Short answers, pulled from the story.
Dmitri Ivanovsky performed the first experiment proving the existence of viruses in 1892. He passed sap from a sick tobacco plant through a porcelain filter that blocked bacteria yet the liquid remained infectious to healthy plants.
The word virus derives from the Latin term meaning poison or noxious liquid. This definition has persisted for over three centuries even as the biological reality of the virus has been revealed to be far more complex than simple poison.
Scientists propose three main hypotheses to explain the evolutionary history of viruses. These include the regressive hypothesis, the cellular origin hypothesis, and the co-evolution hypothesis or virus-first hypothesis.
The Pandoravirus genus was discovered in 2013. This genus possesses genomes twice as large as Mimivirus and can sometimes be seen with a basic optical microscope.
The 1918 influenza pandemic killed between 40 and 100 million people. This event lasted until 1919 and represented 5% of the world's population at the time.
800 million viruses are deposited daily onto every square meter of the planet's surface. These particles circulate above the weather system and play a critical role in regulating marine ecosystems.