In the frigid waters of the ocean surrounding Antarctica, fish have a special trait which allows them to survive the big chill. As scientists discovered in the 1960s, the fish have adapted by evolving a kind of antifreeze. It's composed of molecules called glycoproteins that circulate in the blood of the fishes, slightly lowering the temperature at which their body fluids would otherwise freeze and kill them. The glycoproteins surround tiny ice crystals and keep them from growing. The fish at the other pole of the globe also have a similar protein. It was, however, seen as a mutation after they had diverged from the southern species.

A species of birds exists in stasis for many thousands of years. Suddenly, a bacteria causes their primary tree of sheltering choice to die. The birds must adapt within the environment to trees that are much higher requiring more wing strength. Some birds die. The remaining birds' bodies adapt as necessary and they return to a state of stasis.

The Rough-skinned newt produces a potent neurotoxin that concentrates in their skin. Garter snakes, have evolved resistance to this toxin through a series of genetic mutations, and prey upon the newts. The relationship between these animals has resulted in an evolutionary arms race that has driven toxin levels in the newt to extreme levels.

The Apple Maggot Fly infests the fruit of a native North American Hawthorn Apple tree. In the 1860s some maggot flies began to infest apples. Now there are two populations of the fly feeding on the two food sources. The populations rarely interbreed and are showing genetic differences and therefore are becoming two separate species.