Download DIGGING INTO EARTH`S PAST

DIGGING INTO EARTH’S PAST
This unit focuses on the following content standard and indicators from the Maryland Voluntary
State Curriculum for science.
2.0 Earth/Space Science  Students will use scientific skills and processes to explain the
chemical and physical interactions (i.e., natural forces and cycles, transfer of energy) of
the environment, Earth, and the universe that occur over time.
A. Materials and Processes That Shape A Planet
4. Differentiate among sedimentary, igneous, and metamorphic rocks based upon the
processes by which they are formed.
a. Identify and describe the processes that form sedimentary rock.

Deposition

Compaction

Cementation
b. Identify and describe the processes that form igneous rocks

Volcanic eruptions

Igneous intrusions
c. Identify and describe the processes that form metamorphic rocks.

High temperature

Pressure
d. Cite features that can be used as evidence to distinguish among the three types of
rocks and relate these features to the processes that form each rock type.
e. Describe the processes that change one form of rock into another (rock cycle).
B. Earth History
1. Explain how sedimentary rock is formed periodically, embedding plant and animal
remains and leaving a record of the sequence in which the plants and animals
appeared and disappeared.
a. Explain how sedimentary rock buried deep enough may be reformed by pressure
and heat and these re-formed rock layers may be forced up again to become land
surface and even mountains.
b. Cite evidence to confirm that thousands of layers of sedimentary rock reveal the
long history of the changing surface of the Earth
c. Explain why some fossils found in the top layers of sedimentary rock are older
then those found beneath in lower layers.
 Folding
 Breaking
 Uplift
 Faulting
 Tilting
2. Recognize and explain that fossils found in layers of sedimentary rock provide
evidence of changing life forms.
a. Recognize how different types of fossils are formed, such as petrified remains,
imprints, molds and casts.
b. Recognize and explain that the fossil record of plants and animals describes changes
in life forms over time.
Enduring Knowledge
This unit integrates the study of rock formation and fossils in order for students to investigate
how Earth’s rocks and fossils can be used to investigate changes in Earth’s biologic and geologic
past. Throughout the study of this unit, students should focus on the following questions:
 How do different types of rocks (igneous, sedimentary, and metamorphic) form?
 What characteristics can be used to distinguish among different types of rocks?
 How do fossils form?
 What can fossils in different rock layers indicate about Earth’s past?
Background Information
This unit focuses on the formation of rocks and fossils in order to determine what conditions
were present on Earth during their formation. Although many rocks look the same, different
rocks can have very different compositions. All rocks begin as magma within the Earth.
Geologists classify all rocks into three basic types-igneous, sedimentary and metamorphicdepending on how they were formed. Igneous rocks are formed from magma, and the specific
type of igneous rock is determined by where the magma cools and hardens. Intrusive igneous
rocks are those which form deep within the earth, and extrusive igneous rocks form at the earth’s
surface. Sedimentary rocks are the most abundant rocks found on the earth. Some are formed
from sediments which become cemented together. Metamorphic rocks are created when existing
rocks, buried deep within the earth, are changed by tremendous heat and pressure and/or
chemical reactions. All rocks are subject to change. The continuous changing of rocks from one
kind to another over long periods time is called the rock cycle. By analyzing rock characteristics
and understanding the processes that form rocks, scientists can make many conclusions about the
conditions present on Earth during the time of their formations.
In addition to rocks, fossils can also provide valuable information about the past conditions of
earth. Fossils are the preserved remains or traces of living things. Fossils are formed in many
ways, the most common being when living things die and are buried by sediments. Other times,
some organisms’ remains pile up under sediment. As the sediments slowly harden into rock, the
shape of the organisms is preserved. Fossils found in rock include petrified fossils, molds and
casts, carbon films, and trace fossils. Sometimes the entire remains of organisms can be
fossilized. This process usually occurs when the remains of organisms are preserved in
substances such as tar, amber, or ice. Scientists can learn a great deal about Earth’s past from the
fossil record. The fossil record shows that many different organisms existed at different times
throughout Earth’s history. When fossils are arranged according to age, they reveal that living
things have changed over time.
Fossils can also provide evidence of how Earth’s surface has changed throughout geologic time.
For example, if scientists find fossils of sea animals in rocks that are now in mountainous area,
they can assume that the land was once covered by an ocean. Fossils also provide clues to
Earth’s past climates. If scientists find fossils of organisms that once lived in tropical seas
beneath the ice of Antarctica, this might indicate that the climate of Antarctica was much
different at one point during Earth’s past. By synthesizing data from the fossil record, scientists
are able to formulate theories of how Earth’s geologic past might have influenced the changes of
organisms over time.
Unifying Scenario
The information presented in this unit is centered on the fossils found at Calvert Cliffs.
Students will read a news article outlining the discovery of a whale skull fossil in the rocks of
Calvert Cliffs. Students will then view a PowerPoint presentation that introduces the topic.
In the PowerPoint, students will discover that the fossils of Calvert Cliffs and the rock layers
of the cliffs provide evidence that Maryland’s geologic and biologic past were very different
from today. Throughout the study of the unit, students will continually revisit the big
question presented in the news article and the PowerPoint presentation which is:
“How do the fossils found in Calvert Cliffs provide evidence that the
climate and living things in the area have changed over time?”
At the conclusion of the unit, students will answer the question in a manner of their choosing.
You’ve spent a lot of time researching Earth’s past and now
it’s your turn to be the expert. In the last few weeks, you’ve
asked me about the formation of rocks and fossils and what
all of it had to do with Maryland’s infamous Calvert Cliffs.
You could probably teach me a thing or two. So go ahead, be
a show off! Why not? You’ve earned it. Here’s what I’d like
you to do; think about the following question:
•
How do the fossils found in Calvert Cliffs provide
evidence that the climate and living things in the area
have changed over time?
Now, since you are the expert and it’s your job to provide
this information for another, what are you going to say? Put
your thoughts into action and the choice is yours. You may
respond to the above question in a number of ways, such as:

