Nice Guys Finish Last? Altruism and Survival

Radiolab's "The Good Show" is one of my favorite episodes of all time.  You must listen to it.  Here's a quick summary of what it covers for those who haven't heard it before:

In this episode, a question that haunted Charles Darwin: if natural selection boils down to survival of the fittest, how do you explain why one creature might stick its neck out for another?

The standard view of evolution is that living things are shaped by cold-hearted competition. And there is no doubt that today's plants and animals carry the genetic legacy of ancestors who fought fiercely to survive and reproduce. But in this hour, we wonder whether there might also be a logic behind sharing, niceness, kindness ... or even, self-sacrifice. Is altruism an aberration, or just an elaborate guise for sneaky self-interest? Do we really live in a selfish, dog-eat-dog world? Or has evolution carved out a hidden code that rewards genuine cooperation?

When I stumbled across this article yesterday, then, I was reminded of the same issues Radiolab brings up in "The Good Show." Here are some highlights from the article worth pondering:

• "'Because of our very vulnerable offspring, the fundamental task for human survival and gene replication is to take care of others,' said Keltner, co-director of UC Berkeley's Greater Good Science Center. 'Human beings have survived as a species because we have evolved the capacities to care for those in need and to cooperate. As Darwin long ago surmised, sympathy is our strongest instinct.'" 
• "'Sympathy is indeed wired into our brains and bodies; and it spreads from one person to another through touch,' Keltner said."
• "UC Berkeley psychologist Darlene Francis and Michael Meaney, a professor of biological psychiatry and neurology at McGill University, found that rat pups whose mothers licked, groomed and generally nurtured them showed reduced levels of stress hormones, including cortisol, and had generally more robust immune systems."
• "Overall, these and other findings at UC Berkeley challenge the assumption that nice guys finish last, and instead support the hypothesis that humans, if adequately nurtured and supported, tend to err on the side of compassion."

So what to make of it all?  How do you define the difference between compassion and competition in a world where survival of the fittest shapes the chronological history of every species on Earth?  Is being compassionate--scientifically speaking--actually an instinctual behavior to increase the odds of continuing your blood line?