The frogs are toxic – it’s been calculated that the poison contained in the skin of just one animal could kill a thousand average-sized mice – hence the vivid color, which makes them stand out against the forest floor.
-- Author (Chapter 1 paragraph Page 5)

Importance: The golden frog of Central Panama is bright yellow with brown splotches and highly toxic. The bright color gives its prey fair warning that the frog is nearby.

But what was this primitive earth? And what revolution was able to wipe it out?
-- Jean-Leopold Cuvier (Chapter 2 paragraph Page 30)

Importance: Naturalist Jean-Leopold Cuvier was the first scientist to entertain the concept of animal extinction. He concluded that the bones of the mastodon and other species represented animals that had lived on earth but no longer did. He was the first to be curious about what happened to extinct animals.

The present is the key to the past.
-- Charles Lyell (Chapter 3 paragraph Page 48)

Importance: Charles was an English naturalist who didn’t believe in cataclysm; rather...