A written summary

A cartoon

A story board

A play

A poem

A video production

Or any other idea you may have. Just make
sure to have them approved by your teacher
first.

Well, scurry along and get to work. I look forward to seeing
what you have to say!
Summative Assessments
Students will complete one summative assessment at the conclusion of this unit. The summative
assessment includes selected response questions and constructed response questions related to
the formation of rocks and fossils and their clues to Earth’s past. Throughout the unit, students
will focus on a scenario that requires them to explain how the fossils and rocks of Calvert Cliffs
provide evidence that Maryland’s climate has changed over time. At the conclusion of the unit,
students will answer the unit scenario question.
Order of Study

Administer the pre-assessment on Student Resource Sheet DIP – 1.

Introduce the unit scenario by providing students with “The Mystery of Calvert Cliffs” on
Student Resource Sheet DIP – 2.

Present and discuss the PowerPoint, “The Fossils of Calvert Cliffs.”

Provide students the opportunity to discover the formation of Calvert Cliffs by completing,
“The Search Begins” on Student Resource Sheet DIP – 3.

Complete the investigation, “If Rocks Could Talk” on Student Resource Sheet DIP – 4 to
introduce the characteristics used to identify and classify rocks.

Conduct the investigation, “Igneous Rocks” on Student Resource Sheet DIP – 5 in order to
discover the formation of igneous rocks.

Complete the investigation, “It’s Sedimentary” on Student Resource Sheet DIP – 6 to
introduce the processes of cementation and compaction in forming sedimentary rocks.

Introduce students to the processes needed to form metamorphic rock by completing the
investigation, “Metamorphic Rocks” on Student Resource Sheet DIP – 7.

Provide opportunities for students to investigate the processes in the rock cycle by completing
the investigation, “Recycling Rocks” on Student Resource Sheet DIP – 8.

Complete the investigation, “Time Keeps on Ticking” on Student Resource Sheet DIP – 9 in
order to introduce students to geologic time, the Law of Superposition, and the use of fossils
and rocks to provide clues to Earth’s past.

Compare the processes that form different types of fossils and how fossils can be used to
provide evidence of Earth’s past by completing Student Resource Sheet DIP – 10, “Who’s
Who Among Fossils?”

Provide opportunities to answer the big question by completing Student Resource Sheet DIP 11, “And the Answer Is…”

