External fertilization

Ah, fertilization--that miraculous process to which we all owe our existence. First, a wastefully huge swarm of sperm weakly flops along, its members bumping into walls and flailing aimlessly through thick strands of mucus. Eventually, through sheer odds of pinball-like bouncing more than anything else, a few sperm end up close to an egg. As they mill around, the egg selects one and reels it in, pinning it down in spite of its efforts to escape. The gigantic, hardy egg yanks this tiny sperm inside, distills out the chromosomes, and sets out to become an embryo.