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Evolution
I. The Origin Of Life
A.
Evolution = Species change over time
B.
Biogenesis = Life from life
1. Experiments disprove spontaneous
generation
a) Francisco Redi (1668)- Flies only
come from egg’s of other flies
I. The Origin Of Life
b) Lazzaro Spallanzani (1700’s)
1) Air doesn’t form microorganisms
2) Boiled broth did not grow microorganisms
3) Opponents said boiling destroyed the “vital force” in
air
I. The Origin Of Life
c) Louis Pasteur (1800’s)
1) Boiled broth in curved-neck flask (allows air in)
2) No microorganisms form till curved neck is removed
I. The Origin Of Life
C. Earth’s History
1. Earth is 4.6 billion years old
2. Radioactive Dating
a) Radioactive isotopes are used to date fossils.
b) The isotopes decay at a constant known rate.
c) The time it takes for one half of the radioactive material
to decay is called the half-life.
I. The Origin Of Life
3. Organic Compounds
a) Oparin /Haldane
(1923)
1) Early earth
contained ammonia,
hydrogen, water
vapor, and methane
2) No Oxygen
3) Volcanic energy,
lightning, and UV
radiation could
create amino acids.
Haldane
Oparin
I. The Origin Of Life
b) Stanley Miller &
Harold Urey (1953)
1) Experimented with
Oparin’s hypothesis
2) Created all 20 amino
acids, nitrogen
bases, and ATP
c) Sidney Fox
1) Produced
proteinoids (abiotic
polypeptides)
2) Dripped organic
monomers on hot
sand, clay or rock
Urey
Miller
I. The Origin Of Life
4. First Life-Forms
a) Thomas Cech
1) Ribozymes can act
as enzymes and
self-replicate
2) RNA appears to be
the first genetic
material
b) Anaerobic prokaryotes
appear about 4 billion
years ago
c) Photosynthetic
prokaryotes appear 3.5
billion years ago
d) Oxygen levels increase
I. The Origin Of Life
e) Ozone protects life from UV radiation
f) Eukaryotes appear 2 billion years ago
1) Evolve by Endosymbiosis
2) Mutualism between small aerobic prokaryotes and
larger anaerobic prokaryotes
3) Gave rise to mitochondria and chloroplasts
Autotrophic
bacteria
became mitochondria
and chloroplasts
Anaerobic
heterotrophic bacteria
What is endosymbiosis?
Explain natural selection in your own
words. Use the following words:
genetic variation, adaptation,
overpopulation, struggle for
existence.
(minimum of 5 sentences; use text)
II. Theories of Evolution
A.
James Hutton (1726-1797)
1. Geologist
2. Gradualism (1795)
a) Processes today are the
same as in the past
b) Large changes are the
accumulation of slow,
continuous processes.
II. Theories of Evolution
B.
Thomas Malthus (1766-1834)
1. Published essay on human
population (1798)
2. Resources control populations
3. Influences Darwin on his ideas
about organism’s struggle for
existence
II. Theories of Evolution
C.
Jean Baptiste Lamarck (1744-1829)
1. Naturalist
2. Inheritance of acquired
characteristics (1809)
a) Organisms change in
response to the environment.
b) Structures that are used
become stronger, and
structures that are not used
become weaker.
c) Pass new trait to kids
II. Theories of Evolution
D. Charles Lyell (1797-1875)
1. Geologist
2. Proposed Uniformitarianism
(1830)
3. Processes that occur today
have always occurred
II. Theories of Evolution
E. Charles Darwin (1809-1882)
1. Naturalist
2. HMS Beagle (1831)
a) Made observations in
the Galapagos
b) Noted differences in
finches on each island
3. 1844- begins writing The
Origin of Species
II. Theories of Evolution
4. Alfred Wallace (1823-1913)
a) Sends manuscript on
natural selection to
Darwin (1858)
b) Published that year
5. Darwin publishes The
Origin of Species (1859)
a) Descent with
Modification
b) Natural Selection is
mechanism
6. Adaptive advantages are
determined by nature
7. Fitness is an individual’s
gene contribution to the
next generation
III. Evidence of Evolution
A.
Evidence from Fossils
1. Types: Imprints, molds (impressions),
casts (filled impression), tracks, hard
parts, actual remains.
2. Dating Fossils
a) Absolute Dating- Radioactive
isotopes
b) Relative Dating
1) Sediments are layed down in
strata
2) Lowest layers are oldest
3) A fossil's position in
undisturbed rock gives its age
relative to other fossils.
