Chapter 20.6 - Molecular Evolution

Question 1

Textbook: What is molecular evolution?

Answer 1

The Evolution at the level of DNA, which in time will result in genetic divergence of population.

Question 2

Textbook: Can genetic material be exchanged with members of another species?

Answer 2

No, because they are genetically isolated. The amount of time two species are isolated from each other is the same time since they had their common ancestor.

Question 3

Textbook: What is a molecular clock?

Answer 3

The molecular clock relates the amount of sequence difference between species and the time since the species diverged.

Question 4

Textbook: How is a molecular clock used to determine the time of divergence of two species?

Answer 4

A molecular clock uses mutation rates to estimate species divergence time. More differences mean longer divergence. Fossil data can provide additional clarity.

Question 5

Textbook: Why do we expect a protein’s rate of molecular evolution to be correlated with the protein’s function?

Answer 5

Proteins evolve at different rates due to varying levels of negative selection. Essential proteins, like histones, resist mutations strongly, as any changes disrupt their crucial functions. Less vital proteins can tolerate occasional amino acid changes, indicating weaker negative selection.