malthus & carrying capacity

Thomas Malthus (1798)

English economist who wrote "Essay on the Principle of Population," predicting population growth would outpace food production, leading to mass starvation.

Malthusian Growth Rates

Food production grows arithmetically (1, 2, 3, 4…), while population grows exponentially/geometrically (1, 2, 4, 8, 16…).

Criticisms of Malthusian Theory

Failed to foresee agricultural innovations (fertilizer, tractors, hybridization), widespread family planning (lower CBR), and that famines stem from unequal food distribution, not total food scarcity.

Neo-Malthusians

Modern theorists who argue overpopulation is dangerous due to ecological problems, higher per capita consumption in MDCs, and the depletion of non-food natural resources.

Paul Ehrlich

Prominent Neo-Malthusian who authored "The Population Bomb".

Carrying Capacity

The maximum number of people an area's environment and resources can sustain.

Causes of Overpopulation

Occurs when carrying capacity is exceeded due to resource overconsumption, inefficient distribution of goods, or unsustainable land use.

Population Pyramid

A graphical display showing the age and sex distribution of a population, with males on the left and females on the right.

Sex Ratio

The number of males relative to females in a population.

Cohort

An age group bar represented on a population pyramid.

Triangular Pyramid Shape

Indicates rapid/fast population growth with a high proportion of young people.

Extended Triangle Pyramid Shape

Indicates moderate population growth.

Column Pyramid Shape

Indicates slow or stable population growth.

Reduced Pentagon / Constricting Shape

Indicates a shrinking or declining population.

Epidemiological Transition Model (ETM)

A model that outlines the distinctive causes of death in each stage of the Demographic Transition Model.

ETM Stage 1: Pestilence and Famine

High death rates caused by widespread infectious diseases and food shortages.

ETM Stage 2: Receding Pandemics

Death rates fall due to improved sanitation, better nutrition, and medical advances.

ETM Stage 3: Degenerative Diseases

Deaths shift from infectious diseases to chronic conditions associated with aging, such as heart disease and cancer.

ETM Stage 4: Delayed Degenerative Diseases

Life expectancy extends as medical treatments (chemo, surgeries) delay the impact of chronic diseases.

ETM Stage 5 (Hypothetical): Reemergence of Infectious Diseases

New or drug-resistant strains of disease reemerge and spread rapidly due to globalization.