" To succeed as a predator, simple math explains that it is vital that the consumers do not outnumber the consumees. The older and larger the consumer, the greater the investment of energy, pound for pound. It takes a lot of seeds and grass to make enough mice and rabbits to make a wolf; a lot of little plants to make sufficient numbers of small fish to make a shark. As it turns out, it takes a lot of everything to power human societies. "

― Sylvia A. Earle , The World Is Blue: How Our Fate and the Ocean's Are One