body would enter an environment where the heat contained would transfer from it (cooling) and the process of solidification (crystallization) occurs. This rock is now classified as an igneous rock. Continuing clockwise from igneous, several more changes must occur in order to turn this igneous rock into a sedimentary rock. The igneous rock needs to be subjected to the agents of weathering and erosion, which over geologic time creates pieces or fragments of rock called sediment. As this sediment piles up, compaction and cementation turn the loose sediment into a solid rock through the process of lithification. This rock is now classified as a sedimentary rock. Continuing clockwise this sedimentary rock will become a metamorphic rock with the addition of heat and pressure causing a partial melting of some of the minerals in the sediment. This process is referred to as metamorphism and results in creation of a metamorphic rock. The straight arrows within the rock cycle diagram indicate that any one rock type can turn into any other rock type by passing through several common processes.

Figure 1. The Rock Cycle

For an interactive rock cycle animation, go to
/investigations /es0602/es0602page02.cfm

For additional information related to the rock cycle and three classifications of rocks, go to

Fossils are the remains, molds, or traces of living organisms preserved in media such as sedimentary rock (i.e. sandstone, siltstone, shale or limestone), amber, ice, or tar. Fossils provide evidence of past forms of life and are used by paleontologists, geologists, biologists and others to learn about the past history of Earth. The oldest fossils found indicate life on our planet began at an age of well over 3 billion years ago. These organisms were simple, single-celled organisms. Increasingly complex multi-cellular organisms began to evolve, as preserved in rock, dating from about one billion years old. A significant number of fossils (and diversity) begin around 550 million years ago, as organisms with hard parts burst onto the scene – this is referred to as the Cambrian explosion.

For an animation showing how fossils form, go to
content/visualizations /es2901/es2901page01.cfm?chapter_no=visualization

For detail on the Cambrian explosion, go to

The Principle of Superposition states that, for an undisturbed rock sequence the oldest rock layer is on the bottom, and the higher up one travels, the younger the rock layers become. When comparing fossils in undisturbed strata, fossils can be found in upper strata which, although different from fossils in lower strata, resemble those fossils. This suggests links between modern forms and older forms, as well as divergent pathways from common ancestors. If we examine fossils found in various layers of rock, and look at progressively older layers, we can see that there is a layer below where no human fossils are naturally found. As we progress backward in time, we will eventually see a layer below where no fossils of birds, no mammals, no reptiles, no fish, and eventually, no animal of any kind are found. This is evidence that the kinds of plants and animals, and other organisms have changed over time and is called the Law of Fossil Succession.

Further detail about fossils can be found in the TIPS L12D3 performance benchmark.

To learn more about the importance of the fossil record and the law of fossil succession, go to and

There are gaps in the branches of the fossil records of life. Gaps exist in the fossil record, partly because plants, microorganisms, and soft shelled organisms (majority of marine animals), are not likely to fossilize. Even hard bodied organisms do not frequently fossilize. In addition, changes in the land resulting from forces on our dynamic planet (i.e., erosion, metamorphosis, and geological events) can destroy fossils if they were present. However, the fossil record does provide significant evidence of evolution and of the history of life on earth.

For more information on fossils, visit and

Geologic Time
Earth's history has been divided into a series of time intervals (Figure 2). These time intervals are not equal in duration like hours in a day. Instead they are variable in duration because geologic time is divided using significant events in the history of the Earth. For example, the boundary between the Permian and Triassic is marked by a global extinction in which a large percentage (nearly 90%!) of Earth's plant and animal species went extinct – the end-Permian mass extinction is perhaps the most severe extinction the planet has seen. Another example is the boundary between the Precambrian and the Paleozoic which is marked by the first appearance of animals with hard parts, called the Cambrian explosion occurring some 550 million years ago.

Figure 2. These time scales are drawn to scale so you can
compare the relative lengths of geologic time divisions.

The geologic time scale consists of (from longest to shortest duration) eons, eras, periods, and epochs. The eon is the largest division of geologic time, which is made up of several eras and continues for hundreds of millions or billions of years. Essentially there are two eons, the Precambrian (which covers ~90% of all geologic time) and the Phanerozoic. An era is a geologic division including several periods, but of shorter duration than an eon. In general, eras last for many tens or hundreds of millions of years, and are often characterized by distinct life-forms. The Paleozoic era “age of ancient life” was a time dominated by marine invertebrates. The Mesozoic era “age of middle life” was a time dominated by reptiles, of which the most famous were the dinosaurs. The Cenozoic era “age of recent life” is a time dominated by mammals, of which the most famous are reading this TIPS benchmark. The period is the most commonly used unit of geologic time, representing one subdivision of an era. Each period generally lasts for some thirty to eighty million years. Lastly, epochs, only found in the Cenozoic, are smaller divisions of a period. To describe the current geologic time (from smallest to largest division), we are in the Holocene Epoch of the Quarternary Period within the Cenozoic Era of the Phanerozoic Eon.

For detailed information related to the geologic time scale and an interactive model of major geologic events within the various divisions of time, go to

The Smithsonian interactive geologic timeline is a really great resource for background information related to geologic time, along with detailed surface and atmospheric conditions,

Dating Methods
Dating the age of rocks is critical to reconstructing Earth's history. Geologists rely on two basic types of dating: relative dating and absolute dating. Relative dating places historical events in their correct order, but does not yield numerical estimates of how many years ago the events happened. Absolute dating establishes how many years ago a given event took place. The most important methods of absolute dating are based on the decay of naturally occurring radioactive elements. It may seem odd that the two procedures are kept distinct - if scientists can determine the numerical ages of rocks and fossils, they should be able to put the evidence of ancient life in the correct historical order. The problem is that only some types of rocks and fossils can be numerically dated, so all other evidence of ancient life must be related to age-dated material by the techniques of relative dating.

Relative Dating
James Hutton (known as the Father of Modern Geology) advanced the concept of geologic time and strengthened the belief in an ancient world. Hutton first proposed formally the fundamental principle used to classify rocks according to their relative ages. He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time. Further, he proposed that wherever undisturbed layers were exposed, the bottom layer was deposited first and was, therefore, the oldest layer exposed; each succeeding layer, up to the topmost one, was progressively younger. This came to be known as the Principle of Superposition.

Figure 3. Superposition

Hutton also proposed the Principle of Uniformitarianism, which states “The present is the key to the past”. This manner of thinking assumes that geologic forces and processes (gradual as well as catastrophic) acting on the Earth today are the same as those that have acted in the geologic past. An example of uniformitarianism would be to observe today how rocks weather into sediment and pile up (typically in a body of water) and, as more and more weight is added, the lower layers become compacted and cemented together forming a sedimentary rock – with layers building horizontally (known as the Principle of Original Horizontality). Upon seeing a sequence of faulted, folded, or tilted rock layers, one can assume that these layers were originally deposited horizontal. Once formed, these layers were then subjected to geologic forces that altered their original state.

To see an animation of how originally horizontal layers become tilted, go to

An unconformity is a buried erosion surface separating two rock layers of different ages. An unconformity represents time during which no sediments were deposited and the local record for that time interval is missing. The steps required to form an unconformity are; deposition of sediments creating horizontal rock layers, uplift and tilting, erosion (removal of material), followed by further deposition (Figure 4).

Figure 4. Steps to create an unconformity

For an animation showing the steps to form an unconformity, go to
/books/ earth_science/terc/ content/ visualizations/es2902/es2902page01.cfm?

The Principle of Cross-Cutting Relations states that any feature that cuts across a layer must be younger than the layer it cuts through. Igneous intrusions, faults, and erosion surfaces can cut across any features, including other igneous rocks, other faults, and erosion surfaces. As a consequence, the principle of cross-cutting relations is extremely important in narrowing the relative age of a geologic event.

Figure 5. Cross-cutting by erosion.
Figure 6. Cross-cutting by fault.
Figure 7. Cross-cutting by igneous rock.

The sequence of geologic events in an area can be solved by applying the fundamental principles of geologic relative age dating (e.g., Principle of Superposition). In this diagram, which shows a hypothetical exposure of rock, it is possible to determine the order in which the various geologic events occurred. See if you can tell the story of how this sequence can to be the way it is – from oldest to youngest.

Figure 8. Hypothetical exposure of rock

Answer from oldest to youngest;
1. Conglomerate 2. Shale 3.Sandstone 4. Siltstone 5. Limestone 6. Breccia (using the Principle of Superposition), followed by; 7. Basalt Intrusion (and contact metamorphism) 8. Fault (using the Principle of Cross Cutting Relations) 9. Erosion.

