Download Descent with Modification : A Darwinian View of Life

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Descent with Modification
Chapter 22
: A Darwinian View of Life
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The Darwinian revolution challenged traditional views of a young Earth
inhabited by unchanging species
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Geology and gradualism
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Lamarck’s hypothesis of evolution
Inheritance of acquired characteristics
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Voyage of the Beagle
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Variation in beaks and adaptation
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Descent with modification
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Artificial selection
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Variation is present
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Some individuals do not survive
Unequal ability of individuals to survive and reproduce will lead to the accumulation
of favorable traits in the population over generations

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Natural selection
Natural selection is a process in which individuals that have certain heritable traits
survive and reproduce at a higher rate than other individuals because of those traits.
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Natural selection
Natural selection can increase the match between organisms and their environment
over time
Natural selection cannot result in changes in a new environment, which can give rise
to a new species (more on speciation later)

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Some details
Variation must be present for evolution to occur
Evolution occurs at the population level, not the individual level
Natural selection create favorable mutations; a favorable variant must already be
present in population
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Evidence for evolution
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Soapberry bugs
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Results
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Antibiotic resistance
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MRSA
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Homology
Same structure modified for different functions points towards common ancestry
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present in population
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Evidence for evolution
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Soapberry bugs
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Results
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Antibiotic resistance
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MRSA
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Homology
Same structure modified for different functions points towards common ancestry
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Similarities in development
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Vestigial structures
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Convergent evolution causes similarities (analogous traits) not due to
common ancestry
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Fossil evidence
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An adaptation is _____.
A. a trait that gives rise to a new species
B. an individual's attempt to conform to its environment
C. a trait that gives an organism a reproductive advantage in the current environment
D. the cause of natural selection
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A group of small fish live in a lake with a uniformly light-brown sandy
bottom. Most of the fish are light brown, but about 10% are mottled. This
fish species is often prey for large birds that live on the shore. A
construction company dumps a load of gravel in the bottom of the lake,
giving it a mottled appearance. Which of these statements presents the
most accurate prediction of what will happen to this fish population?
A. The ratios will not change.
B. The proportion of mottled fish will increase over time.
C. As the mottled fish are eaten, more will be produced to fill the gap.
D. There is no way to predict the result.
E. In two generations, all the fish will be mottled.
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The wing of a bat is homologous to the _____ of a whale.
A. baleen
B. rib cage
C. flipper
D. blowhole
E. tail
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Which of these lists contains the four postulates of natural selection?
A. Uniform population, heritable traits, selection, differential survival or reproduction
B. Variation in population, heritable variation, selection, unlimited survival and
reproduction
C. Variation in population, environmental variation, selection, differential survival or
reproduction
D. Variation in population, heritable variation, selection, differential survival or
reproduction
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B. Variation in population, heritable variation, selection, unlimited survival and
reproduction
C. Variation in population, environmental variation, selection, differential survival or
reproduction
D. Variation in population, heritable variation, selection, differential survival or
reproduction
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