1. 22
The Origin of Species

2. That “Mystery of Mysteries”
In the Galápagos Islands Darwin discovered plants and animals found nowhere else on Earth
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3. Figure 22.1
Figure 22.1 How did this flightless bird come to live on the isolated Galápagos Islands?
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4. Speciation is the process by which one species splits into two or more species
Speciation explains the features shared between organisms due to inheritance from their recent common ancestor
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5. Speciation forms a conceptual bridge between microevolution and macroevolution
Microevolution consists of changes in allele frequency in a population over time
Macroevolution refers to broad patterns of evolutionary change above the species level
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6. Concept 22.1: The biological species concept emphasizes reproductive isolation
Species is a Latin word meaning “kind” or “appearance”
Biologists compare morphology, physiology, biochemistry, and DNA sequences when grouping organisms
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7. The Biological Species Concept
The biological species concept states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations
Gene flow between populations holds the populations together genetically
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8. (a) Similarity between different species
Figure 22.2
Figure 22.2 The biological species concept is based on the potential to interbreed rather than on physical similarity.
(a) Similarity between different species
(b) Diversity within a species
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9. (a) Similarity between different species
Figure
Figure The biological species concept is based on the potential to interbreed rather than on physical similarity. (part 1: similarity)
(a) Similarity between different species
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10. Figure a
Figure a The biological species concept is based on the potential to interbreed rather than on physical similarity. (part 1a: Eastern meadowlark)
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11. Figure b
Figure b The biological species concept is based on the potential to interbreed rather than on physical similarity. (part 1b: Western meadowlark)
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12. (b) Diversity within a species
Figure
Figure The biological species concept is based on the potential to interbreed rather than on physical similarity. (part 2: diversity)
(b) Diversity within a species
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13. Reproductive Isolation
Reproductive isolation is the existence of biological barriers that impede two species from producing viable, fertile offspring
Sometimes hybrids, the offspring of crosses between different species, are successfully produced
Reproductive barriers can be classified by whether they act before or after fertilization
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14. Prezygotic barriers block fertilization from occurring by
Impeding different species from attempting to mate
Preventing the successful completion of mating
Hindering fertilization if mating is successful
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15. Habitat isolation Temporal isolation Behavioral isolation (a) (c) (e)
Figure
Prezygotic barriers
Habitat
isolation
Temporal
isolation
Behavioral
isolation
MATING
ATTEMPT
(a)
(c)
(e)
Figure Exploring reproductive barriers (part 1: prezygotic barriers)
(d)
(b)
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16. Habitat isolation: Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers
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17. Figure a
(a)
Figure a Exploring reproductive barriers (part 1a: habitat isolation, apple maggot fly)
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18. Figure b
(b)
Figure b Exploring reproductive barriers (part 1b: habitat isolation, blueberry maggot fly)
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19. Temporal isolation: Species that breed at different times of the day, different seasons, or different years cannot mix their gametes
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20. Figure c
(c)
Figure c Exploring reproductive barriers (part 1c: temporal isolation, summer)
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21. Figure d
(d)
Figure d Exploring reproductive barriers (part 1d: temporal isolation, winter)
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22. Behavioral isolation: Courtship rituals and other behaviors unique to a species are effective barriers
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23. Figure e
(e)
Figure e Exploring reproductive barriers (part 1e: behavioral isolation)
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24. Mechanical isolation Gametic isolation (f) (g)
Figure
Prezygotic barriers
Mechanical
isolation
Gametic
isolation
MATING
ATTEMPT
FERTILIZATION
Figure Exploring reproductive barriers (part 2: prezygotic barriers)
(f)
(g)
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25. Mechanical isolation: Morphological differences prevent successful mating
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26. Figure f
(f)
Figure f Exploring reproductive barriers (part 2f: mechanical isolation)
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27. Gametic isolation: Sperm of one species may not be able to fertilize eggs of another species
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28. Figure g
(g)
Figure g Exploring reproductive barriers (part 2g: gametic isolation)
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29. Postzygotic barriers prevent the hybrid zygote from developing into a viable, fertile adult by
Reduced hybrid viability
Reduced hybrid fertility
Hybrid breakdown
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30. Reduced hybrid viability Reduced hybrid fertility Hybrid breakdown (h)
Figure
Postzygotic barriers
Reduced
hybrid
viability
Reduced
hybrid
fertility
Hybrid
breakdown
VIABLE,
FERTILE
OFFSPRING
FERTILIZATION
(h)
(i)
(l)
Figure Exploring reproductive barriers (part 3: postzygotic barriers)
(j)
(k)
© 2017 Pearson Education, Ltd.

