Bio 152 Exam 2 Learning Objectives
UPDATED ACTUAL Exam Questions and
CORRECT Answers
List and explain four sources of evidence for common ancestry - CORRECT ANSWER -
biogeography- similar species occur near one another
fossil record- transitional forms in temporal sequence
homology- surprising similarities among organisms
classification- hierarchical nesting of biological taxa
Explain why evidence of common ancestry means that evolution must have occurred -
CORRECT ANSWER - all of the differences between species that share a common
ancestor must have evolved since they last shared a common ancestor
Determine whether evolution happened given evidence on whether the frequency of heritable
traits in a population changed over time - CORRECT ANSWER - evolution is a change in
population over time
change in frequency of variants
Explain why natural selection tends to improve organismal adaptiveness - CORRECT
ANSWER - genetic variants that improve organismal function tend to increase in
frequency
population tends to become better at surviving and reproducing over time (natural selection)
Identify the different parts of a phylogenetic tree (clade, root, node, branch, sister taxa) -
CORRECT ANSWER - clade- comprises all descendants of ancestral lineage
sister- lineages or clades from same node
root- where time enters the tree
branch- population branches
nodes- branching points and 2 species begin developing independently
, page 3
Explain how geographic isolation can result in lineage splitting and associate this phenomenon
with nodes in a phylogenetic tree - CORRECT ANSWER - geographic isolation allows
populations to accumulate differences
lineages isolated for long enough lose ability to interbreed
trees form because divergence events tend to become permanent
List the clades present in a phylogenetic tree and use this to determine if two trees have the same
topology. - CORRECT ANSWER - set of clades in a tree is in the tree's topology
tree topology is stable to pruning
page 4
Determine the relative degree of evolutionary relationship from phylogenetic trees of various
types. - CORRECT ANSWER - relatedness- recency of common ancestry
to determine relatedness only look at ancestry and ignore tip proximity, node numbers, or
physical similarity
Explain why evolutionary advancement is not a meaningful concept - CORRECT
ANSWER - all species are equally "evolved"
equal time to accumulate evolutionary innovation
present isn't goal of evolution
Describe the evolutionary history of a clade of interest in non-progressive terms. - CORRECT
ANSWER - lineage splitting results in living species w/different degrees of relatedness
branching process is not directional or progressive: no species are more advanced than any others
List the expected characteristic of tips based on changes mapped onto a tree. - CORRECT
ANSWER - tips are summations over their evolutionary history
if we know where changes occurred, we also know ancestral states
UPDATED ACTUAL Exam Questions and
CORRECT Answers
List and explain four sources of evidence for common ancestry - CORRECT ANSWER -
biogeography- similar species occur near one another
fossil record- transitional forms in temporal sequence
homology- surprising similarities among organisms
classification- hierarchical nesting of biological taxa
Explain why evidence of common ancestry means that evolution must have occurred -
CORRECT ANSWER - all of the differences between species that share a common
ancestor must have evolved since they last shared a common ancestor
Determine whether evolution happened given evidence on whether the frequency of heritable
traits in a population changed over time - CORRECT ANSWER - evolution is a change in
population over time
change in frequency of variants
Explain why natural selection tends to improve organismal adaptiveness - CORRECT
ANSWER - genetic variants that improve organismal function tend to increase in
frequency
population tends to become better at surviving and reproducing over time (natural selection)
Identify the different parts of a phylogenetic tree (clade, root, node, branch, sister taxa) -
CORRECT ANSWER - clade- comprises all descendants of ancestral lineage
sister- lineages or clades from same node
root- where time enters the tree
branch- population branches
nodes- branching points and 2 species begin developing independently
, page 3
Explain how geographic isolation can result in lineage splitting and associate this phenomenon
with nodes in a phylogenetic tree - CORRECT ANSWER - geographic isolation allows
populations to accumulate differences
lineages isolated for long enough lose ability to interbreed
trees form because divergence events tend to become permanent
List the clades present in a phylogenetic tree and use this to determine if two trees have the same
topology. - CORRECT ANSWER - set of clades in a tree is in the tree's topology
tree topology is stable to pruning
page 4
Determine the relative degree of evolutionary relationship from phylogenetic trees of various
types. - CORRECT ANSWER - relatedness- recency of common ancestry
to determine relatedness only look at ancestry and ignore tip proximity, node numbers, or
physical similarity
Explain why evolutionary advancement is not a meaningful concept - CORRECT
ANSWER - all species are equally "evolved"
equal time to accumulate evolutionary innovation
present isn't goal of evolution
Describe the evolutionary history of a clade of interest in non-progressive terms. - CORRECT
ANSWER - lineage splitting results in living species w/different degrees of relatedness
branching process is not directional or progressive: no species are more advanced than any others
List the expected characteristic of tips based on changes mapped onto a tree. - CORRECT
ANSWER - tips are summations over their evolutionary history
if we know where changes occurred, we also know ancestral states
