BIOL 226 EXAM – Questions With Reliable
Solutions
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Terms in this set (172)
What facts would you use to explain · The fossil record shows us the evolution of
to a creationist that evolution is an organisms through time through mineralized remains
historical fact? of organisms.
· The DNA record shows us how similar the genetic
code for all life forms is and is consistent with the
fossil record.
· Direct observation shows us that organisms always
match their environment, and they can thank
evolution for that.
· Vestigial structures show us historical remnants that
use to serve a purpose in organisms' ancestors. An
example is the dorsal leg on a whale that is now
rendered useless but tells us that it once was useful
and that whales evolved from something with legs.
· Homologous structures show us similar structures
are in different organisms who share a common
ancestor. These structures have different functions in
all these organisms.
· Analogous structures or convergent evolution
shows us different structures that have a similar
function in different organisms. These structures have
been inherited separately in these organisms and
have not come from a common ancestor.
,Why is it crucial to construct It is crucial to construct evolutionary trees based on
evolutionary trees based on homologies because they come from common
homologies rather than analogies ancestors, whereas analogies are separately
(convergent evolution)? inherited in unrelated organisms. If we tried to
construct it based on analogies, then we would have
a messy tree of unrelated organisms which does not
showcase the evolution that has taken place.
Explain how Darwin used artificial He said that we can create many new variations
selection as part of his argument through artificial selection (based on what we deem
about the power of natural selection. to be desirable traits) very easily, like when we took a
wild mustard plant to create broccoli and cabbage,
we altered organisms to our needs. Natural selection
works in a similar way, except nature makes the
decisions of what is desirable for what context. (i.e.,
the landscape, the available resources, the prey and
predators, the weather, etc.)
Natural selection is an editing process Natural selection does not just create new species
rather than a creative process. Explain out of thin air with new adaptations that allow them
by using an example. Your answer to survive and reproduce more successfully. Rather,
should be 2-3 sentences long. the desirable traits exist within variations of the same
species. What natural selection does is that it edits
the species by allowing the organisms within the
species with undesirable traits to die off, while the
one's with desirable traits survive and reproduce
more. Eventually, this gives rise to evolution and the
population is populated with mostly that desirable
trait. This is what is important to note about natural
selection and evolution. Variation within the species
is necessary for evolution to take place. Natural
selection is always at work. What is a desirable trait
now in a given species may not have been desirable
generations ago and maybe will not be desirable
generations later.
,3 modes on natural selection · Directional Selection: is a mode of natural selection
in which one extreme phenotype is favored over
other phenotypes, causing the allele frequency to
shift over time in the direction of that phenotype
· Disruptive Selection: describes changes in
population genetics in which both extreme values for
a trait are favored over intermediate values.
· Stabilizing Selection: where the intermediate
phenotype is favored over the two extremes.
Which of the five mechanisms cause Natural selection, gene flow, and genetic drift.
the most evolutionary change at the
microevolutionary scale?
Why is genetic drift important for Endangered species are the "narrow" portion of a
conservation biology? genetic bottleneck (reduced genetic variation, less
able to adapt to change).
The size of the population affects the 1. Natural selection (effect of population size: stays
strength of each mechanism the same)
2. Mutation (effect of population size: more mutations
per generation in big populations)
3. Drift (effect of population size: weaker in big
populations)
4. Gene flow (effect of population size: weaker when
population is large)
5. Non-random mating (effect of population size:
stays the same)
Hardy Weinberg Theorem Assumption With this theorem, we are assuming that there will be
the same number of offspring, no mutation, no gene
flow, will happen in a large population, and random
mating.
, What does it mean if a population if This means that 1 of the 5 evolutionary mechanisms
different from Hardy Weinberg? must be at work.
Why do we care about the Hardy- Hardy Weinberg states that it is not enough to have
Weinberg Theorem? variation to have evolution; the frequencies of alleles
and genotypes in a population will remain constant
unless acted upon by outside forces.
Why is geographic isolation so · Keeps the gene pool separate (Gene flow is the
important for speciation? "enemy" of the local adaptation & speciation)
· Allows populations to diverge due to: selection,
drift, mutation, and assortative mating
What happens if populations come 1. Geographic barrier
back into contact after separation? 2. Period of isolation
3. Re-contact
4. Either renewed gene flow or reproductive isolation
Gene flow may be reduced by: · Polyploidy (Auto or Allo): a state of a cell or an
organism that has more than 2 paired homologous
sets of chromosomes.
· Habitat or food differentiation
· Sexual selection
What do hybrid zones tell us? · Speciation is not always complete, and does not
happen instantly (it is a process)
· Speciation can sometimes be reversed
Possible outcomes after hybridization: 1. Re-fusion of the two species into one: loss of
reproductive barriers
2. Reinforcement of reproductive barriers
3. Stable hybrid zone with low gene flow between
species
Solutions
Save
Terms in this set (172)
What facts would you use to explain · The fossil record shows us the evolution of
to a creationist that evolution is an organisms through time through mineralized remains
historical fact? of organisms.
