scott foresman science - plain local schools 4 fossil detectives.pdfscott foresman science 4.8 genre...

Scott Foresman Science 4.8

Genre Comprehension Skill Text Features Science Content

Nonfi ction Summarize • Captions

• Labels

• Text Boxes

• Glossary

Rocks and Minerals

ISBN 0-328-13882-7

ì

1. How is a fossil formed?

2. What is Mary Anning famousfor discovering?

3. What led to the feud between Othniel Charles Marsh and Edward Drinker Cope?

4. The people in this book enjoyed the study of fossils. Explain on your own paper why you think someone would want to become a paleontologist. Include details from the book to support your answer.

5. Summarize Write a brief summary of the life and work of Barnum Brown.

What did you learn?Extended VocabularyanatomyCretaceousextinctJurassicpaleontologyprotrudingquarry

Vocabulary

igneous rocklustermetamorphic rockmineral sedimentsedimentary rock

Picture CreditsEvery effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.

Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).

4 Richard T. Nowitz/Corbis; 6 (CR) ©The Natural History Museum, London; 8 (TR) Photo Researchers, Inc.;12 (T, B) Bettmann/Corbis; 14 (TR) ©The Natural History Museum, London.

Scott Foresman/Dorling Kindersley would also like to thank: 9 (BR) Natural History Museum, London/DK Images;15 (TR) Natural History Museum, London/DK Images.

Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-13882-7

Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to anyprohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,mechanical, photocopying, recording, or likewise. For information regarding permission(s), write toPermissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.

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13882_01-04_CVR_FSD.indd Cover213882_01-04_CVR_FSD.indd Cover2 5/11/05 1:22:45 PM5/11/05 1:22:45 PM

by Joyce A. Churchill

13882_05-20_FSD.indd 113882_05-20_FSD.indd 1 5/11/05 1:26:11 PM5/11/05 1:26:11 PM

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You can learn a great deal about Earth, and the plants and animals that live on it, from rocks. Rocks can form both above and below the surface of Earth. They form in many layers. By studying the different layers, scientists can fi gure out Earth’s past and present.

Minerals, which are natural, nonliving crystals, combine to form rocks. Scientists can identify rock-forming minerals through their properties. Color and luster are properties of minerals that relate to the way light refl ects from the surface of rocks. A mineral’s hardness is measured by how easily it can be scratched. The color of the powder that the mineral leaves behind after being scratched is another property called streak.

Three kinds of rock have been found on Earth: igneous, metamorphic, and sedimentary. All three kinds can change from one to another over time. This process is called the rock cycle.

sedimentary rockigneous rock metamorphic rock

What You Already Know


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Igneous rocks form from molten (melted) or partly molten rock deep below Earth’s surface. Rock is melted by the intense heat that causes volcanic eruptions. Dead plant and animal matter combines with bits of rock to form soil, which settles on the bottoms of lakes, rivers, and oceans. This is called sediment. This material can be moved by water, ice, wind, or gravity to form layers. These layers press together and become sedimentary rock. Metamorphic rock can form from any kind of rock as a result of heat and pressure deep below Earth’s surface.

Fossils in sedimentary rock give scientists clues to what lived on Earth hundreds of millions of years ago. Fossils are the bones, teeth, leaves, or any evidence of a living thing from long ago. Scientists must be good detectives to fi nd and fi gure out the clues.

fossil of a dinosaur footprint


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Layers of CluesDo you like to spend hours solving riddles, playing

games, and fi tting together puzzles? Then you might want to become a paleontologist. You would be a scientist who studies fossils to discover what Earth was like long ago. You would be a fossil detective!

Paleontologists search for the answers to many questions. What creatures lived on Earth? What did they eat? Were these creatures mammals? Were they reptiles? Were they birds? Why did they disappear? The list of questions goes on and on.

Over the past 200 years, fossil detectives have answered some of these questions. Giant birds and reptiles that we now call dinosaurs lived from 65 million to over 200 million years ago. Scientists know that these strange creatures lived on each of Earth’s continents.

A paleontologist searches for fossils.


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Scientists have developed a geologic time scale to study fossils in the layers and layers of sedimentary rock. They agree that dinosaurs fi rst appeared, lived, and then disappeared during the Mesozoic era on their scale. This is the middle period in the history of Earth.

Using pieces of skeletons and other fossils as clues, scientists have fi gured out what some dinosaurs looked like and how they lived. But before they can fi gure all that out, they fi rst have to fi nd the pieces and put them together!

fossilized fi sh

How a Fossil Is Formed

After millions of years of erosion and weathering, the bones appear at the surface. They poke through the soil, where they are discovered.

