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

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All species that have ever lived are related
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Macroevolution refers to patterns, trends, and rates of change among lineages over geologic time
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Fossil and geologic records and radiometric dating of rocks provide evidence of macroevolution
Chapter 19

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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
Chapter 19

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Large scale patterns, trends and rates of change among families and other more inclusive groups of species.
Chapter 19

A mixed herd of zebroids & horses.
Zebroids – are interspecies hybrids (horses & zebras)
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♂ & ♀ fish
What is a Species?
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Morphological Species Concept
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Based on appearance alone
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Biological Species Concept
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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
Chapter 19
Two plants of the same species

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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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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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Reproductive Isolating
Mechanisms
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Any heritable feature of body, form, functioning, or behavior that prevents breeding between one or more genetically divergent populations
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Prezygotic or Postzygotic
Prezygotic-
Mechanical isolation
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Isolating
Mechanisms

Temporalcicada
Pre-Zygotic
Isolation
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Mating or zygote formation is blocked
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Temporal Isolation
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Behavioral Isolation
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Mechanical Isolation
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Ecological Isolation
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Gamete Mortality
Behavioral - albatross
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Post-Zygotic Isolation
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Takes effect after hybrid zygotes form
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Zygotic mortality - Egg is fertilized but zygote or embryo dies
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Hybrid inviability - First generation hybrid forms but shows low fitness
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Hybrid infertility - Hybrid is fully or partially sterile
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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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Allopatric speciation
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Sympatric speciation
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Parapatric speciation
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Allopatric Speciation
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Physical barrier prevents gene flow between populations of a species
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Effectiveness of barrier varies with species
Archipelago hotbed of speciation
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Allopatric Speciation on
Archipelagos (Island
Chain)

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Allopatric Speciation
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Physical separation between populations promotes genetic changes that eventually lead to speciation.
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Sympatric speciation
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Species form within the home range of the parent species
Parapatric speciation
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Neighboring populations become distinct species while maintaining contact along a common barrier
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Sympatric Speciation
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New species forms within home range
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Polyploidy leads to speciation in plants
Self-fertilization and asexual reproduction
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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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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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Bullock’s oriole
Parapatric Speciation
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Neighboring populations become distinct species while maintaining contact along a common border, the hybrid zone.
Baltimore oriole
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Models of speciation
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Cladogenesis
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Branching pattern
Lineage splits, isolated populations diverge
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Anagenesis
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No branching
Changes occur within single lineage
Gene flow throughout process
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new species branch point
(a time of divergence, speciation) branch point
(a time of divergence, speciation) a single lineage a new species a single lineage
Chapter 19 extinction
(branch ended before present) dashed line
(only sketchy evidence of presumed evolutionary relationship)

Punctuated equilibrium
Gradualism
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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
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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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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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Irrevocable loss of a species
Mass extinctions have played a major role in evolutionary history
Fossil record shows 20 or more largescale extinctions
Reduced diversity is followed by adaptive radiation
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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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Identifying Species
Past and Present
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Taxonomy – field of biology concerned with identifying, naming and classifying species
Somewhat subjective
Devised by Carl von Linne
Assigning species names
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Binomial nomenclature system
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Genus (generic) and Species (specific)
Higher Taxa
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Family, Order, Class, Phylum, and Kingdom
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The scientific study of evolutionary relationships among species
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Practical applications
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Allows predictions about the needs or weaknesses of one species on the basis of its known relationship to another
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How Many Kingdoms?
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Whittaker’s Five-Kingdom Scheme (1969)
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Monera
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Protista
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Fungi
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Plantae
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Animalia
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Six Kingdom Scheme
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Carl Woese
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Includes the Archaebacteria
Eubacteria Archaebacteria Protista Fungi Plantae Animalia
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Favored by microbiologists
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Eubacteria
Archaebacteria
Eukaryotes
EUBACTERIA
(Bacteria)
ARCHAEBACTERIA
(Archaea)
EUKARYOTES
(Eukarya)
Chapter 19

Constructing
A
Cladogram
Taxon Traits (Characters)
Lamprey
Turtle
Cat
Gorilla
Lungfish
Trout
Human
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Jaws Limbs Hair Lungs Tail Shell
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Please note: the tail column was changed as it was incorrect in the text.
Taxon Traits (Characters)
Lamprey 0
Turtle 1
Cat
Gorilla
Lungfish
Trout
Human
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1
1
1
1
1
Jaws Limbs Hair Lungs Tail Shell
0
1
0
0
1
1
1
0
0
0
0
1
1
1
0
1
1
0
1
1
1
1
1
1
1
1
0
0
0
1
0
0
0
0
0

lamprey
turtle, gorilla, trout, cat, lungfish, human jaws
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turtle, gorilla, cat, lungfish, human lamprey trout jaws lungs
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lamprey trout lungfish turtle, gorilla, cat, human jaws lungs limbs
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lamprey trout lungfish turtle gorilla, cat, human jaws lungs limbs
Chapter 19 hair

lamprey trout lungfish turtle cat gorilla human hair tail loss limbs lungs jaws
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Constructing a Cladogram
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PLANTS flowering plants conifers ginkgos cycads
FUNGI sac fungi club fungi
ANIMALS arthropods annelids mollusks chordates roundworms echinoderms rotifers horsetails ferns lycophytes zygosporeforming fungi flatworms cnidarians bryophytes chlorophytes sponges green algae amoeboid chytrids protozoans
PROTISTANS
(stramenopiles) brown algae chrysophytes red algae ciliates (alveolates) sporozoans oomycotes slime molds
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crown of eukaryotes
(rapid divergences) dinoflagellates euglenoids kinetoplastids parabasalids
(e.g., Trichomonas)
ARCHAEBACTERIA methanogens diplomonads extreme halophiles
(e.g., Giardia)
Gram-positive bacteria cyanobacteria extreme thermophiles
EUBACTERIA spirochetes chlamydias proteobacteria
Chapter 19 molecular origin of life

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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
Chapter 19

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Comparative morphology reveals similarities in embryonic development and identified homologous structures
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Comparative biochemistry has identified similarities and differences among species
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Taxonomists identify, name, and classify species
Chapter 19