Thomas Malthus - Population and Carrying Capacity

Accompanying Mendel and Darwin in coming to a theory of evolutionary thought was Thomas Malthus. Malthus is mostly credited with the theory of natural selection, though his focus on population lent itself more toward humanity than to animal selection. Malthus's theory of population proposed that there were natural limiting factors, such as food resources, which limited a given population. Malthus noted that populations as a whole tend to grow exponentially or geometrically, whereas natural resources grow arithmetically if they grow at all. When a population reaches beyond the amount of resources available to its survival, it has reached its carrying capacity. When a population reaches its carrying capacity a number of limiting factors, such as disease or famine, can occur to bring the population down, and back to naturally acceptable limits. Malthus had a strong influence on Charles Darwin and Lyell in their evolutionary thought, in that he was the first to realize that population growth and surpluses were kept in check by mortality.