31. Reduced hybrid viability: Genes of the different parent species may interact and impair the hybrid’s development or survival
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32. Figure h
(h)
Figure h Exploring reproductive barriers (part 3h: reduced hybrid viability)
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33. Reduced hybrid fertility: Even if hybrids are vigorous, they may be sterile
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34. Figure i
(i)
Figure i Exploring reproductive barriers (part 3i: reduced hybrid fertility, donkey)
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35. Figure j
(j)
Figure j Exploring reproductive barriers (part 3j: reduced hybrid fertility, horse)
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36. Figure k
(k)
Figure k Exploring reproductive barriers (part 3k: reduced hybrid fertility, mule)
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37. Hybrid breakdown: Some first-generation hybrids are fertile, but when they mate with another species or with either parent species, offspring of the next generation are feeble or sterile
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38. Figure l
(l)
Figure l Exploring reproductive barriers (part 3l: hybrid breakdown)
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39. Figure 22.3 Exploring reproductive barriers
Prezygotic barriers
Postzygotic barriers
Habitat
isolation
Temporal
isolation
Behavioral
isolation
Mechanical
isolation
Gametic
isolation
Reduced
hybrid
viability
Reduced
hybrid
fertility
Hybrid
breakdown
VIABLE,
FERTILE
OFF-
SPRING
MATING
ATTEMPT
FERTILI-
ZATION
(a)
(c)
(e)
(f)
(g)
(h)
(i)
(l)
(d)
(j)
(b)
Figure 22.3 Exploring reproductive barriers
(k)
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40. Limitations of the Biological Species Concept
The biological species concept cannot be applied to fossils or asexual organisms (including all prokaryotes)
The biological species concept emphasizes absence of gene flow
However, gene flow can occur between distinct species
For example, grizzly bears and polar bears can mate to produce “grolar bears”
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41. Grizzly bear (U. arctos)
Figure 22.4
Grizzly bear (U. arctos)
Polar bear
(U. maritimus)
Figure 22.4 Hybridization between two species of bears in the genus Ursus
Hybrid “grolar bear”
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42. Grizzly bear (U. arctos) Figure 22.4-1
Figure Hybridization between two species of bears in the genus Ursus (part 1: grizzly bear)
Grizzly bear
(U. arctos)
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43. Polar bear (U. maritimus) Figure 22.4-2
Figure Hybridization between two species of bears in the genus Ursus (part 2: polar bear)
Polar bear
(U. maritimus)
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44. Hybrid “grolar bear” Figure 22.4-3
Figure Hybridization between two species of bears in the genus Ursus (part 3: “grolar” bear)
Hybrid “grolar bear”
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45. Other Definitions of Species
Other species concepts emphasize the unity within a species rather than the separateness of different species
The morphological species concept defines a species by structural features
It applies to sexual and asexual species and does not rely on information about gene flow but on subjective criteria
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46. The ecological species concept views a species in terms of its ecological niche
It applies to sexual and asexual species and emphasizes the role of disruptive selection
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47. The phylogenetic species concept defines a species as the smallest group of individuals that share a common ancestor, a single branch on a phylogenetic tree
It applies to sexual and asexual species, but it can be difficult to determine the degree of difference required for separate species
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48. Concept 22.2: Speciation can take place with or without geographic separation
Speciation can occur in two ways
Allopatric speciation
Sympatric speciation
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49. (a) Allopatric speciation (b) Sympatric speciation
Figure 22.5
Figure 22.5 The geography of speciation
(a) Allopatric speciation
(b) Sympatric speciation
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50. Allopatric (“Other Country”) Speciation
In allopatric speciation, gene flow is interrupted when a population is divided into geographically isolated subpopulations
For example, the flightless cormorant of the Galápagos likely originated from a flying species on the mainland
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51. The Process of Allopatric Speciation
The definition of a geographic barrier depends on the ability of a population to disperse
For example, a canyon may create a barrier for small rodents, but not birds, coyotes, or pollen
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52. Reproductive isolation may arise as a result of genetic divergence
Separate populations may evolve independently through mutation, natural selection, and genetic drift
Reproductive isolation may arise as a result of genetic divergence
For example, mosquitofish in the Bahamas comprise several isolated populations in different ponds
Populations in ponds with high predation rates have evolved different body shapes from populations in “low-predation” ponds
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53. shape that enables rapid bursts of speed Without predators: body
Figure 22.6
With predators: body
shape that enables rapid
bursts of speed
Without predators: body
shape that favors long,
steady swimming
(a) Differences in body shape
Escape acceleration (m per s2)
110
Survival rate with predators
1.0
100
0.8 90
0.6 80
Figure 22.6 Evolution in mosquitofish populations
0.4 70
0.2 60 50
0.0
Source pond:
predators
present
Source pond: no
predators
Source pond:
predators
present
Source pond: no
predators
(b) Differences in escape acceleration and survival
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54. (a) Differences in body shape
Figure
With predators: body
shape that enables rapid
bursts of speed
Without predators: body
shape that favors long,
steady swimming
Figure Evolution in mosquitofish populations (part 1: body shape)
(a) Differences in body shape
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55. shape that enables rapid bursts of speed
Figure a
With predators: body
shape that enables rapid
bursts of speed
Figure a Evolution in mosquitofish populations (part 1a: body shape under high predation)
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56. Without predators: body shape that favors long, steady swimming
Figure b
Without predators: body
shape that favors long,
steady swimming
Figure b Evolution in mosquitofish populations (part 1b: body shape under low predation)
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57. (b) Differences in escape acceleration and survival
Figure
Escape acceleration (m per s2)
Survival rate with predators
110
1.0
100
0.8 90
0.6 80
0.4 70
0.2 60
Figure Evolution in mosquitofish populations (part 2: acceleration and survival) 50
0.0
Source pond:
predators
present
Source pond: no
predators
Source pond:
predators
present
Source pond: no