· The DNA record shows us how similar the genetic
code for all life forms is and is consistent with the
fossil record.
· Direct observation shows us that organisms always
match their environment, and they can thank
evolution for that.
· Vestigial structures show us historical remnants that
use to serve a purpose in organisms' ancestors. An
example is the dorsal leg on a whale that is now
rendered useless but tells us that it once was useful
and that whales evolved from something with legs.
· Homologous structures show us similar structures
are in different organisms who share a common
ancestor. These structures have different functions in
all these organisms.
· Analogous structures or convergent evolution
shows us different structures that have a similar
function in different organisms. These structures have
been inherited separately in these organisms and
have not come from a common ancestor.
,Why is it crucial to construct It is crucial to construct evolutionary trees based on
evolutionary trees based on homologies because they come from common
homologies rather than analogies ancestors, whereas analogies are separately
(convergent evolution)? inherited in unrelated organisms. If we tried to
construct it based on analogies, then we would have
a messy tree of unrelated organisms which does not
showcase the evolution that has taken place.
Explain how Darwin used artificial He said that we can create many new variations
selection as part of his argument through artificial selection (based on what we deem
about the power of natural selection. to be desirable traits) very easily, like when we took a
wild mustard plant to create broccoli and cabbage,
we altered organisms to our needs. Natural selection
works in a similar way, except nature makes the
decisions of what is desirable for what context. (i.e.,
the landscape, the available resources, the prey and
predators, the weather, etc.)
Natural selection is an editing process Natural selection does not just create new species
rather than a creative process. Explain out of thin air with new adaptations that allow them
by using an example. Your answer to survive and reproduce more successfully. Rather,
should be 2-3 sentences long. the desirable traits exist within variations of the same
species. What natural selection does is that it edits
the species by allowing the organisms within the
species with undesirable traits to die off, while the
one's with desirable traits survive and reproduce
more. Eventually, this gives rise to evolution and the
population is populated with mostly that desirable
trait. This is what is important to note about natural
selection and evolution. Variation within the species
is necessary for evolution to take place. Natural
selection is always at work. What is a desirable trait
now in a given species may not have been desirable
generations ago and maybe will not be desirable
generations later.
,3 modes on natural selection · Directional Selection: is a mode of natural selection
in which one extreme phenotype is favored over
other phenotypes, causing the allele frequency to
shift over time in the direction of that phenotype
· Disruptive Selection: describes changes in
population genetics in which both extreme values for
a trait are favored over intermediate values.
· Stabilizing Selection: where the intermediate
phenotype is favored over the two extremes.
Which of the five mechanisms cause Natural selection, gene flow, and genetic drift.
the most evolutionary change at the
microevolutionary scale?
Why is genetic drift important for Endangered species are the "narrow" portion of a
conservation biology? genetic bottleneck (reduced genetic variation, less
able to adapt to change).
The size of the population affects the 1. Natural selection (effect of population size: stays
strength of each mechanism the same)
2. Mutation (effect of population size: more mutations
per generation in big populations)
3. Drift (effect of population size: weaker in big
populations)
4. Gene flow (effect of population size: weaker when
population is large)
5. Non-random mating (effect of population size:
stays the same)
Hardy Weinberg Theorem Assumption With this theorem, we are assuming that there will be
the same number of offspring, no mutation, no gene
flow, will happen in a large population, and random
mating.
, What does it mean if a population if This means that 1 of the 5 evolutionary mechanisms
different from Hardy Weinberg? must be at work.
Why do we care about the Hardy- Hardy Weinberg states that it is not enough to have
Weinberg Theorem? variation to have evolution; the frequencies of alleles
and genotypes in a population will remain constant
unless acted upon by outside forces.
Why is geographic isolation so · Keeps the gene pool separate (Gene flow is the
important for speciation? "enemy" of the local adaptation & speciation)
· Allows populations to diverge due to: selection,
drift, mutation, and assortative mating
What happens if populations come 1. Geographic barrier
back into contact after separation? 2. Period of isolation
3. Re-contact
4. Either renewed gene flow or reproductive isolation
Gene flow may be reduced by: · Polyploidy (Auto or Allo): a state of a cell or an
organism that has more than 2 paired homologous
sets of chromosomes.
· Habitat or food differentiation
· Sexual selection
What do hybrid zones tell us? · Speciation is not always complete, and does not
happen instantly (it is a process)
· Speciation can sometimes be reversed
Possible outcomes after hybridization: 1. Re-fusion of the two species into one: loss of
reproductive barriers
2. Reinforcement of reproductive barriers
3. Stable hybrid zone with low gene flow between
species
