AdvertisementOf Fish And Flies: The Evolutionary Role Of GenesDecember 18, 2009Joe PalcafacebookEmailThe marine stickleback fish (top) has much more pronounced spikes to protect it from the predators in its habitat. But the freshwater stickleback has less pronounced spikes because it's up against different predators. Marine and freshwater sticklebacks started diverging roughly 10,000 years ago. (Science)