The Rock and Fossil Record

The Rock and Fossil Record
Chapter 6 The Rock and Fossil Record

Chapter 6 Table of Contents
The Rock and Fossil Record Table of Contents Section 1 Earth’s Story and Those Who First Listened Section 2 Relative Dating: Which Came First? Section 3 Absolute Dating: A Measure of Time Section 4 Looking at Fossils Section 5 Time Marches On

Chapter 6 Section 1 Earth’s Story and Those Who First Listened Bellringer “The Present Is the Key to the Past.” This phrase was the cornerstone of the uniformitarianist theory developed by geologist James Hutton in the late 1700s. Write a few sentences in your science journal about how studying the present could reveal the story of Earth’s history. Use sketches to illustrate processes that occurred millions of years ago that you can still see today.

Chapter 6 Section 1 Earth’s Story and Those Who First Listened Review 11/8/11 A scientists who studies fossils is a __________. The rocks at the bottom are ________ than the rocks on top. What is the difference between catastrophism and uniformitarianism? What are two things we can learn from fossils? Identify whether or not the following would be uniformitarianism or catastrophism: A flood Weathering Erosion A sunami Deposition

Chapter 6 Objectives Compare uniformitarianism and catastrophism.
Section 1 Earth’s Story and Those Who First Listened Objectives Compare uniformitarianism and catastrophism. Describe how the science of geology has changed over the past 200 years. Explain the role of paleontology in the study of Earth’s history.

Chapter 6 Vocab Catastrophism: Ka – Tas – Tro – Fizz – Um
Section 1 Earth’s Story and Those Who First Listened Vocab Catastrophism: Ka – Tas – Tro – Fizz – Um Uniformitarianism: You – Ni – For – Mit – Arian - Ism Paleontology: Pay – Lee – Un – Tall – O - G

The Principle of Catastrophism
Chapter 6 Section 1 Earth’s Story and Those Who First Listened The Principle of Catastrophism The earth has not always looked the way it does today. Our planet is changing all the time.

The Principle of Catastrophism
Chapter 6 Section 1 Earth’s Story and Those Who First Listened The Principle of Catastrophism Catastrophism- An idea that the earth changes due to sudden catastrophic events such as a flood or earthquake. Until about 200 years ago this is how people believed changes in the Earth took place.

The Principle of Uniformitarianism
Chapter 6 Section 1 Earth’s Story and Those Who First Listened The Principle of Uniformitarianism James Hutton A scientist who made observations of the geologic forces he saw here on Earth. He believed these forces had been occurring since the formation of the Earth. Uniformitarianism- An idea that the same geologic processes shaping the Earth today have been at work throughout Earth’s history. Small changes occurring over long periods of time.

Chapter 6 Section 1 Earth’s Story and Those Who First Listened

Chapter 6 The Principle of Uniformitarianism, continued
Section 1 Earth’s Story and Those Who First Listened The Principle of Uniformitarianism, continued Uniformitarianism Versus Catastrophism What is difference between the two theories? Why such controversy? People believed that the Earth was only a few thousand years old. Hutton’s theories of uniformitarianism suggested that the earth was much older than a few thousand years.

Modern Geology -- A Happy Medium
Chapter 6 Section 1 Earth’s Story and Those Who First Listened Modern Geology -- A Happy Medium What we believe today Scientists gradually came to see that both theories were correct The Earth is changed by both sudden catastrophic events (catastrophism) and small gradual changes (uniformitarianism). Most change occurs by uniformitarianism

Uniformitarianism and Catastrophism
Chapter 6 Section 1 Earth’s Story and Those Who First Listened Uniformitarianism and Catastrophism Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

Paleontology -- The Study of Past Life
Chapter 6 Section 1 Earth’s Story and Those Who First Listened Paleontology -- The Study of Past Life In order to learn about Earth’s past we must study the organisms that lived in the past. The study of fossils and ancient life is called paleontology. paleo – old onto – life ology – the study of Paleontologists study fossils, which are the preserved remains of once living organisms.

Chapter 6 What fossils tell us…
Section 1 Earth’s Story and Those Who First Listened What fossils tell us… Fossils provide us with evidence that life on Earth has changed. Different organisms have appeared and disappeared throughout history Ex. Dinosaurs They also provide evidence for how the Earth has changed over time. Ex. – There are fossils of sea life found in deserts and on the tops of mountains. What would that tell us about how the structure of our Earth has changed?