For more background information and examples of relative dating of rock layers, go to
/~pgore/ geology/historical _lab/relativedating.htm

Absolute Age Dating of Rocks
Radioactive elements are unstable; they breakdown spontaneously into more stable atoms over time, a process known as radioactive decay. Radioactive parent elements decay to stable daughter elements. This decay occurs at a constant rate, specific to each radioactive isotope (Figure 9), and is not affected by changes in temperature and pressure.

Figure 9. Parents and daughters for some isotopes commonly used to establish numeric ages
of rocks (from

Each radioactive isotope has its own unique half-life. A half-life is the time it takes for half of the radioactive isotope (parent material) to decay to a stable element (daughter product). The proportion of parent to daughter reveals the number of half-lives, which can be used to find the age in years.

Figure 10. Radioactive decay graph showing parent isotope decay
(red line) and time for each half-life (blue line).

For example, if there is an equal amount of parent and daughter (such as; 500 atoms of both carbon-14 and nitrogen-14 in the graph above), then one half-life has passed. If two complete half-lives have passed then 25% (or 250 atoms) of radioactive parent and 75% (or 750 atoms) of daughter product are present.

For more information about radioactive half-life, visit TIPS P12C4 performance benchmark.

Radiometric dating has been used to determine the ages of the Earth, Moon, meteorites, ages of fossils, including early man, timing of glaciations, ages of mineral deposits, recurrence rates of earthquakes and volcanic eruptions, the history of reversals of Earth's magnetic field, and many of other geological events and processes.

For additional information related to radiometric dating visit
legacy/college/levin/0470000201/ chap_tutorial/ch01/chapter01-3.html

Radiocarbon dating
All living plants and animals have a constant ratio of carbon-14 (radioactive carbon) to carbon-12 (nonradioactive carbon). After the death of an organism, the amount of radiocarbon gradually decreases as it radioactively decays to nitrogen-14. Radiocarbon dating works by measuring the amount of radioactivity remaining in organic materials (amount of carbon-14). From this the age of the organic material can be determined.
For example, if carbon from a sample of wood is found to contain only half as much carbon-14 as that from a living plant, the estimated age of the old wood would be 5730 years. If only ¼ as much carbon-14 was present, then the estimated age would be 11,460 years [2 half-lives x 5730 years/half-life].
The radiocarbon clock has become an extremely useful and efficient tool in dating the important episodes in the recent prehistory and history of man, but because of the relatively short half-life of carbon-14, this method can be used for dating events that have taken place only within the past 50,000 years, and therefore is not useful for dating older geological events.

Extensive background information on radiocarbon dating can be found at

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Content Benchmark E.12.C.1

Students know how successive rock strata and fossils can be used to confirm the age, history, and changing life forms of the Earth, including how this evidence is affected by the folding, breaking, and uplifting of layers. E/S

Common misconceptions associated with this benchmark:

1. Students have difficulty with the numerical literacy required to identify with geological and biological concepts.

We have all been there: pose a question to students such as “How tall is that building?” and their typical responses range from 100 feet to two miles! Now think about the human life span of experience. We can expect to live 60 or 80, maybe even 100 years. To a high school student of 16 years old…100 appears incredibly far away. Now consider the age of the Earth and the geologic time scale. When talking about dates in Earth’s history such as; 10 thousand years ago the last ice age ended, or 65 million years ago to dinosaurs went extinct, or further still the formation of the Earth 4.6 billion years ago students will have difficulty relating to these large numbers. In the intervention strategies and resources section of this benchmark, several activities are presented to assist students in gaining a deeper understanding of scale and time.

For further information on this misconception and for strategies to address it, visit the Action Bioscience website from the American Institute of Biological Sciences at,

Overcoming geological misconceptions article from Planet No.17, December 2006, and

How big is 1 billion – scale perspective activity

2. Students incorrectly believe that fossil evidence does NOT support evolution because there are too many “missing links” or missing transitional fossils.

A transitional fossil is one that links a more modern organism with a more primitive organism. A transitional fossil would have characteristics in common with both the primitive organism and the more modern organism. Transitional fossils are often called “missing links.” According to evolutionary theory, however, all organisms are in transition, and therefore, a specific “missing links” may not actually exist as organisms evolve. In addition, there are many organisms that have existed in the past for which no fossils will ever be found, so there will always be gaps in the fossil record. This is because conditions required for fossilization to occur are not always present when on organism dies. Many examples of transitional fossils do exist, providing evidence that species do transition. Several examples are listed below, with links for additional information.

