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Ch 18: Praxis Earth & Space Sciences: Earth History & Life Forms

About This Chapter

Learn more about the history of Earth and its life forms through this series of easy-to-follow lessons. These videos and online quizzes will aid you in preparing for the Praxis Earth and Space Sciences exam.

Praxis Earth and Space Sciences: Earth History and Life Forms - Chapter Summary

The lessons in this chapter explore the earth's past and the methods scientists use to study it. You can review the geologic time scale, theories of geologic evolution and relative dating principles. Other lessons explore scientific ideas about the origin of life on Earth. These lessons will prepare you to:

  • Explain relative dating with fossils as indicators of time
  • Recognize the conditions of fossil preservation
  • Discuss the history of life on Earth
  • Define extinction and mass extinction

You will be guided through these topics by expert instructors who know how to make studying fun. The self-assessment quizzes included with each lesson enable you to test your knowledge. Feel free to watch the video more than once and repeat the quiz!

8 Lessons in Chapter 18: Praxis Earth & Space Sciences: Earth History & Life Forms
Test your knowledge with a 30-question chapter practice test
Geologic Time Scale: Major Eons, Eras, Periods and Epochs

1. Geologic Time Scale: Major Eons, Eras, Periods and Epochs

The geologic time scale is an essential tool for understanding the history of Earth and the evolution of life. In this lesson, explore the principal eons, eras, periods, and epochs that help us track major events in geologic history.

Theories of Geological Evolution: Catastrophism vs Uniformitarianism

2. Theories of Geological Evolution: Catastrophism vs Uniformitarianism

Geologists haven't always agreed about the history of our planet. They have debated between catastrophism and uniformitarianism over the last few hundred years! Learn about the two main theories of geologic evolution and how scientists came to resolve the dispute.

What is Relative Dating? - Law of Superposition, Principles of Original Horizontality & Cross-Cutting Relationships

3. What is Relative Dating? - Law of Superposition, Principles of Original Horizontality & Cross-Cutting Relationships

Discover how geologists study the layers in sedimentary rock to establish relative age. Learn how inclusions and unconformities can tell us stories about the geologic past. We'll even visit the Grand Canyon to solve the mystery of the Great Unconformity!

Relative Dating with Fossils: Index Fossils as Indicators of Time

4. Relative Dating with Fossils: Index Fossils as Indicators of Time

You may already know how to date a fossil with a rock. But did you know that we can also date a rock with a fossil? Watch this video to find out how we use index fossils to establish the relative ages of rocks.

Conditions of Fossil Preservation: Rapid Burial, Hard Parts & the Elements

5. Conditions of Fossil Preservation: Rapid Burial, Hard Parts & the Elements

Learn how fossils are formed and how varying conditions affect the preservation of organisms. What is the best way for a dinosaur to become fossilized? Find out here!

The Origin of Life on Earth: Theories and Explanations

6. The Origin of Life on Earth: Theories and Explanations

Ever wonder how living things came from non-living things? We will explore what conditions on early Earth may have created life from non-living items.

The History of Life on Earth: Timeline and Characteristics of Major Eras

7. The History of Life on Earth: Timeline and Characteristics of Major Eras

The Earth is over 4 billion years old. Ever wonder what happened during certain time periods in that large amount of time? We will look at the major eons and eras of Earth's history along with important characteristics of each.

What Is Extinction? - Defining Background and Mass Extinction

8. What Is Extinction? - Defining Background and Mass Extinction

In this lesson you'll discover what the term 'extinction' means as well as learn the two different types of extinction: mass extinction and background extinction. You will also discover how humans contribute to extinction events.

Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
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Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
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