Descent with Modification

1. LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Descent with Modification: A Darwinian View of Life Chapter 22

2. Overview: Endless Forms Most Beautiful • A new era of biology began in 1859 when Charles Darwin published The Origin of Species • The Origin of Species focused biologists’ attention on the great diversity of organisms © 2011 Pearson Education, Inc.

3. • Darwin noted that current species are descendants of ancestral species • Evolution can be defined by Darwin’s phrase descent with modification • Evolution can be viewed as both a pattern and a process © 2011 Pearson Education, Inc.

4. Figure 22.1

5. • Darwin’s ideas had deep historical roots Concept 22.1: The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species © 2011 Pearson Education, Inc.

6. Figure 22.2 1809 1798 1812 1795 1830 1790 1809 1831  36 1844 1859 1870 Lamarck publishes his hypothesis of evolution. Malthus publishes “Essay on the Principle of Population.” Hutton proposes his principle of gradualism. Charles Darwin is born. Darwin travels around the world on HMS Beagle. The Gal ápagos Islands Darwin writes his essay on descent with modification. On the Origin of Species is published. While studying species in the Malay Archipelago, Wallace (shown in 1848) sends Darwin his hypothesis of natural selection. 1858 Cuvier publishes his extensive studies of vertebrate fossils. Lyell publishes Principles of Geology.

7. Figure 22.2a

8. Figure 22.2b

9. Figure 22.2c

10. Figure 22.2d

11. Scala Naturae and Classification of Species • The Greek philosopher Aristotle viewed species as fixed and arranged them on a scala naturae • The Old Testament holds that species were individually designed by God and therefore perfect © 2011 Pearson Education, Inc.

12. • Carolus Linnaeus interpreted organismal adaptations as evidence that the Creator had designed each species for a specific purpose • Linnaeus was the founder of taxonomy, the branch of biology concerned with classifying organisms • He developed the binomial format for naming species (for example, Homo sapiens ) © 2011 Pearson Education, Inc.

13. Ideas About Change over Time • The study of fossils helped to lay the groundwork for Darwin’s ideas • Fossils are remains or traces of organisms from the past, usually found in sedimentary rock, which appears in layers or strata © 2011 Pearson Education, Inc. Video: Grand Canyon

14. Figure 22.3 Sedimentary rock layers (strata) Younger stratum with more recent fossils Older stratum with older fossils

15. • Paleontology , the study of fossils, was largely developed by French scientist Georges Cuvier • Cuvier advocated catastrophism , speculating that each boundary between strata represents a catastrophe © 2011 Pearson Education, Inc.

16. • Geologists James Hutton and Charles Lyell perceived that changes in Earth’s surface can result from slow continuous actions still operating today • Lyell’s principle of uniformitarianism states that the mechanisms of change are constant over time • This view strongly influenced Darwin’s thinking © 2011 Pearson Education, Inc.

17. Lamarck’s Hypothesis of Evolution • Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics • The mechanisms he proposed are unsupported by evidence © 2011 Pearson Education, Inc.

18. Figure 22.4

19. • Some doubt about the permanence of species preceded Darwin’s ideas Concept 22.2: Descent with modification by natural selection explains the adaptations of organisms and the unity and diversity of life © 2011 Pearson Education, Inc.

20. Darwin’s Research • As a boy and into adulthood, Charles Darwin had a consuming interest in nature • Darwin first studied medicine (unsuccessfully), and then theology at Cambridge University • After graduating, he took an unpaid position as naturalist and companion to Captain Robert FitzRoy for a 5-year around the world voyage on the Beagle © 2011 Pearson Education, Inc.

21. The Voyage of the Beagle • During his travels on the Beagle, Darwin collected specimens of South American plants and animals • He observed that fossils resembled living species from the same region, and living species resembled other species from nearby regions • He experienced an earthquake in Chile and observed the uplift of rocks © 2011 Pearson Education, Inc.

22. • Darwin was influenced by Lyell’s Principles of Geology and thought that the earth was more than 6000 years old • His interest in geographic distribution of species was kindled by a stop at the Galápagos Islands west of South America • He hypothesized that species from South America had colonized the Galápagos and speciated on the islands © 2011 Pearson Education, Inc.

