Question 1

Which of the following best describes a clade in a phylogenetic tree?

Accepted Answer

A group of organisms that share a common ancestor and includes all descendants of that ancestor.

Question 2

In a cladogram, what does a node represent?

Accepted Answer

A point where a lineage splits, representing a common ancestor.

Question 3

Which of the following is the correct order for constructing a cladogram based on shared derived traits?

Accepted Answer

Identify the outgroup, determine shared derived traits, group organisms by these traits, and draw the tree.

Question 4

Which of the following statements about outgroups in phylogenetic analysis is correct?

Accepted Answer

An outgroup is a species or group that is closely related to but not part of the group being studied, used to root the tree.

Question 5

Refer to the phylogenetic tree with the kangaroo, lemur, human, mouse, and rat. Which species is the outgroup?

Accepted Answer

Kangaroo

Question 6

If two species share a derived trait that is not found in the outgroup, what does this suggest about their evolutionary relationship?

Accepted Answer

They share a more recent common ancestor with each other than with the outgroup.

Question 7

Which of the following best explains why molecular evidence (such as DNA sequences) is useful in constructing phylogenies?

Accepted Answer

Molecular evidence provides objective data that can reveal evolutionary relationships not obvious from morphology.

Question 8

In the vertebrate cladogram, which trait evolved most recently?

Accepted Answer

Fur; mammary glands

Question 9

A biologist is comparing DNA sequences from several primate species. Which of the following is the best reason to use an outgroup in this analysis?

Accepted Answer

To determine which traits are ancestral and which are derived.

Question 10

Which of the following is a correct interpretation of the circular phylogenetic tree diagram?

Accepted Answer

The length of the branches can represent evolutionary time or genetic change.

Question 11

Which of the following is NOT a requirement for a group to be considered a clade?

Accepted Answer

The group must include species with similar ecological roles.

Question 12

A student claims that all animals with lungs form a clade. Based on the vertebrate cladogram, is this claim correct?

Accepted Answer

No, because not all descendants of the common ancestor with lungs are included.

Question 13

Which of the following best describes adaptive radiation, as seen in the evolution of anole lizards?

Accepted Answer

The rapid diversification of a single ancestral species into multiple species adapted to different environments.

Question 14

Given the following character matrix, which trait is unique to humans among the listed taxa: Shark, Bullfrog, Kangaroo, Human?

Accepted Answer

Placenta

Question 15

Which of the following is an example of a paraphyletic group?

Accepted Answer

A group that includes a common ancestor and some, but not all, of its descendants.

Question 16

If a new DNA sequence is discovered that is shared by all mammals but not by reptiles or birds, how should this trait be mapped on a vertebrate cladogram?

Accepted Answer

At the branch point where mammals diverge from other vertebrates.

Question 17

Which of the following best explains why rotating branches above a node does not change the evolutionary relationships in a cladogram?

Accepted Answer

Because the branching pattern, not the order of tips, shows relationships.

Question 18

A researcher finds that two bird species share a unique DNA sequence not found in other birds. What is the most likely explanation?

Accepted Answer

They share a recent common ancestor.

Question 19

Which of the following equations best represents the principle of parsimony in phylogenetic analysis?

Accepted Answer

$$N_{changes} = \min(	ext{number of evolutionary changes required})$$

Phylogenies and Cladograms: Understanding Evolutionary Relationships

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