Chapter 6 Journal 11/14/12 Email me your relative dating worksheets.
Section 1 Earth’s Story and Those Who First Listened Journal 11/14/12 me your relative dating worksheets. The sedimentary rocks are found on the _______ are the youngest and the rocks found on the bottom are the ______. What is the name of the principle stated in question #1? What 4 things can happen to disturb or shift rock layers and make it difficult to date them?

Chapter 6 Section 2 Relative Dating: Which Came First? Bellringer Arrange the following sentences in a logical order to make a short story: I stood in the checkout line. I selected two apples. I walked home from the store. I gave the cashier money. I went to the store. The cashier gave me change. I was hungry. Write your story in your science journal.

Chapter 6 Objectives Explain how relative dating is used in geology.
Section 2 Relative Dating: Which Came First? Objectives Explain how relative dating is used in geology. Explain the principle of superposition. Describe how the geologic column is used in relative dating. Identify two events and two features that disrupt rock layers. Explain how physical features are used to determine relative ages.

The Principle of Superposition
Chapter 6 Section 2 Relative Dating: Which Came First? The Principle of Superposition Geologists try to determine the order in which events occurred during Earth’s history. They rely on rocks and fossils to help them in their investigation. The process of determining whether an event or object is older or younger than other events or objects is called relative dating. Joe has two older sisters, and one younger brother.

The Principle of Superposition, continued
Chapter 6 Section 2 Relative Dating: Which Came First? The Principle of Superposition, continued Layers of sedimentary rock, such as the ones shown below, are stacked like pancakes.

Chapter 6 Section 2 Relative Dating: Which Came First? The Principle of Superposition, continued What are some of the ways we listen to music?

Chapter 6 Section 2 Relative Dating: Which Came First? The Principle of Superposition, continued In a landfill where will we each type of music?

Chapter 6 Section 2 Relative Dating: Which Came First? The Principle of Superposition, continued Superposition is a principle that states that younger rocks lie above older rocks, if the layers have not been disturbed. Top – Younger Bottom - Older

Chapter 6 Disturbing Forces
Section 2 Relative Dating: Which Came First? Disturbing Forces You can use superposition to determine the relative age of rocks as long as the rock layers have not been changed. Some rock sequences have been changed by forces within the Earth. These forces can push other rocks up into another layer, tilt or fold rock layers, and break sequences into moveable parts.

Chapter 6 The Geologic Column
Section 2 Relative Dating: Which Came First? The Geologic Column The geologic column is an ideal sequence of rock layers that contains all the known fossils and rock formations on Earth, arranged from oldest to youngest. Geologists use the geologic column to interpret rock sequences and to identify the layers in puzzling rock sequences.

Chapter 6 Geologic Column Click below to watch the Visual Concept.
Section 2 Relative Dating: Which Came First? Geologic Column Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

Chapter 6 Disturbed Rock Layers
Section 2 Relative Dating: Which Came First? Disturbed Rock Layers Geologists often find features that cut across existing layers of rock. Geologists use the relationships between rock layers and the features that cross them to assign relative ages to the features and the layers. The features must be younger than the rock layers because the rock layers had to be present before the features could cut across them.

Disturbed Rock Layers, continued
Chapter 6 Section 2 Relative Dating: Which Came First? Disturbed Rock Layers, continued Events That Disturb Rock Layers Geologists assume that the way sediment is deposited to form rock layers — in horizontal layers — has not changed over time. If rock layers are not horizontal, something must have disturbed them after they formed. The next slide describes four ways that rock layers may become disturbed.

Chapter 6 Section 2 Relative Dating: Which Came First? Disturbed Rock Layers, continued A fault is a break in the Earth’s crust along which blocks of the crust slide relative to one another.

Chapter 6 Section 2 Relative Dating: Which Came First? Disturbed Rock Layers, continued An intrusion is molten rock from the Earth’s interior that squeezes into existing rock and cools.

Chapter 6 Section 2 Relative Dating: Which Came First? Disturbed Rock Layers, continued Folding occurs when rock layers bend and buckle from Earth’s internal forces.

