Why is it that Overpopulation Occurs?

Overpopulation occurs mostly due to great availability of life-supporting resources. In climates that have plentiful resources, there will naturally be a larger population than in climates with few resources that are necessary for life.

http://app.discoveryeducation.com/techbook2:concept/view/guidConceptId/96eaf89e-6745-4bed-83a5-2db26d0f4364/
guidUnitId/4be31ac2-7b0f-4762-a2ad-4ee6691ec694 (info)

http://www.weogeo.com/data/OpenStreetMap-Priority_Rendering_Tiles.html (Above image)

http://mindprod.com/environment/population.html (Image above)

Due to the increase in birth rate and the decrease in the death rate, population has grown.

http://www.conserve-energy-future.com/causes-effects-solutions-of-overpopulation.php (Some info)