The hard parts of the animal, such as the bones, are preserved in the layers. Eggs, skin, and even footprints of dinosaurs harden as they slowly become fossils.

Fossils are the remains of plants and animals that once lived. When a dinosaur died, its body was slowly covered by layers of sedimentary rock.


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You might not think of a young, uneducated girl as being an important dinosaur fossil collector, but Mary Anning was one. Anning, born in 1799, and her brother collected fossils with their father. After his death, they continued scouring the cliffs near their home in Lyme Regis in southern England. They sold the fossils they found to help support the family.

Paleontology Pioneers

Mary Anning

Before the 1800s, a few large fossil bones were found sticking out of the ground. No one knew what they were from. Once scientists identifi ed the fossils as the remains of dinosaurs, they became fascinated with these mysterious creatures.

Anning and her brother looking for fossils

Mary Anning


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Plesiosaurus fossil

When she was twelve years old, Anning uncovered the skeleton of a marine reptile in a cliff. She chipped away the rock to reveal four fl ippers and a long jaw with sharp teeth. This was the fi rst Ichthyosaurus ever found, and it was more than thirty-two feet long. This was just one of Anning’s many discoveries.

The leading scientists of the time did not want to give Anning credit for her fi ndings. Finally, after Anning’s many years of hard work, they recognized the importance of her discoveries.

Tools for Fossil HuntingUncovering a skeleton embedded in rock takes time and patience. The hammer and chisel remove fossils from a rock. The pick chips away dirt from a bone. The brush dusts away any remaining dirt.

chisel

hammer

brush

pick


Gideon Mantell was a doctor, but he loved hunting for fossils. As a young boy he hunted for them in the quarries near his home in Lewes, Sussex, England.

In 1822, he and his wife were exploring Tilgate Forest, a quarry near their home. They stumbled across a large, fossilized tooth.

This was unlike anything the doctor had seen before, so he took it to several leading paleontologists to fi nd out what it was. One scientist told him that it was a tooth from a rhinoceros. Mantell didn’t believe him. Finally, in 1825, the tooth Mantell found was linked to the Iguanodon, a large, plant-eating dinosaur.

Gideon Mantell

Gideon Mantell

fossilized Iguanodon tooth

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Mantell lecturing on his discoveries


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Othniel Charles Marsh was a respected vertebrate paleontologist in the 1800s. Marsh was an “armchair paleontologist,” who collected fossils as a hobby. He didn’t like to go into the fi eld to collect the fossils. Marsh preferred to quietly sort and catalog

fossils at the Peabody Museum at Yale University, where he worked.

His friend Edward Drinker Cope, a younger paleontologist, had proudly assembled the skeleton of the Elasmosaurus, a giant dinosaur. So Marsh went to look at the skeleton. He quickly pointed out to Cope where the body parts were mixed up. This started a bitter feud between the two men that lasted more than twenty years.

Othniel Charles Marsh

Keeping accurate records of where bones are found is important. Paleontologists can match the location of fossils in sedimentary rock with the times that animals lived on the Earth.

Marsh discussing his fossil fi nds

Othniel Charles Marsh

Keeping Records


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Edward Drinker Cope was a hard-working paleontologist who looked for dinosaur remains. He explored in the western United States between 1870 and 1890.

Some of the biggest dinosaur graveyards are in the western United States. The bones of giant animals such as the Diplodocus, Stegosaurus, and Triceratops have been found there.

In the science of paleontology, if you fi nd a new dinosaur species, you have the honor of naming it. After Othniel Charles Marsh insulted Cope, they became enemies. They competed in the West to fi nd, document, and name new species. This was called the Bone War.

Edward Drinker Cope

Edward Drinker Cope

Cope used dynamite to blast his way through to hidden bones.


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The huge Brachiosaurus, or “arm lizard,” was a giant land animal from the late Jurassic period. Werner Janensch, a German paleontologist, fi rst collected its bones during an expedition to East Africa, in what is now the country of Tanzania, from 1909 to 1913.

Janensch shipped tons of bones back to the Natural History Museum of Berlin. He and other scientists unpacked the bones and assembled them piece by piece into a giant skeleton. Their work was like putting

together a jigsaw puzzle that is as tall as a four-story

building!

Werner Janensch

Werner Janensch

Fossils have to be chipped out of rocks with great care. The more carefully preserved the fossil is, the more scientists can learn from it.

