Overpopulation is a condition where an organism's numbers exceed the carrying capacity of its habitat. In common parlance, the term often refers to the relationship between the human population and its environment, the Earth. Steve Jones, head of the biology department at University College London,
has said, "Humans are 10,000 times more common than we should be,
according to the rules of the animal kingdom, and we have agriculture
to thank for that. Without farming, the world population would probably
have reached half a million by now."