1. Humans and chimpanzees share several polymorphic loci. Which is the LEAST plausible explanation for this fact?
A. Balancing selection has maintained polymorphism in both species
B. Incomplete lineage sorting left polymorphic loci and those have persisted since the speciation event.
C. Interbreeding has allowed introgression of alleles at theses loci in both directions.
D. Genetic variation provided by the polymorphic alleles enhances resistance to pathogens.
2. According to the social brain hypothesis, we should expect primates living in larger social groups to have:
A. Larger brains, specifically, a neocortex of relatively larger size
B. Lager incisors and canines, to defend against more social competitors
C. Smaller brains, because many individuals can work together to solve problems
D. Great variation in brain and neocortex size, with the dominant individuals having the largest
3. You extract DNA from human bones in an ancient village buried by volcanic ash. You discover that there is an extremely high frequency of the LCT allele for lactase persistence. What might you reasonably conclude about the population?
A. This population is likely the source of the high frequency of the LCT gene in Northern Europe
B. The village could not be more than 4,500 years old
C. The members of this population likely used domesticated livestock for their milk
D. villagers had a diet rich in wheat or another domesticated crop
4. Why do populations father from Africa have more deleterious mutations in their genome?
A. Repeated bottlenecks and founder effects made drift more intense more often
B. Populations farther from Africa have been exposed to more mutagens in the environment
C. As people migrated over the globe they interbred with Neanderthals and Denisovans
D. The populations are younger, so purifying selection has not had time to purge delirious mutations from the populations.
