A typical bacterium reproduces every half hour. One makes two, two make four, four make eight, eight make sixteen, and so on. Start with a single bacterium, and 20 generations later -- 10 hours -- you have a million, enough, by my calculation, to cover the head of a pin.
Two days later -- 120 generations -- you will have enough bacteria to fill the oceans of the world chock-a-block with goo. A few hours later, the entire surface of the Earth will be wrapped in a layer of bacteria 10 miles thick!
Clearly, something must be wrong with my calculation; the globe is not wrapped in a thick layer of bacterial slime.
No definition of life is complete that does not include death. Death is the driving engine of evolution. As microbiologist Ursula Goodenough writes: "Death is the price paid to have trees and clams and birds and grasshoppers, and death is the price paid to have human consciousness, to be aware of all that shimmering awareness and all that love."