SFSU BIO 240 EXAM 1 QUESTIONS AND ANSWERS
VERIFIED 100% CORRECT
● How is evolution defined, and why doesn't it occur within individuals? -
ANSWER -Evolution is defined as the change in inherited characteristics within a
population of organisms over generations, meaning it occurs at the population
level, not within individual organisms because individuals cannot change their
genetic makeup significantly during their lifetime; instead, evolution happens
when advantageous traits are passed on from parents to offspring, gradually
altering the characteristics of the entire population over time
● How is evolution different from selection? - ANSWER -Evolution refers to the
overall change in the inherited traits of a population over generations, while
selection is a specific mechanism within evolution, where certain individuals with
advantageous traits are more likely to survive and reproduce, thus driving the
population towards those traits over time; essentially, selection is a key process
that contributes to evolution, but not the entire concept itself
Four mechanisms of evolution - ANSWER -Mutation, genetic drift, gene flow,
selection
○ Mutation example - ANSWER -Peppered moth: In England, the industrial
revolution led to darkened tree bark, which favored the survival of dark-colored
peppered moths that had a genetic mutation for darker coloration, while the
previously dominant light-colored moths became less common due to predation
bottleneck example - ANSWER -The northern elephant seal population
experienced a bottleneck in the 1890s due to hunting, which reduced their
population to as few as 20 individuals. The population has since rebounded, but the
genetic variation is still reduced compared to other elephant seal populations.
founder effect example - ANSWER -This population is descended from a small
number of Dutch colonists who carried a higher than average percentage of the
gene that causes Huntington's disease. The Afrikaner population has a much higher
frequency of the Huntington's disease gene than the total human population.
gene flow example - ANSWER -pollen from one flower species carried by wind to
another population of the same species can introduce new genetic variations to that
population, enhancing its overall diversity
, selection example - ANSWER -A moth with a coloration that effectively
camouflages it against tree bark in a forest will have a higher fitness than a brightly
colored moth in that same forest. However, if the same moth species moves to a
desert environment with sandy coloration, the previously camouflaged moth would
now be easily visible to predators, making its fitness significantly lower in that
new context
Critique the phrase "Survival of the fittest in the struggle for existence, leading to
progress and more complexity." - ANSWER -it should be "long term reproduction
of the the "fittest" in the struggle for existence sometimes leads to "progress" in a
specific environment."
● What 3 conditions must be present for natural selection to occur? - ANSWER -
variation within a population, inheritance of traits from parents to offspring
(heritability), and differential reproductive success
How do variations in traits affect an organism's fitness - ANSWER -determines
how well it can survive and reproduce in its environment; traits that provide an
advantage in a specific environment will increase an organism's fitness, allowing it
to produce more offspring, while traits that are disadvantageous will decrease
fitness and limit reproductive success.
directional selection example - ANSWER -In a changing climate, a population of
rabbits may experience directional selection if those with thicker fur are more
likely to survive harsh winters, leading to a gradual increase in the population's
average fur thickness.
stabilizing selection example - ANSWER -In a bird species, individuals with
average wing size are more efficient flyers and thus more likely to survive and
reproduce, while birds with extremely small or large wings are less successful
disruptive selection example - ANSWER -In a population of finches, birds with
small beaks are efficient at eating small seeds, while birds with large beaks are
better at eating large seeds, while birds with medium-sized beaks are not well
adapted to either seed type.
How does antibiotic resistance evolve in bacteria and what is the role of selection,
type of selection and selective pressures, and what is changing over time? -
ANSWER -Antibiotic resistance in bacteria evolves through a process of natural
VERIFIED 100% CORRECT
● How is evolution defined, and why doesn't it occur within individuals? -
ANSWER -Evolution is defined as the change in inherited characteristics within a
population of organisms over generations, meaning it occurs at the population
level, not within individual organisms because individuals cannot change their
genetic makeup significantly during their lifetime; instead, evolution happens
when advantageous traits are passed on from parents to offspring, gradually
altering the characteristics of the entire population over time
● How is evolution different from selection? - ANSWER -Evolution refers to the
overall change in the inherited traits of a population over generations, while
selection is a specific mechanism within evolution, where certain individuals with
advantageous traits are more likely to survive and reproduce, thus driving the
population towards those traits over time; essentially, selection is a key process
that contributes to evolution, but not the entire concept itself
Four mechanisms of evolution - ANSWER -Mutation, genetic drift, gene flow,
selection
○ Mutation example - ANSWER -Peppered moth: In England, the industrial
revolution led to darkened tree bark, which favored the survival of dark-colored
peppered moths that had a genetic mutation for darker coloration, while the
previously dominant light-colored moths became less common due to predation
bottleneck example - ANSWER -The northern elephant seal population
experienced a bottleneck in the 1890s due to hunting, which reduced their
population to as few as 20 individuals. The population has since rebounded, but the
genetic variation is still reduced compared to other elephant seal populations.
founder effect example - ANSWER -This population is descended from a small
number of Dutch colonists who carried a higher than average percentage of the
gene that causes Huntington's disease. The Afrikaner population has a much higher
frequency of the Huntington's disease gene than the total human population.
gene flow example - ANSWER -pollen from one flower species carried by wind to
another population of the same species can introduce new genetic variations to that
population, enhancing its overall diversity
, selection example - ANSWER -A moth with a coloration that effectively
camouflages it against tree bark in a forest will have a higher fitness than a brightly
colored moth in that same forest. However, if the same moth species moves to a
desert environment with sandy coloration, the previously camouflaged moth would
now be easily visible to predators, making its fitness significantly lower in that
new context
Critique the phrase "Survival of the fittest in the struggle for existence, leading to
progress and more complexity." - ANSWER -it should be "long term reproduction
of the the "fittest" in the struggle for existence sometimes leads to "progress" in a
specific environment."
● What 3 conditions must be present for natural selection to occur? - ANSWER -
variation within a population, inheritance of traits from parents to offspring
(heritability), and differential reproductive success
How do variations in traits affect an organism's fitness - ANSWER -determines
how well it can survive and reproduce in its environment; traits that provide an
advantage in a specific environment will increase an organism's fitness, allowing it
to produce more offspring, while traits that are disadvantageous will decrease
fitness and limit reproductive success.
directional selection example - ANSWER -In a changing climate, a population of
rabbits may experience directional selection if those with thicker fur are more
likely to survive harsh winters, leading to a gradual increase in the population's
average fur thickness.
stabilizing selection example - ANSWER -In a bird species, individuals with
average wing size are more efficient flyers and thus more likely to survive and
reproduce, while birds with extremely small or large wings are less successful
disruptive selection example - ANSWER -In a population of finches, birds with
small beaks are efficient at eating small seeds, while birds with large beaks are
better at eating large seeds, while birds with medium-sized beaks are not well
adapted to either seed type.
How does antibiotic resistance evolve in bacteria and what is the role of selection,
type of selection and selective pressures, and what is changing over time? -
ANSWER -Antibiotic resistance in bacteria evolves through a process of natural