Chapter 6 Section 2 Relative Dating: Which Came First? Disturbed Rock Layers, continued Tilting occurs when internal forces in the Earth slant rock layers.

Things to know for the quiz tomorrow.
Chapter 6 Section 1 Earth’s Story and Those Who First Listened Things to know for the quiz tomorrow. Uniformitarianism vs catastrophism. Paleo = Onto = Ology = What do fossils tell us about the Earth? What is superposition? What is relative dating? What is a fault? What is an intrusion? What is folding? What is tilting? What is an unconformity and what are the three types of unconformitites?

Gaps in the Record -- Unconformities
Chapter 6 Section 2 Relative Dating: Which Came First? Gaps in the Record -- Unconformities Missing Evidence Sometimes, layers of rock are missing, creating a gap in the geologic record. Missing rock layers create breaks in rock-layer sequences called unconformities. An unconformity is a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time.

Chapter 6 Unconformities Click below to watch the Visual Concept.
Section 2 Relative Dating: Which Came First? Unconformities Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

Types of Unconformities
Chapter 6 Section 2 Relative Dating: Which Came First? Types of Unconformities Most unconformities form by both erosion and nondeposition, but other factors may be involved. Three major categories: Disconformities Nonconformities Angular unconformities

Types of Unconformities, continued
Chapter 6 Section 2 Relative Dating: Which Came First? Types of Unconformities, continued Disconformities exist where part of a sequence of parallel rock layers is missing.

Chapter 6 Section 2 Relative Dating: Which Came First? Types of Unconformities, continued Nonconformities exist where sedimentary rock layers lie on top of an eroded surface of nonlayered igneous or metamorphic rock.

Chapter 6 Section 2 Relative Dating: Which Came First? Types of Unconformities, continued Angular Unconformities exist between horizontal rock layers and rock layers that are tilted or folded.

Chapter 6 Rock-Layer Puzzles
Section 2 Relative Dating: Which Came First? Rock-Layer Puzzles Rock-layer sequences often have been affected by more than one geological event or feature. For example, intrusions may squeeze into rock layers that contain an unconformity, as shown at right.

Rock-Layer Puzzles, continued
Chapter 6 Section 2 Relative Dating: Which Came First? Rock-Layer Puzzles, continued Determining the order of events in a rock sequence is like solving a jigsaw puzzle. Geologists must use their knowledge of the events that disturb rock-layer sequences to piece together the history of the Earth.

Rock-Layer Puzzles, continued
Chapter 6 Section 2 Relative Dating: Which Came First? Rock-Layer Puzzles, continued

Chapter 6 Review What is relative dating?
Section 2 Relative Dating: Which Came First? Review What is relative dating? What is the principle of superposition? What is the geologic column and what is it used for? Name and describe the four ways rock layers can be disturbed by forces within the Earth. What is an unconformity and what are the three main types of unconformities?

Chapter 6 Section 2 Relative Dating: Which Came First? Journal – 11/19/12

Chapter 6 Section 3 Absolute Dating: A Measure of Time Bellringer Do the following statements describe relative or absolute age? 1. She is my younger sister. 2. He is 12 years old. Why do geologists use both absolute and relative dating to interpret the past? Why are both absolute and relative dates valid dates for geologists, and other earth scientists to use? Write a paragraph in your science journal.

Chapter 6 Objectives Describe how radioactive decay occurs.
Section 3 Absolute Dating: A Measure of Time Objectives Describe how radioactive decay occurs. Explain how radioactive decay relates to radiometric dating. Identify four types of radiometric dating. Determine the best type of radiometric dating to use to date an object.

Chapter 6 Radioactive Decay
Section 3 Absolute Dating: A Measure of Time Radioactive Decay Absolute dating is any method of measuring the age of an event or object in years. To determine the absolute ages of fossils and rocks, scientists analyze isotopes of radioactive elements. Atoms of the same element that have the same number of protons but different numbers of neutrons are called isotopes.

Chapter 6 Radioactive Decay Isotopes
Section 3 Absolute Dating: A Measure of Time Radioactive Decay Isotopes

Radioactive Decay, continued
Chapter 6 Section 3 Absolute Dating: A Measure of Time Radioactive Decay, continued Most isotopes are stable, meaning that they stay in their original form. Some isotopes are unstable, meaning they want to break apart and change into something new. Scientists call unstable isotopes radioactive.

