1. Changes Over Time Chapter 5

2. SOL Standards LS.1 The student will plan and conduct investigations in which a) data are organized into tables showing repeated trials and means; d) models are constructed to illustrate and explain phenomena; and j) an understanding of the nature of science is developed and reinforced. LS.14 The student will investigate and understand that organisms change over time. Key concepts include a) the relationships of mutation, adaptation, natural selection, and extinction; b) evidence of evolution of different species in the fossil record; and c) how environmental influences, as well as genetic variation, can lead to diversity of organisms.

3. Chapter 5 Section 1 Darwin’s Voyage After completing this section, students will be able to: 1.state how Darwin explained variations among similar species; 2.Explain how natural selection leads to evolution, and explain the role of genes in evolution; 3.Describe how new species form.

4. Darwin’s Voyage – the Beginning In ____________ _________, the British navel ship HMS Beagle set sail from England on a five-year-long trip around the world. _____-year-old Charles Darwin was on board and eventually he became the ship’s ________. A ________________ is a person who studies the natural world. Darwin’s observations led him to develop one of the most important theories of all time: the ______________________________________ _____________________________________.

5. Darwin’s Voyage – the Beginning In December 1831, the British navel ship HMS Beagle set sail from England on a five-year- long trip around the world. 22-year-old Charles Darwin was on board and eventually he became the ship’s naturalist. A naturalist is a person who studies the natural world. Darwin’s observations led him to develop one of the most important theories of all time: the theory of evolution by natural selection.

6. Darwin’s Observations A ___________ is a group if similar organisms that can mate with each other and produce fertile offspring.

7. Darwin’s Observations A species is a group if similar organisms that can mate with each other and produce fertile offspring.

8. Galapagos: Similarities and Differences Darwin was surprised by the number of plants and animals that were similar to those found on the mainland. However, there were also important __________ between the organisms on the island and the mainland. Large sea birds called _____________ lived in both places. The _________________ on the mainland were able to _________, while those on the Islands cannot.

9. Galapagos: Similarities and Differences Darwin was surprised by the number of plants and animals that were similar to those found on the mainland. However, there were also important differences between the organisms on the island and the mainland. Large sea birds called cormorants lived in both places. The cormorants on the mainland were able to fly, while those on the Islands cannot.

10. Galapagos: Similarities and Differences Darwin also noticed a ___________ among similar organisms as he traveled from one Galapagos island to the next. An example is the ________________: (Top: Saddle back and Bottom: Dome)

11. Galapagos: Similarities and Differences Darwin also noticed a difference among similar organisms as he traveled from one Galapagos island to the next. An example is the tortoises: (Top: Saddle back and Bottom: Dome)

12. Adaptations Darwin made these drawings of four species of Galapagos ____________. The ______ of each ___________ is adapted to the type of food it eats. _______ shape is an example of an ___________, a trait that helps an organism survive and reproduce.

13. Adaptations Darwin made these drawings of four species of Galapagos finches. The beak of each finch is adapted to the type of food it eats. Beak shape is an example of an adaptation, a trait that helps an organism survive and reproduce.

14. Mini Lab Mini Lab Mini Lab Bird Beak Adaptations Each group member will select either a clothes pin, hair pin, or tweezers for this experiment. This item will represent your beak. There are two plates of seeds and insects. Each member will see how many of each type of food they can pick up in 10 seconds. Record the results in your notebook.

15. Evolution Darwin reasoned that plants or animals that arrived on one of the Galapagos Islands faced _______________ that were ______________ from those on the mainland. Perhaps, Darwin thought, the species __________________ changed over many __________________ and became better _______________ to the new conditions. The _______________ change in a species over time is called __________________. Darwin’s ideas are often referred to as the theory of evolution. A __________________ _______________ is a well-tested concept that explains a wide range of observations.