III. Evidence of Evolution
3. The Fossil Record
a) Creates the Geologic Time
Scale
b) Oldest fossils found are 3.5
billion years old and are
prokaryotic cells (bacteria).
c) Fossils show earth's changes
(Organisms, Climate,
Environment)
4. Biogeography- geographical
distribution of species.
4. Biogeography- geographical distribution of species.
III. Evidence of Evolution
B.
Evidence from Living Organisms
1. Homologous Structures
a) Similar features that
originate in a shared
ancestor
b) Structures may have
different uses in adult, but
come from same tissue in
embryo.
c) Analogous Structures
1) Identical functions
2) No embryo tissue in
common
3) Not closely related
III. Evidence of Evolution
2. Vestigial Organs
a) Structures that serve no useful
purpose.
b) Shows relationship to
organisms in which the
structure is functional.
3. Embryology
a) Similarities of embryos
b) Embryo development repeats
evolutionary history
III. Evidence of Evolution
4. Biochemistry
a) Enzymes and structures
for important biological
pathways are universal
(respiration,
photosynthesis)
b) The more similar the
amino acid sequences,
the more closely related
the species.
c) Universal genetic code
IV. Evolution of Populations
A.
Populations are the smallest
unit that can evolve (adapt)
B. Variation exists in a population
1. Due to resources- food, soil
2. Due to heredity- genotype
C. Cause of variation in Genotypes
1. Mutation
2. Recombination (independent
assortment, crossing-over)
3. Random fusion of gametes
IV. Evolution of Populations
D.
Gene Pool
1. All genetic information in a
population
2. Frequency of a certain
allele in a population will
determine the phenotype
frequency
E. Hardy-Weinberg
Equilibrium
1. Allele frequencies stay the
same in an undisturbed
population (genetic
equilibrium)
2. Allows scientists to
measure changes in a
gene pool
A.
V. Disruption of Genetic
Equilibrium
Mutation
1. Caused by mutagens
2. Change DNA
producing totally new
alleles
3. Most are harmful
B. Migration
1. Immigration and
emigration of
individuals
2. Ensures gene flow
V. Disruption of Genetic
Equilibrium
C.
Genetic Drift
1. Change of allele
frequencies due to
random events
2. Small populations
are highly affected
D. Nonrandom Mating
1. Geographic
proximity
2. Assortive matinglike to like
V. Disruption of Genetic
Equilibrium
E.
Natural Selection
1. Most significant factor in evolution of
populations
2. Nature selects against non-fit
individuals
3. Reduces harmful alleles
4.
V. Disruption of Genetic
Equilibrium
Types
a)
b)
c)
d)
Stabilizing Selection- towards the average
Directional Selection- towards one extreme
Disruptive Selection- away from the average
Sexual Selection- females tend to choose
VI. Speciation= 1 species becomes 2
A.
When populations become
significantly different
B. Morphological Species
Concept
1. Physically different
2. Problem- individual variation
C. Biological Species Concept
1. Proposed by Ernst Mayr
2. A population that can
interbreed
3. Problem- Extinct species?
D. Modern Species Concept
1. Morphologically similar
2. Can interbreed to produce
fertile offspring
3. Biochemistry –DNA, Proteins
VI. Speciation
E.
Extinction can be a natural process
1. When conditions change too rapidly
2. When a species is out competed
3. When specialization restricts a lifestyle and conditions
change
VII. Human Evolution
A.
Hominids are extinct humans
and immediate ancestors
B. All hominids are primates
1. Moveable fingers and toes
2. Nails instead of claws
3. Color vision (unusual for
mammals)
4. Binocular Vision
VII. Human Evolution
C.
The First Hominids
1. Australopithecus
a) A. afarensis (3 to 3.9 mya)
1) Lucy
2) Walked upright
b) A. africanus (2.3 to 3 mya)
1) Taller and heavier than
Lucy
2) Slightly larger brain
3) Probably not our direct
ancestor
VII. Human Evolution
2. Genus Homo
a) H. habilis (1.6 to 2.5 mya)
1) “handy human”
2) Stone tools
b) H. erectus (1.8 mya to 500,000 ya)
1) “upright human”
2) Hunted and used fire
3) Typical “cave-man”
VII. Human Evolution
c) H. sapiens (800,000 ya)
1) Neanderthals (230,000 to 300,000 ya)
2) Cro-Magnons (100,000 ya)
a. Modern humans
b. Out competed H. erectus and Neanderthals
VII. Human Evolution
D.
African-origin Hypothesis
1. Based on similarities in mitochondrial DNA
2. Modern humans came from Africa 100000 to 200000 years
ago.