1. Evolutionary Patterns, Rates, and Trends
AP Biology:
Chapter 19
Starr & Taggart – 11th Edition

2. Key Concepts: All species that have ever lived are related
Macroevolution refers to patterns, trends, and rates of change among lineages over geologic time
Fossil and geologic records and radiometric dating of rocks provide evidence of macroevolution
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3. Key Concepts:
Anatomical comparisons help reconstruct patterns of change through time
Biochemical comparisons also provide evidence of macroevolution
Diversity characterizes the distribution of species through time
Taxonomy is concerned with identifying and naming new species
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4. Macroevolution
Large scale patterns, trends and rates of change among families and other more inclusive groups of species.
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5. What is a Species? A mixed herd of zebroids & horses.
Zebroids – are interspecies hybrids (horses & zebras)
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6. What is a Species? Morphological Species Concept
♂ & ♀ fish
Morphological Species Concept
Based on appearance alone
Biological Species Concept
A species is one or more populations of individuals that are interbreeding under natural conditions and producing fertile offspring, and are reproductively isolated from other such populations
Two plants of the same species
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7. Species Example
Lions and tigers do not meet in the wild, so don’t interbreed; in captivity can mate to produce a liger (sterile)
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8. Reproductive Isolation
Cornerstone of the biological species concept
Speciation is the attainment of reproductive isolation
Reproductive isolation arises as a by-product of genetic change
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9. Reproductive Isolating Mechanisms
Any heritable feature of body, form, functioning, or behavior that prevents breeding between one or more genetically divergent populations
Prezygotic or Postzygotic
Prezygotic-
Mechanical isolation
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10. Types of Isolation
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11. Isolating Mechanisms
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12. Pre-Zygotic Isolation
Temporal-
cicada
Pre-Zygotic Isolation
Mating or zygote formation is blocked
Temporal Isolation
Behavioral Isolation
Mechanical Isolation
Ecological Isolation
Gamete Mortality
Behavioral - albatross
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13. Post-Zygotic Isolation
Takes effect after hybrid zygotes form
Zygotic mortality - Egg is fertilized but zygote or embryo dies
Hybrid inviability - First generation hybrid forms but shows low fitness
Hybrid infertility - Hybrid is fully or partially sterile
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14. Genetic Divergence
Gradual accumulation of differences in the gene pools of genetically separated populations
Natural selection, genetic drift and mutation can contribute to divergence
Gene flow counters genetic divergence
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15. Mechanisms of Speciation
Allopatric speciation
Sympatric speciation
Parapatric speciation
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16. Allopatric Speciation
Physical barrier prevents gene flow between populations of a species
Effectiveness of barrier varies with species
Archipelago hotbed of speciation
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17. Allopatric Speciation on Archipelagos (Island Chain)
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Hawaiian Honeycreepers