For greater detail on this misconception visit

3. Students incorrectly believe that fossils are pieces of dead animals and plants.

While in some unique circumstances actual remains of organisms become preserved (such as saber-toothed cats in tar, mosquitoes in amber, and a mammoth in ice), the majority of fossils are not actually pieces of dead animals and plants. They are only the impression or cast of the original organism or plant. The actual living portion of the organism decay away but their shape is permanently recorded in the rock as it formed.

To learn more about this misconception go to

A straight forward overview of what fossils are can be found at

4. Students incorrectly think that fossils of tropical plants cannot be found in deserts.

Fossils and the rocks in which they are found record ancient environments present during the time the rocks were deposited. The climate and topography in a particular region could have been very different in geologic past from current day conditions. For example, during the Paleozoic Era, Southern Nevada was a shallow sea teeming with marine life, in sharp contrast from the desert conditions of today. Plate tectonics resulted in shifting land masses, carrying continents from tropical regions of the planet to temperate and polar regions. As a result of this movement, fossils can be found in areas that today could not support those types of organisms.

For more information on this and other misconceptions go to,

To see the distribution of key fossils, access the following link. Once there, “click” the reptile image to see where fossils were found.

For a review of the geologic evolution of Southern Nevada (part of the virtual field trip of Frenchman Mountain), go to

5. Students may incorrectly believe that radiometric dating is unreliable.

When presenting the facts about radiometric dating to students, it is important that they understand how isotopic age dating works and that it is very accurate – typically less than 1% error of measurement. Methods used for radiometric dating are based on sound physics, the same physics that is at work in the students’ everyday lives. Often times students only know about one or two isotopes (typically U-238 and/or C-14 ) and are not aware of other common radioactive isotopes (see figure 9 for a partial list) that can be tested within the same material yielding similar ages – supporting the reliability of radiometric dating.

For more information on this and other misconceptions, go to

For an activity that models radioactive decay titled Determining Age of Rocks and Fossils,

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Content Benchmark E.12.C.1

Students know how successive rock strata and fossils can be used to confirm the age, history, and changing life forms of the Earth, including how this evidence is affected by the folding, breaking, and uplifting of layers. E/S

Sample Test Questions

1st Item Specification: Explain the basics of the process of fossil formation.

Depth of Knowledge Level 1

  1. Which two factors provide the BEST opportunity for a fossil to form? The organism is buried
    1. slowly and composed of hard parts.
    2. rapidly and composed of hard parts.
    3. slowly and composed of soft parts.
    4. rapidly and composed of soft parts.
  1. An organism is most likely to become an index fossil if it lived for a
    1. short period of time and was geographically widespread.
    2. long period of time and was geographically widespread.
    3. short period of time and was geographically limited.
    4. long period of time and was geographically limited.

Depth of Knowledge Level 2

  1. The three cross sections of sedimentary bedrock shown below represent widely separated surface exposures of layers that contain fossils. Letters A, B, C, D represent four different marine fossils found in these rock layers.


Which letter best represents an index fossil?

  1. Fossil A
  2. Fossil B
  3. Fossil C
  4. Fossil D
  1. Which of the following methods of fossilization would most likely preserve the original remains of the organism?
    1. Brachiopod mold and cast
    2. Dinosaur footprint
    3. Petrification of wood
    4. Mosquito trapped in amber

2nd Item Specification: Apply the principles of superposition to relative dating of rock layers.

Depth of Knowledge Level 1

  1. The Principle of Superposition states that for a rock sequence that has not been overturned
    1. a fault is older than the layers through which it cuts.
    2. the igneous intrusion is older than the layers through which it cuts.
    3. the oldest rock layer is located on the top.
    4. the oldest rock layer is located on the bottom.
  1. The diagram below shows a geologic cross section. The rock layers have not been overturned. Point A is located in the zone of contact metamorphism.


Which rock formation is the oldest?

  1. Conglomerate
  2. Shale
  3. Sandstone
  4. Limestone

Depth of Knowledge Level 2

  1. The diagram below shows a geologic cross section. Letters A through D represent different rock units.


Which sequence correctly shows the age of the lettered rock units, from OLDEST to YOUNGEST?

  1. A → B → C → D
  2. B → A → D → C
  3. C → D → A → B
  4. D → C → B → A
  1. The diagram below shows a geologic cross section. The rock layers have not been overturned. Point A is located in the zone of contact metamorphism.


Which of the following lists the correct order of rock layers from OLDEST to YOUNGEST?

