Final answer:
The important phenomenon changing population distribution is the rural-to-urban shift, where people move to urban areas for better opportunities, leading to increased urbanization and smaller family sizes.
Step-by-step explanation:
An important phenomenon changing the population distribution everywhere is the rural-to-urban shift. This reflects the trend initiated during the Industrial Revolution and sustained into the current century. The rural-to-urban shift is evidenced by people moving from rural areas to urban environments in search of job opportunities, education, and a different lifestyle as countries advance through the five stages of the index of economic development.
As a result of industrialization and urbanization, there's a subsequent decrease in family sizes and a traditional increase in incomes. This migration pattern is common globally, with people moving from 'have-not' countries to 'have' countries, or within a country, from resource-scarce rural areas to resource-rich urban areas. Additionally, regions that experience high rates of rural-to-urban migration often become targets for multinational corporations due to their labor supply, which leads to urban growth and changed family dynamics such as smaller family sizes.
Areas with significant urbanization, like some major cities, are often in the latter stages of the development index, showing higher incomes and declining family sizes. In high income countries, urbanization is pronounced, with a predominance of the population living in metropolitan areas. Predictions indicate that as this trend continues, populations will eventually stabilize.