The central event for the novel Oryx in Crake is the advent of a mega-virus, named JUVE, which nearly completely obliterates the human population. All that remains after it sweeps the world are Snowman, aka Jimmy, and a bunch of "Crakes"...genetically engineered humans designed to live easily and peacefully. Oh, and apparently some other humans...but we don't find that out till the end (and book doesn't say much about them).

Anyways, the novel is divided into two distinct parts -- before and after this apocalypse respectively -- that are interwoven together such that we alternate between the past and the present Jimmy/Snowman. The "before" period shows Jimmy's life and work with Crake up until the virus, and the "after" Jimmy's (now called Snowman) life as the only surviving regular human (so he believes).

Description aside, one of the more interesting aspects of this event is the fact that a new species of humans comes out of it nearly alone. These Crakes are an interesting sort, and before the catastrophe were intended just to be models of how humans could be improved...and become self sufficient. However, Crake himself apparently had other ideas in mind and intentionally killed off pretty much all of the world's population in what appears to be an attempt to restart the human race...hence making the Crakes immune to his virus.

The question now: did he succeed in his aims? From what I can tell, Crake had some sort of conviction to fix the way humans lived and interacted with the environment. He viewed the current human society as wasteful, destructive, and violent....and he wished to change those tendencies. Case in point, the Crakes. Totally docile, self sufficient, and easily adaptable...these new "humans" were his attempt to create a perfect sort of race that could live in harmony forever. His virus was the method by which to remove the flawed humans to give way for new ones.

So did it have the desired effect? Personally, I would say yes....and no. Yes, he did eradicate nearly all humans and created a self-sufficient peaceful group of humans. Yes, his plans fell into place as he expected. NO, because of Snowman. Much as Snowman is only one human and will not reproduce...he still exists to propagate the old human way. He is still an influence on the Crakes, teaching them random things that they would otherwise not care for. Snowman's recollections and descriptions of the Crakes contrast jarringly...showing just how simple and almost animalistic they are. Perhaps this was the idea, but one could argue that this demeans humanity more than it improves it.

I'll put this simply. While Crake may have removed many of the flaws inherent to humans, he also removed most (if not all) of the things that make them truly human. Sure, they can talk and be curious about things...but will they ever discover, design, invent, be creative?

They have intelligence, but because of Crake it is put to no use.