Download 16 BioA Evolution2012

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Video Clip
•  100 Greatest Discoveries
Lamarck
•  Organisms adapted by
acquiring traits
–  change in their life time
•  Disuse
Cave fish No eyes
TapewormNo digestive system
•  Use & Need
–  transmit acquired characteristics
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Charles Darwin
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1809-1882
Naturalist
natural selection
Collected clear
evidence
Voyage of the HMS
Beagle
•  travel around the world
–  1831-1836 (22 years old!)
–  Mission: Chart the S.
American coastline
–  Collector
Robert Fitzroy
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Voyage of the HMS Beagle
Found Fossils
Armadillos are native to the
Americas, with most species
found in South America.
Glyptodont fossils are
also unique to South
America.
Why should extinct
armadillo-like species
& living armadillos be
found on the same
continent?
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Darwin found! birds
Collected many
different birds on the
Galapagos Islands.
Finch?
Sparrow?
Thought he had found
very different kinds!
Woodpecker?
Warbler?
But Darwin found! a lot of
Darwin was amazed to finches
find out:
All 14 species of birds
were finches!
But there is only one
species of finch on the
mainland!
Finch?
Large Ground
Finch?
Finch
Sparrow?
Small Ground
Sparrow?
Finch
How did
one species
of finches become
so many different
species now?
Woodpecker?
Warbler Finch
Woodpecker?
Warbler?
Veg. Tree Finch
Warbler?
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Tree Thinking
Descendant
species
Ancestral
species
Large-seed
Large Ground
eater?
Finch
Warbler?
Warbler Finch
Small-seed
Small Ground
eater?
Finch
Leaf-browser?
Veg. Tree Finch
Artificial selection
This is not just a
process of the
past!
It is all
around
us today
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Selective
breeding
the raw genetic
material (variation)
is hidden there
November 24, 1859, Darwin published
“On the Origin of Species by Means of Natural Selection”
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A Mechanism of Natural Selection
•  Observation:
Organisms have
great reproductive
potential
A Mechanism of Natural Selection
•  Observation:
Population sizes are
stable
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A Mechanism of Natural Selection
•  Observation:
Resources are limited
A Mechanism of Natural Selection
•  Inference:
Competition
Struggle for
Existence
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A Mechanism of Natural Selection
•  Observation:
Variation exists in the
population
A Mechanism of Natural Selection
•  Observation:
Variation is
inheritabled
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A Mechanism of Natural Selection
•  Inference: Survival
depends on hereditary
characteristics;
•  Best fit for
environment will leave
more offspring
Differential Reproduction
Essence of Darwin’s ideas
•  Natural selection
–  Heritable variation exists in populations
–  over-production of offspring
•  more offspring than the environment can support
–  competition
•  for food, mates, nesting sites, escape predators
–  differential survival
•  successful traits = adaptations
–  differential reproduction
•  adaptations become more
common in population
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Artificial Selection of Domestic Breeds
Mustard Plant
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Artificial Selection of Domestic Breeds
Dogs
Artificial Selection of Domestic Breeds
Chili Pepper Plants
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Artificial Selection:
Drosophilia
Bristle number in Drosophilia
EXAMPLE
TODAY:
Antibiotic
and
Pesticide
Resistance
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Evidence for Evolution
Fossil Evidence
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Transitional
Fossils
Land Mammal
?!
?!
the
are l
e
r
Whe sitiona
tran sils?
fos
?!
?!
Show Film on Whale
Fossils (2:56 - 16:40)
Basilosaurus!
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2006 Fossil Discovery of Early Tetrapod
•  Tiktaalik!
!  “missing link” from sea
to land animals!
Evidence for Evolution
Biogeographic Evidence
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Biogeographic Evidence
Niche
Burrower
Placental Mammals
Mole
Marsupial mole
Anteater
Numbat
Anteater
Nocturnal
insectivore
Australian Marsupials
Mouse
Climber
Marsupial mouse
Spotted cuscus
Lemur
Glider
Stalking
predator
Chasing
predator
Flying
squirrel
Sugar glider
Ocelot
Tasmanian cat
Wolf
Tasmanian “wolf”
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Evidence for Evolution
Comparative Anatomy Evidence
Draw using 8 straight lines:
! An Airplane Wing
! A Tripod
! A Canoe Paddle
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Homologous Structures
Homologous Structures
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Analogous Structures
Convergent evolution
•  Fish: aquatic vertebrates !
•  Dolphins: aquatic mammals!
Tails
Fins
Body
Shape
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Vestigial Structures
Vestigial Structures
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Evidence for Evolution
Comparative Embryological Evidence
Vidio clip:http://www.pbs.org/wgbh/evolution/library/04/2/l_042_02.html
Evidence for Evolution
Comparative Embryological Evidence
Which is a dolphin? Human? Cat?
Cat
Human
Dolphin
GUESS THE EMBRYO HERE: http://www.pbs.org/wgbh/nova/evolution/guess-embryo.html
Vidio clip:http://www.pbs.org/wgbh/evolution/library/04/2/l_042_02.html
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Evidence for Evolution
Molecular/Biochemical Evidence
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All cells have DNA
All cells have same DNA code
All cells have RNA
All cells use same 20 amino acids
All cells use ATP to transfer energy
Biochemical Evidence
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Molecular Biology Evidence
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Practice applying the Hardy-Weinberg Equation
Pg. 184 (HW), Pg. 187-8
What can cause a change in allele frequencies?
