Sedentary agricolture introduced 12000 years ago → the population has grow exponentially

Today → there are over 7 bilion human beings

Food is essential to survive, and it has an effect on the population

Maltuhs (the 18^th English economist) thinks that food constrains population growth and that is has a levelling effect

According to Malthus population increase by food is exponential, but the food production is not the same of the population, it is constant.

Land availability is outside human control such as famine and disease that Malthus called positive checks

Malthus acknowledged positive checks in the Elizabethan “Poor Laws”

Malthus had preventative checks → human preventative behaviour: celibacy, delayed marriage and emigration