16. Evolution Darwin reasoned that plants or animals that arrived on one of the Galapagos Islands faced conditions that were different from those on the mainland. Perhaps, Darwin thought, the species gradually changed over many generations and became better adapted to the new conditions. The gradual change in a species over time is called evolution. Darwin’s ideas are often referred to as the theory of evolution. A scientific theory is a well-tested concept that explains a wide range of observations.

17. Natural Selection _________ ____________ is the process by which individuals that are better ____________ to their environment are more likely to _______ and __________ than other members of the same species. Darwin identified a number of factors that affect the process of natural selection: _________________________________ _________________________________

18. Natural Selection Natural Selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species. Darwin identified a number of factors that affect the process of natural selection: overproduction, competition, and variations.

19. Natural Selection ___________________: Most species produce far more ___________ than can possibly survive. In some species, so many offspring are produced that there are not enough resources – ____________________ ____________________ ________________ – for all of them. For example, each year a female loggerhead turtle lays more than ________ eggs.

20. Natural Selection Overproduction: Most species produce far more offspring than can possibly survive. In some species, so many offspring are produced that there are not enough resources – food, water, and living space – for all of them. For example, each year a female loggerhead turtle lays more than 100 eggs.

21. Competition and Variations ____________ are __________, the offspring must ___________ with each other to survive. ___________ does not usually mean a physical fight between members of the species, but an ___________ competition. An example might be that one turtle may find food while another does not. ___________ – Members of a species ______ from one another in many of their _________. Any _____________ between individuals of the same species is called a ______________. An example could be that one turtle swims faster than another.

22. Competition and Variations Competition – Since food and other resources are limited, the offspring must compete with each other to survive. Competition does not usually mean a physical fight between members of the species, but an indirect competition. An example might be that one turtle may find food while another does not. Variations – Members of a species differ from one another in many of their traits. Any difference between individuals of the same species is called a variation. An example could be that one turtle swims faster than another.

23. Selection Some _____________ make certain individuals better _________ to their environment making those individuals more likely to _________ and _________. The offspring in return _________ the adapted trait and pass it to their offspring. After many generations, more members of the species will have the trait. In effect, the environment has “_________” organisms with helpful traits to be the parents of the next generation – hence the term “____________ ________________.” Over a long period of time, _______ ________ can lead to _____________. Helpful variations gradually accumulate in a species, while unfavorable ones disappear.

24. Selection Some variations make certain individuals better adapted to their environment making those individuals more likely to survive and reproduce. The offspring in return inherit the adapted trait and pass it to their offspring. After many generations, more members of the species will have the trait. In effect, the environment has “selected” organisms with helpful traits to be the parents of the next generation – hence the term “natural selection.” Over a long period of time, natural selection can lead to evolution. Helpful variations gradually accumulate in a species, while unfavorable ones disappear.

25. Natural Selection Mini Lab Have a group member time you to see how many of the buttons you can pick up in 10 seconds. Pick up the buttons ONE at a time. Each member should get a turn to pick up the buttons. Record how many buttons each member picked up and record the number of each color.

26. Putting it all together….. The Industrial Revolution affected _______ _________ in peppered moths in England. As pollution blackened the tree trunks, _______ moths became more likely to survive and reproduce. How does this relate to the button mini lab??

27. Putting it all together….. The Industrial Revolution affected natural selection in peppered moths in England. As pollution blackened the tree trunks, black moths became more likely to survive and reproduce. How does this relate to the button mini lab??

28. The Role of Genes in Evolution Darwin did not know about _____________ or _________________. Scientists learned that ______________ can result from _________ ____ ______________ or from shuffling of _____________ during ______________. Only _____________ are passed from parents to their offspring. Because of this, only traits that are _______________, or controlled by genes, can be acted upon by ______________ _____________________.

29. The Role of Genes in Evolution Darwin did not know about genes or mutations. Scientists learned that variations can result from mutations in genes or from shuffling of alleles during meiosis. Only genes are passed from parents to their offspring. Because of this, only traits that are inherited, or controlled by genes, can be acted upon by natural selection.