  1. Shale → Breccia → Limestone → Siltstone
  2. Conglomerate → Shale → Sandstone → Siltstone
  3. Limestone → Siltstone → Shale → Conglomerate
  4. Siltstone → Sandstone → Shale → Breccia

3rd Item Specification: Describe the process of absolute dating.

Depth of Knowledge Level 1

  1. What would happen to the half-life of a radioactive isotope if it were taken to the below-freezing temperatures of the North Pole?
    1. Increase
    2. Decrease
    3. Remain the same
    4. Increase, then decrease
  1. The amount of initial radioactive material is doubled from 1000 to 2000 atoms. What affect does doubling the radioactive material have on its half-life? The half life would be
    1. Constant
    2. Doubled
    3. Quadrupled
    4. Halved
  1. Use graphs #1-4 to answer the following question.


Which graph best shows the radioactive decay of carbon-14?

  1. Graph 1
  2. Graph 2
  3. Graph 3
  4. Graph 4

Depth of Knowledge Level 2

  1. The diagram below represents a sample of a radioactive isotope.

Diagram 1
Diagram 2
Diagram 3
Diagram 4


Which diagram best represents the percentage of this radioactive isotope sample that will remain after 2 half-lives?

  1. Diagram 1
  2. Diagram 2
  3. Diagram 3
  4. Diagram 4
  1. The diagram below shows the decay of a 50-gram sample of a radioactive isotope.


According to the graph, what is the half-life of this isotope?

  1. 100 years
  2. 150 years
  3. 200 years
  4. 300 years

4th Item Specification: Sequence the age, history, and changing life forms of Earth using strata and fossil evidence.

Depth of Knowledge Level 1

  1. Which statement is most accurate regarding the current fossil record? The fossil record is
    1. complete and contains fossils of all the types of plants and animals that ever lived.
    2. complete and contains fossils of all plants and some animals that ever lived.
    3. Incomplete and contains fossils of a few of the plants and animals that ever lived.
    4. incomplete and contains most of the plants and animals that ever lived.
  1. The best indicator of an area’s ancient environmental conditions and climate would be the
    1. type and distribution of fossils.
    2. present plant and animal life.
    3. amount of carbon-14 in rock layers.
    4. depth and composition of soil.

Depth of Knowledge Level 2

  1. Base your answer to the question on the cross section below, which show widely separated outcrops at locations W, X, Y, and Z. The rock layers have not been overturned. Line AB in the cross section at location W represents an unconformity. Fossils are shown in some of the layers.


Determine the relative geologic age of the four fossils by correlating the rock layers between these outcrops. Which sequence best illustrates the relative age from OLDEST to YOUNGEST?

  1. Base your answer to the question on the cross sections of the three rock outcrops, A, B, and C. Line XY represents a fault. Overturning has not occurred in the rock outcrops.

(Click Image to Enlarge)

Which sedimentary rock shown in the outcrops is the YOUNGEST?

  1. Conglomerate
  2. Brown sandstone
  3. Black shale
  4. Tan siltstone

5th Item Specification: Describe how folding, breaking, and uplifting of strata complicate geological evidence.

Depth of Knowledge Level 1

  1. The diagram below shows four major types of fault motion occurring in Earth’s crust.

(Click Image to Enlarge)

Which type of fault motion best matches the general pattern of crustal movement at California’s San Andreas Fault?

  1. Diagram 1
  2. Diagram 2
  3. Diagram 3
  4. Diagram 4
  1. Base your answers to the question on the geologic cross section of bedrock shown below. A through G identify rock layers and Q represents a fault. Lines W, X, Y, and Z are locations of unconformities. The rocks have not been overturned.


Which geologic event is the OLDEST (occurred first)?

  1. Intrusion at E
  2. Disconformity at X
  3. Unconformity at Y
  4. Fault at Q

Depth of Knowledge Level 2

  1. Geologic cross sections A through F shown below represent different stages in the development of one part of Earth’s crust over a long period of geologic time.


What is the correct order of development from the original (OLDEST) stage to the most recent (YOUNGEST) stage?

