Chapter 8 In-class Questions

Genetic drift causes changes in

• the strength of natural selection.

• allele frequencies.

• population size.

• phenotypes.

Genetic drift is caused by ________ processes.

• random.

• directed

• catastrophic

• selective

The two graphs show the change in allele frequency, p, over 100 generations. Each graph shows 10 different populations, all experiencing the same evolutionary forces. What is the most likely difference between the populations shown in the top graph compared to the populations in the bottom graph?

• There is no difference between the populations; the differences in the graphs are due to chance.

• The populations in the graph on top have a longer generation time than the populations in the bottom graph.

• The populations in the graph on top are experiencing genetic drift; the populations in the graph on the bottom are experiencing directional selection.

• The population sizes in the graph on top are smaller than the population sizes in the graph on the bottom.

Imagine an island archipelago where all of the islands are founded by individuals heterozygous at a particular locus. If there is no migration or mutation, and the alleles at that locus are neutral, what do you expect the island populations to look like after many generations?

• Some island populations will have fixed one allele, and other populations will have fixed the other allele.

• The populations on every island will have fixed the same allele.

• The island populations will have high levels of genetic diversity at this locus.

• We cannot predict any outcome because genetic drift is a random process.

The figure shows the relationship between the size of an island and the number of alleles found at microsatellite loci in lizard populations. What do these data demonstrate?

• Lizards are more successful on larger islands.

• 
  Effective population size does not affect allelic diversity.

• Populations on smaller islands experience more natural selection.

• Genetic drift is stronger in smaller populations.

What does the picture represent?

• Founder Effect
• Mutations
• Bottleneck effect
• Gene Flow

Tags

NGSS.HS-LS4-5

Which of the following scenarios is most likely to result in a bottleneck effect?

• A large population experiencing a sudden increase in food supply.

• A small population experiencing a natural disaster that drastically reduces its size.

• A population that undergoes a gradual increase in genetic diversity.

• A population that remains stable in size over many generations.

What is saturation in the context of genetic mutations?

• The accumulation of mutations in different genes

• Multiple substitutions occurring at the same nucleotide or amino acid site over time

• The complete loss of genetic variation in a population

• The process by which DNA sequences become more similar over time

What is one major effect of saturation in genetic analysis?

• Overestimation of genetic divergence between species

• Underestimation of genetic divergence between species

• Elimination of all genetic differences among species

• Increased accuracy in reconstructing phylogenetic trees