L E S S O N 7 - F O S S I L S

EARTH UNIT

OBJECTIVE

• Students will be able to define what a fossil is and describe how they are formed

VOCABULARY

• fossil – traces of plants/or animals trapped in the layers of sedimentary rock

• imprint – a mark made by applying pressure

• paleontologist – a scientist who studies fossil animals/plants that lived a long time ago

• excavation – the place where paleontologists dig for fossils

• extinct – when a type of animal or plant that was alive once is no longer on earth

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Fossilsand theStoriesThey Tell

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TABLE OF CONTENTS

Introduction……………………………………………3

Is It a Fossil? Yes or No?…………………………..8

How Do Fossils Form?…………………………….12

What Stories Do Fossils Tell?……………………22

Introduction 6

Tyrannosaurus rex

Once there were dinosaurs. They roamed the earth for 140 million years. But about 60 million years ago, the last of the giant dinosaurs died out long before there were people to see them, tell about them, or draw their pictures.

Introduction 7

Giant ground sloth

Once there were giant ground sloths as big as the elephants that live today. But about 25 thousand years ago, like the dinosaurs, they all died out before any people saw them. 

How do we know about animals from long ago that no longer live on earth?

Introduction 8

Tyrannosaurus rex skull

We know about dinosaurs and giant ground sloths because we have found their fossil bones.

Fossils form a diary telling the story of the earth’s past.

But that diary can’t be read by people who don’t know about fossils.

Introduction 9

Giant ground sloth skeleton

Today you’ll learn just what is and is not a fossil.

You’ll also learn about four ways fossils can be made, and finally, you’ll learn some of the stories fossils tell about what the earth was like long ago.

FOUR TYPES OF FOSSILS

• Trace Fossil - show evidence of activity

• Mold Fossil – they show the impression of the animal or plant

• Cast Fossil – this shows the positive image of the animal/plant sticking out of the rock

• True Form Fossil – the actual plant/ animal is the fossil

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IS IT A FOSSIL? YES OR NO?

DETECTIVE’S GUIDE

Is It a Fossil? Yes or No? 12

After you complete Is It a Fossil? Yes or No?, you will be able to identify an object as a fossil or not a fossil, and give a reason for your choice.

Is It a Fossil? Yes or No? 13

Fossils form a diary telling the story of the earth’s past. But reading and understanding the fossil diary can be tricky because there are many pages missing.

Some were destroyed by changes in the earth. Some have not been found. Still other pages are blank.

These pages were never written on because most living things do not become fossils when they die.

What no pig

fossils?

Is It a Fossil? Yes or No? 14

Because the fossil diary of the earth’s past can be so tricky to read, if you want to understand the story it tells, you’ll need to become a fossil detective. Just as police detectives use clues to figure out what happened at the scene of a crime, fossil detectives use fossil clues to help figure out the story of what happened on earth long ago.

These fossil detectives are called paleontologists. Paleontologists are scientists who look for fossils to try and fill in the missing pages of the fossil diary to better understand the earth’s past.

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When conducting an investigation, what’s the first thing a detective needs to do? Find clues. The trick is, what’s really a clue and what isn’t?

When a police detective studies the scene of a crime, there are many things to look at, but only some of them are really clues that will help solve the crime.

The same is true for fossil detectives. When paleontologists look for fossil clues, they have to be able to tell if what they are looking at really is a fossil or not.

Is It a Fossil? Yes or No? 16

To know if something is a fossil or not, you have to know exactly what a fossil is.

 

What do you think a fossil is?

Is It a Fossil? Yes or No? 17

Fossils are the remains of living things.  

They can be the remains of plants.

Fossil leaf

Is It a Fossil? Yes or No? 18

Or they can be the remains of animals. Animal fossils are usually shells or bones. The shells or bones are usually quite heavy, as they have been “turned into stone”. They are also usually a different color from when they were alive.

Fossil shell Fossil alligator

Is It a Fossil? Yes or No? 19

But do fossils have to be the actual remains of a living thing? The picture below shows the footprints of a snipe-like shore bird that lived among the dinosaurs about 100 million years ago. No bones of this bird are known to exist.

Bird footprints

Do you think this is a fossil? Why or why not?

Is It a Fossil? Yes or No? 20

Fossil dinosaur footprint

Yes, the footprints are fossils. Fossils aren’t just the remains of living things. Fossils can be something that a living thing made.

Is It a Fossil? Yes or No? 21

Fossil dinosaur tracks

Footprints are not parts of a living thing. But they were made by living things.

Because they were made by living things, they are evidence that a living thing was there.

Is It a Fossil? Yes or No? 22

So, fossils are more than just the remains of living things. Fossils are the remains or evidence of living things.

Egyptian mummy

This picture shows an Egyptian mummy.

Is the mummy the remains of a living thing?

Do you think the mummy is a fossil? Why or why not?

Is It a Fossil? Yes or No? 23

No, an Egyptian mummy is not a fossil.

Egyptian mummy

How was the mummy formed? Priests took the dead person’s body and cut out the internal organs, dried out the rest of the body with a chemical called natron, rubbed oils on the body and wrapped it in linen.

In other words, the mummy was made by man. That’s why the mummy isn’t a fossil. Fossils have to form naturally, without any help from man.

Is It a Fossil? Yes or No? 24

Hieroglyphic writing

The Egyptian mummy isn’t a fossil for another reason. It’s not old enough.

Fossils are prehistoric. Prehistoric means that it comes from a time before people could record their history. But Egyptians wrote about their lives using hieroglyphics.

Because the mummy comes from a time when people were recording their history, the mummy is not prehistoric, so it isn’t a fossil. People started writing and recording their history about four to five thousand years ago.

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Cave man skull

What about the bones of a cave man? Cave men drew pictures of animals on the walls of their caves.

Would the bones of a cave man be a fossil?

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Cave paintings

Yes, the bones of a cave man would be a fossil. While the pictures cave men made show animals that lived at the time, the pictures don’t record the history of the cave men. Because people started writing their history about four to five thousand years ago, for something to be a fossil it has to be older than that.

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So, as fossil detectives, we now know exactly what kind of clues we’re looking for as we search for missing pages of the fossil diary.

Fossils are the natural remains or evidence of living things from prehistoric times.

Trilobite

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This picture shows a 40 million year old gnat. The entire body of the gnat has been preserved in a clear stone called amber.

Gnat preserved in amber

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IS IT A FOSSIL? YES OR NO?

Thumbs up if you think it’s a fossil.

Thumbs down if you think it’s not.

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

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IS IT A FOSSIL? YES OR NO?

FOSSIL VIDEO

• What’s a fossil?• Watch the and fill in the activity sheet.

• https://www.youtube.com/watch?v=3rkGu0BItKM

READ

• Read Fossils Tell of Long Ago by Aliki

FOSSIL MAKING(OPTIONAL)

• Use the graphic organizer to make your fossils.