predators
(b) Differences in escape acceleration and survival
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58. Evidence of Allopatric Speciation
Reproductive barriers can develop in lab populations that are experimentally isolated and subjected to different environmental conditions
For example, isolated lab populations of fruit flies raised on different diets evolve to digest their food source more efficiently and prefer to mate with partners adapted to the same food source
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59. Experiment Initial population of fruit flies (Drosophila
Figure 22.7
Experiment
Initial population
of fruit flies
(Drosophila
pseudoobscura)
Some flies raised
on starch medium
Some flies raised
on maltose medium
Mating experiments
after 40 generations
Results
Female
Female
Starch
population 1
Starch
population 2
Starch
Maltose
Figure 22.7 Inquiry: Can divergence of allopatric populations lead to reproductive isolation?
population 1
Starch
Starch 22 9 18 15
Male
Male
population 2
Starch
Maltose 8 20 12 15
Number of matings
in experimental group
Number of matings
in control group
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60. Experiment Initial population of fruit flies (Drosophila
Figure
Experiment
Initial population
of fruit flies
(Drosophila
pseudoobscura)
Some flies raised
on starch medium
Figure Inquiry: Can divergence of allopatric populations lead to reproductive isolation? (part 1: experiment)
Some flies raised on
maltose medium
Mating experiments
after 40 generations
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61. Results Female Female Starch Maltose 22 9 18 15 Male Male 8 20 12 15
Figure
Results
Female
Female
Starch
population 1
Starch
population 2
Starch
Maltose
population 1
Starch
Starch 22 9 18 15
Male
Male
population 2
Starch
Maltose
Figure Inquiry: Can divergence of allopatric populations lead to reproductive isolation? (part 2: results) 8 20 12 15
Number of matings
in experimental group
Number of matings
in control group
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62. Allopatric speciation has also been observed in nature
For example, sister species of snapping shrimp (Alpheus) began to diverge 9 to 3 million years ago when they became isolated by the formation of the Isthmus of Panama
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63. A. formosus A. nuttingi ATLANTIC OCEAN Isthmus of Panama PACIFIC OCEAN
Figure 22.8
A. formosus
A. nuttingi
ATLANTIC OCEAN
Isthmus of Panama
PACIFIC OCEAN
Figure 22.8 Allopatric speciation in snapping shrimp (Alpheus)
A. panamensis
A. millsae
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64. Figure
A. formosus
Figure Allopatric speciation in snapping shrimp (Alpheus) (part 1a: A. formosus)
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65. Figure
A. nuttingi
Figure Allopatric speciation in snapping shrimp (Alpheus) (part 1b: A. nuttingi)
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66. Figure
A. panamensis
Figure Allopatric speciation in snapping shrimp (Alpheus) (part 1c: A. panamensis)
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67. Figure
A. millsae
Figure Allopatric speciation in snapping shrimp (Alpheus) (part 1d: A. millsae)
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68. Regions with many geographic barriers typically have more species than do regions with fewer barriers
Reproductive isolation between populations generally increases as the geographic distance between them increases
Reproductive isolation is the result of intrinsic barriers; physical separation is not a biological barrier
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69. Sympatric (“Same Country”) Speciation
In sympatric speciation, speciation takes place in populations that live in the same geographic area
Sympatric speciation occurs when gene flow is reduced between groups that remain in contact through factors including
Polyploidy
Habitat differentiation
Sexual selection
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70. Polyploidy
Polyploidy is the presence of extra sets of chromosomes due to accidents during cell division
Polyploidy is much more common in plants than in animals
An autopolyploid is an individual with more than two chromosome sets, derived from one species
The offspring of mating between autopolyploids and diploids have reduced fertility
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71. An allopolyploid is a species with multiple sets of chromosomes derived from different species
Allopolyploids can successfully mate with each other but cannot interbreed with either parent species
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72. Tetraploid cell 4n New species (4n)
Figure 22.9
Cell
division
error
2n = 6
Tetraploid cell 4n
Meiosis 2n
Figure 22.9 Sympatric speciation by autopolyploidy 2n
New species
(4n)
Gametes produced
by tetraploids
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73. At least five new plant species have evolved by polyploidy speciation since 1850
For example, three diploid species of goatsbeard plant (Tragopogon) have interbred to produce two new tetraploid species
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74. Species A 2n = 6 Species B 2n = 4 Normal gamete n = 3 Normal gamete
Figure s1
Species A
2n = 6
Species B
2n = 4
Normal gamete
n = 3
Normal gamete
n = 2
Figure s1 One mechanism for allopolyploid speciation in plants (step 1)
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75. Species A 2n = 6 Species B 2n = 4 Normal gamete n = 3 Normal gamete
Figure s2
Species A
2n = 6
Species B
2n = 4
Normal gamete
n = 3
Normal gamete
n = 2
Sterile hybrid with
5 chromosomes
Figure s2 One mechanism for allopolyploid speciation in plants (step 2)
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76. Mitotic or meiotic error doubles the chromosome number.
Figure s3
Species A
2n = 6
Species B
2n = 4
Normal gamete
n = 3
Normal gamete
n = 2
Sterile hybrid with
5 chromosomes
Figure s3 One mechanism for allopolyploid speciation in plants (step 3)
Mitotic or meiotic error
doubles the chromosome
number.
New species:
viable, fertile hybrid
(allopolyploid)
2n = 10
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77. Many important crops (oats, cotton, potatoes, tobacco, and wheat) are polyploids
Plant geneticists can produce new polyploid species using chemicals to induce errors in cell division
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78. Habitat Differentiation
Sympatric speciation can also result from the appearance of new ecological niches
For example, the North American maggot fly can live on native hawthorn trees as well as more recently introduced apple trees
Flies that use different host species are reproductively isolated by both habitat and temporal barriers
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79. Sexual Selection Sexual selection can drive sympatric speciation
Sexual selection for mates of different colors has likely contributed to speciation in cichlid fish in Lake Victoria
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80. T. dubius (12) Hybrid species: T. miscellus (24) Hybrid species:
Figure 22.11
T. dubius
(12)
Hybrid species:
T. miscellus
(24)
Hybrid species:
T. mirus
(24)
Figure Allopolyploid speciation in Tragopogon
T. pratensis
(12)
T. porrifolius
(12)
© 2017 Pearson Education, Ltd.

