Final answer:
The transition from stage 1 to stage 2 of the demographic transition model in Western Europe followed the Industrial Revolution, which caused a shift from rural agrarian societies to urban industrial ones, resulting in lower death rates and subsequent population growth.
Step-by-step explanation:
In Western Europe, the transition from stage 1 to stage 2 of the demographic transition model followed the Industrial Revolution when societies transitioned from rural to urban. This shift is marked by the demographic transition theory, which is a multistage model based on Western Europe's experience. High birth rates and death rates, which are characteristic of a pre-industrial, rural society in stage 1, are followed by rapidly declining death rates due to improvements in healthcare and sanitation during the Industrial Revolution. This creates a net population gain when moving to stage 2. As industrial activity and urban growth rise, benefits such as a higher standard of living and smaller family sizes become more pronounced.
The Demographic Transition Model outlines the development from a rural, pre-industrial society with high birth and death rates to an urban, industrialized economic system with low birth and death rates. During this transitional phase, as societies become industrialized, there is a high rate of rural-to-urban migration, commonly driven by employment opportunities in manufacturing, industrial activities, and the service sector, leading to increased urban populations.