1
BLG 144 Midterm 1 Exam Questions
And Verified Answers
what conditions must be met for the hardy-weinberg principle to occur - correct-
answer -1. random mating
2. no mutation
3. no gene flow
4. no genetic drift/random allele frequency change
genetic variation - correct-answer -# and relative frequency of alleles present in
particular population
-lack of genetic variation is usually a bad thing
types of selection - correct-answer --directional
-stabilizing
-purifying
-disruptive
-balancing
, 2
-frequency-dependent
directional selection - correct-answer -when average phenotype of population has
changed in ONE DIRECTION
-tends to reduce genetic diversity
purifying selection - correct-answer -when deleterious or harmful alleles are
removed from population
stabilizing selection - correct-answer -no change in average trait value overtime
and genetic variation in populations is reduced
(favors average trait value and reduces extreme traits)
disruptive selection - correct-answer -extreme traits are favored and eliminates
the average phenotypes
-crucial since sometimes play a part in formation of new species
balancing selection - correct-answer -no single allele has a distinct advantage and
increases in frequency
-neutral in terms of fitness and frequency
, 3
heterozygous advangtage - correct-answer -heterozygous individuals hae higher
fitness than homozygous (sometimes)
genetic drift - correct-answer -any change in alele frequencies due to change
-random with respect to fitness
-happens often in small population
-increased genetic differences between populations
frequent-dependent selection - correct-answer -certain alleles are favoured when
rare, not when common
sampling error - correct-answer -allele frequencies change due to blind luck
founder event - correct-answer -when a group of individuals immigrate to a new
geographic area and establish a new population
BLG 144 Midterm 1 Exam Questions
And Verified Answers
what conditions must be met for the hardy-weinberg principle to occur - correct-
answer -1. random mating
2. no mutation
3. no gene flow
4. no genetic drift/random allele frequency change
genetic variation - correct-answer -# and relative frequency of alleles present in
particular population
-lack of genetic variation is usually a bad thing
types of selection - correct-answer --directional
-stabilizing
-purifying
-disruptive
-balancing
, 2
-frequency-dependent
directional selection - correct-answer -when average phenotype of population has
changed in ONE DIRECTION
-tends to reduce genetic diversity
purifying selection - correct-answer -when deleterious or harmful alleles are
removed from population
stabilizing selection - correct-answer -no change in average trait value overtime
and genetic variation in populations is reduced
(favors average trait value and reduces extreme traits)
disruptive selection - correct-answer -extreme traits are favored and eliminates
the average phenotypes
-crucial since sometimes play a part in formation of new species
balancing selection - correct-answer -no single allele has a distinct advantage and
increases in frequency
-neutral in terms of fitness and frequency
, 3
heterozygous advangtage - correct-answer -heterozygous individuals hae higher
fitness than homozygous (sometimes)
genetic drift - correct-answer -any change in alele frequencies due to change
-random with respect to fitness
-happens often in small population
-increased genetic differences between populations
frequent-dependent selection - correct-answer -certain alleles are favoured when
rare, not when common
sampling error - correct-answer -allele frequencies change due to blind luck
founder event - correct-answer -when a group of individuals immigrate to a new
geographic area and establish a new population
