Practice Questions for BIO 182: General
Biology II
1. Evolutionary Biology:
1. Define natural selection. How does it differ from
genetic drift? Provide an example of each.
o Answer Guide: Explain natural selection as the process where
organisms better adapted to their environment tend to survive
and produce more offspring. Contrast with genetic drift,
which involves random changes in allele frequencies in small
populations. Provide examples like peppered moth evolution
(natural selection) vs. founder effect in isolated populations
(genetic drift).
2. What are the main types of selection (e.g.,
directional, stabilizing, disruptive)? Describe
each with an example.
o Answer Guide:
▪Directional Selection: Favors one extreme phenotype
(e.g., antibiotic resistance in bacteria).
▪ Stabilizing Selection: Favors intermediate phenotypes
(e.g., human birth weight).
▪ Disruptive Selection: Favors both extreme phenotypes
(e.g., beak sizes in finches).
3. Explain the concept of a "molecular clock" and
how it is used in evolutionary biology.
o Answer Guide: A molecular clock uses mutation rates in
DNA to estimate the time that two species have been
evolving independently. It is useful for constructing
phylogenetic trees.
, 4. Describe how speciation can occur through
allopatric and sympatric mechanisms. Give
examples of each.
o Answer Guide: Allopatric speciation occurs due to
geographic isolation (e.g., Galápagos finches), while
sympatric speciation occurs without geographic barriers (e.g.,
polyploidy in plants).
2. Biodiversity and Classification:
5. What is a phylogenetic tree? How can it be used
to show evolutionary relationships among
species?
o Answer Guide: A phylogenetic tree is a diagram that
represents evolutionary relationships among organisms. It
shows common ancestors and points of divergence.
6. Differentiate between homologous and
analogous structures. Provide examples.
o Answer Guide: Homologous structures arise from a common
ancestor (e.g., vertebrate forelimbs), while analogous
structures have similar functions but different evolutionary
origins (e.g., wings of birds and insects).
7. Name the three domains of life. What are the
main characteristics that distinguish each
domain?
o Answer Guide:
▪ Bacteria: Unicellular prokaryotes with peptidoglycan
in cell walls.
▪ Archaea: Unicellular prokaryotes without
peptidoglycan, often extremophiles.
▪ Eukarya: Eukaryotic organisms with membrane-bound
organelles and a nucleus.
Biology II
1. Evolutionary Biology:
1. Define natural selection. How does it differ from
genetic drift? Provide an example of each.
o Answer Guide: Explain natural selection as the process where
organisms better adapted to their environment tend to survive
and produce more offspring. Contrast with genetic drift,
which involves random changes in allele frequencies in small
populations. Provide examples like peppered moth evolution
(natural selection) vs. founder effect in isolated populations
(genetic drift).
2. What are the main types of selection (e.g.,
directional, stabilizing, disruptive)? Describe
each with an example.
o Answer Guide:
▪Directional Selection: Favors one extreme phenotype
(e.g., antibiotic resistance in bacteria).
▪ Stabilizing Selection: Favors intermediate phenotypes
(e.g., human birth weight).
▪ Disruptive Selection: Favors both extreme phenotypes
(e.g., beak sizes in finches).
3. Explain the concept of a "molecular clock" and
how it is used in evolutionary biology.
o Answer Guide: A molecular clock uses mutation rates in
DNA to estimate the time that two species have been
evolving independently. It is useful for constructing
phylogenetic trees.
, 4. Describe how speciation can occur through
allopatric and sympatric mechanisms. Give
examples of each.
o Answer Guide: Allopatric speciation occurs due to
geographic isolation (e.g., Galápagos finches), while
sympatric speciation occurs without geographic barriers (e.g.,
polyploidy in plants).
2. Biodiversity and Classification:
5. What is a phylogenetic tree? How can it be used
to show evolutionary relationships among
species?
o Answer Guide: A phylogenetic tree is a diagram that
represents evolutionary relationships among organisms. It
shows common ancestors and points of divergence.
6. Differentiate between homologous and
analogous structures. Provide examples.
o Answer Guide: Homologous structures arise from a common
ancestor (e.g., vertebrate forelimbs), while analogous
structures have similar functions but different evolutionary
origins (e.g., wings of birds and insects).
7. Name the three domains of life. What are the
main characteristics that distinguish each
domain?
o Answer Guide:
▪ Bacteria: Unicellular prokaryotes with peptidoglycan
in cell walls.
▪ Archaea: Unicellular prokaryotes without
peptidoglycan, often extremophiles.
▪ Eukarya: Eukaryotic organisms with membrane-bound
organelles and a nucleus.
