1. NEW CHAPTER The History of Life on Earth CHAPTER the BIG idea Living things, like Earth itself, change over time. Earth has been home to living things for about 3.8 billion years. Species change over time. Many types of evidence support evolution. CHAPTER OUTLINE 1.1 1.2 1.3 CHAPTER RESOURCES

2. VOCABULARY KEY CONCEPT CHAPTER HOME unicellular organism multicellular organism mass extinction fossil Earth has been home to living things for about 3.8 billion years. SECTION OUTLINE SECTION OUTLINE Fossil records inform humans about the development of life on Earth. Information from fossils can help scientists reconstruct Earth's history. 250 million years ago 70 million years ago55 million years ago 1.1 VISUALIZATION CLASSZONE.COM Explore how fossils form. CHAPTER RESOURCES CHAPTER RESOURCES

3. VOCABULARY KEY CONCEPT CHAPTER HOME A trace or the remains of a once-living thing from long ago. fossil Earth has been home to living things for about 3.8 billion years. unicellular organism multicellular organism mass extinction fossil KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1.1 CHAPTER RESOURCES CHAPTER RESOURCES

4. VOCABULARY KEY CONCEPT CHAPTER HOME A term used to describe an organism that is made up of a single cell. unicellular organism Earth has been home to living things for about 3.8 billion years. unicellular organism multicellular organism mass extinction fossil KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1.1 CHAPTER RESOURCES CHAPTER RESOURCES

5. VOCABULARY KEY CONCEPT CHAPTER HOME An organism that is made up of many cells. multicellular organism Earth has been home to living things for about 3.8 billion years. unicellular organism multicellular organism mass extinction fossil KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1.1 CHAPTER RESOURCES CHAPTER RESOURCES

6. VOCABULARY KEY CONCEPT CHAPTER HOME One of several periods in Earth’s history when large numbers of species became extinct at nearly the same time. mass extinction Earth has been home to living things for about 3.8 billion years. unicellular organism multicellular organism mass extinction fossil KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1.1 CHAPTER RESOURCES CHAPTER RESOURCES

7. VOCABULARY KEY CONCEPT CHAPTER HOME Species change over time. SECTION OUTLINE SECTION OUTLINE natural selection adaptation evolution speciation Darwin's theory of natural selection explains evolution. Four principals of natural selection are overproduction Overproduction adult salmon eggs 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

8. VOCABULARY KEY CONCEPT CHAPTER HOME Species change over time. SECTION OUTLINE SECTION OUTLINE natural selection adaptation evolution speciation Darwin's theory of natural selection explains evolution. Four principals of natural selection are overproduction variation Variation curve 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

9. VOCABULARY KEY CONCEPT CHAPTER HOME Species change over time. SECTION OUTLINE SECTION OUTLINE natural selection adaptation evolution speciation Darwin's theory of natural selection explains evolution. Four principals of natural selection are overproduction variation adaptation Adaptation 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

10. VOCABULARY KEY CONCEPT CHAPTER HOME Species change over time. SECTION OUTLINE SECTION OUTLINE natural selection adaptation evolution speciation Darwin's theory of natural selection explains evolution. Four principals of natural selection are overproduction variation adaptation selection Selection 1.2 SIMULATION Match different finch beaks with the foods they eat, and learn how each beak functions. CHAPTER RESOURCES CHAPTER RESOURCES

11. VOCABULARY KEY CONCEPT CHAPTER HOME The process through which species change over time; can refer to the changes in a particular population or to the formation and extinction of species over the course of Earth’s history. evolution KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Species change over time. natural selection adaptation evolution speciation 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

12. VOCABULARY KEY CONCEPT CHAPTER HOME The process through which members of a species that are best suited to their environment survive and reproduce at a higher rate than other members of the species. natural selection KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Species change over time. natural selection adaptation speciation evolution 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

13. VOCABULARY KEY CONCEPT CHAPTER HOME A characteristic, a behavior, or any inherited trait that makes a species able to survive and reproduce in a particular environment. adaptation KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Species change over time. natural selection adaptation speciation evolution 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

