Question 1

Which of the following best describes a phylogenetic tree?

Accepted Answer

A graphical representation of the evolutionary relationships among organisms based on shared characteristics.

Question 2

In a phylogenetic tree, what does the 'root' represent?

Accepted Answer

The most recent common ancestor of all taxa in the tree.

Question 3

Which term refers to a group that includes an ancestor and all of its descendants?

Accepted Answer

Monophyletic group

Question 4

What is the primary assumption when constructing a phylogenetic tree?

Accepted Answer

Species that share many characteristics are closely related.

Question 5

Which of the following is an example of a synapomorphy?

Accepted Answer

Hair in mammals

Question 6

A trait that appears similar in two taxa due to convergent evolution, not shared ancestry, is called:

Accepted Answer

Homoplasy

Question 7

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

Accepted Answer

The most parsimonious tree is the one with the fewest evolutionary changes.

Question 8

In a phylogenetic tree, what does a polytomy indicate?

Accepted Answer

Uncertainty about the exact relationships among the taxa.

Question 9

Which of the following is NOT a valid character for building phylogenetic trees?

Accepted Answer

A trait that is invariant across all taxa.

Question 10

If two species share a trait due to common ancestry, this trait is called:

Accepted Answer

Homology

Question 11

Which equation would you use to calculate the minimum number of evolutionary changes required for a trait on a phylogenetic tree?

Accepted Answer

$$n_{steps} = \sum_{i=1}^{m} c_i$$

Question 12

Which of the following best describes an outgroup in a phylogenetic analysis?

Accepted Answer

A taxon that diverged before the taxa of interest and is used for comparison.

Question 13

Which of the following scenarios would most likely result in a polyphyletic group?

Accepted Answer

Grouping species based on a convergent trait.

Question 14

A paraphyletic group is defined as:

Accepted Answer

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

Question 15

Which rule about phylogenetic trees states that only the branching order matters, not the order at the top?

Accepted Answer

Phylogeny Rule #3

Question 16

In the context of flu vaccines, why is phylogeny important?

Accepted Answer

It helps predict which viral strains are most likely to spread based on evolutionary relationships.

Question 17

Which of the following is a derived trait?

Accepted Answer

A trait that is present in the ingroup but not in the outgroup.

Question 18

When mapping a new character onto a phylogenetic tree, which principle should be used to choose the best tree?

Accepted Answer

The principle of parsimony

Question 19

Which of the following would increase the likelihood of a polytomy in a phylogenetic tree?

Accepted Answer

Conflicting or insufficient data about evolutionary relationships.

Question 20

If a newly discovered species shares a synapomorphy with a known group, what does this indicate?

Accepted Answer

The species likely belongs to that group.

Phylogenetics: Understanding Evolutionary Relationships

Study Guide - Practice Questions