Chapter 6 Section 3 Absolute Dating: A Measure of Time Radioactive Decay, continued Radioactive isotopes tend to break down into stable isotopes of the same or other elements in a process called radioactive decay.

Chapter 6 Section 3 Absolute Dating: A Measure of Time Radioactive Decay, continued Dating Rocks — How Does It Work? The unstable radioactive isotope is called the parent isotope. The stable isotope produced by the radioactive decay of the parent isotope is called the daughter isotope. The rate of radioactive decay is constant, so scientists can compare the amount of parent material with the amount of daughter material to date rock.

Chapter 6 Radiometric Dating
Section 3 Absolute Dating: A Measure of Time Radiometric Dating Determining the absolute age of a sample, based on the ratio of parent material to daughter material is called radiometric dating. If you know the rate of decay for a radioactive element in a rock, you can figure out the absolute age of the rock.

Radiometric Dating, continued
Chapter 6 Section 3 Absolute Dating: A Measure of Time Radiometric Dating, continued A half-life is the time needed for half of a sample of a radioactive substance to undergo radioactive decay. After every half-life, the amount of parent material decreases by one-half.

Types of Radiometric Dating
Chapter 6 Section 3 Absolute Dating: A Measure of Time Types of Radiometric Dating Scientists use different radiometric-dating methods depending on the estimated age of a rock. There are four radiometric-dating techniques. Potassium-Argon Method Half-life of 1.3 billion years. Used to date rocks older than 100,000 years. Uranium-Lead Method Half-life of 4.5 billion years. Used to date rocks older than 10 million years

Types of Radiometric Dating, continued
Chapter 6 Section 3 Absolute Dating: A Measure of Time Types of Radiometric Dating, continued Rubidium-Strontium Method Half-life of 49 billion years. Used to date rocks older than 10 million years. Carbon-14 Method Half-life of 5,730 years. Used to date things that lived within the past ,000 years.

Chapter 6 Radiometric Dating Click below to watch the Visual Concept.
Section 3 Absolute Dating: A Measure of Time Radiometric Dating Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

Chapter 6 Review What is absolute dating? What are isotopes?
Section 3 Absolute Dating: A Measure of Time Review What is absolute dating? What are isotopes? What is radioactive decay? The rate of decay is always ____________. What is a half life? What are the 4 methods of radiometric dating?

Chapter 6 Section 3 Absolute Dating: A Measure of Time Journal: 11/20/12 What is radioactive decay and how does it help us determine the absolute age of a rock?

Chapter 6 Section 3 Absolute Dating: A Measure of Time Journal: 11/20/12

Chapter 6 Section 4 Looking at Fossils Bellringer Describe the fossil record of your own life that might be found 65 million years from now. What items, or artifacts, might be likely to survive? What kinds of things would decay and disappear? Do you think your fossil record would produce an accurate picture of your life? What might be missing? Write your description in your science journal.

Chapter 6 Section 4 Looking at Fossils Objectives Describe five ways that different types of fossils form. List three types of fossils that are not part of organisms. Explain how fossils can be used to determine the history of changes in environments and organisms. Explain how index fossils can be used to date rock layers.

Chapter 6 Fossilized Organisms
Section 4 Looking at Fossils Fossilized Organisms The trace or remains of an organism that lived long ago is called a fossil. Fossils are most often preserved in sedimentary rock, but other materials can also preserve evidence of past life.

Fossilized Organisms, continued
Chapter 6 Section 4 Looking at Fossils Fossilized Organisms, continued Fossils in Rocks When an organism dies, it either begins to decay or is consumed by other organisms. Sometimes dead organisms are quickly buried by sediment, which slows down decay. Shells and bones are more resistant to decay, so when sediments become rock, the harder structures are more commonly preserved.

Chapter 6 Section 4 Looking at Fossils Fossilized Organisms, continued Fossils in Amber Organisms occasionally become trapped in soft, sticky tree sap, which hardens and becomes amber. Insect fossils have often been preserved in this way, but frogs and lizards have also been found in amber.

