Malthusianism
In 1798, Mathus published a book, called An Essay on the Principle of Population. In it, he describes his Malthusian growth model. He wrote that the growth of the population is exponential, but the growth of the food supply is only arithmetical. This means if there are no limits to the growth of the population, it will not be possible to produce food for all of them. Malthus was read by Charles Darwin. It showed Darwin that the survival of a species was something which needed explaining.