W Delta Z

Gelb: [explaining the W Delta Z equation] The selfish gene...

Helen Westcott: Go on.

Gelb: You think a bird will sacrifice itself for the flock, or a bee will sting a predator and die for the hive? How noble. How heroic.

Helen Westcott: And it isn't true?

Gelb: No, it isn't true. Suppose you put a snake into the cage and one of the monkeys is a hero - yeah, lures it away, lets it eat him. But it's not heroism. It's not selflessness. Forget the bees. Forget the monkey. The monkey's nothing. Just think what the monkey's made of.

Helen Westcott: What's that?

Gelb: Genes. The monkey is just the gene's way of making copies of itself. All these monkeys, they're all related. They all share their genes. So the monkey dies. What do the genes care? That's what Price proved. There's no altruism in nature. It's just genes looking after themselves. Ha.