BIOL 1120 LAB MIDTERM EXAM WITH
CORRECT ANSWERS 2025
Define evolution in terms of allele frequency. ( correct answers )
evolution is the change in allele frequencies of a gene from one
generation to the next
What criteria must be met for an equilibrium of allele ( corre
frequencies to exist? answers ) (Hardy-Weinberg equilibrium ct
@population level)
1. the population is large
2. 3.population
mutations doisnot occur from other populations so there is no migration
isolated
into or out of the population
4. mating is completely random
5. no selection takes place. all genotypes have equal reproductive success
What is genetic drift? ( correct answers ) random
change in frequency of alleles simply by chance (occurs when a
population goes through bottleneck)
How does natural selection differ from genetic drift? ( correct answers )
in genetic drift, allele frequencies change over successive generations
simply by chance, but in natural selection, one allele of a given gene has
an advantage
evolution ( correct answers ) The gradual change in a species (1
generation to the next) over time
population ( correct answers ) A group of individuals that belong to the
same species and live in the same area at the same time, interbreed, and
share gene pool
allele ( correct answers ) An alternative form of a gene.
Hardy-Weinberg equilibrium ( correct answers )
condition that occurs when the frequency of alleles in a particular gene
pool remain constant over time
genotype ( correct answers ) genetic makeup of an organism
phenotype ( correct answers ) physical characteristics of an
organism
Chi-square analysis ( correct answers ) assesses how closely the observed
frequencies fit the pattern of the expected frequencies (hypothesis) and is
referred to as a "goodness-of-fit" test
, bottleneck ( correct answers ) A change in allele frequency
following a dramatic reduction in the size of a population
fixed allele ( correct answers ) an allele that is the only variant that
exists for that gene in all the population
natural selection ( correct answers ) A process in which individuals that
have certain inherited traits tend to survive and reproduce at higher rates
than other individuals because of those traits.
How does the Hardy-Weinberg equilibrium serve as the baseline to
determine whether evolution is occurring in a population? ( correct
answers ) It allows us to see how evolution occurs
@ population level and it monitors changes in allele frequencies in a
population- therefore, if they don't change between generations then
evolution clearly does not occur
what effect can genetic drift have on allele frequencies of future
generations? ( correct answers ) it can reduce or increase frequencies of
alleles or even be lost or fixed in the population
What are the four mechanisms of evolutionary ( correct answers ) 1.
biology? selection natural
2. mutation
3. migration
4. genetic drift
review how these mechanisms lead to evolutionary ( correct answers )
change
2.1) page 24 lab manual (table
review difference between micro- and macro-evolution. How are the two
linked? ( correct answers )
c
What is the defining feature of speciation? ( correct
what is the
answers ) BSC definition of a species? reproductive ( correct
what are its isolation
limitations? "good but not perfect" answers )
limitations:
1. not all organisms can interbreed
2. sometimes barriers to inter-species breeding are weak (sometimes
2 different species can interbreed)
review the difference between allopatric, sympatric and parametric
speciation
( correct answers ) Allopatric speciation occurs when geographically isolated
populations diverge and become reproductively isolated. Sympatric
speciation occurs when sub- populations in the same geographic area
diverge and become reproductively isolated.
CORRECT ANSWERS 2025
Define evolution in terms of allele frequency. ( correct answers )
evolution is the change in allele frequencies of a gene from one
generation to the next
What criteria must be met for an equilibrium of allele ( corre
frequencies to exist? answers ) (Hardy-Weinberg equilibrium ct
@population level)
1. the population is large
2. 3.population
mutations doisnot occur from other populations so there is no migration
isolated
into or out of the population
4. mating is completely random
5. no selection takes place. all genotypes have equal reproductive success
What is genetic drift? ( correct answers ) random
change in frequency of alleles simply by chance (occurs when a
population goes through bottleneck)
How does natural selection differ from genetic drift? ( correct answers )
in genetic drift, allele frequencies change over successive generations
simply by chance, but in natural selection, one allele of a given gene has
an advantage
evolution ( correct answers ) The gradual change in a species (1
generation to the next) over time
population ( correct answers ) A group of individuals that belong to the
same species and live in the same area at the same time, interbreed, and
share gene pool
allele ( correct answers ) An alternative form of a gene.
Hardy-Weinberg equilibrium ( correct answers )
condition that occurs when the frequency of alleles in a particular gene
pool remain constant over time
genotype ( correct answers ) genetic makeup of an organism
phenotype ( correct answers ) physical characteristics of an
organism
Chi-square analysis ( correct answers ) assesses how closely the observed
frequencies fit the pattern of the expected frequencies (hypothesis) and is
referred to as a "goodness-of-fit" test
, bottleneck ( correct answers ) A change in allele frequency
following a dramatic reduction in the size of a population
fixed allele ( correct answers ) an allele that is the only variant that
exists for that gene in all the population
natural selection ( correct answers ) A process in which individuals that
have certain inherited traits tend to survive and reproduce at higher rates
than other individuals because of those traits.
How does the Hardy-Weinberg equilibrium serve as the baseline to
determine whether evolution is occurring in a population? ( correct
answers ) It allows us to see how evolution occurs
@ population level and it monitors changes in allele frequencies in a
population- therefore, if they don't change between generations then
evolution clearly does not occur
what effect can genetic drift have on allele frequencies of future
generations? ( correct answers ) it can reduce or increase frequencies of
alleles or even be lost or fixed in the population
What are the four mechanisms of evolutionary ( correct answers ) 1.
biology? selection natural
2. mutation
3. migration
4. genetic drift
review how these mechanisms lead to evolutionary ( correct answers )
change
2.1) page 24 lab manual (table
review difference between micro- and macro-evolution. How are the two
linked? ( correct answers )
c
What is the defining feature of speciation? ( correct
what is the
answers ) BSC definition of a species? reproductive ( correct
what are its isolation
limitations? "good but not perfect" answers )
limitations:
1. not all organisms can interbreed
2. sometimes barriers to inter-species breeding are weak (sometimes
2 different species can interbreed)
review the difference between allopatric, sympatric and parametric
speciation
( correct answers ) Allopatric speciation occurs when geographically isolated
populations diverge and become reproductively isolated. Sympatric
speciation occurs when sub- populations in the same geographic area
diverge and become reproductively isolated.