30. How Do New Species Form? Kaibab Squirrel Abert’s Squirrel A new species might form when a group of individuals remains separated from the rest of its species long enough to evolve different traits. The Kaibab squirrel is an example of evolution occurring through geographic isolation. The Abert's squirrel, with its several subspecies, has a much broader distribution and is found on the South Rim of the Grand Canyon. The canyon became a formidable barrier geographically separating the forests and squirrels on each rim. The genetic isolation of the squirrels on the North Rim allowed the evolution of distinct characteristics.evolution geographic isolation subspecies

31. Continental Drift Geographic ________ has also occurred on a world wide scale. Once there was a supercontinent called ______________. __________ gradually split apart from one another in a process called __________ ___________.

32. Continental Drift Geographic isolation has also occurred on a world wide scale. Once there was a supercontinent called Pangaea. Pangaea gradually split apart from one another in a process called Continental Drift.

33. Marsupials Why does Australia have so many species of marsupials???

34. Chapter 5 Section 2 The Fossil Record After completing this section, students will be able to: 1.Describe how most fossils form; 2.Explain how a scientist determines a fossil’s age; 3.Explain what fossils reveal; 4.Describe the main events of the Geologic Time Scale; 5.Distinguish between gradualism and punctuated equilibria.

35. Chapter 5 Section 2 The Fossil Record A fossil is the ________ _________ or traces of an organism that lived in the past. A fossil can be formed from a ______, _______, _______, or other part of an organism. Other fossils can be traces of the organism, such as _____________ or worm burrows left in mud that later turned to stone.

36. Chapter 5 Section 2 The Fossil Record A fossil is the preserved remains or traces of an organism that lived in the past. A fossil can be formed from a bone, tooth, shell, or other part of an organism. Other fossils can be traces of the organism, such as footprints or worm burrows left in mud that later turned to stone.

37. How Do Fossils Form? Formation of any fossil is VERY _______. Most fossils form when organisms that die become buried in _______________. ______________ are particles of soil and rock. When a river flows into a lake or ocean, the _____________ build up and cover the dead organisms. Over millions of years, the layers harden to become _______________ _____________.

38. How Do Fossils Form? Formation of any fossil is VERY rare. Most fossils form when organisms that die become buried in sediments. Sediments are particles of soil and rock. When a river flows into a lake or ocean, the sediments build up and cover the dead organisms. Over millions of years, the layers harden to become sedimentary rock.

39. Petrified Fossil Some remains that become buried in sediments are actually changed to _________. ____________ dissolved in the water soak into the buried remains. Gradually, the ________ replace the remains, changing them into _______. Fossils that form in this way are called __________ __________.

40. Petrified Fossil Some remains that become buried in sediments are actually changed to rock. Minerals dissolved in the water soak into the buried remains. Gradually, the minerals replace the remains, changing them into rock. Fossils that form in this way are called petrified fossils.

41. Molds and Casts Sometimes shells and other hard parts buried by sediments are gradually ________ leaving an empty space. A hollow space in sediment in the shape of an organism or part of an organism is called a __________. Sometimes a _________ becomes filled in with hardened minerals, forming a ___________.

42. Molds and Casts Sometimes shells and other hard parts buried by sediments are gradually dissolved leaving an empty space. A hollow space in sediment in the shape of an organism or part of an organism is called a mold. Sometimes a mold becomes filled in with hardened minerals, forming a cast.

43. Preserved Remains _______ organisms, such as this mammoth, have been preserved in ________. The low temperatures preserved the mammoth’s ______ _________. The bones and teeth of other ancient animals have been preserved in ______ _________.

44. Preserved Remains Entire organisms, such as this mammoth, have been preserved in ice. The low temperatures preserved the mammoth’s soft parts. The bones and teeth of other ancient animals have been preserved in tar pits.