14. VOCABULARY KEY CONCEPT CHAPTER HOME The evolution of a new species from an existing species. speciation KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Species change over time. natural selection adaptation speciation evolution 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

15. VOCABULARY KEY CONCEPT CHAPTER HOME Many types of evidence support evolution. SECTION OUTLINE SECTION OUTLINE ancestor vestigial organ gene Three different types of evidence provide a bigger picture of evolution fossil genetic biological 1.3 CHAPTER RESOURCES CHAPTER RESOURCES

16. VOCABULARY KEY CONCEPT CHAPTER HOME A distant or early form of an organism from which later forms descend. ancestor KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Many types of evidence support evolution. ancestor vestigial organ gene 1.3 CHAPTER RESOURCES CHAPTER RESOURCES

17. VOCABULARY KEY CONCEPT CHAPTER HOME A physical structure that was fully developed and functional in an earlier group of organisms but is reduced and unused in later species. vestigial organ KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Many types of evidence support evolution. ancestor vestigial organ gene 1.3 CHAPTER RESOURCES CHAPTER RESOURCES

18. VOCABULARY KEY CONCEPT CHAPTER HOME The basic unit of heredity that consists of a segment of DNA on a chromosome. gene KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY Many types of evidence support evolution. ancestor vestigial organ gene 1.3 CHAPTER RESOURCES CHAPTER RESOURCES

19. VOCABULARY KEY CONCEPT CHAPTER HOME I. Earth has been home to living things for about 3.8 billion years. A. Fossils provide evidence of earlier life. B. More complex organisms developed over time. C. Earth’s history includes mass extinctions. 1. Unicellular Organisms 2. Multicellular Organisms 3. Life on Land Earth has been home to living things for about 3.8 billion years. unicellular organism multicellular organism mass extinction fossil 1. Types of Fossils 2. Finding the Age of Fossils 3. Assembling the Fossil Record 1. Permian Extinction 2. Cretaceous Extinction KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1.1 CHAPTER RESOURCES CHAPTER RESOURCES

20. VOCABULARY KEY CONCEPT CHAPTER HOME II. Species change over time. A. Scientists explore the concept of evolution. B. Natural selection explains how living things evolve. Species change over time. KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1. Early Ideas 2. Darwin’s Observations 1. Overproduction 2. Variation 3. Adaptation 4. Selection natural selection adaptation evolution speciation 5. Isolation 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

21. VOCABULARY KEY CONCEPT CHAPTER HOME II. Species change over time. C. New species develop from earlier species. Species change over time. KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY 1. Speciation 2. Isolation natural selection adaptation evolution speciation 1.2 CHAPTER RESOURCES CHAPTER RESOURCES

22. VOCABULARY KEY CONCEPT CHAPTER HOME III. Many types of evidence support evolution. A. Observations provide evidence for theories. 1. Similarities in Structure 2. Similarities in Development B. Fossil evidence supports evolution. Many types of evidence support evolution. KEY CONCEPT SUMMARY KEY CONCEPT SUMMARY ancestor vestigial organ gene C. Biological evidence supports evolution. D. Genetic evidence supports evolution. 1.3 CHAPTER RESOURCES CHAPTER RESOURCES

23. CHAPTER HOME Image Gallery Click on the icons to see a larger image or animation. VISUALIZATION CLASSZONE.COM Explore how fossils form. SIMULATION Match different finch beaks with the foods they eat, and learn how each beak functions.

24. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY 250 million years ago 70 million years ago55 million years ago

25. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY Overproduction adult salmon eggs

26. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY Variation curve

27. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY Adaptation

28. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY Selection

29. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY fossil genetic biological

30. CHAPTER HOME Image Gallery BACK TO IMAGE GALLERY

31. BACK TO CHAPTER Click on the items below to access resources on Standardized Test Practice Practice state standardized tests Math Tutorial Review math concepts Resource Centers Get more information on select science topics Content Review Review key concepts and vocabulary Audio Readings Hear chapter audio readings CLASSZONE.COM Chapter Resources CHAPTER HOME Animations Link to all the McDougal Littell Science animations Review Game Play a fun interactive review game Image Gallery Click here to review chapter images and animations