1. Chapter 7 Changes Over Time Table of Contents 7.5 Branching Trees 7.4 Classifying Organisms 7.3 Evolution of Species 7.2 Evidence of Evolution 7.1 Darwin’s Theory Chapter Preview

2. Chapter 7 Changes Over Time Chapter Preview Questions 1.Compared to body cells, the cells that result from meiosis have a.half the number of chromosomes. b.the same number of chromosomes. c.double the number of chromosomes. d.triple the number of chromosomes.

3. Chapter 7 Changes Over Time Chapter Preview Questions 1.Compared to body cells, the cells that result from meiosis have a.half the number of chromosomes. b.the same number of chromosomes. c.double the number of chromosomes. d.triple the number of chromosomes.

4. Chapter 7 Changes Over Time Chapter Preview Questions 2. Which is true of the alleles for a gene? a.There are only two alleles for every gene. b.The alleles are always identical. c.The alleles are never identical. d.One allele may be dominant.

5. Chapter 7 Changes Over Time Chapter Preview Questions 2. Which is true of the alleles for a gene? a.There are only two alleles for every gene. b.The alleles are always identical. c.The alleles are never identical. d.One allele may be dominant.

6. Chapter 7 Changes Over Time Chapter Preview Questions 3. An organism’s traits are determined by its a.carbohydrates. b.DNA. c.mitochondria. d.chloroplasts.

7. Chapter 7 Changes Over Time Chapter Preview Questions 3. An organism’s traits are determined by its a.carbohydrates. b.DNA. c.mitochondria. d.chloroplasts.

8. Chapter 7 Changes Over Time Chapter Preview Questions 4. Where do sexually reproducing organisms inherit their alleles from? a.half from each parent b.mostly from their mother c.mostly from their father d.only from their mother

9. Chapter 7 Changes Over Time Chapter Preview Questions 4. Where do sexually reproducing organisms inherit their alleles from? a.half from each parent b.mostly from their mother c.mostly from their father d.only from their mother

10. Chapter 7 Changes Over Time You plant a packet of zinnia seeds, and later, the zinnias begin to bloom. You notice that no two plants are exactly alike. For example, some flowers have different colors than others. What accounts for these differences? Write an explanation. What factors have caused the evolution and diversity of organisms?

11. Chapter 7 Changes Over Time Identify Multiple Meanings WordEveryday MeaningScientific Meaning theory n. A guess; an idea of how or why something might happen Example: Emily has a theory that basketball is harder to play than baseball. n. A well-tested concept that explains a wide range of observations Example: The cell theory says that all organisms are made of cells.

12. Chapter 7 Changes Over Time Identify Multiple Meanings WordEveryday MeaningScientific Meaning cast n. A device that protects a broken bone by preventing it from moving Example: Tim's broken elbow has healed, so the cast can be removed. n. A type of fossil that forms when a mold becomes filled with minerals Example: The cast of the foot print shows that the extinct animal had five toes.

13. Chapter 7 Changes Over Time Apply It! In the sentences below, identify which meaning of the word theory was used—the everyday meaning or the scientific meaning. 1.The theory of evolution explains how organisms have changed over time. Theory (science use) 2.Do you have a theory about why Sarah is a vegetarian? Theory (everyday use)

14. Chapter 7 Changes Over Time End of Chapter Preview Changes Over Time

15. Chapter 7 Changes Over Time Section 1: Darwin’s Theory What important observations did Darwin make on his voyage? How did Darwin account for the diversity of species and the differences between similar species? How does natural selection lead to evolution? Changes Over Time

16. Chapter 7 Changes Over Time Darwin’s Voyage Charles Darwin sailed on the Beagle, from England to the Galápagos Islands. Changes Over Time

17. Chapter 7 Changes Over Time Overproduction and Variation Natural selection is the process by which individuals who are better adapted to their environment are more likely to survive and reproduce than other members of the same species. Changes Over Time

18. Chapter 7 Changes Over Time Competition and Selection Variations among turtles make some of them better able to survive. Turtles that survive to become adults will be able to reproduce. Changes Over Time

19. Chapter 7 Changes Over Time End of Section: Darwin’s Theory Changes Over Time

20. Chapter 7 Changes Over Time Section 2: Evidence of Evolution What evidence supports the theory of evolution? How do fossils form? What do scientists learn from fossils?

