(a) Outline the main features of the Malthusian theory on population. (b) Explain the developments that render the theory irrelevant to the present day situ...

(a) Main features of the Malthusian theory of population. Thomas Malthus (1798) argued that:

• Population, when unchecked, grows in a geometric progression (1, 2, 4, 8, 16 ...), roughly doubling every 25 years.
• The means of subsistence (food) can grow only in an arithmetic progression (1, 2, 3, 4, 5 ...) because land is fixed and subject to diminishing returns.
• Population therefore tends to outrun the food supply, pushing living standards down to subsistence level.
• The imbalance is corrected by positive checks that raise the death rate (famine, disease, war) and preventive checks that lower the birth rate (moral restraint, late marriage, celibacy).

(b) Developments that make the theory less relevant today.

• Agricultural revolution. Improved seeds, fertilisers, irrigation and mechanisation (the Green Revolution) have raised food output far faster than arithmetically, disproving the fixed-food assumption.
• Birth control. Modern contraception and family-planning programmes now limit births, something Malthus (who allowed only moral restraint) did not foresee.
• Opening of new lands and international trade. Countries can import food and settle new regions, so a nation's population is no longer tied to its own land.
• Industrialisation and rising incomes. Economic growth has raised living standards, and the demographic transition shows that richer, educated societies choose smaller families, so birth rates fall as income rises.
• Improved transport and medicine. Food can be moved quickly to shortage areas, and better health has changed the pattern of the positive checks.

Examination takeaway: note that the theory is not wholly dead. It still describes some poor, high-birth-rate economies, so a balanced answer says why technology, trade and birth control weakened its general validity.