Extracting Fossils

Janensch and workers with a Brachiosaurus bone

removing a fossil


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Barnum Brown was named after P. T. Barnum, the nineteenth-century American showman and circus founder. He began picking up the fossils of extinct animals as a boy in Kansas. He collected fossils for more than sixty-six years as a paleontologist.

Brown loved working in the fi eld collecting fossils. He searched for dinosaur remains in the United States, Canada, South America, India, and Ethiopia.

Brown discovered the skeletal remains of Tyrannosaurus rex. The T rex was displayed in the American Museum of Natural History in New York City, where Brown was the curator for many years.

Barnum Brown

Barnum Brown

Barnum Brown supervised the assembly of many dinosaur skeletons.


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Brown discovered his fi rst T rex in 1902. He then discovered an even better skeleton in 1908. He assembled both in the Museum of Natural History. Years later, the fi rst skeleton Brown discovered was moved to the Carnegie Museum in Pittsburgh, Pennsylvania.

The fossils revealed that the T rex had a huge jaw that helped it devour nearly any food it wanted. It was between fi fteen and twenty feet tall and almost forty feet long. It weighed between fi ve and seven tons.

Barnum Brown also discovered the duck-billed Corythosaurus from the Cretaceous period. He found its skeleton in the Red Deer River in Alberta, Canada.

Putting together the skeleton of a giant, extinct reptile such as the Allosaurus is a challenging job. You must know anatomy and the bone structure of similar animals in order to put each part in the right place.

Reconstructing Fossils

Tyrannosaurus rex

reconstructing an Allosaurus skeleton


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John R. Horner had trouble in school as a boy because of a learning disability. Yet he has collected and cataloged fossils since he was seven years old.

In 1978, he found the fi rst nest of baby dinosaurs in Montana. He named this new dinosaur the Maiasaura. The babies were about the size of a crow.

The next year he found the remains of a herd of more than ten thousand Maiasaurs. He also has found eggs and more nesting grounds. Horner’s discoveries show that some dinosaurs were cared for by their parents, instead of having to fend for themselves as soon as they hatched.

John R. Horner

model of a Maiasaura nest

John R. Horner


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Horner explains that hunting for dinosaur fossils is not a simple or exact science. It is not just collecting and organizing fossil bones. You have to look carefully at the clues you collect. Then you need to consider many possibilities about how these animals lived.

Men and women have been hunting and collecting dinosaur fossils for more than 200 years. Yet they still don’t know the complete history of dinosaurs. They know that these giants once lived on each of the Earth’s continents. They know what some of them looked like and how they lived. But they don’t know exactly why they suddenly became extinct.

Some scientists say we have only found and collected a small number of the fossilized remains of dinosaurs. We don’t know the full story yet. We have to keep digging. There is still much work for fossil detectives to do.

The Archaeopteryx was both a bird and a reptile.


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Glossaryanatomy the science of the parts of living things

Cretaceous a period of time at the end of the Mesozoic era that ended 66.4 million years ago

extinct no longer existing

Jurassic a period of time in the middle of the Mesozoic era when dinosaurs lived

paleontology the science of studying fossils

protruding sticking out from its surroundings

quarry a place where stone is dug, cut, or blasted out


1. How is a fossil formed?

2. What is Mary Anning famousfor discovering?

3. What led to the feud between Othniel Charles Marsh and Edward Drinker Cope?

4. The people in this book enjoyed the study of fossils. Explain on your own paper why you think someone would want to become a paleontologist. Include details from the book to support your answer.

5. Summarize Write a brief summary of the life and work of Barnum Brown.

What did you learn?Extended VocabularyanatomyCretaceousextinctJurassicpaleontologyprotrudingquarry

Vocabulary

igneous rocklustermetamorphic rockmineral sedimentsedimentary rock

Picture CreditsEvery effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.

Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).

4 Richard T. Nowitz/Corbis; 6 (CR) ©The Natural History Museum, London; 8 (TR) Photo Researchers, Inc.;12 (T, B) Bettmann/Corbis; 14 (TR) ©The Natural History Museum, London.

Scott Foresman/Dorling Kindersley would also like to thank: 9 (BR) Natural History Museum, London/DK Images;15 (TR) Natural History Museum, London/DK Images.

Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-13882-7

Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to anyprohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,mechanical, photocopying, recording, or likewise. For information regarding permission(s), write toPermissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.

3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05

13882_01-04_CVR_FSD.indd Cover213882_01-04_CVR_FSD.indd Cover2 5/11/05 1:22:45 PM5/11/05 1:22:45 PM

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