Marine fish won an evolutionary lottery 66 million years ago
Why do our oceans contain such a staggering diversity of fish of so many different sizes, shapes and colors? A team of biologists reports that the answer dates back 66 million years, when a six-mile-wide asteroid crashed to Earth, wiping out the dinosaurs and approximately 75 percent of the world's animal and plant species, according to Science Daily.
Slightly more than half of today's fish are "marine fish," meaning they live in oceans. And most marine fish, including tuna, halibut, grouper, sea horses and mahi-mahi, belong to an extraordinarily diverse group called acanthomorphs.