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Scientist’s Full Name: __________________________
College: __________________________
Date: Week of September 12th, 2011
Subject: Science
Unit 2: Diversity of Life — Lesson 4 Study Guide
Fossils: What are Fossils? What can They Tell Us About the Past?
Learning Targets: I can…
 create a model of a fossil.
 explain how a fossil is formed.
 understand how “fossils” provide evidence of plants and animals that lived
long ago as well as the environmental conditions at that time
Part I: Tuesday, September 13th, 2011
Do Now: What do you know about fossils? (10 minutes)
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Brain Pop + In-Class Review (15 minutes)
Science Crew: Making your own trace fossil model (25 min)
Materials
2 cups of flour
2 cups of salt
2 teaspoons of vegetable oil
1 tablespoons of alum
1 cup of water
1 zip lock bag
1 waxy paper plate bowl
1 hand-sized object from
nature
Step 0: Write your heading on the underside of a waxy paper
plate bowl, as well as the name of your hand-sized object
from nature.
Step 1: Carefully mix the appropriate measures of flour, salt,
oil, alum and water into a large zip lock bag.
Step 2: Zip the bag shut and carefully squeeze it around until
it is doughy and no part is left dry.
Step 3: Open the bag and create four equal sized balls.
Step 4: Place each ball into a waxy paper plate bowl.
Step 5: Flatten the dough in the paper plate bowl.
Step 6: Press your object deeply into the bowl, then carefully
take it out.
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Closing (5 min.)
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______ / 4
HW Grade
Scientist’s Full Name: __________________________
College: __________________________
Date: Week of September 12th, 2011
Subject: Science
Due Friday, September 16, 2011
Unit 2: Diversity of Life- Homework #7— Fossils Review
1. Which of the following is an example of a body fossil?
a.
a perfect mold of a dinosaur bone
b.
a carbon print left by a leaf
c.
the skull of a mammoth that fell into a tar pit
d.
a dinosaur footprint
2. Which of the following is an example of a trace fossil?
a.
a skeleton preserved in a tar pit
b.
a footprint of an extinct animal
c.
a mummy buried in ice
d.
an insect preserved in amber
3. In order to form a fossil, an organism must usually ___________ quickly after
it dies.
a.
decompose
b.
go extinct
c.
rot
d.
be buried
4. Although a cast fossil looks like an original bone or shell, how is it different?
a.
it is made of rock
b.
it contains skin, hair, and other remnants
c.
it has been liquefied
d.
it is completely colorless
5. A mold is most similar to
a.
an eggshell with no egg inside
b.
a replica of your teeth made at the dentist office
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c.
d.
a bone your dog buries in the back yard
an insect trapped in tree sap
6. What can you infer from the fact that fossil-fuels are made from carbon?
a.
over time, flesh turns into carbon
b.
most life on earth is made from carbon
c.
trees are made from carbon, but animals are not
d.
swampy environments are carbon-poor environments
7. What two forces can turn carbon into fossil fuels?
a.
lift and thrust
b.
wind and rain
c.
temperature and pressure
d.
motion and time
8. A fossil is pictured below:
The feet and legs in this fossil where most likely used for
a.
running
b.
swimming
c.
climbing trees
d.
grasping prey
9. In your own words, what are fossils? How can they tell you information about the
past? _________________________________________________________
______________________________________________________________
______________________________________________________________
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Part II: Thursday, September 15th, 2011
Do Now: Read “Journal of a Fossil Hunter”
Summarize in your own words:
1.)
What do fossils show us? ___________________________________
______________________________________________________________
2.)
What is a fossil? __________________________________________
______________________________________________________________
3.)
What is the difference between a mold fossil and a cast fossil? _______
______________________________________________________________
4.)
What does the fossil record tell us about ammonites? ______________
______________________________________________________________
Whole Class Investigations:
Becoming a Fossil
a. How do scientists think that Lucy may have died? _______________________
b. What made her bones turn to stone? ________________________________
c. What natural events made it possible for her fossilized bones to be discovered?
_________________________________________________________
How a Dinosaur became a Fossil?
How does the fossilization of the dinosaur differ from a footprint?
______________________________________________________________
Which one is similar to the type of fossil created by Lucy? _________________
Which one is similar to the fossil model that you made on Tuesday? ___________
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Part III: Friday, September 16th, 2011
Do Now: Read and Answer the Questions
What is a living fossil? What is one example of a living fossil? _______________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
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A piece of petrified wood is an example of what type of fossil? Explain. ________
______________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
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Who is Lucy? Why was her discovery important? _________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
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What is a paleontologist? Would you consider being a paleontologist? Why or Why
not?
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
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Whole Class Investigations:
Fossil Flash (guiding questions)
a. Is this a plant or an animal fossil?
b. What do you think this plant or animal looked like when it was alive?
The Grand Canyon: Evidence of the Earth’s past
What evidence suggests that the Grand Canyon was once covered by an ocean?
Homework #8 (on loose college-ruled paper) [4 points]
Due Monday, September 19th, 2011
Directions— Chose one scenario below and sketch it. (1 point)
a. a worm living in a rainforest
b. a polar bear running across a snowfield in the Arctic
c. a fish swimming in a lake
d. a snail living in a rainforest
e. a snake crawling through a desert
f. a tree growing in a swamp
g. a deer living in a forest
Answer the following questions in complete sentences. (3 points)
1. Based on its characteristics and the environment in which it lives, do you
think the organism has the potential to fossilize? Why or why not?
2. If so, which of the organism's characteristics do you think will be visible in
the fossil?
3. If not, what do you think would need to be different about the organism's
environment to make it more likely to fossilize?
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Wonder Wall Questions and Answers about Fossils