45. Determining a Fossil’s Age Scientists can determine a fossil’s age in two ways: _______________ _____________________________ _____________________________

46. Determining a Fossil’s Age Scientists can determine a fossil’s age in two ways: relative dating and absolute dating.

47. Relative Dating Scientists use ______ _________ to determine which of two fossils is older. Fossils found in layers near the top of the canyon are _______ than fossils found near the bottom of the canyon. Relative dating can help determine which fossil is _______, but cannot give the __________ ______.

48. Relative Dating Scientists use relative dating to determine which of two fossils is older. Fossils found in layers near the top of the canyon are younger than fossils found near the bottom of the canyon. Relative dating can help determine which fossil is older, but cannot give the actual age.

49. Absolute Dating Another technique, called _______ _________, allows scientists to determine the __________ age of fossils. The rocks that fossils are found near contain _________ __________, unstable elements that decay, or break down, into different elements. The _____________ of a radioactive element is the time it takes for half of the atoms in a sample to decay. Scientists can compare the amount of a _____________ ______________ in a sample to the amount of the element into which it breaks down.

50. Absolute Dating Another technique, called absolute dating, allows scientists to determine the actual age of fossils. The rocks that fossils are found near contain radioactive elements, unstable elements that decay, or break down, into different elements. The half-life of a radioactive element is the time it takes for half of the atoms in a sample to decay. Scientists can compare the amount of a radioactive element in a sample to the amount of the element into which it breaks down.

51. The Fossil Record The millions of fossils that scientists have collected are called the _______ ______. Almost all of the species preserved as fossils are now _______. A species is __________ if no members of that species are still alive.

52. The Fossil Record The millions of fossils that scientists have collected are called the fossil record. Almost all of the species preserved as fossils are now extinct. A species is extinct if no members of that species are still alive.

53. The Geologic Time Scale Using _______ ________, scientists have calculated the ages of many different fossils and rocks. From this information, scientists have created a “_________” of Earth’s history that spans more than 4.6 billion years. Scientists have decided this large time period into smaller units called _______ and ___________. This calendar of Earth’s history is sometimes called the ________ _________ ______.

54. The Geologic Time Scale Using absolute dating, scientists have calculated the ages of many different fossils and rocks. From this information, scientists have created a “calendar” of Earth’s history that spans more than 4.6 billion years. Scientists have decided this large time period into smaller units called eras and periods. This calendar of Earth’s history is sometimes called the Geologic Time Scale.

55. Book Activity Turn to Pages 162 + 163 in your text book. Answer the following questions in your notebook: 1.List two creatures that lived during the Cambrian Period. 2.List the two periods that made up the Cenozoic Era. 3.What period and era did Sharks appear? 4.What is the timeframe of the Mesozoic Era? 5.What period did seed plants become common?

56. How Fast Does Evolution Occur? One theory, called _________________, proposes that evolution occurs ________ _____ __________. Tiny changes in a species gradually add up to a major change over a long period of time. (This is how Darwin thought evolution occurred.) The second theory, called the _________ __________, states that species evolve during short periods of ____ _______. These periods of rapid change are separated by long periods of little or no change. According to this theory, species evolve quickly when groups become isolated and adapt to new environments. Today most scientists think that evolution can occur gradually at some times and fairly rapidly at others. _______ ______ ____ ______________ seem to have occurred during Earth’s long history.

57. How Fast Does Evolution Occur? One theory, called gradualism, proposes that evolution occurs slowly but steadily. Tiny changes in a species gradually add up to a major change over a long period of time. (This is how Darwin thought evolution occurred.) The second theory, called the punctuated equilibria, states that species evolve during short periods of rapid change. These periods of rapid change are separated by long periods of little or no change. According to this theory, species evolve quickly when groups become isolated and adapt to new environments. Today most scientists think that evolution can occur gradually at some times and fairly rapidly at others. Both forms of evolution seem to have occurred during Earth’s long history.

58. Chapter 5 Section 3 Other Evidence for Evolution After completing this section, students will be able to: 1.State evidence from modern-day organisms that scientists use to show evolutionary relationships among groups; 2.Explain what a branching tree diagram is.