Chapter 6 Section 4 Looking at Fossils Fossilized Organisms, continued Petrifaction Petrification is a process in which minerals replace and organism’s tissues. One form of petrifaction is called permineralization, a process in which the pore space in an organism’s hard tissue is filled up with mineral. Replacement is a process in which an organism’s tissues are completely replaced by minerals.

Chapter 6 Section 4 Looking at Fossils Fossilized Organisms, continued

Chapter 6 Section 4 Looking at Fossils Fossilized Organisms, continued Fossils in Tar There are places where Tar wells up at the Earth’s surface. These thick, sticky pools can trap and preserve organisms. Frozen Fossils Since cold temperatures slow down decay, many types of fossils have been found preserved in ice.

Chapter 6 Other Types of Fossils Trace Fossils
Section 4 Looking at Fossils Other Types of Fossils Trace Fossils Trace fossils are naturally preserved evidence of animal activity. Preserved animal tracks are an example of a trace fossil. Other types of trace fossils include preserved burrows or shelters that were made by animals, and coprolite, which is preserved animal dung.

Other Types of Fossils, continued
Chapter 6 Section 4 Looking at Fossils Other Types of Fossils, continued Molds and Casts A mold is a mark or cavity made in a sedimentary surface by a shell or other body. A cast is a type of fossil that forms when sediments fill the cavity left by a decomposed organism.

Chapter 6 Section 4 Looking at Fossils Mold and Cast Fossils

Using Fossils to Interpret the Past
Chapter 6 Section 4 Looking at Fossils Using Fossils to Interpret the Past The Information in the Fossil Record The fossil record offers only a rough sketch of the history of life on Earth. The fossil record is incomplete because most organisms never became fossils. Scientists know more information about organisms that had hard body parts and that lived in environments that favored fossilization.

Using Fossils to Interpret the Past, continued
Chapter 6 Section 4 Looking at Fossils Using Fossils to Interpret the Past, continued History of Environmental Changes The fossil record reveals changes in an area’s climate over time. By using the fossils of plants and land animals, scientists can reconstruct past climates. History of Changing Organisms By studying the relationships between fossils, scientists can interpret how life has changed over time.

Using Fossils to Date Rocks
Chapter 6 Section 4 Looking at Fossils Using Fossils to Date Rocks Scientists have learned that particular types of fossils appear only in certain layers of rock. By dating the rock layers above and below these fossils, scientists can determine the time span in which the organisms that formed the fossils lived.

Using Fossils to Date Rocks, continued
Chapter 6 Section 4 Looking at Fossils Using Fossils to Date Rocks, continued If a type of organism existed for only a short period of time, its fossils would show up in a limited range of rock layers. These fossils are called index fossils. Index fossils are fossils that are found in the rock layers of only one geologic age, and can be used to establish the age of the rock layers.

Chapter 6 Section 4 Looking at Fossils Using Fossils to Date Rocks, continued Ammonites An example of an index fossil is the fossil of a genus of ammonites called Tropites. Tropites, a marine mollusk similar to a modern squid, lived between 230 million and 208 million years ago.

Chapter 6 Section 4 Looking at Fossils Using Fossils to Date Rocks, continued Trilobites Fossils of a genus of trilobites called Phacops are another example of an index fossil. Trilobites are extinct and lived approximately 400 million years ago. When scientists find Phacops in a rock, they assume that the rock is approximately 400 million years old.

Chapter 6 Review Name 5 ways fossils form.
Section 4 Looking at Fossils Review Name 5 ways fossils form. What type of organisms form fossils more commonly? What is a trace fossil? What are mold an cast fossils? What does it mean when we say that the fossil record is incomplete. What is an index fossil?

Chapter 6 Section 5 Time Marches On Bellringer Archaeologists and paleontologists believe that modern humans have lived on Earth for 150,000 to 200,000 years. If we imagine the history of Earth to be the length of one calendar year, on which date do you think modern humans arrived? Record your answer in your science journal.

Chapter 6 Section 5 Time Marches On Objectives Explain how geologic time is recorded in rock layers. Identify important dates on the geologic time scale. Explain how changes in climate resulted in the extinction of some species.