81. Allopatric and Sympatric Speciation: A Review
In allopatric speciation, geographic isolation restricts gene flow between populations
Intrinsic barriers to reproduction may then arise by natural selection, genetic drift, or sexual selection in the isolated populations
Even if contact is restored between populations, interbreeding is prevented by reproductive barriers
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82. In sympatric speciation, a reproductive barrier isolates a subset of a population without geographic separation from the parent species
Sympatric speciation can result from polyploidy, natural selection, or sexual selection
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83. Concept 22.3: Hybrid zones reveal factors that cause reproductive isolation
A hybrid zone is a region in which members of different species mate and produce hybrids
Hybrids are the result of mating between species with incomplete reproductive barriers
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84. Patterns Within Hybrid Zones
A hybrid zone can occur in a single band where adjacent species meet
For example, two species of toad in the genus Bombina interbreed in a long and narrow hybrid zone
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85. Monochromatic orange light
Figure 22.12
Experiment
Monochromatic
orange light
Normal light
P. pundamilia
Figure Inquiry: Does sexual selection in cichlids result in reproductive isolation?
P. nyererei
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86. Normal light P. pundamilia Figure 22.12-1
Figure Inquiry: Does sexual selection in cichlids result in reproductive isolation? (part 1: P. pundamilia, normal)
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87. Monochromatic orange light
Figure
Monochromatic
orange light
P. pundamilia
Figure Inquiry: Does sexual selection in cichlids result in reproductive isolation? (part 2: P. pundamilia, monochromatic)
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88. Normal light P. nyererei Figure 22.12-3
Figure Inquiry: Does sexual selection in cichlids result in reproductive isolation? (part 3: P. nyererei, normal)
© 2017 Pearson Education, Ltd.