21. Chapter 7 Changes Over Time Homologous Structures The structure of the bones in a dolphin’s flipper, a bird’s wing, and a dog’s leg is similar. Homologous bones are shown in the same color.

22. Chapter 7 Changes Over Time How Do Fossils Form? Most fossils form when organisms that die become buried in sediments.

23. Chapter 7 Changes Over Time Changes Over Time The fossils record provides evidence about the history of life and past environments on Earth. In addition, scientists use fossils to study the rate at which evolution has occurred.

24. Chapter 7 Changes Over Time End of Section: Evidence of Evolution

25. Chapter 7 Changes Over Time Section 3: Evolution of Species What factors have contributed to the diversity of species? How do new species form? How do scientists infer evolutionary relationships among species? What causes the extinction of species?

26. Chapter 7 Changes Over Time Kaibab and Abert’s Squirrels These two kinds of squirrels have been isolated from one another for a long time. Eventually this isolation may result in two different species.

27. Chapter 7 Changes Over Time A Branching Tree This branching tree shows how scientists now think that raccoons, lesser pandas, giant pandas, and bears are related.

28. Chapter 7 Changes Over Time Extinction of Species Extinction is caused by a change in species' environment. The members of a species may not have adaptations that allow them to survive and reproduce in the changed environment.

29. Chapter 7 Changes Over Time End of Section: Evolution of Species

30. Chapter 7 Changes Over Time Section 4: Classifying Organisms Why do biologists organize living things into groups? What do the levels of classification indicate about the relationship between organisms? What characteristics are used to classify organisms into domains and kingdoms?

31. Chapter 7 Changes Over Time Levels of Classification As you move down the levels of classification, the number of organisms decreases. The organisms at lower levels share more characteristics with each other.

32. Chapter 7 Changes Over Time Three Domains of Life In the three-domain system of classifications, all known organisms belong to one of three domains–Bacteria, Archaea, or Eukarya. ProtistsFungiPlantsAnimals Bacteria Archaea Eukarya

33. Chapter 7 Changes Over Time End of Section: Classifying Organisms

34. Chapter 7 Changes Over Time Section 5: Branching Trees How does a branching tree diagram show evolutionary relationships?

35. Chapter 7 Changes Over Time A Branching Tree Branching trees such as this show relationships between groups of organisms. It also shows the order in which specific characteristics may have evolved.

36. Chapter 7 Changes Over Time Shared Derived Characteristics A branching tree diagram shows evolutionary relationships by grouping organisms according to shared derived characteristics. Reptiles Amphibians Egg with shell Fishes Four limbs Backbone Invertebrates Ancestor of animals

37. Chapter 7 Changes Over Time Characteristics of Plants PlantTrue RootsSeedsFlowers MossNo FernYesNo Spruce treeYes No Apple treeYes Data for a Branching Tree Diagram The data in the table show shared derived characteristics of different types of plants.

38. Chapter 7 Changes Over Time Characteristics of Plants PlantTrue RootsSeedsFlowers MossNo FernYesNo Spruce treeYes No Apple treeYes Data for a Branching Tree Diagram Interpreting Data Do mosses have any of the characteristics indicated at the top of the table? No

39. Chapter 7 Changes Over Time Characteristics of Plants PlantTrue RootsSeedsFlowers MossNo FernYesNo Spruce treeYes No Apple treeYes Data for a Branching Tree Diagram Interpreting Data Which plant has the greatest number of the characteristics? The apple tree

40. Chapter 7 Changes Over Time Characteristics of Plants PlantTrue RootsSeedsFlowers MossNo FernYesNo Spruce treeYes No Apple treeYes Data for a Branching Tree Diagram Drawing Conclusions Use the information in the table to draw a branching tree. (Hint: Mosses go at the base of the tree.) The organisms will branch off in the order listed, with moss branching off at the bottom and the apple tree at the top.

41. Chapter 7 Changes Over Time Characteristics of Plants PlantTrue RootsSeedsFlowers MossNo FernYesNo Spruce treeYes No Apple treeYes Data for a Branching Tree Diagram Inferring A fossil plant shows evidence of flowers. Where in the diagram would the plant go? With the apple tree

42. Chapter 7 Changes Over Time End of Section: Branching Trees