SLIDE 6.
Six hundred and fifty
million years later, the outlines of Earth’s new continents glow by
night like a neon diadem against the darkness, shouting
consciousness at the sky in a blare of radio-wavelength emissions
as loud as a star.
There have been five
major epochs dominated by different families of land-based
vertebrates in the time between slides 5 and 6. All the Earth’s
coal and oil deposits were laid down in this time, different animal
families developed flight at least four times, and the partial
pressure of oxygen in the atmosphere rose from around 4 percent to
well over 16 percent. At the very end, a strangely bipedal,
tailless omnivore appeared on the plains of Africa—its brain
turbocharged on a potent mixture of oxygen and readily available
sugars—and erupted into sentience in a geological
eyeblink.
Here’s what isn’t going to
happen: