evolutionary patterns, rates, and trends
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Evolutionary Patterns, Rates, and Trends. AP Biology: Chapter 19. Key Concepts:. All species that have ever lived are related Macroevolution refers to patterns, trends, and rates of change among lineages over geologic time - PowerPoint PPT PresentationTRANSCRIPT
Starr & Taggart – 11th Edition
Evolutionary Patterns, Rates, and Trends
AP Biology: Chapter 19
Chapter 19
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
Chapter 19
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
Chapter 19
Macroevolution Large scale patterns,
trends and rates of change among families and other more inclusive groups of species.
Chapter 19
What is a Species?
A mixed herd of zebroids & horses. Zebroids – are interspecies hybrids (horses & zebras)
Chapter 19
What is a Species?
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
♂ & ♀ fish
Chapter 19
Species Example
Lions and tigers do not meet in the wild, so don’t interbreed; in captivity can mate to produce a liger (sterile)
Chapter 19
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
Chapter 19
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
Chapter 19
Types of Isolation
Chapter 19
Isolating Mechanisms
Chapter 19
Pre-Zygotic Isolation
Mating or zygote formation is blocked Temporal Isolation
Behavioral Isolation
Mechanical Isolation
Ecological Isolation
Gamete Mortality
Behavioral - albatross
Temporal-cicada
Chapter 19
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
Chapter 19
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
Chapter 19
Mechanisms of Speciation
Allopatric speciation
Sympatric speciation
Parapatric speciation
Chapter 19
Allopatric Speciation
Physical barrier prevents gene flow between populations of a species Effectiveness of
barrier varies with species
Archipelago hotbed of speciation
Chapter 19
Allopatric Speciation on Archipelagos (Island Chain)
Hawaiian Honeycreepers
Chapter 19
Hawaiian Honeycreepers
Chapter 19
Allopatric Speciation
Physical separation between populations promotes genetic changes that eventually lead to speciation.
Chapter 19
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
Chapter 19
Sympatric Speciation
New species forms within home range Polyploidy leads to speciation in plants Self-fertilization and asexual reproduction
Chapter 19
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.
Chapter 19
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
Chapter 19
Allopatric vs. SympatricSpeciation
Chapter 19
Parapatric Speciation Neighboring
populations become distinct species while maintaining contact along a common border, the hybrid zone.
Bullock’s oriole
Baltimore oriole
Chapter 19
Models of speciation
Models of Speciation
Chapter 19
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
Chapter 19
Evolutionary Trees
new species
branch point (a time of divergence, speciation)
a single lineage
branch point (a time of divergence, speciation)
a new species
a single lineage
extinction (branch ended before present)
dashed line (only sketchy evidence of presumed evolutionary relationship)
Chapter 19
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
Punctuated equilibrium
Gradualism
Tim
e
Chapter 19
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
Chapter 19
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”
Chapter 19
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
Chapter 19
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
Chapter 19
Identifying SpeciesPast 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
Chapter 19
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
Chapter 19
Examples of Classification
Chapter 19
How Many Kingdoms?
Whittaker’s Five-Kingdom Scheme (1969) Monera Protista Fungi Plantae Animalia
Chapter 19
Six Kingdom Scheme
Carl Woese Includes the Archaebacteria
Eubacteria Archaebacteria Protista Fungi Plantae Animalia
Chapter 19
Three Domain Scheme Favored by microbiologists
Eubacteria Archaebacteria Eukaryotes
EUBACTERIA(Bacteria)
ARCHAEBACTERIA(Archaea)
EUKARYOTES(Eukarya)
Chapter 19
ConstructingACladogram
Jaws Limbs Hair Lungs Tail Shell
- - - - + -
+ + - + + +
+ + + + + -+ + + + - -+ - - + + -+ - - - + -+ + + + - -
Lamprey
Turtle
CatGorillaLungfishTroutHuman
Taxon Traits (Characters)
Jaws Limbs Hair Lungs Tail Shell
0 0 0 0 1 0
1 1 0 1 1 1
1 1 1 1 1 01 1 1 1 0 01 0 0 1 1 01 0 0 0 1 01 1 1 1 0 0
Lamprey
Turtle
CatGorillaLungfishTroutHuman
Taxon Traits (Characters)
Please note: the tail column was changed as it was incorrect in the text.
Chapter 19
jaws
lampreyturtle, gorilla, trout, cat,
lungfish, human
Constructing a Cladogram
Chapter 19
trout
Constructing a Cladogram
jaws
lampreyturtle, gorilla, cat, lungfish, human
lungs
Chapter 19
lungfish
Constructing a Cladogram
trout
jaws
lamprey turtle, gorilla, cat, human
lungs
limbs
Chapter 19
gorilla, cat, humanturtle
Constructing a Cladogram
lungfishtrout
jaws
lamprey
lungs
limbs
hair
Chapter 19
gorilla
Constructing a Cladogram
humanturtlelungfishtrout
jaws
lamprey
lungs
limbs
hair
tail loss
cat
Chapter 19
Constructing a Cladogram
A Cladogram
Chapter 19
Evolutionary Tree
extreme
thermophiles
halophilesmethanogens cyanobacteria
ARCHAEBACTERIA
PROTISTANS
FUNGIPLANTS
ANIMALS
clubfungi
sacfungi
zygospore-forming
fungi
echino-derms
chordatesannelids
mollusks
flatworms
sponges
cnidarians
flowering plants conifers
horsetails
lycophytes
ferns
bryophytes
sporozoans
green algae amoeboidprotozoans
slime molds
ciliatesredalgae
brown algaechrysophytes
cycads
ginkgos
rotifers
arthropodsround-worms
chytrids
oomycotes
euglenoids
dinoflagellates
Gram-positive bacteria
spirochetes
chlamydias
proteobacteria
? crown of eukaryotes
(rapid divergences)
molecular origin of life
EUBACTERIAparabasalids
diplomonads(e.g., Giardia)
(alveolates)
(stramenopiles)
chlorophytes
kinetoplastids
extreme
(e.g., Trichomonas)
Chapter 19
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
Chapter 19
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