Why are fossils so important? Have we learned anything from them?
Fossils are a great indicator of what existed in Earth’s past. From dinosaurs to cavemen,
paleontologists—scientists who study geology and fossils—can tell a whole lot about evolution,
extinction, and Earth’s existence. We’ve learned about scores of extinct organisms, and what the
climate was like during different points in Earth’s history. We can even use fossils to deduce how all
the continents were once connected! When things are preserved, they hold a key to the past.

What are fossils?
Fossils are remnants of organisms. They are usually thousands of years old. These remains can come
in many forms: bones, footprints, shells, feces, fur, teeth, eggs, and even impressions of leaves. A
fossil can even be the flesh of an organism, if the organism's flesh was somehow preserved.
Fossils give us important evidence about the past, helping us learn more about Earth’s history. The
easiest place to see a fossil is in a museum, but in the natural world fossils are usually found in
layers of sedimentary rock. The oldest fossils known to man are about 3.5 billion years old.
Paleontologists study fossils to better understand prehistoric life.
Most people think of dinosaur bones when they think of fossils; however, dinosaurs make up only a
small part of the fossils found on the earth.

How can you tell how old a fossil is?
In order for scientists to get a better idea of how old a fossil is, they use a method called
radiometric dating. Radiometric dating uses unstable or radioactive atoms to measure how old
something is. Radioactive elements decay into stable elements at specific rates. Each radioactive
element has something called a half-life. The half-life of an element is the amount of time it takes
for half of its atoms to decay into a stable element. For instance, carbon-14, an isotope of carbon,
is radioactive. After 5,700 years (carbon-14’s half-life), an item would only have half as much
carbon-14 as it originally did. By measuring the amount of carbon-14 left in the item, we can
estimate its age.

Can fossils exist in water?
Absolutely! In fact, the majority of fossils are found (or at least formed) underwater. Since marine
organisms evolved before land organisms, more fossils probably formed in the ocean then formed on
land. Through water fossils, we can see the evolution of aquatic creatures into land creatures.
Fossils are normally found in sedimentary rock, which is found on the ocean floor. When we find
ocean fossils on land, it is a good indicator that there was water in that area at some point in
Earth’s history. The ocean is teeming with fossilized fish.
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
What are cast fossils and mold fossils?
A mold fossil is a fossilized impression made in the material, called substrate. Mold fossils create a
negative impression of an organism. A cast fossil is the molded impression created from the mold
fossil. Petrification is when something that was living turns to stone, or becomes fossilized, over
thousands and thousands of years. A good example of this would be petrified wood that has turned
to stone and no longer maintains any properties of wood.

