Question 1

Which of the following best describes the difference between homology and analogy in evolutionary biology?

Accepted Answer

Homology refers to similarities due to shared ancestry, while analogy refers to similarities due to convergent evolution.

Question 2

In the context of phylogenetic trees, what does a monophyletic group (clade) include?

Accepted Answer

An ancestor and all of its descendants.

Question 3

Which of the following is an example of a shared derived character?

Accepted Answer

A trait that is unique to a particular clade and not found in distant ancestors.

Question 4

A researcher is comparing the DNA sequences of two species and finds a high degree of similarity in a complex gene sequence. What does this most likely indicate?

Accepted Answer

The sequences are homologous, indicating shared ancestry.

Question 5

Which of the following best explains the concept of a molecular clock?

Accepted Answer

It uses the constant rate of genetic mutations to estimate the time of evolutionary divergence between species.

Question 6

Why are highly conserved genes, such as cytochrome c, useful for studying deep evolutionary relationships?

Accepted Answer

They accumulate mutations very slowly, allowing comparisons across distant lineages.

Question 7

Given the following equation for a molecular clock: $$D = 2rt$$, where $$D is $$the number of genetic differences, $$r is $$the mutation rate per million years, and $$t is $$the time since divergence, how would you solve for $$t$$?

Accepted Answer

$$t = \frac{D}{2r}$$

Question 8

Which of the following is a limitation of using molecular clocks?

Accepted Answer

Natural selection can influence mutation rates, making the clock less reliable.

Question 9

A group that includes an ancestor and some, but not all, of its descendants is called:

Accepted Answer

Paraphyletic

Question 10

Why is it important to distinguish between homology and analogy when constructing phylogenetic trees?

Accepted Answer

Homologies reflect shared ancestry, while analogies do not, which affects the accuracy of evolutionary relationships.

Question 11

Which of the following strategies can improve the reliability of molecular clock estimates?

Accepted Answer

Calibrating with fossil records and using multiple genes from different taxa.

Question 12

In a phylogenetic analysis, what is the purpose of including an outgroup?

Accepted Answer

To help determine the ancestral character states for the group being studied.

Question 13

Which of the following best describes a polyphyletic group?

Accepted Answer

A group composed of members with different ancestors.

Question 14

If a gene is essential for survival and highly conserved, what would you expect about its mutation rate and usefulness for studying recent evolutionary events?

Accepted Answer

It mutates slowly and is less useful for studying recent events.

Question 15

Which of the following is an example of convergent evolution?

Accepted Answer

Wings of bats and birds, which evolved independently for flight.

Question 16

A scientist finds that two species have a similar protein sequence, but the function of the protein is different in each species. What does this suggest?

Accepted Answer

The protein is homologous, but its function has diverged.

Question 17

Which of the following is a shared ancestral character for mammals?

Accepted Answer

The presence of a backbone.

Question 18

If the mutation rate for a gene is $$1 	imes 10$$^{-8}$$ mutations per site per year, and two species differ by 0.01 substitutions per site, estimate the time since their divergence using the formula D = 2rt$.

Accepted Answer

$$t = \frac{0.01}{2 	imes 1 	imes 10$$^{-8}$$} = 500,000$$ years

Question 19

Which of the following statements about neutral mutations is correct?

Accepted Answer

They are not beneficial or detrimental to fitness and are often used in molecular clocks.

Phylogeny, Molecular Clocks, and Cladistics: Study Notes for Biology Students

Study Guide - Practice Questions

Study Guide - Flashcards