Chapter 6 Section 5 Time Marches On Geologic Time The Rock Record and Geologic Time Grand Canyon National Park is one of the best places in North America to see Earth’s history recorded in rock layers. These rock layers represent almost half, or nearly 2 billion years, of Earth’s history.

The Geologic Time Scale
Chapter 6 Section 5 Time Marches On The Geologic Time Scale The geologic column represents the 4.6 billion years that have passed since the first rocks formed on the Earth. To aid in their study, geologists have created the geologic time scale. The geologic time scale is the standard method used to divide the Earth’s long natural history into manageable parts.

Chapter 6 Section 5 Time Marches On

The Geologic Time Scale, continued
Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued Divisions of Time Geologists have divided the Earth’s history into sections of time. An eon is the largest division of geologic time. The four eons are the Hadean eon, the Archean eon, the Proterozoic eon, and the Phanerozoic eon.

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued Eons are divided into eras. For example, the Phanerozoic Eon is divided into three eras. Periods are the third-largest divisions of geologic time and are the units into which eras are divided. Periods are divided into epochs, the fourth-largest division of geologic time.

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued The Appearance and Disappearance of Species At certain times during Earth’s history, the number of species has increased or decreased dramatically. An increase or decrease in the number of species often comes as a result of a relatively sudden increase or decrease in competition among species.

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued The number of species decreases dramatically over a relatively short period of time during a mass extinction event. Extinction is the death of every member of a species. Events such as global climate change can cause mass extinctions.

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued The Paleozoic Era — Old Life 542 million to 251 million years ago First era with well represented by fossils. The beginning Marine life flourished at the beginning of the era. There were few land organisms. The middle Modern land plants appeared

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued The End Amphibians and reptiles lived on the land, and insects were abundant. The era came to an end with the largest mass extinction in Earth’s history. Some scientists believe that changes in seawater circulation were a likely cause of this extinction, which killed nearly 90% of all marine species.

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued The Mesozoic Era — The Age of Reptiles 251 million years ago Reptiles, such as dinosaurs, dominated the land. Small mammals appeared about the same time as dinosaurs, and birds evolved late in the era. At the end of the Mesozoic era, about 15% to 20% of all species on Earth, including the dinosaurs, became extinct. Global climate change may have been the cause.

Chapter 6 Section 5 Time Marches On The Geologic Time Scale, continued The Cenozoic Era — The Age of Mammals 65.5 million years ago and continues to the present. This era is known as the “Age of Mammals.” After the mass extinction at the end of the Mesozoic era, mammals flourished. Mammals were able to survive the environmental changes that probably caused the extinction of the dinosaurs.

Chapter 6 Review How old is the Earth?
Section 5 Time Marches On Review How old is the Earth? Name the 4 divisions of geologic time from largest to smallest? What marks the beginning and end of geologic time periods? What is extinction? What eon are we currently in? In what era are mammals dominant? In what era are reptiles dominant? What era ended with the largest mass extinction in Earth’s history?

Chapter 6 The Rock and Fossil Record Concept Map Use the terms below to complete the concept map on the next slide. sedimentary rocks fossils half-life radioactive isotope absolute dating faults

Chapter 6 The Rock and Fossil Record

End of Chapter 6 Show

Chapter 6 Standardized Test Preparation Reading Read each of the passages. Then answer the questions that follow each passage.

Chapter 6 Standardized Test Preparation Passage 1 Three hundred million years ago, the region that is now Illinois had a different climate than it does today. Swamps and shallow bays covered much of the area. No fewer than 500 species of plants and animals lived in this environment. Today, the remains of these organisms are found beautifully preserved within nodules. Continued on the next slide

Chapter 6 Standardized Test Preparation Passage 1, continued Nodules are round or oblong structures usually composed of cemented sediments that sometimes contain the fossilized hard parts of plants and animals. The Illinois nodules are exceptional because the soft parts of organisms are found together with hard parts. For this reason, these nodules are found in fossil collections around the world.

Chapter 6 Standardized Test Preparation 1. In the passage, what is the meaning of the word exceptional? A beautiful B extraordinary C average D large

Chapter 6 Standardized Test Preparation 2. According to the passage, which of the following statements about nodules is correct? F Nodules are rarely round or oblong. G Nodules are usually composed of cemented sediment. H Nodules are not found in present-day Illinois. I Nodules always contain fossils.