18. Hawaiian Honeycreepers
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19. Allopatric Speciation
Physical separation between populations promotes genetic changes that eventually lead to speciation.
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20. Speciation without a Barrier
Sympatric speciation
Species form within the home range of the parent species
Parapatric speciation
Neighboring populations become distinct species while maintaining contact along a common barrier
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21. Sympatric Speciation New species forms within home range
Polyploidy leads to speciation in plants
Self-fertilization and asexual reproduction
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22. Sympatric Speciation
A species forms within the home range of an existing species, in the absence of a physical barrier.
A lake in West Africa in which 9 species of cichlids (a small fish)
evolved.
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23. Speciation by Polyploidy
Change in chromosome number (3n, 4n, etc.)
Offspring with altered chromosome number cannot breed with parent population
Common mechanism of speciation in flowering plants
Polyploidy cotton
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24. Allopatric vs. Sympatric Speciation
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25. Parapatric Speciation
Neighboring populations become distinct species while maintaining contact along a common border, the hybrid zone.
Bullock’s oriole
Baltimore oriole
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26. Models of Speciation
Models of speciation
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27. Patterns of Change in a Lineage
Cladogenesis
Branching pattern
Lineage splits, isolated populations diverge
Anagenesis
No branching
Changes occur within single lineage
Gene flow throughout process
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28. Evolutionary Trees extinction (branch ended before present)
new species
branch point (a time of divergence, speciation)
a single lineage
a new species
extinction (branch ended before present)
dashed line (only sketchy evidence of presumed evolutionary relationship)
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29. Gradual Model
Speciation model in which species emerge through many small morphological changes that accumulate over a long time period
Fits well with evidence from certain lineages in fossil record
Time
Punctuated
equilibrium
Gradualism
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30. Punctuation Model
Speciation model in which most changes in morphology are compressed into brief period near onset of divergence
Supported by fossil evidence in some lineages
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31. Adaptive Radiation Burst of divergence
Single lineage gives rise to many new species
New species fill vacant adaptive zone
Adaptive zone is “way of life”
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32. Extinction Irrevocable loss of a species
Mass extinctions have played a major role in evolutionary history
Fossil record shows 20 or more large-scale extinctions
Reduced diversity is followed by adaptive radiation
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33. Who Survives? Species survival is to some extent random
Asteroids have repeatedly struck Earth, destroying many lineages
Changes in global temperature favor lineages that are widely distributed
Mass extinctions
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34. Identifying Species Past and Present
Taxonomy – field of biology concerned with identifying, naming and classifying species
Somewhat subjective
Devised by Carl von Linne
Assigning species names
Binomial nomenclature system
Genus (generic) and Species (specific)
Higher Taxa
Family, Order, Class, Phylum, and Kingdom
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35. Phylogeny
The scientific study of evolutionary relationships among species
Practical applications
Allows predictions about the needs or weaknesses of one species on the basis of its known relationship to another
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36. Examples of Classification
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37. How Many Kingdoms? Whittaker’s Five-Kingdom Scheme (1969) Monera
Protista
Fungi
Plantae
Animalia
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38. Six Kingdom Scheme Carl Woese Includes the Archaebacteria Eubacteria
Protista
Fungi
Plantae
Animalia
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39. Three Domain Scheme Favored by microbiologists Eubacteria
Archaebacteria
Eukaryotes
EUBACTERIA
(Bacteria)
ARCHAEBACTERIA
(Archaea)
EUKARYOTES
(Eukarya)
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40. Constructing A Cladogram
Taxon
Traits (Characters)
Jaws
Limbs
Hair
Lungs
Tail
Shell
Lamprey - - - - + -
Turtle + + - + + +
Cat + + + + + -
Constructing A Cladogram
Gorilla + + + + - -
Lungfish + - - + + -
Trout + - - - + -
Human + + + + - -
Taxon
Traits (Characters)
Jaws
Limbs
Hair
Lungs
Tail
Shell
Lamprey 1
Turtle 1 1 1 1 1
Cat 1 1 1 1 1
Please note: the tail column was changed as it was incorrect in the text.
Gorilla 1 1 1 1
Lungfish 1 1 1
Trout 1 1
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Human 1 1 1 1

41. Constructing a Cladogram
lamprey
turtle, gorilla, trout, cat, lungfish, human
jaws
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42. Constructing a Cladogram
turtle, gorilla, cat, lungfish, human
lamprey
trout
lungs
jaws
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43. Constructing a Cladogram
lamprey
trout
lungfish
turtle, gorilla, cat, human
limbs
lungs
jaws
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44. Constructing a Cladogram
lamprey
trout
lungfish
turtle
gorilla, cat, human
hair
limbs
lungs
jaws
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45. Constructing a Cladogram
lamprey
trout
lungfish
turtle
cat
gorilla
human
tail loss
hair
limbs
lungs
jaws
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46. Constructing a Cladogram
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47. Evolutionary Tree ANIMALS PLANTS arthropods FUNGI chordates
flowering plants
conifers
annelids
round-worms
ginkgos
sac
club
mollusks
echino-derms
fungi
fungi
cycads
horsetails
rotifers
zygospore-
ferns
forming
flatworms
fungi
lycophytes
cnidarians
bryophytes
chlorophytes
sponges
chytrids
green algae
amoeboid
PROTISTANS
protozoans
(stramenopiles)
brown algae
red
ciliates
(alveolates)
algae
chrysophytes
sporozoans
oomycotes ?
dinoflagellates
crown of eukaryotes
slime molds
(rapid divergences)
euglenoids
kinetoplastids
parabasalids
(e.g., Trichomonas)
EUBACTERIA
diplomonads
spirochetes
ARCHAEBACTERIA
(e.g., Giardia)
extreme
Gram-positive bacteria
chlamydias
methanogens
halophiles
cyanobacteria
proteobacteria
extreme
thermophiles
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molecular origin of life

48. In Conclusion
Macroevolution is the study of patterns, trends, or rates of change among groups of species over long periods of time
There is extensive evidence of evolution based on similarities and differences in body form, function, behavior, and biochemistry
Completeness of fossil records are variable
Fossil and geologic record show that such changes have influenced evolution
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49. In Conclusion
Comparative morphology reveals similarities in embryonic development and identified homologous structures
Comparative biochemistry has identified similarities and differences among species
Taxonomists identify, name, and classify species
Chapter 19