89. Monochromatic orange light
Figure
Monochromatic
orange light
P. nyererei
Figure Inquiry: Does sexual selection in cichlids result in reproductive isolation? (part 4: P. nyererei, monochromatic)
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90. Hybrids often have reduced fitness compared with parent species
The distribution of hybrid zones can be more complex if parent species are found in patches within the same region
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91. Hybrid Zones over Time
When closely related species meet in a hybrid zone, there are three possible outcomes
Reinforcement
Fusion
Stability
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92. B. variegata-specific allele
Figure 22.13
Fire-bellied
toad range
Fire-bellied toad, Bombina
bombina
Hybrid zone
Yellow-bellied
toad range
B. variegata-specific allele
Frequency of
0.99
Hybrid
zone
Figure A hybrid zone for Bombina toads in Europe
0.9
0.5
Yellow-bellied
toad range
Fire-bellied
toad range
Yellow-bellied toad, Bombina
variegata
0.1
0.01 40 30 20 10 10 20
Distance from hybrid zone center (km)
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93. Fire-bellied toad range Hybrid zone Yellow-bellied toad range
Figure
Fire-bellied
toad range
Figure A hybrid zone for Bombina toads in Europe (part 1: map)
Hybrid zone
Yellow-bellied
toad range
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94. B. variegata-specific allele
Figure
0.99
B. variegata-specific allele
Frequency of
Hybrid
zone
0.9
0.5
Yellow-bellied
toad range
Fire-bellied
toad range
0.1
Figure A hybrid zone for Bombina toads in Europe (part 2: graph)
0.01 40 30 20 10 10 20
Distance from hybrid zone center (km)
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95. Yellow-bellied toad, Bombina variegata
Figure
Figure A hybrid zone for Bombina toads in Europe (part 3: B. variegata)
Yellow-bellied toad, Bombina
variegata
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96. Fire-bellied toad, Bombina bombina
Figure
Figure A hybrid zone for Bombina toads in Europe (part 4: B. bombina)
Fire-bellied toad, Bombina
bombina
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97. Reinforcement occurs when hybrids are less fit than the parent species
Natural selection strengthens (reinforces) reproductive barriers, and over time the rate of hybridization decreases
Where reinforcement occurs, reproductive barriers should be stronger for sympatric than for allopatric species
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98. Fusion of the parent species into a single species may occur if hybrids are as fit as parents, allowing substantial gene flow between species
For example, fusion of cichlid species in Lake Victoria may be occurring because water pollution has reduced the ability of female cichlids to distinguish males of different species by color
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99. Gene flow Population Barrier to gene flow Figure 22.14-s1
Figure s1 Formation of a hybrid zone and possible outcomes for hybrids over time (step 1)
Barrier to
gene flow
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100. Isolated population diverges. Gene flow Population Barrier to
Figure s2
Isolated
population
diverges.
Gene flow
Population
Figure s2 Formation of a hybrid zone and possible outcomes for hybrids over time (step 2)
Barrier to
gene flow
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101. Isolated population diverges. Hybrid zone Gene flow Population
Figure s3
Isolated
population
diverges.
Hybrid
zone
Gene flow
Population
Figure s3 Formation of a hybrid zone and possible outcomes for hybrids over time (step 3)
Barrier to
gene flow
Hybrid
individual
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102. Isolated population diverges. Possible outcomes: Hybrid zone
Figure s4
Isolated
population
diverges.
Possible
outcomes:
Hybrid
zone
Reinforcement
Gene flow
Fusion
Population
Figure s4 Formation of a hybrid zone and possible outcomes for hybrids over time (step 4)
Barrier to
gene flow
Hybrid
individual
Stability
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103. Stability of the hybrid zone will result if hybrids continue to be produced over time
This may occur if hybrids are at least as likely to survive and reproduce as their parent species
If they are not, gene flow from outside may overwhelm selection for increased reproductive isolation inside the hybrid zone
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103

