Viruses, Evolution and Pandemics : Past, Present and Future

When the 1918-19 Spanish FLU pandemic raged, humans were not aware of viruses. Viruses were discovered and studied in the latter part of the 20 th century, and caused an explosion in our understanding of cancer (which was briefly thought to be a viral disease). Today, we know that viruses play an important role in evolution by forcing complex organisms to adapt and survive to leave behind copies of their genomes. The global pandemics they cause cost lives, but from the perspective of evolution, they create selection pressure on survival, and are responsible for sexual dimorphism, the adaptive immune response, and many social customs.  I will describe this interplay of viral evolution and human adaptation, with a focus on the FLU and SARS-Cov-2 (Covid-19) viruses. The talk will be at an elementary level.