Bacteria have been around longer than any multicellular species. How have bacteria influenced the evolution of multicellular species? Use specific examples from the text to explore this connection.

Many people have come to believe that the immune system is strictly for defense against pathogens. The immune system plays a larger role, more like a balancing act. How have our microbes shaped our immune system, for better or for worse?

Darwin’s On the Origin of Species was a foundational evolutionary text for multicellular animals. How have his theories of evolution impacted how we view our relationship to our microbes? Do these same theories apply to bacteria and our symbiotic relationship with them?