Administer the summative assessment “Digging Into Earth’s Past.”
Unit Vocabulary
Absolute Age
The age of a rock given as the number of years since the rock formed.
Cast:
Cementation:
A fossil formed in a rock showing the organism's outward shape. It formed after the organism dissolved
and the space in the rock was filled.
Process by which sedimentary rock is formed from sediments being glued together by mineral deposits.
Climate:
The average temperature and rainfall for a particular place over hundreds of years.
Compaction:
Process by which sedimentary rock is formed when layers of sediment are compressed by the weight of
layers above them.
The chemical make up of a given substance.
Composition:
Erosion:
Evolution:
The carrying away of weathered soil, rock, and other materials on the Earth's surface by gravity, water,
and wind.
Changes in species as a consequence of processes such as mutation and natural selection.
Extrusion:
The elimination of a species (also applicable to levels other than species) due to natural processes or
human activity.
An igneous rock layer formed when lave allows onto Earth’s surface and hardens.
Extrusive Rock:
Igneous rock that forms from lave on Earth’s surface.
Faulting:
The process of movement along a break or crack in Earth's crust.
Folding:
The process of bending rock layers in Earth's crust.
Fossil:
The remains or imprint of a prehistoric plant or animal.
Geologic:
Of or relating to Earth or Earth processes.
Geologic Time Scale:
A record of the geologic events and life forms in Earth’s history.
Igneous rock:
Rock formed through the process of magma or lava cooling and hardening.
Imprint:
A fossil that is an organism's impression which was formed in mud that later hardened into rock.
Index fossil:
A fossil of an organism that lived a relatively short time on Earth, used to determine the relative age of
rock layers.
Extinction:
Intrusion:
An igneous rock layer formed when magma hardens beneath Earth’s surface.
Intrusive Rock
Igneous rock that forms when magma hardens beneath Earth’s surface.
Lava:
Liquid magma that reaches the surface.
Law of Superposition: Law that states in undisturbed sedimentary rock layers, the younger layer is closer to Earth's surface and
the older layer is below this.
The molten mixture of rock-forming substances from the mantle.
Magma:
Metamorphic (rock):
Rock formed when igneous or sedimentary rock is changed by pressure, heat, or chemical reactions.
Mold:
A fossil that is an empty space in a rock that shows the outward shape of a dissolved organism.
Petrified:
Fossilized remains that have been turned into stone.
Relative age:
The age of a rock (older or younger) in comparison with the age of other rocks.
Rock:
The material that forms Earth’s hard surface.
Rock Cycle:
A series of processes on the surface and inside Earth that slowly change rocks form one kind to another.
Sediment:
Small pieces of rock, shell, and plant and animal matter that is moved and deposited by water, wind, or
ice.
Rock formed from sedimentation.
Sedimentary rock:
Species:
The settling out of fragments of weathered rock or remains of living things that are carried and deposited
by wind, water, or ice.
Organisms whose members are alike and successfully reproduce among themselves.
Trace Fossil:
A type of fossil that provides evidence of the activities of ancient organisms.
Weathering:
A chemical or physical process in which rocks exposed to the weather are worn down by water, wind, or
ice.
Sedimentation:
Student Misconceptions
Students come to science class filled with prior knowledge and misconceptions. The
misconceptions students come to middle school with need to be addressed. However, it is
equally important that the Digging Into Earth’s Past unit be taught in a way that does not lead to
new misconceptions. Several of the skills and concepts in this unit can easily be misinterpreted
if not implemented properly. The areas in this unit that can lead students to have misconceptions
are summarized on this resource sheet.
Rocks and Rock Formation

Rocks are associated with heaviness.
Small rock fragments are stones, not
rocks. (Ex: a small piece of pumice
would not be considered a rock).

Rocks are stronger than the forces of
nature (water, wind, ice).

Rocks can only be changed by a blow of
a hammer or other powerful object.

Fossils and Geologic Time

The Earth was always as it is now, or that
any changes that have occurred must
have been sudden and comprehensive.

Fossils are actual preserved animals or
plant parts.

Large numbers like a billion are
incomprehensible in magnitude to some
students.
Rock is a hard solid material.

All organisms can form fossils.

Rocks are uniform inside and have the
same characteristics.

Fossils are the only clues to Earth’s past
environments.

Rocks on earth are unchanging; how
rocks look today is how they have always
looked.

Youngest rock layers are always found
on top.
DIGGING INTO EARTH’S PAST
LEARNING STYLES MATRIX
LEARNING STYLE
INVESTIGATION
VISUAL
SEQUENTIAL GLOBAL
Pre-assessment
ACTIVE
REFLECTIVE SENSING INTUITIVE VERBAL
X
X
DIP - ???
Mystery of Calvert Cliffs
X
X
X
X
X
The Search Begins
X
X
X
X
X
X
If Rocks Could Talk
X
X
X
X
Igneous Rocks
X
X
X
It’s Sedimentary
X
X
X
Metamorphic Rocks
X
X
X
Recycling Rocks
X
X
X
Time Keeps on Ticking
X
X
X
Who’s Who Among Fossils
X
And the Answer Is
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X