What are trace fossils?
A trace fossil is a type of fossil left by the movements and activities of animals. They may be
fossilized footprints, nests, or dung. Trace fossils include remnants of burrows in which animals
once lived, and trails on which they once walked, crawled, or slithered.

Are petrified forests scary?
Definitely not! In this case, the word “petrified” means “turned into stone.” Petrified wood is just
fossilized wood. The woody parts are replaced with minerals through a lengthy process that takes
place underground. Many places on Earth contain large collections of petrified wood. These places
are called petrified forests. Petrified Forrest National Park is in Arizona, and there are large
petrified redwood trees in California. Petrified wood is as hard as quartz and is the state gem of
Washington!

What evidence is there for continental drift?
Fossils of the same plant species from the Paleozoic era have been found across many continents.
Since these plants weren’t able to travel across oceans, they probably spread everywhere because
the continents were once connected together. Fossils of tropical plants were found in Antarctica, so
it probably was formally located by the equator. Large belts of rock on the eastern coast of South
America match up with belts of rock on the western coast of Africa. Evidence also suggests that
glaciers moved from Africa to South America, which would not have been likely to happen if there
was an ocean in between the continents.

What are trilobites?
A trilobite is an extinct marine animal from the class called "Trilobita." These unusual arthropods
lived during the Paleozoic Era. Their flattened, oval-shaped bodies ranged in lengths between 2.5
cm (1 in.) and 61 cm (2 ft.). Many people have seen fossils of these creatures. In fact, the fossils
can be found all over the world. Did you know that the name "trilobite" comes from the Greek word
"trilobos" meaning three-lobed.

Where does amber come from?
Amber is the fossilized resin or sap from trees. Most of the amber in the world is between 30
million and 90 million years old! While amber is not a mineral, it is often considered a gemstone and
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is commonly found in different types of jewelry. Amber is soft and lightweight, making it easy to
cut and polish into many different shapes. People cut it with special gem cutting tools.

How do we know that fossils were once living species rather than just patterns in rock?
People believe fossils to be the remains of once living species for many reasons. One of them is that
the chances of a piece of rock coincidentally looking exactly like a complex animal, and it not having
anything to do with that animal, are really slim. It would be hard to imagine finding a whole dinosaur
skeleton and believing that it was simply a coincidence that it looked like the remains of an animal.
Another reason is that scientists often find biological traces of the animal within the fossil.

Can you tell me about the Bone Wars?
During the late 19th century, two paleontologists named Othniel Marsh and Edward Cope hunted
fossils in the American West. From the 1870s to the 1890s, the two men competed in what became
known as “The Bone Wars,” a quest to find the most and most impressive dinosaurs fossils. During
the 1870s, excavation for the construction of the Transcontinental Railroad resulted in the
discovery of numerous fossils. Cope and Marsh spied on each other, bribed people who found fossils
to keep them exclusive, deliberately destroyed fossils to keep the other person from getting them,
and even fought out in the field.

What does math have to do with fossils?
In order to figure out how old a fossil is, people must use science and math! Math can also be used
to measure fossils and to count different features or appendages of the fossils. Math is also
helpful when trying to understand the timeline of evolution—in particular, when organisms lived in
relation to other organisms.

What is a living fossil?
A living fossil is an organism whose closest evolutionary relatives are all extinct. Most living fossils
evolved hundreds of millions of years ago, and have changed very little over the years. For example,
the horseshoe crab is believed to have first appeared around 445 million years ago. It is not closely
related to any other living species. However, it is very similar to an animal called the trilobite, which
has been extinct for 250 million years.