23. Figure 22.5 Darwin in 1840, after his return from the voyage The Gal ápagos Islands NORTH AMERICA ATLANTIC OCEAN PACIFIC OCEAN PACIFIC OCEAN Pinta Marchena Genovesa Equator Chile Santiago Daphne Islands Fernandina Isabela Santa Cruz Santa Fe San Cristobal Espa ñola Kilometers 0 20 40 Florenza Pinz ón SOUTH AMERICA AFRICA EUROPE Great Britain HMS Beagle in port Equator PACIFIC OCEAN Malay Archipelago AUSTRALIA Tasmania New Zealand Brazil Argentina Cape Horn Andes Mtns. Cape of Good Hope

24. Figure 22.5a The Gal ápagos Islands NORTH AMERICA ATLANTIC OCEAN Chile SOUTH AMERICA AFRICA EUROPE Great Britain Equator PACIFIC OCEAN Malay Archipelago AUSTRALIA Tasmania New Zealand Brazil Argentina Cape Horn Andes Mtns. Cape of Good Hope PACIFIC OCEAN

25. Figure 22.5b Darwin in 1840, after his return from the voyage

26. Figure 22.5c The Gal ápagos Islands PACIFIC OCEAN Pinta Marchena Genovesa Equator Santiago Daphne Islands Fernandina Isabela Santa Cruz Santa Fe San Cristobal Espa ñola Kilometers 0 20 40 Florenza Pinz ón

27. Figure 22.5d HMS Beagle in port

28. © 2011 Pearson Education, Inc. Video: Galápagos Islands Overview Video: Blue-footed Boobies Courtship Ritual Video: Albatross Courtship Ritual Video: Galápagos Sea Lion Video: Galápagos Marine Iguana Video: Galápagos Tortoises Video: Soaring Hawk

29. Darwin’s Focus on Adaptation • In reassessing his observations, Darwin perceived adaptation to the environment and the origin of new species as closely related processes • From studies made years after Darwin’s voyage, biologists have concluded that this is what happened to the Galápagos finches © 2011 Pearson Education, Inc.

30. Figure 22.6 (a) Cactus-eater (b) Insect-eater (c) Seed-eater

31. Figure 22.6a (a) Cactus-eater

32. Figure 22.6b (b) Insect-eater

33. Figure 22.6c (c) Seed-eater

34. • In 1844, Darwin wrote an essay on natural selection as the mechanism of descent with modification, but did not introduce his theory publicly • Natural selection is a process in which individuals with favorable inherited traits are more likely to survive and reproduce • In June 1858, Darwin received a manuscript from Alfred Russell Wallace, who had developed a theory of natural selection similar to Darwin’s • Darwin quickly finished The Origin of Species and published it the next year © 2011 Pearson Education, Inc.

35. The Origin of Species • Darwin explained three broad observations: – The unity of life – The diversity of life – The match between organisms and their environment © 2011 Pearson Education, Inc.

36. Descent with Modification • Darwin never used the word evolution in the first edition of The Origin of Species • The phrase descent with modification summarized Darwin’s perception of the unity of life • The phrase refers to the view that all organisms are related through descent from an ancestor that lived in the remote past © 2011 Pearson Education, Inc.

37. • In the Darwinian view, the history of life is like a tree with branches representing life’s diversity • Darwin’s theory meshed well with the hierarchy of Linnaeus © 2011 Pearson Education, Inc.

38. Figure 22.7

39. Figure 22.8 Hyracoidea (Hyraxes) Sirenia (Manatees and relatives) † Deinotherium † Mammut † Platybelodon † Stegodon † Mammuthus Elephas maximus (Asia) Loxodonta africana (Africa) Loxodonta cyclotis (Africa) † Moeritherium † Barytherium 60 Millions of years ago 34 24 5.5 2 10 4 0 Years ago

40. Figure 22.8a † Platybelodon † Stegodon † Mammuthus Elephas maximus (Asia) Loxodonta africana (Africa) Loxodonta cyclotis (Africa) 60 Millions of years ago 34 24 5.5 2 10 4 0 Years ago

41. Figure 22.8b Hyracoidea (Hyraxes) Sirenia (Manatees and relatives) † Deinotherium † Mammut † Moeritherium † Barytherium 60 Millions of years ago 34 24 5.5 2 10 4 0 Years ago

42. Artificial Selection, Natural Selection, and Adaptation • Darwin noted that humans have modified other species by selecting and breeding individuals with desired traits, a process called artificial selection • Darwin drew two inferences from two observations © 2011 Pearson Education, Inc.

