Chapter 4.2, Problem 4MI

Summary Introduction

To summarize:

Two examples of events that could produce the given effects.

Introduction:

The study of human population size, density, distribution, movement, death rate and birth rate is called demography. According to demographic studies the human population on Earth was relatively stable until recent times when the population began to grow exponentially. After the bubonic plague in 1300s, when one third of the population of Europe died, there has been a significant increase in human population.

Answer to Problem 4MI

Effect: decline in world population growth

Events that could produce this effect: pandemic, world war

Effect: increase in world population growth

Events that could produce this effect: new medicines that cure many diseases, improved farming techniques that produce more food per unit area of land.

Explanation of Solution

For thousands of years environmental conditions kept the population of humans at a relatively constant number, below the carrying capacity. Population trends can be altered by events such as a disease and a war. A worldwide outbreak of a disease such as pandemic can cause a decline in world population growth. A world war that involves many countries may also cause a decline in world population growth as there are many casualties in wars.

Humans have learned to alter the environment in ways that changed the carrying capacity. Agriculture and domestication of animals have increased the human food supply. Technological advancements and improved medicines have increased the chances of human survival by reducing the number of deaths from parasites and diseases. Improvements in shelter have also made humans less vulnerable to climatic impact.