Question 1

Refer to the figure showing a phylogenetic tree.  Should the common ancestor of crocodiles and pigeons be considered an amniote? Explain.

Accepted Answer

The answer of Refer to the figure showing a phylogenetic...

Question 2

Two clades of beetles split off from a node more recently than these clades diverged from other clades.Thus, these clades are _______ clades.
A) nodal
B) rooted
C) sister
D) daughter
E) homologous

Accepted Answer

Sister clades are groups of organisms that share an immediate common ancestor and hence are each other's closest relatives. In this scenario, the two clades of beetles that split off from a node more recently than they diverged from other clades are considered sister clades because they share a more recent common ancestor with each other than with any other clade.

Question 3

Which statement about phylogenetic trees is false?
A) Rotation of lineages around a node can change the meaning of a tree.
B) "Node" is another word for "branching point."
C) A phylogenetic tree is a representation of the history of evolutionary relationships among organisms or their genes.
D) Phylogenetic trees can represent genes within species.
E) All lineages can be traced back to the root of the tree.

Accepted Answer

Rotation of lineages around a node does not change the meaning of a tree because the evolutionary relationships remain the same; only the presentation changes.

Question 4

Not counting the root, how many nodes are in a phylogenetic tree with five species?
A) One
B) Two
C) Three
D) Four
E) Five

Accepted Answer

A phylogenetic tree with five species has four nodes not counting the root.

Question 5

Refer to the figure.  Which species is most closely related to the clade formed by species A and species B?
A) Species C
B) Species D
C) Species E
D) Species D and E are equally closely related to the clade, and both are more closely related to the clade than is species C.
E) Species C, D, and E are equally closely related to the clade.

Accepted Answer

The answer of Refer to the figure.  Which species...

Question 6

Biologists estimate that there are tens of millions of species on Earth.How many have been described?
A) 18,000
B) 90,000
C) 180,000
D) 1.8 million
E) 9 million

Accepted Answer

As of 2021, it is estimated that around 1.8 million species have been described by biologists, leaving the vast majority of species on Earth undiscovered and unnamed.

Question 7

Refer to the table.  The table shows the divergence times (time since last common ancestor) between different species of butterflies and the numbers of changes that have occurred at two different genes.Graph the relationship between the divergence time and the number of changes in the gene for alcohol dehydrogenase.Explain why we can say that the gene is evolving as expected under the principle of the molecular clock?

Accepted Answer

The answer of Refer to the table.  The table...

Question 8

Refer to the diagram below showing a phylogenetic tree of immunodeficiency viruses.  Based on the information in the figure, can we infer whether HIV-1 or HIV-2 moved into humans first? Explain.

Accepted Answer

The answer of Refer to the diagram below showing a...

Question 9

Refer to the figure.Most classification systems are designed to reflect evolutionary relationships of organisms.This is also the case in this phylogenetic tree, where there are three groups (taxa) that have been classified: group 1 (red), group 2 (yellow), and group 3 (blue).  Most classification systems are designed to reflect evolutionary relationships of organisms.This is also the case in this phylogenetic tree, where there are three groups (taxa) that have been classified: group 1 (green), group 2 (orange), and group 3 (blue).
Which of the taxa in the diagram is monophyletic, and which is polyphyletic?

Accepted Answer

The answer of Refer to the figure.Most classification systems are...

Question 10

Refer to the figure.  Which of these phylogenetic trees conveys different phylogenetic information from the others?
A) Tree 1
B) Tree 2
C) Tree 3
D) Tree 4
E) All of the trees convey the same information.

Accepted Answer

The answer of Refer to the figure.  Which of...

Question 11

Refer to the table.  The table shows the divergence times (time since last common ancestor) between different species of butterflies and the numbers of changes that have occurred at two different genes.If two species of these butterflies had 200 differences in the gene for alcohol dehydrogenase, approximately how long ago did they diverge from a common ancestor, assuming that they were evolving in accordance with the molecular clock?

Accepted Answer

The answer of Refer to the table.  The table...

Question 12

Refer to the figure showing a phylogenetic tree of immunodeficiency viruses.  Suppose L'Hoest monkeys were more closely related to African green monkeys than they were to sun-tailed monkeys.Given the phylogeny of viruses in the figure, what would this phylogeny of primates imply for the transmission of viruses.

Accepted Answer

The answer of Refer to the figure showing a phylogenetic...

Question 13

Suppose you follow the descendants of a group of squirrels along a phylogenetic tree.In doing so, you would be tracing a _______ of these squirrels.
A) node
B) root
C) synapomorphy
D) lineage
E) homoplasy

Accepted Answer

Following the descendants of a group of squirrels along a phylogenetic tree involves tracing their lineage, which is represented by branches on the tree.