43. Figure 22.9 Brussels sprouts Kale Selection for leaves Selection for axillary (side) buds Selection for apical (tip) bud Cabbage Broccoli Kohlrabi Wild mustard Selection for stems Selection for flowers and stems

44. Figure 22.9a Wild mustard

45. Figure 22.9b Kale

46. Figure 22.9c Brussels sprouts

47. Figure 22.9d Cabbage

48. Figure 22.9e Broccoli

49. Figure 22.9f Kohlrabi

50. • Observation #1: Members of a population often vary in their inherited traits © 2011 Pearson Education, Inc.

51. Figure 22.10

52. • Observation #2: All species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce © 2011 Pearson Education, Inc.

53. Figure 22.11 Spore cloud

54. • Inference #1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals © 2011 Pearson Education, Inc.

55. • Inference #2: This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations © 2011 Pearson Education, Inc.

56. • Darwin was influenced by Thomas Malthus, who noted the potential for human population to increase faster than food supplies and other resources • If some heritable traits are advantageous, these will accumulate in a population over time, and this will increase the frequency of individuals with these traits • This process explains the match between organisms and their environment © 2011 Pearson Education, Inc.

57. Natural Selection: A Summary • Individuals with certain heritable characteristics survive and reproduce at a higher rate than other individuals • Natural selection increases the adaptation of organisms to their environment over time • If an environment changes over time, natural selection may result in adaptation to these new conditions and may give rise to new species © 2011 Pearson Education, Inc. Video: Seahorse Camouflage

58. Figure 22.12 (a) A flower mantid in Malaysia (b) A leaf mantid in Borneo

59. Figure 22.12a (a) A flower mantid in Malaysia

60. Figure 22.12b (b) A leaf mantid in Borneo

61. • Note that individuals do not evolve; populations evolve over time • Natural selection can only increase or decrease heritable traits that vary in a population • Adaptations vary with different environments © 2011 Pearson Education, Inc.

62. Concept 22.3: Evolution is supported by an overwhelming amount of scientific evidence • New discoveries continue to fill the gaps identified by Darwin in The Origin of Species © 2011 Pearson Education, Inc.

63. Direct Observations of Evolutionary Change • Two examples provide evidence for natural selection: natural selection in response to introduced plant species, and the evolution of drug-resistant bacteria © 2011 Pearson Education, Inc.

64. Natural Selection in Response to Introduced Plant Species • Soapberry bugs use their “beak” to feed on seeds within fruits • In southern Florida soapberry bugs feed on balloon vine with larger fruit; they have longer beaks • In central Florida they feed on goldenrain tree with smaller fruit; they have shorter beaks • Correlation between fruit size and beak size has also been observed in Louisiana, Oklahoma, and Australia © 2011 Pearson Education, Inc.

65. • In all cases, beak size has evolved in populations that feed on introduced plants with fruits that are smaller or larger than the native fruits • These cases are examples of evolution by natural selection • In Florida this evolution in beak size occurred in less than 35 years © 2011 Pearson Education, Inc.

66. Figure 22.13a Soapberry bug with beak inserted in balloon vine fruit FIELD STUDY

67. Figure 22.13b On native species, southern Florida Museum-specimen average On introduced species, central Florida Number of individuals 10 8 6 4 2 0 10 8 6 4 2 0 Beak Beak length (mm) 6 7 8 10 11 RESULTS 9

68. The Evolution of Drug-Resistant Bacteria • The bacterium Staphylococcus aureus is commonly found on people • One strain, methicillin-resistant S. aureus (MRSA) is a dangerous pathogen • S. aureus became resistant to penicillin in 1945, two years after it was first widely used • S. aureus became resistant to methicillin in 1961, two years after it was first widely used © 2011 Pearson Education, Inc.

69. • Methicillin works by inhibiting a protein used by bacteria in their cell walls • MRSA bacteria use a different protein in their cell walls • When exposed to methicillin, MRSA strains are more likely to survive and reproduce than nonresistant S. aureus strains • MRSA strains are now resistant to many antibiotics © 2011 Pearson Education, Inc.

70. 1 2,750,000 2,500,000 2,250,000 2,000,000 1,750,000 1,500,000 1,250,000 1,000,000 750,000 500,000 250,000 base pairs Chromosome map of S. aureus clone USA300 Key to adaptations Methicillin resistance Ability to colonize hosts Increased disease severity Increased gene exchange (within species) and toxin production Figure 22.14

71. • Natural selection does not create new traits, but edits or selects for traits already present in the population • The local environment determines which traits will be selected for or selected against in any specific population © 2011 Pearson Education, Inc.