59. Evolutionary Relationships Scientists compare ______________ _____________________________ _____________________________ to determine the evolutionary relationships among organisms.

60. Evolutionary Relationships Scientists compare body structures, development before birth, and DNA sequences to determine the evolutionary relationships among organisms.

61. Are these similar? How? __________, __________, __________, __________, and ____________, for example, all have similar body structure – an internal skeleton with a ____________. This is why scientists classify theses groups of animals together as _____________________. Presumably, these groups all inherited these similarities in structure from an early ___________ _______________ that they shared.

62. Are these similar? How? Fishes, amphibians, reptiles, birds, and mammals, for example, all have similar body structure – an internal skeleton with a backbone. This is why scientists classify theses groups of animals together as vertebrates. Presumably, these groups all inherited these similarities in structure from an early vertebrate ancestor that they shared.

63. Similarities in Body Structure An organism’s body structure is its __________ _________ ________, such as how the bones are arranged. Similar structures that related species have inherited from a common ancestor are called ____________________ ______________.

64. Similarities in Body Structure An organism’s body structure is its basic body plan, such as how the bones are arranged. Similar structures that related species have inherited from a common ancestor are called homologous structures.

65. Scientists can also make inferences about evolutionary relationships by comparing the ________ __________ of different organisms. During the early stages of development all three organisms have a ______________ and ___________ ___________ slits in their throats. These similarities suggest that these three vertebrate species are related and share a common _________________. Turtle Embryo Chicken Embryo Rat Embryo Similarities in Early Development

66. Scientists can also make inferences about evolutionary relationships by comparing the early development of different organisms. During the early stages of development all three organisms have a tail and tiny gill slits in their throats. These similarities suggest that these three vertebrate species are related and share a common ancestor. Turtle Embryo Chicken Embryo Rat Embryo Similarities in Early Development

67. Similarities in DNA Scientists infer that the species inherited many of the same ________ from a common ___________. Sometimes DNA evidence does not confirm earlier conclusions about relationships between species. For example, aside from the long nose, the tiny elephant shrew looks very similar to rodents and mice. However, the elephant shrew’s DNA is closer to an _________ than a ______________.

68. Similarities in DNA Scientists infer that the species inherited many of the same genes from a common ancestor. Sometimes DNA evidence does not confirm earlier conclusions about relationships between species. For example, aside from the long nose, the tiny elephant shrew looks very similar to rodents and mice. However, the elephant shrew’s DNA is closer to an elephant than a mouse.

69. DNA and Fossils Recently, scientists have developed techniques that allow them to ________, or remove, _______ from fossils. Using these techniques, scientists have now ___________ __________ from fossils of ________, _________, and __________, and from insects trapped in amber. The DNA from fossils has provided scientists with new evidence about ____________.

70. DNA and Fossils Recently, scientists have developed techniques that allow them to extract, or remove, DNA from fossils. Using these techniques, scientists have now extracted DNA from fossils of bones, teeth, and plants, and from insects trapped in amber. The DNA from fossils has provided scientists with new evidence about evolution.

71. Combining the Evidence Scientists have ___________ _________ from fossils, body structures, ________ _________, and DNA and _______ ________ to determine the _________ _________ among species. (In most cases the DNA and protein sequences have _____________ conclusions based on earlier evidence.) For example, Scientists have confirmed that dogs are more closely related to wolves than coyotes. Scientists use ___________ __________, a diagram that shows how scientists think different groups of organisms are related.

72. Combining the Evidence Scientists have combined evidence from fossils, body structures, early development, and DNA and protein sequences to determine the evolutionary relationships among species. (In most cases the DNA and protein sequences have confirmed conclusions based on earlier evidence.) For example, Scientists have confirmed that dogs are more closely related to wolves than coyotes. Scientists use branching trees, a diagram that shows how scientists think different groups of organisms are related.