Question 14

Refer to the figure showing a phylogenetic tree of immunodeficiency viruses.  Based on the figure, what is the likely number of independent origins of HIV in humans? Explain, pointing out the human virus's origins.

Accepted Answer

The answer of Refer to the figure showing a phylogenetic...

Question 15

Biologists have described well over a million species of eukaryotes.Most species that have been described are known primarily by their
A) DNA sequence information.
B) gene expression data.
C) fossil record.
D) morphology.
E) behavior.

Accepted Answer

Morphology, or physical appearance and structure, has traditionally been the primary method for identifying and describing species. While DNA sequence information and gene expression data can be used in combination with morphology to distinguish between closely related species, these methods are not yet widespread enough to have characterized most of the known eukaryotic species. The fossil record can be used to trace the evolutionary history of species, but is less helpful in identifying individual organisms themselves. Behavior, while useful for studying certain aspects of an organism's ecology, is often variable within a species and therefore not a reliable tool for species identification.

Question 16

Refer to the figure showing a phylogenetic tree.  Should the common ancestor of lizard and salamander be considered an amniote? Explain.

Accepted Answer

The answer of Refer to the figure showing a phylogenetic...

Question 17

Refer to the table.  The table shows the divergence times (time since last common ancestor) between different species of butterflies and the numbers of changes that have occurred at two different genes.What is the rate of evolution of the gene for alcohol dehydrogenase? Note that there are two lineages (branches) from the common ancestor within which evolution is occurring.

Accepted Answer

The answer of Refer to the table.  The table...

Question 18

Refer to the table.  The table which shows the divergence times (time since last common ancestor) between different species of butterflies and the numbers of changes that have occurred at two different genes.Explain how the data show that the gene for cytochrome oxidase is not evolving in accordance with the molecular clock principle.

Accepted Answer

The answer of Refer to the table.  The table...

Question 19

Consider six species of grasshoppers (A-F).Species A, B, and C form a clade.Species D and E also form a clade.The clade containing species A, B, and C is a sister to species F.Which species groups would be a clade?
A) Species A, B, and D
B) Species A, B, C, and D
C) Species A, B, C, and F
D) Species A, B, and E
E) Species B, C, D, and E

Accepted Answer

A clade includes a common ancestor and all of its descendants. In this scenario, species A, B, and C form a clade, and species F is a sister to this clade. Therefore, any group that includes A, B, C, and F would not be a clade because it would not include species D and E, which form their own clade. The only choice that is a clade is C, which includes the clade formed by A, B, and C, as well as species F.

Question 20

What would you find at the root of a phylogenetic tree?
A) All living species
B) Some living species and some dead species
C) The common ancestor of some, but not all, of the species depicted in the tree
D) The common ancestor of all species depicted in the tree
E) Synapomorphies

Accepted Answer

The root of a phylogenetic tree represents the common ancestor of all the species depicted in the tree.

Quiz 21: Reconstructing and Using Phylogenies

Refer to the figure showing a phylogenetic tree. Should the common ancestor of crocodiles and pigeons be considered an amniote? Explain.

Two clades of beetles split off from a node more recently than these clades diverged from other clades.Thus, these clades are _______ clades.

Which statement about phylogenetic trees is false?

Not counting the root, how many nodes are in a phylogenetic tree with five species?

Refer to the figure. Which species is most closely related to the clade formed by species A and species B?

Biologists estimate that there are tens of millions of species on Earth.How many have been described?

Refer to the diagram below showing a phylogenetic tree of immunodeficiency viruses. Based on the information in the figure, can we infer whether HIV-1 or HIV-2 moved into humans first? Explain.

Refer to the figure. Which of these phylogenetic trees conveys different phylogenetic information from the others?

Suppose you follow the descendants of a group of squirrels along a phylogenetic tree.In doing so, you would be tracing a _______ of these squirrels.

Refer to the figure showing a phylogenetic tree of immunodeficiency viruses. Based on the figure, what is the likely number of independent origins of HIV in humans? Explain, pointing out the human virus's origins.

Biologists have described well over a million species of eukaryotes.Most species that have been described are known primarily by their

Refer to the figure showing a phylogenetic tree. Should the common ancestor of lizard and salamander be considered an amniote? Explain.

Consider six species of grasshoppers (A-F) .Species A, B, and C form a clade.Species D and E also form a clade.The clade containing species A, B, and C is a sister to species F.Which species groups would be a clade?

What would you find at the root of a phylogenetic tree?