Human Population and Demographics PPT PDF

The Human Population Think of the earth as a living organism that is being attacked by billions of bacteria whose numbers double every forty years. Either the …bacteria dies, or both die. - Gore Vidal  Topic Outline:  1. Human Population and Human Population Growth 2. Human...

The Human Population Think of the earth as a living organism that is being attacked by billions of bacteria whose numbers double every forty years. Either the …bacteria dies, or both die. - Gore Vidal  Topic Outline:  1. Human Population and Human Population Growth 2. Human Population Dynamics a. Demographic measures b. Density c. Distribution 3. Age-Sex Structure and Population Pyramid Graph  At the end of the unit,…..: 1. trace the human population through time 2. identify possible causes of human population growth Learning 3. describe the possible effects of human Objectives population growth to the Earth’s resources 4. propose measures to lessen population growth and its effect to the Earth’s resources 5. construct and interpret population pyramid graph on age-sex structure  After studying this unit, you should be able to answer the following questions: Learning Outcomes Why are we concerned about human population growth? Will the world’s population double again as it did between 1965 and 2000? What is the relationship between population growth and environmental impact? How is human population growth changing in different parts of the world? How does population growth change as a society develops? What factors slow down or speed up human population growth? Realities  Early Human History ⚫ During the earliest parts of human history, our population survived as hunter-gatherers. ⚫ Population during this time was low due to density- dependent growth limiting factors: ⚫ Competition for food ⚫ Availability of water ⚫ Predators ⚫ Disease The indigeonous Hadza people of Tanzania. 6 ⚫ Agriculture helped reduce the impact of food availability and competition as a density-dependent growth limiting factor, and the human population began to increase. ⚫ Other factors, such as disease, were still present. 7  Past and Current Population Growth Are Very Different 2. Will the world’s population double again as it did between 1965 and 2000? Human population levels throughout history. It is clear from the J-shaped growth curve that human population is growing exponentially. 8 ⚫ Prior to the industrial revolution, human population growth was fixed, meaning it grew at a consistent rate. ⚫ About 0.1% per year. 9  The Industrial Revolution ⚫ The Industrial Revolution was a transition from hand production methods to machines, including the increased use of steam power and factories. ⚫ During this time, many important medical discoveries were made: ⚫ The Germ Theory, (Louis Pasteur-the understanding that microbes caused infection) the idea that microscopic bacteria and viruses cause disease. ⚫ Vaccines, injections of dead or weakened viruses that prevent disease. ⚫ Antibiotics theory (“magic bullets”-against bacterial infection) chemical compounds that kill bacteria. ⚫ Water treatment, the filtration and addition of chlorine to water to remove microorganisms and toxins. 1 ⚫ Following the industrial revolution, human population growth was exponential, an increasingly rapid rate with a continuously growing base and a low doubling time. ⚫ Will it do so again in the twenty-first century? 1  Past and Current Population Growth Are Very Different 3. What is the relationship between population growth and environmental impact? ⚫ World population has risen sharply Global human population was