From similarity and differences of morphological, biochemical, cellular characteristics, biologist have constructed 'phylogenetic (evolutionary) trees' (who is most closely related to who, analogous to a family tree)
In the United States, lightning routinely kills more people each year than tornadoes or hurricanes. Tornadoes, hail, and wind gusts get the most attention, but only lightning can strike outside the storm itself. Lightning is the first thunderstorm hazard to arrive and the last to leave.
On average, tornadoes kill about 60 people per year--most from flying or falling (crushing) debris. The actual number of tornado deaths in a year can vary wildly -- from single digits to hundreds, depending on many factors from both weather and society.