104. Concept 22.4: Speciation can occur rapidly or slowly and can result from changes in few or many genes
Many questions remain concerning how long it takes for new species to form, or how many genes need to differ between species
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104

105. The Time Course of Speciation
Broad patterns in speciation can be studied using the fossil record, morphological data, or molecular data
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105

106. Patterns in the Fossil Record
The fossil record includes examples of species that appear suddenly, persist essentially unchanged for some time, and then disappear
These periods of apparent stasis punctuated by sudden change are called punctuated equilibria
The punctuated equilibrium model contrasts with a model of gradual change in a species’ existence
© 2017 Pearson Education, Ltd.
106

107. Pundamilia pundamilia
Figure 22.15
Pundamilia nyererei
Pundamilia pundamilia
Figure Fusion: the breakdown of reproductive barriers
Pundamilia “turbid water,”
hybrid offspring from a
location with turbid water
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108. Pundamilia nyererei Figure 22.15-1
Figure Fusion: the breakdown of reproductive barriers (part 1: P. nyererei)
Pundamilia nyererei
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109. Pundamilia pundamilia
Figure
Figure Fusion: the breakdown of reproductive barriers (part 2: P. pundamilia)
Pundamilia pundamilia
© 2017 Pearson Education, Ltd.

110. Pundamilia “turbid water,” hybrid offspring from a location
Figure
Figure Fusion: the breakdown of reproductive barriers (part 3: P. “turbid water”)
Pundamilia “turbid water,”
hybrid offspring from a location
with turbid water
© 2017 Pearson Education, Ltd.