When is this change adaptive?
1) Mutations
Brown Body !
Green Body!
Increase the Variety
How else does nature
increase variety?
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2) Genetic Drift
Changes in gene pool over!
time due to chance.!
Increase “drift” in small!
populations.!
2) Genetic Drift
--> 2 “things” that decrease a population
Bottleneck effect
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2) Genetic Drift
--> 2 “things” that decrease a population
Founder effect
Boy with Huntington’s in Venezuela
3) Gene Flow --> Migration of…..
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3) Gene Flow --> concerns with GMO crops
4) Nonrandom Mating
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5) Natural Selection
PRACTICE
•  Look at pg. 189
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1) Stabilizing!
Frequency of individuals
Types of
Natural Selection!
Original
population
Phenotypes (fur color)
Original
population
Evolved
population
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Frequency of individuals
Types of
Natural Selection
1)  Stabilizing!
2)  Directional!
Original
population
Phenotypes (fur color)
Original
population
Evolved
population
Types of
Natural Selection
Frequency of individuals
Stabilizing selection
Original
population
1)  Stabilizing!
2)  Directional!
3)  Disruptive!
!
Phenotypes (fur color)
Original
population
Evolved
population
Stabilizing selection
Directional selection
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Banded Snails
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# with Trait!
R O Y G B I V!
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# with Trait!
# with Trait!
# with Trait!
R O Y G B I V!
R O Y G B I V!
R O Y G B I V!
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# with Trait!
# with Trait!
R O Y G B I V!
R O Y G B I V!
PRACTICE
•  Look at page. 185
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How does one species turn into two?!
How do different species stay different species?!
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Ligers: Hybrid of male lion and female
Tigons: Male tiger
and female lion
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Horse + Donkey = Mule
64 + 62
= 63
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Mechanisms of Speciation
Geographic Isolation
Population
Geographical
Barrier
Evolve:
Genetically
Different
Unable to
breed
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Mechanisms of Speciation
Squirrels of the Grand Canyon separated by the Colorado River
N
S
Kaibab squirrel (Sciurus
aberti kaibabensis)
Abert squirrel (Sciurus aberti
aberti)
Pangea
Other Continents
Australia
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Mechanisms of Speciation
•  one species to several
•  species find a specific niche
•  become own species
Honey Creepers,
Hawaiian Islands
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Mechanisms of Speciation
When one or very few species give rise to many new
species within a relatively short period of time.
Adaptive Radiation
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Adaptive Radiation:
Hawaiian Honeycreepers
How does a species STAY a species?
Reproductive Isolation --> #1 Temporal Isolation
Rana aurora
breeds January - March
Rana boylii
breeds late March - May
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How does a species STAY a species?
Temporal Isolation: Another Example
How does a species STAY a species?
Reproductive Isolation --> #2 Habitat Isolation
Rana aurora (Red-legged frog)
breeds in fast-moving, streams.
Rana catesbiana (Bullfrog)
breeds in permanent ponds.
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How does a species STAY a species?
Reproductive Isolation --> #3 Behavioral Isolation
Reproductive Isolation: Behavioral
Rana utricularia
(Southern Leopard
Frog)
Rana
catesbiana
(Bullfrog)
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More Examples: Behavioral Isolation
How does a species STAY a species?
Reproductive Isolation --> #4 Mechanical Isolation
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How does a species STAY a species?
Reproductive Isolation --> #5 Gametic Isolation
How does a species STAY a species?
Postzygotic --> Reproductive Isolation
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How does a species STAY a species?
Summary of Reproductive Barriers
Zygote
Gametes
Prezygotic barriers
Postzygotic barriers
• Temporal isolation
• Habitat isolation
• Behavioral isolation
• Mechanical isolation
• Gametic isolation
• Hybrid
incompatibility
Viable,
fertile
offspring
Mechanisms of Speciation
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Patterns of Evolution
Species of different ancestry begin to share similar traits.
Shared environment (same selection pressures)
Patterns of Evolution
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Patterns of Evolution
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Predation and Coevolution
Butterfly and the Passion Vine!
HIGH FITNESS
• Lots of offspring
• Pass on most # of genes to gene pool
LOW FITNESS
• Few offspring
• Pass on least # of genes to gene pool
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Natural Selection --> Perfect Organisms?????
1. Organisms are limited by the structure of their ancestors.
You can only change so much.
2. Adaptations are often compromised.
Which is better?? Large or small webbed feet?
3. Chance a bigger factor than we realize.
What are the chances of finding “perfect trait” &
selecting for it.
4. Select from only existing variations.
Can’t create variation on demand.
Evolutionary
Relationships
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Binomial
nomenclature
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Phylogeny - The evolutionary history of a species.
Cladistics - a system of taxonomy that reconstructs
phylogenies by inferring relationships based on characteristics.
Cladogram
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What is a Clade?
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Trees not Ladders
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Not “Higher or lower”
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Shared Derived
Characteristics
CAUTION:
Homology vs Analogy
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Adding
Time to a
Cladogram
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Cladistics – Using characteristics to determine
evolutionary relationships
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Cladogram
dimetrodon
dimetrodon
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