Transcript ChapterEvolutionAP[1]

Chapter 9 Evolution
Barron’s Book
Microevolution
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House sparrows have adapted to the
climate of North America, ]
mosquitoes have evolved in response to
global warming,
and insects have evolved resistance to
our pesticides.
These are all examples of
microevolution — evolution on a small
scale.
Macroevolution
Anagenesis vs. Cladogenesis
Evidence for Evolution
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We will discuss FIVE
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Fossil Record
Transitional fossils
Comparative Anatomy
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Homologous
Analogous
Vestigial
Comparative Embryology
Comparative Embryology
Comparative Embryology
Molecular Biology
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Cytochrome C – polypeptide (amino
acid sequence)
Biogeography
Biogeography
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Most of the 140 species of marsupials in
Australia are found nowhere else in the
world.
Worldwide Distribution of the Order Marsupiala
No.
No.
Common Names
Scientific
Name
Oppossums
Didelphidae
12
70
Americas
Marsupial Mice, Marsupial Cats,
Tasmanian Devil
Dasyuridae
14
50
Australasia
Tasmanian Wolf
Thylacinidae
1
1
Tasmania
Numbats/Banded Anteaters
Myrmecobiid
ae
1
1
Australia
Bandicoots
Peramelidae
8
18
Australasia
Shrew Oppossums
Caenolestida
e
3
7
South America
Possums, Cuscuses, Gledero,
Ringtails
Phalangerida
e
13
40
Australasia
Noolkanger or Honey Possum
Tarsipedidae
1
1
Australia
Koalas
Phoscolaratid
ae
1
1
Australia
Wombats
Vombatidae
2
4
Australia
Kangaroo/Wallabies, Potoroos, Rat
Kangaroos
Macrophodid
ae
15
47
Australasia
Gen
era
Speci
es
Distribution
Bi-nomial nomenclature
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Homo sapiens
Lizardus Dominicanus
Cuvier
Hutton and Lyell
Lamarck
“acquired characteristics”
Alfred Wallace
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Published an essay discussing natural
selection, prompting Darwin to publish
his book
Charles Darwin
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Early 1840’s theory is worked out
Publishes “On the origin of Species” in
1859
4 tenets of natural selection
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Over population
Advantageous traits
Types of Selection
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Stabilizing
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MRSA - The deadliest form of Staph
MRSA stands for methicillin-resistant staphylococcus aureus
Staph bacteria that are resistant to the action of methicillin and related
antibiotics are referred to as MRSA
MRSA are not only resistant to all penicillin-like antibiotics, but they are often
resistant to many other types of antibiotics as well.
Infections with MRSA can be costly and difficult to treat because of limited
antibiotic options.
The proportion of staph infections that are methicillin-resistant has been steadily
increasing, especially in the last 15-20 years.
By 2003, the percentage of MRSA among all staph isolates had risen three-fold
to 38.6%. Almost 40% of staph found is MRSA now!
MRSA is spread by physical contact, person to person, or person to
contaminated object
MRSA symptoms for the most part, not different from any other staph infection
Diagnosis is confirmed by identifying the bacteria grown in a laboratory culture
from a sample. The sample may be from a sterile site, such as blood or
cerebrospinal fluid (CSF), or from a non-sterile site such as a draining lesion or a
swab of the back of the nose.
Sexual Selection
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sexual dimorphism bestows upon the
females a large, pink, pillowy buttocks
sexual dimorphism bestows upon the females a large, pink, pillowy buttocks
Artificial Selection
Sources of Variation in Population
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100’s of breeds of dogs…1 species,
demonstrates the tremendous potential
for variation
…extent of variability, is a major
determinant of capacity for evolution
Balanced Polymorphism
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Two phenotypes in one species, each
better for its own environment
Mutations
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Provide new alleles in gene pool
Adaptations
Sexual Reproduction
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Provides variation
Independent assortment of
chromosomes
Crossing Over
Random Fertilization
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A zygote is formed by
the random union of
independentlyproduced gametes.
For humans, the
number of different
gametes is 223 * 223,
or 8,388,6082, giving
70,368,744,177,664
(70 trillion) possible
combinations.
Outbreeding
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Mating organisms that are not closely
related….
Is that bad or good?
Promotion of Outbreeding
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Flowering plants..male and female parts
mature at different times
Lions---dominant male chases away
young maturing males…
Diploidy
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2n condition, whole other set of genes
that could be an advantage when
conditions change
Heterozygote superiority
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Hybrids have an advantage **
Population retains greater variation
Ex sickle cell anemia
Ss- no sickle cell, and resistance to
malaria
SS no sickle cell, die from malaria
ss has sickle cell, and may die from
that
Frequency Dependent
Selection
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Minority advantage
Decrease frequency of
more common
phenotypes
Ex.) Search
image….predators are
used to chasing prey that
looks a certain way, if
you look different you
Evolutionary Neutral Traits
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Bloodtype
Fingerprint variation
Where from?
Why?
Function?
….all unknowns
Causes of Evolution
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Genetic Drift: change due to chance
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Bottleneck effect (fire, earthquake, flood)…
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Founder effect
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Small population
breaks away from a
larger one. Rarer
alleles are over
represented…..
Amish 1770’s German
population, extreme
isolation, and
intermarriage
Gene Flow
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Movement of alleles in or out of
population
Migrations
Mutations
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Changes in genetics material
Nonrandom mating
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Individuals chose mates for a specific
reason
http://www.pbs.org/wgbh/evolution/libr
ary/01/6/quicktime/l_016_08.html
Natural selection
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Environment changes
Those who are better adapted to it
“are selected for”
They survive
They reproduce and those genes are
passed on…
Sources of Stability in
populations
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Hardy and Weinberg
Stable population would require 5
things
large
Isolated
No mutations
Mating random
No natural selection
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This is purely hypothetical, it CANNOT
exist
Hardy Weinberg Equation
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Calculate frequencies of alleles in
population
P dominant allele
Q recessive allele
Problems 1, 2, 3 – go over together
Speciation
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To be of the same species….
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Potential to interbreed in nature
Produce fertile viable offspring
Allopatric speciation
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Caused by geographic isolation
Sympatric Speciation
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Polyploidy- more than 1 set of chrom
Habitat isolationBehavioral isolation
Temporal isolation
Reproductive isolation
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Plants that are polyploidy CANNOT
breed with plants that have the normal
number of chromosomes
Habitat Isolation
Behavioral Isolation
Temporal Isolation
Reproductive Isolation
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Anatomical incompatibility
Small male dog and large female dog
cannot mate
Prezygotic barriers- prevent mating
Postzygotic barriers- mating occurs but
offspring is infertile
Patterns of Evolution
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Divergent
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Convergent
Convergent
Parallel Evolution
Coevolution
Adaptive Radiation
Macroevolution
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Gradualism- organisms descended from
a common ancestor gradually, in a
linear and branched fashion.
Prob: A lot of missing links haven’t been
found
Punctuated Equilibrium
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Gould and Eldridge- new species appear
suddenly after long periods of stasis…
See figures page 183
Origin of Life
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Earth age 4.6 billion years
Ancient atmosphere, had many gases
but lacked free oxygen
UV rays and lightening
Mimicking early Early Earth….
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Mitochondrial DNA, is inherited from the
mother…..