BIO 243 Final Exam Questions with Correct Answers Latest Update 2025/2026
What did Darwin think about natural selection ? - Answers he reasoned that if a PERSON can
select different characteristics when breeding organisms the so can NATURE
Analogous features... - Answers share a similar function, but NOT common ancestry
Homologous features... - Answers have simimilar internal bone structure inherited from
common ancestor
-ex. wings of birds and bats
what was darwin missing when he formulated his theory of natural selection - Answers he didnt
know about mendelian inheritance
Mendelian inheritance - Answers principle of dominant and recessive alleles
Vestigial structures - Answers seemingly useless structure that functioned in ANCESTRAL
organisms
Environmental variation - Answers environmental factors including (not always genetic)
-parents
-sunlight exposure
-diet
-exercise
Phenotype - Answers -expression of a trait
-physical
what is the ultimate source of genetic variation ? - Answers mutations
A single character controlled by multiple genes is known as a _____________character - Answers
polygenic
-poly=many...genes
A reproductive cell/gamete has - Answers -one allele for each gene
-either dominant or recessive
, In mice, yellow fur is dominnat to brown fur, and the yellow allele is a dominant mutation.
Interestingly, mice that have a genotype that is homozygous for the yellow allele do not survive
embryonic development. In this example, what ratio of phenotypes would you expect to see in
living offspring from a cross between two yellow mice ? - Answers 2 yellow: 1 brown
(GO OVER THIS ONE) Round pea seed shape is dominant over a wrinkled pea seed shape. From
a monohybrid crross of heterozygous round peas, what is the probability that a pea pod
containing four peas will have exactly two wrinkled peas and both are in the middle positions ? -
Answers 9/256
5 Conditions of Hardy Weinberg Equilibrium - Answers 1. no mutations
2. random mating
3. no natural selection
4. large population size
5. no gene flow
-if all conditions are met, then no evolution is occuring
What is the only assumption of the HWE model that, if violated, generates novelty within a
population of organisms ? - Answers no mutation (most important one essentially)
if totalled, the frequencies for a given gene found within the same population would equal... -
Answers 1.00
Separation of alleles corresponds to the separation of - Answers homologous chromosomes
a genotype is - Answers the particular combination of alleles present in a given organism
for which of the following is the HWE formula valuable ? - Answers calculating changes in allele
frequencies
segregation results from... - Answers the assignment of only one allele of a gene to each
gamete
Imagine that you compared the observed genotype frequencies in a population to the expected
genotype frequencies under HWE using a chi-square value of 1.32. If the critical value of the chi-
square test statistic is 3.81 (at alpha = 0.05), what can you safely conclude about this
population ? - Answers -it is at hardy-weinberg equilibrium
-the value is less than the critical value in the table, so its not significant, and the populations
gene frequency variation is due to chance, so the population is not evolving, and is therefore at
What did Darwin think about natural selection ? - Answers he reasoned that if a PERSON can
select different characteristics when breeding organisms the so can NATURE
Analogous features... - Answers share a similar function, but NOT common ancestry
Homologous features... - Answers have simimilar internal bone structure inherited from
common ancestor
-ex. wings of birds and bats
what was darwin missing when he formulated his theory of natural selection - Answers he didnt
know about mendelian inheritance
Mendelian inheritance - Answers principle of dominant and recessive alleles
Vestigial structures - Answers seemingly useless structure that functioned in ANCESTRAL
organisms
Environmental variation - Answers environmental factors including (not always genetic)
-parents
-sunlight exposure
-diet
-exercise
Phenotype - Answers -expression of a trait
-physical
what is the ultimate source of genetic variation ? - Answers mutations
A single character controlled by multiple genes is known as a _____________character - Answers
polygenic
-poly=many...genes
A reproductive cell/gamete has - Answers -one allele for each gene
-either dominant or recessive
, In mice, yellow fur is dominnat to brown fur, and the yellow allele is a dominant mutation.
Interestingly, mice that have a genotype that is homozygous for the yellow allele do not survive
embryonic development. In this example, what ratio of phenotypes would you expect to see in
living offspring from a cross between two yellow mice ? - Answers 2 yellow: 1 brown
(GO OVER THIS ONE) Round pea seed shape is dominant over a wrinkled pea seed shape. From
a monohybrid crross of heterozygous round peas, what is the probability that a pea pod
containing four peas will have exactly two wrinkled peas and both are in the middle positions ? -
Answers 9/256
5 Conditions of Hardy Weinberg Equilibrium - Answers 1. no mutations
2. random mating
3. no natural selection
4. large population size
5. no gene flow
-if all conditions are met, then no evolution is occuring
What is the only assumption of the HWE model that, if violated, generates novelty within a
population of organisms ? - Answers no mutation (most important one essentially)
if totalled, the frequencies for a given gene found within the same population would equal... -
Answers 1.00
Separation of alleles corresponds to the separation of - Answers homologous chromosomes
a genotype is - Answers the particular combination of alleles present in a given organism
for which of the following is the HWE formula valuable ? - Answers calculating changes in allele
frequencies
segregation results from... - Answers the assignment of only one allele of a gene to each
gamete
Imagine that you compared the observed genotype frequencies in a population to the expected
genotype frequencies under HWE using a chi-square value of 1.32. If the critical value of the chi-
square test statistic is 3.81 (at alpha = 0.05), what can you safely conclude about this
population ? - Answers -it is at hardy-weinberg equilibrium
-the value is less than the critical value in the table, so its not significant, and the populations
gene frequency variation is due to chance, so the population is not evolving, and is therefore at
