Comprehension Questions

Section 26.1

Question 26.1

How is biological evolution defined?

Question 26.2

What are the two steps in the process of evolution?

Question 26.3

How is anagenesis different from cladogenesis?

Section 26.2

Question 26.4

Why does protein variation, as revealed by electrophoresis, underestimate the amount of true genetic variation?

Question 26.5

What are some of the advantages of using molecular data in evolutionary studies?

Question 26.6

What is the key difference between the neutral-mutation hypothesis and the balance hypothesis?

Question 26.7

Describe some of the methods that have been used to study variation in DNA.

Section 26.3

Question 26.8

What is the biological species concept?

Question 26.9

What is the difference between prezygotic and postzygotic reproductive isolating mechanisms? List different types of each.

Question 26.10

What is the basic difference between allopatric and sympatric modes of speciation?

Question 26.11

Briefly outline the process of allopatric speciation.

Question 26.12

What are some of the difficulties with sympatric speciation?

Question 26.13

Briefly explain how switching from hawthorn fruits to apples has led to genetic differentiation and partial reproductive isolation in Rhagoletis pomonella.

Section 26.4

Question 26.14

Draw a simple phylogenetic tree and identify a node, a branch, and an outgroup.

Question 26.15

Briefly describe differences among the distance approach, the maximum parsimony approach, and the maximum likelihood approach to the reconstruction of phylogenetic trees.

Section 26.5

Question 26.16

Outline the different rates of evolution that are typically seen in different parts of a protein-encoding gene. What might account for these differences?

Question 26.17

What is the molecular clock?

Question 26.18

What is exon shuffling? How can it lead to the evolution of new genes?

Question 26.19

What is a multigene family? What processes produce multigene families?

Question 26.20

Define horizontal gene transfer. What problems does it cause for evolutionary biologists?

For more questions that test your comprehension of the key chapter concepts, go to for this chapter.