111. Speciation Rates
The punctuated pattern in the fossil record and evidence from lab studies suggest that speciation can be rapid
For example, the sunflower Helianthus anomalus originated from the hybridization of two other sunflower species and quickly diverged into a new species
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111

112. (a) Punctuated model Time (b) Gradual model Figure 22.16
Figure Two models for the tempo of speciation
(b) Gradual model
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113. Figure 22.17 A hybrid sunflower species and its dry sand dune habitat
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114. The interval between documented speciation events ranges from 4,000 years (some cichlids) to 40 million years (some beetles), with an average of 6.5 million years
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114

115. Studying the Genetics of Speciation
A fundamental question of evolutionary biology persists: How many genes change when a new species forms?
Depending on the species in question, speciation might require the change of only a single gene or many genes
For example, in Japanese Euhadra snails, the direction of shell spiral affects mating and is controlled by a single gene
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115

116. In monkey flowers (Mimulus), two genes affect flower color, which influences pollinator attraction
Monkey flowers with different alleles at the flower color loci are less likely to interbreed because they attract different species of pollinators
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116

117. chromosomes are shown)
Figure 22.18
Experiment
H. annuus
gamete
H. petiolarus
gamete
F1 experimental hybrid
(4 of the 2n = 34
chromosomes are shown)
Results
H. anomalus
Chromosome 1
Figure Inquiry: How does hybridization lead to speciation in sunflowers?
Experimental hybrid
H. anomalus
Chromosome 2
Experimental hybrid
H. annuus–specific marker
H. petiolarus–specific marker
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118. In other organisms, speciation can be influenced by larger numbers of genes and gene interactions
For example, isolation between species of sunflowers in the genus Helianthus is influenced by at least 26 chromosome sections (number of genes unknown)
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118

119. From Speciation to Macroevolution
Macroevolution is large-scale evolutionary change resulting from the cumulative effect of many speciation and extinction events
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119

120. (b) M. lewisii with M. cardinalis allele
Figure 22.19
(a) Mimulus lewisii
(b) M. lewisii with M. cardinalis allele
Figure A locus that influences pollinator choice
(c) Mimulus cardinalis
(d) M. cardinalis with M. lewisii allele
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121. (a) Mimulus lewisii Figure 22.19-1
Figure A locus that influences pollinator choice (part 1: M. lewisii)
(a) Mimulus lewisii
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122. (b) M. lewisii with M. cardinalis allele
Figure
Figure A locus that influences pollinator choice (part 2: M. lewisii with M. cardinalis allele)
(b) M. lewisii with M. cardinalis allele
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123. (c) Mimulus cardinalis
Figure
Figure A locus that influences pollinator choice (part 3: M. cardinalis)
(c) Mimulus cardinalis
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124. (d) M. cardinalis with M. lewisii allele
Figure
Figure A locus that influences pollinator choice (part 4: M. cardinalis with M. lewisii allele)
(d) M. cardinalis with M. lewisii allele
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125. Figure 22.UN01-1
Figure 22.UN01-1 Skills exercise: identifying independent and dependent variables, making a scatter plot, and interpreting data (part 1)
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126. Figure 22.UN01-2
Figure 22.UN01-2 Skills exercise: identifying independent and dependent variables, making a scatter plot, and interpreting data (part 2)
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127. Allopatric speciation Sympatric speciation
Figure 22.UN02
Original population
Figure 22.UN02 Summary of key concepts: speciation and geographic separation
Allopatric speciation
Sympatric speciation
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128. Ancestral species: AA BB DD Triticum monococcum (14) Wild Triticum
Figure 22.UN03
Ancestral species: AA BB DD
Triticum
monococcum
(14)
Wild
Triticum
(14)
Wild
T. tauschii
(14)
Product:
Figure 22.UN03 Test your understanding, question 7 (polyploidy)
AA BB DD
T. aestivum
(bread wheat)
(42)
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129. Figure 22.UN04
Figure 22.UN04 Test your understanding, question 11 (strawberry poison dart frog, Dendrobates pumilio)
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