72. Homology • Homology is similarity resulting from common ancestry © 2011 Pearson Education, Inc.

73. Anatomical and Molecular Homologies • Homologous structures are anatomical resemblances that represent variations on a structural theme present in a common ancestor © 2011 Pearson Education, Inc.

74. Figure 22.15 Humerus Radius Ulna Carpals Metacarpals Phalanges Human Cat Whale Bat

75. • Comparative embryology reveals anatomical homologies not visible in adult organisms © 2011 Pearson Education, Inc.

76. Figure 22.16 Pharyngeal pouches Post-anal tail Chick embryo (LM) Human embryo

77. Figure 22.16a Pharyngeal pouches Post-anal tail Chick embryo (LM)

78. Figure 22.16b Pharyngeal pouches Post-anal tail Human embryo

79. • Vestigial structures are remnants of features that served important functions in the organism’s ancestors • Examples of homologies at the molecular level are genes shared among organisms inherited from a common ancestor © 2011 Pearson Education, Inc.

80. Homologies and “Tree Thinking” • Evolutionary trees are hypotheses about the relationships among different groups • Homologies form nested patterns in evolutionary trees • Evolutionary trees can be made using different types of data, for example, anatomical and DNA sequence data © 2011 Pearson Education, Inc.

81. Figure 22.17 Branch point Lungfishes Amphibians Mammals Lizards and snakes Crocodiles Ostriches Hawks and other birds Feathers Amnion Digit- bearing limbs Homologous characteristic Tetrapods Amniotes Birds 1 2 3 4 5 6

82. A Different Cause of Resemblance: Convergent Evolution • Convergent evolution is the evolution of similar, or analogous , features in distantly related groups • Analogous traits arise when groups independently adapt to similar environments in similar ways • Convergent evolution does not provide information about ancestry © 2011 Pearson Education, Inc.

83. Figure 22.18 Sugar glider Flying squirrel NORTH AMERICA AUSTRALIA

84. Figure 22.18 NORTH AMERICA AUSTRALIA

85. The Fossil Record • The fossil record provides evidence of the extinction of species, the origin of new groups, and changes within groups over time © 2011 Pearson Education, Inc.

86. Figure 22.19 Most mammals Cetaceans and even-toed ungulates (a) Canis (dog) (b) Pakicetus (c) Sus (pig) (d) Odocoileus (deer)

87. Figure 22.19a (a) Canis (dog)

88. Figure 22.19b (b) Pakicetus

89. Figure 22.19c (c) Sus (pig)

90. Figure 22.19d (d) Odocoileus (deer)

91. Figure 22.UN01

92. • Fossils can document important transitions – For example, the transition from land to sea in the ancestors of cetaceans © 2011 Pearson Education, Inc.

93. Figure 22.20 Other even-toed ungulates Hippopotamuses † Pakicetus † Rodhocetus † Dorudon Living cetaceans Common ancestor of cetaceans Millions of years ago 70 Key 60 50 40 30 20 10 0 Pelvis Tibia Femur Foot

94. Biogeography • Biogeography , the geographic distribution of species, provides evidence of evolution • Earth’s continents were formerly united in a single large continent called Pangaea , but have since separated by continental drift • An understanding of continent movement and modern distribution of species allows us to predict when and where different groups evolved © 2011 Pearson Education, Inc.

95. • Endemic species are species that are not found anywhere else in the world • Islands have many endemic species that are often closely related to species on the nearest mainland or island • Darwin explained that species on islands gave rise to new species as they adapted to new environments © 2011 Pearson Education, Inc.

96. What Is Theoretical About Darwin’s View of Life? • In science, a theory accounts for many observations and data and attempts to explain and integrate a great variety of phenomena • Darwin’s theory of evolution by natural selection integrates diverse areas of biological study and stimulates many new research questions • Ongoing research adds to our understanding of evolution © 2011 Pearson Education, Inc.

97. Figure 22.UN02 Observations Individuals in a population vary in their heritable characteristics. Organisms produce more offspring than the environment can support. Individuals that are well suited to their environment tend to leave more offspring than other individuals. Inferences and Over time, favorable traits accumulate in the population.

98. Figure 22.UN03

99. Figure 22.UN04