Bio 1108 Exam 1 (Herrick) Questions
with Correct Answers 2025-2026
what are two factors that contribute to phenotype? CORRECT ANSWER
genotype and environment
species - CORRECT ANSWER -individuals that are able to exchange genetic material
gene pool - CORRECT ANSWER -all alleles present in individuals of that species
populations - CORRECT ANSWER -
interbreeding groups of organisms of the same species living in the same geographical area
what are two main sources that lead to genetic variation? CORRECT
ANSWER mutation and recombination
what can somatic mutations lead to? CORRECT
ANSWER cancer, disease and even death to an
INDIVIDUAL
what can germ line mutations lead to? CORRECT
ANSWER mutations that are passed down to offspring
recombination; name two ways it can occur - CORRECT ANSWER -
new alleles may be generated through crossing over and independent assortment
allele frequency - CORRECT ANSWER -rate of occurrences of alleles in a population
,gene locus - CORRECT ANSWER -the location of a certain gene/allele
allele - CORRECT ANSWER -a form of a gene; one copy of a gene
example: A, a
how is genetic variation measured? CORRECT ANSWER
through the allele frequency equation
what is the allele frequency equation? CORRECT
ANSWER AF=(# of copies of an allele)/(total # of alleles in
population)
evolution - CORRECT ANSWER -change in allele frequency or genotype frequency over time
how is evolution measured? - CORRECT ANSWER -
examinable physical traits, gel electrophoresis, DNA sequences;
most importantly: the hardy-weinberg equilibrium
what does the hardy-weinberg equilibrium model describe? CORRECT
ANSWER the situation in which evolution does NOT occur
a population in the HW equilibrium meets what requirements? - CORRECT ANSWER -
1. closed population (no migration or gene flow)
2. no mutations
3. large population (no genetic drift)
4. random mating (no sexual selection)
, 5. no natural selection
what is the HW equation? - CORRECT ANSWER -p^2 + 2pq + q^2
natural selection occurs when... - CORRECT ANSWER -
...individuals with certain traits reproduce more offspring than do individuals without those
traits
stabilizing selection - CORRECT ANSWER -against the extremes
directional selection - CORRECT ANSWER -against one extreme
disruptive selection - CORRECT ANSWER -against the mean
STRONG and QUICK
artificial selection - CORRECT ANSWER -selection by breeder rather than competition
positive selection - CORRECT ANSWER -
selection that increases the frequency of a FAVORABLE allele
negative selection - CORRECT ANSWER -
selection that decreases the frequency of a deleterious allele
balancing selection - CORRECT ANSWER -
refers to when two allele are maintained in the population
ex: malaria and the heterozygote advantage (heterozygote's fitness is higher than either ho
mozygotes resulting in selection that ensures both alleles to remain in the population)
with Correct Answers 2025-2026
what are two factors that contribute to phenotype? CORRECT ANSWER
genotype and environment
species - CORRECT ANSWER -individuals that are able to exchange genetic material
gene pool - CORRECT ANSWER -all alleles present in individuals of that species
populations - CORRECT ANSWER -
interbreeding groups of organisms of the same species living in the same geographical area
what are two main sources that lead to genetic variation? CORRECT
ANSWER mutation and recombination
what can somatic mutations lead to? CORRECT
ANSWER cancer, disease and even death to an
INDIVIDUAL
what can germ line mutations lead to? CORRECT
ANSWER mutations that are passed down to offspring
recombination; name two ways it can occur - CORRECT ANSWER -
new alleles may be generated through crossing over and independent assortment
allele frequency - CORRECT ANSWER -rate of occurrences of alleles in a population
,gene locus - CORRECT ANSWER -the location of a certain gene/allele
allele - CORRECT ANSWER -a form of a gene; one copy of a gene
example: A, a
how is genetic variation measured? CORRECT ANSWER
through the allele frequency equation
what is the allele frequency equation? CORRECT
ANSWER AF=(# of copies of an allele)/(total # of alleles in
population)
evolution - CORRECT ANSWER -change in allele frequency or genotype frequency over time
how is evolution measured? - CORRECT ANSWER -
examinable physical traits, gel electrophoresis, DNA sequences;
most importantly: the hardy-weinberg equilibrium
what does the hardy-weinberg equilibrium model describe? CORRECT
ANSWER the situation in which evolution does NOT occur
a population in the HW equilibrium meets what requirements? - CORRECT ANSWER -
1. closed population (no migration or gene flow)
2. no mutations
3. large population (no genetic drift)
4. random mating (no sexual selection)
, 5. no natural selection
what is the HW equation? - CORRECT ANSWER -p^2 + 2pq + q^2
natural selection occurs when... - CORRECT ANSWER -
...individuals with certain traits reproduce more offspring than do individuals without those
traits
stabilizing selection - CORRECT ANSWER -against the extremes
directional selection - CORRECT ANSWER -against one extreme
disruptive selection - CORRECT ANSWER -against the mean
STRONG and QUICK
artificial selection - CORRECT ANSWER -selection by breeder rather than competition
positive selection - CORRECT ANSWER -
selection that increases the frequency of a FAVORABLE allele
negative selection - CORRECT ANSWER -
selection that decreases the frequency of a deleterious allele
balancing selection - CORRECT ANSWER -
refers to when two allele are maintained in the population
ex: malaria and the heterozygote advantage (heterozygote's fitness is higher than either ho
mozygotes resulting in selection that ensures both alleles to remain in the population)