  1. B → F → D → C → A → E
  2. B → F → C → D → E → A
  3. E → A → D → F → C → B
  4. E → A → F → C → D → B

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Content Benchmark E.12.C.1

Students know how successive rock strata and fossils can be used to confirm the age, history, and changing life forms of the Earth, including how this evidence is affected by the folding, breaking, and uplifting of layers. E/S

Answers to Sample Test Questions

  1. B, DOK Level 1
  2. A, DOK Level 1
  3. C, DOK Level 2
  4. D, DOK Level 2
  5. D, DOK Level 1
  6. A, DOK Level 1
  7. D, DOK Level 2
  8. B, DOK Level 2
  9. C, DOK Level 1
  10. A, DOK Level 1
  11. D, DOK Level 1
  12. B, DOK Level 2
  13. C, DOK Level 2
  14. C, DOK Level 1
  15. A, DOK Level 1
  16. B, DOK Level 2
  17. D, DOK Level 2
  18. A, DOK Level 1
  19. D, DOK Level 1
  20. B, DOK Level 2

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Content Benchmark E.12.C.1

Students know how successive rock strata and fossils can be used to confirm the age, history, and changing life forms of the Earth, including how this evidence is affected by the folding, breaking, and uplifting of layers. E/S

Intervention Strategies and Resources

The following is a list of intervention strategies and resources that will facilitate student understanding of this benchmark.

1. Who’s On First? A Relative Age Dating Activity
Developed by The Museum of Paleontology of The University of California, Berkeley; the Regents of the University of California; and The Paleontological Society. In this activity, students are introduced to sequencing and geologic time through relative dating techniques. Students begin by categorizing cards of nonsense words, then move on to cards with pictures of fossils. Once students begin to grasp "relative" dating, they can extend their knowledge of geologic time by exploring radiometric dating and developing a timeline of Earth's history. There is a teacher's guide to this activity with background information and templates to use for teaching about relative dating. There are also objectives, materials, procedure, and questions.

To access this activity go to

2. Relative Dating – Telling Time Using Fossils
Developed by Oregon Public Broadcasting and PBS. This website integrates video footage and information with lesson plans and activities to teach students about the concept of relative dating. Students will graph a range chart for ammonites, determine the geologic age for several rocks, and determine which rocks will be most useful for oil companies looking to drill oil. This site contains lesson plans, student worksheets, discussion questions, and links for more information.

The unit summary can be found at

To download this PDF Lesson visit

3. Teaching Geoscience with Visualizations: Using Images, Animations, and Models Effectively
This is a really great website resource developed by the Science Education Resource Center (SERC) at Carleton College and its partners with funding from the National Science Foundation. This site contains teaching ideas, activities, animations, models, and current data sets related to the Geosciences.

The link to visualizations can be accessed at

On the Cutting Edge search page for activities, assessments, and more is found at

4. Virtual Fossil Museum – Fossil Image Directory
The Virtual Fossil Museum is an educational resource that provides an ever-growing extensive collection of fossil images. From their homepage you can access information such as; Geologic Time, Paleobiology, Geologic History, Tree of Life, Fossils and Fossil Sites, Evolution, and Fossil Record.

Link to Virtual Fossil Museum homepage,

The fossil image directory can be directly accessed at

5. Construct Seven Paper Models that Describe Faulting of the Earth
USGS site resource that contains an instructional activity where seven 3-D paper models are constructed by students. These models are intended to help students and others visualize the main classes of faults and learn some of the terminology used by geologists to describe faults. By constructing and examining these models, students will obtain a greater appreciation of the relationship between fault displacements and the landforms that result.

To reach the teachers guide for this activity, go to

To access the print friendly models, go to

6. Smithsonian National Museum of Natural History – Geologic Time: The Story of a Changing Earth
This is an interactive geologic timeline that is really well done. From the top navigation bar users select an Eon, Era, Period, or Epoch of geologic time for exploration and are immediately provided with an overview of that division, biologic significance of the time (where appropriate), atmospheric information and related plate tectonic evidence. Foundational concepts such as dating methods, Earth processes, and life processes are accessed via navigation links on the left portion of the site.

To access this site, go to

7. Geologic Time Activity
A really great scaling activity that has students scale geologic time to a 100 yard football field in order to gain a perspective for the various divisions of geologic time. An alternative activity is provided for students to make a circle, pie diagram, or clock that shows the amount of time in degrees or in percentages. Contained within this site are links to additional topics and activities on a variety of science topics. This website is developed by Wheeling Jesuit University and part of the NASA supported Classroom of the Future.

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8. Understanding Geologic Time
Educational module (sponsored by the National Science Foundation and Berkeley University of California) that introduces students to geologic time, the evidence for events in Earth's history, relative and absolute dating techniques, and the significance of the geologic time scale.

To access this educational module, go to

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