Chapter 6 3. Which of the following is a fact in the passage?
Standardized Test Preparation 3. Which of the following is a fact in the passage? A The Illinois nodules are not well known outside of Illinois. B Illinois has had the same climate throughout Earth’s history. C Both the hard and soft parts of organisms are preserved in the Illinois nodules. D Fewer than 500 species of plants and animals have been found in Illinois nodules.

Chapter 6 Standardized Test Preparation Passage 2 In 1995, paleontologist Paul Sereno and his team were working in an unexplored region of Morocco when they made an astounding find — an enormous dinosaur skull! The skull measured approximately 1.6 m in length, which is about the height of a refrigerator. Given the size of the skull, Sereno concluded that the skeleton of the animal it came from must have been about 14 m long — about as big as a school bus. Continued on the next slide

Chapter 6 Standardized Test Preparation Passage 2, continued The dinosaur was even larger than Tyrannosaurus rex! The newly discovered 90 million-year-old predator most likely chased other dinosaurs by running on large, powerful hind legs, and its bladelike teeth meant certain death for its prey.

Chapter 6 1. In the passage, what does the word astounding mean?
Standardized Test Preparation 1. In the passage, what does the word astounding mean? A important B new C incredible D one of a kind

Chapter 6 Standardized Test Preparation 2. Which of the following is evidence that the dinosaur described in the passage was a predator? F It had bladelike teeth. G It had a large skeleton. H It was found with the bones of a smaller animal nearby. I It is 90 million years old.

Chapter 6 Standardized Test Preparation 3. What types of information do you think that fossil teeth provide about an organism? A the color of its skin B the types of food it ate C the speed that it ran D the mating habits it had

Interpreting Graphics
Chapter 6 Standardized Test Preparation Interpreting Graphics Use the graph below to answer the questions that follow.

Chapter 6 Standardized Test Preparation 1. At which point in Earth’s history did the greatest mass-extinction event take place? A at point 1, the Ordovician-Silurian boundary B at point 3, the Permian-Triassic boundary C at point 4, the Triassic-Jurassic boundary D at point 5, the Cretaceous-Tertiary boundary

Chapter 6 Standardized Test Preparation 2. Immediately following the Cretaceous-Tertiary extinction, represented by point 5, approximately how many families of marine organisms remained in the Earth’s oceans? F 200 marine families G 300 marine families H 500 marine families I 700 marine families

Chapter 6 Standardized Test Preparation 3. Approximately how many million years ago did the Ordovician-Silurian mass-extinction event, represented by point 1, take place? A 200 million years ago B 250 million years ago C 350 million years ago D 420 million years ago

Chapter 6 Math Read each question and choose the best answer.
Standardized Test Preparation Math Read each question and choose the best answer.

Chapter 6 Standardized Test Preparation 1. Carbon-14 is a radioactive isotope with a half-life of 5,730 years. How much carbon-14 would remain in a sample that is 11,460 years old? A 12.5% B 25% C 50% D 100%

Chapter 6 Standardized Test Preparation 2. If a sample contains an isotope with a half-life of 10,000 years, how old would the sample be if 1/8 of the original isotope remained in the sample? F 20,000 years G 30,000 years H 40,000 years I 50,000 years

Chapter 6 Standardized Test Preparation 3. If a sample contains an isotope with a half-life of 5,000 years, how old would the sample be if 1/4 of the original isotope remained in the sample? A 10,000 years B 20,000 years C 30,000 years D 40,000 years

Chapter 6 Standardized Test Preparation 4. If Earth history spans 4.6 billion years and the Phanerozoic eon was 543 million years, what percentage of Earth history does the Phanerozoic eon represent? F about 6% G about 12% H about 18% I about 24%

Chapter 6 Standardized Test Preparation 5. Humans live in the Holocene epoch. If the Holocene epoch has lasted approximately 10,000 years, what percentage of the Quaternary period, which began 1.8 million years ago, is represented by the Holocene? A about % B about 0.055% C about 0.55% D about 5.5%

Section 2 Relative Dating: Which Came First?
Chapter 6

Section 3 Absolute Dating: A Measure of Time
Chapter 6

Chapter 6 Standardized Test Preparation

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