1. What were the historical limitations of previous classification systems that led to and are solved by the three domain system that is use today?
2. Why is the gene coding for ribosomal RNA (rRNA) used for establishing phylogenetic relationships and how does this compare to previous methods for placing organisms in appropriate taxa?
3. What are the factors that limit our ability to fully classify and understand microbial diversity and what implications do these challenges have for environmental and health management.