Short answers, pulled from the story.
The word economics originates from the ancient Greek term oikonomia, which literally translates to the management of a household. The term evolved from the Greek words oikos, meaning house, and nomos, meaning custom or law. This ancient definition described the practical know-how required to run a farm, manage a family, and oversee slaves.
Adam Smith's The Wealth of Nations was published in 1776. This publication is widely regarded as the effective birth of economics as a separate discipline. Smith, a Scottish philosopher born in 1723, argued that the true wealth of a nation lay in the production of goods and services driven by the division of labor.
Thomas Robert Malthus earned economics the nickname the dismal science because he argued that human population tends to increase geometrically while food production can only increase arithmetically. His theory of diminishing returns suggested that the force of a rapidly growing population against a limited amount of land would prevent economic progress for the masses. This pessimistic view stood in stark contrast to the optimism of Adam Smith.
Karl Marx proposed the theory of surplus value in the first volume of his major work Das Kapital, published in 1867. He argued that workers were only paid a proportion of the value their work had created, with the remainder being appropriated by capitalists as profit. This theory formed the core of Marxian economics, which viewed the capitalist system as inherently exploitative and prone to crisis.
The neoclassical revolution took place between 1870 and 1910. This movement, led by economists such as Alfred Marshall and Mary Paley Marshall, rejected the classical labor theory of value in favor of a marginal utility theory of value. The revolution introduced the concept of opportunity cost and shifted the focus from production to individual choice.
Lionel Robbins proposed the modern definition of economics in 1932. He argued that economics is the science which studies human behavior as a relationship between ends and scarce means which have alternative uses. This definition shifted the focus from the study of wealth to the study of human behavior under conditions of scarcity.