CH08-1 Population Measuring its growth & impact ronmental%20Science/course%20files/multimedia/l esson35/animations/3b_Cultural_Carrying_Capacity.html

CH08-2 The Growing Human Population  The human population has grown slowly for most of human history.  The rapid increase in population size is a relatively recent phenomenon.

CH08-3 Human Population through Time

CH08-4 Why Has the Human Population Grown So Large?  The human population has skyrocketed in the last 200 years.  Global decline of death rates without a decrease in birth rates.  result of increases in food supply and better medicine and sanitation. Infant mortality in the U.S.

CH08-5 The Ecology of Expanding the Earth’s Carrying Capacity  Technological advances  lower environmental resistance  promote population growth.  Technology increases the carrying capacity for humans.  Technology decreases the prospects of other species and may cause adverse effects in human populations as well.

CH08-6 What Is the Earth’s Carrying Capacity for Humans?  Determining the Earth’s carrying capacity for humans is a task fraught with difficulty.  Some people think we have not reached the carrying capacity.  Others believe that the human population already exceeds the Earth’s long-term carrying capacity.  Economics, Diet, & Culture

CH08-7 Too Many People, Reproducing Too Quickly Population is at the root of virtually all environmental problems  pollution  resource depletion  social and economic problems  environmental problems and solutions

CH08-8 Too Many People, Reproducing Too Quickly  The massive size of the human population causes environmental problems evident in urban and rural areas.  shortages of resources  environmental deterioration  a host of possible social problems

CH08-9 Reproducing Too Quickly  Social, economic, and environmental problems of cities and rural areas are aggravated by rapid population growth.  The large size of many populations makes it difficult for governments to keep up with current demands.  Continued rapid growth makes it nearly impossible to improve conditions and create a sustainable human presence.

CH08-10 Fig. 8-4 Graph of global population growth

CH08-11 Understanding Populations and Population Growth  Measuring Population Growth – Growth Rates and Death Rates  Global population growth is determined by subtracting the crude death rate from the crude birth rate.

CH08-12 Doubling Time  the time it takes a population to double in size.  determined by dividing 70 by the growth rate.  small growth rates can result in rapid doubling.  Growth rates  developed countries are relatively low.  less developed nations, generally much higher.

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CH08-14 The Total Fertility Rate and Replacement-Level Fertility  Total fertility rate is the average number of children women are expected to have during their reproductive age span.  Replacement-level fertility occurs when couples produce exactly the number of children needed to replace themselves.  Zero population growth occurs when the death rate equals the birth rate and when the net migration is zero.

CH08-15 Migration  The growth of a town, city, state, or region is determined by two factors:  Growth rate (natural increase)  Migration (the movement of people into and out of the population)  Immigration, the movement of people from one region of a country to another, affects regional population growth.

CH08-16  Population Histograms  Graphs of populations  various age groups  males and females  provide useful information for planners.  A countries histogram may be  Expansive  Constrictive  Stationary  Global population  Expansive due to continued growth in the less developed nations

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CH08-18  Exponential Growth  Human populations are growing exponentially.  Globally, the human population has “rounded the bend” of the exponential growth curve.  This means that even small percentage increases result in huge numbers of new world residents.

CH08-19  Exponential Growth  Exponential growth is cause for great concern.  As our population increases, so do:  our demand for resources  our waste production  our environmental damage

CH08-20 The Future of World Population: Some Projections and Concerns  Predicting the future size of the world’s population is difficult.  It is likely that the population of the world will increase dramatically before it stabilizes.  This increase could bring about massive changes in the environment.

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CH08-22 Population Growth in the Less Developed World: Why Should We Worry?  Impacts:  Social -- disease, war, equitable distribution of resources  Economic -- education, available resources, sustainable development  Environmental -- overuse of resources and pollution

CH08-23 A World of Possibilities  The human population cannot grow indefinitely.  Transition Options  Smooth transition to a stable population size.  Periodic crashes that will eliminate large numbers of people.  Overshooting the carrying capacity  destroy their ability to support people  populations may fall to much lower levels.

CH08-24 Fig Patterns of population growth

CH Science/course%20files/multimedia/lesson36/animations/3b_Popu lation_Crash.html

CH08-26 A Bit of Good News… Population growth is slowing 1960 – Average family had 5 kids 2005 – Average family has 3 kids Sustainable – Average family has 2 kids (ZPG) 1994 – U.N. International Conference on Population & Development (ICPD) in Cairo, Egypt Multi-Faceted Approach Equity for Women – Education, Social, Political, Economic Economic Equity between rich and poor 2015 – affordable family planning and reproductive health care for all Sustainable Economic Development throughout the world