World Population Log http://www.census.gov/ipc/www/popclockworld.html Date: 11/02/2010 Population: Date: Population:

Bellwork Question Your parents give you two options for allowance 1,000 a month A penny on the first day of the month that doubles to two pennies on the second day and so on until the last day of the month How much money do you have at the end of the month under option 2? Which option do you choose?

.01 .02 .04 .08 .16 .32 .64 1.28 2.56 5.12 10.24 20.48 40.96 81.92 163.84 327.68 655.36 1310.72 2621.44 5242.88 10,485.76 209711.52 41943.04 83886.08 167772.16 671088.64 2684354.56 335544.32 1342177.28 10,737,418.24 Over 10 million!! 5368709.12

Question Which type of population exhibits this sort of growth?

Population & Development Botkin & Heller Chapter 4 The Human Population/ Population & Development Botkin & Heller Chapter 4 Cartoon Guide Chapter 08 PART A

The Human Population and the Environment Chapter 4 The Human Population and the Environment

Basic Concepts of Population Dynamics A group of individuals of the same species living in the same area, at the same time. Species: All individuals that are capable of interbreeding & producing fertile offspring. Population dynamics The general study of population changes.

Accelerated World Population Growth First Billion: 1804 Second Billion: 1927 (123 yrs) Third Billion: 1960 (33 yrs) Fourth Billion: 1974 (14 yrs) Fifth Billion: 1987 (13 yrs) Sixth Billion: 1999 (11 yrs)

A Brief History of Human Population Growth Hunters and gatherers The world’s population was probably less than a few million Early, pre-industrial agriculture Allowed a much greater density of people The first major increase in human population Machine age Industrial revolution led to rapid increase in human population The Modern era Rate of population has slowed in wealthy nations but continues to increase rapidly in poorer, less developed nations.

© 2008 John Wiley and Sons Publishers

Past and forecasted human population growth rate by geographic region and major nations © 2008 John Wiley and Sons Publishers

Logistic growth curve. World population as total numbers and growth per decade and by development status 1750-2100 © 2008 John Wiley and Sons Publishers

Disparities Developed countries Low-income developing countries 15% of the world’s population Control 80% of the world’s wealth Low-income developing countries 37% of the world’s population Control 3.0% of the world’s gross national income Difference in per capita income: 63 to 1!

Doubling Time Changes with Changes in Growth Rate Because the world’s population rate is increasing at a rate between 1-2% we can expect the world’s population to DOUBLE within the next 35 to 70 years. QUESTIONS: Look at the graph on the left. As growth rate increases what happens to doubling time? Why is this a problem? Do you remember the formula to calculate doubling time? If you have forgotten check page 58. © 2008 John Wiley and Sons Publishers

© 2008 John Wiley and Sons Publishers

United States Population 1790-2000 QUESTIONS: The growth rate in the United States is slowing. So why then is the global population continuing to rise? What can be done about it? United States population 1790-2000. Growth rate of the US population appears to be slowing. © 2008 John Wiley and Sons Publishers

90% of population growth is happening in Third World

Age Structure Population age structure: The proportion of the population in each age class Affects current and future birth rates, death rates and growth rates Has an impact on the environment Has complications for current and future social and economic status.

A B C Which age structure diagram has the most young people? Why might that be? Which age structure diagrams have more men than women at age 80+ Which age structure diagram has the fewest elderly people? B C

© 2008 John Wiley and Sons Publishers

Population Growth Rates (b) crude birth rate= number birth per 1000 individuals (d) crude death rate= number death per 1000 individuals (r) growth rate = natural increase in population expressed as percent per years (If this number is negative, the population is shrinking.)   equation: r = b – d But other factors affect population growth in a certain area…

Rates continued… increase population decrease population births   deaths immigration   emigration (exit) r = (birth - death)+ (immigration-emigration) immigration = migration of individuals into a population from another area or country emigration = migration of individuals from a population bound for another country

Growth Rate Example r = (b - d)+ (i - e) example: population of 10,000 has 100 births (10 per 1000) 50 deaths (5 per 1000) 10 immigration (1 per 1000) 100 emigration (10 per 1000) You try. B D I E r=( 10/1000) – (5/1000) + (1/1000) – (10/1000) r=(0.01-0.005) + (0.001 – 0.01) r = 0.005 – 0.009 = -0.004 or –0.4% per year

Projecting Future Population Growth Exponential growth and doubling time The logistic growth curve “S” shaped curve that is generated by the logistic growth equation. A small population grows rapidly But the growth rate slows down The population eventually reaches a constant size. Logistic carrying capacity The population size at which births equal deaths and there is no net change in population

Forecasting Population Change Formula to represent population change: P2 = P1 + (B – D) + (I – E) P1 = number of individuals in a population at time 1 P2 = number of individuals in a population at time 2 (time 2 = a later time)

The Demographic Transition Three-stage pattern of change in birth rates and death rates. Occurred during the process of industrial and economic development of Western nations. Leads to a decline in population growth. Stage I: Decline in death rate Stage II: High growth rate Stage III: Birth rate drops toward the death rate, leading to low or zero growth rate.

Population and Technology The total impact of the human population on the environment is: the average impact of an individual multiplied by the total number of individuals T = P x I T=total impact P= population size I=average environmental impact per person

The Human Population, the Quality of Life, and the Human Carrying Capacity The number of people that can live on Earth at the same time? To determine: Extrapolate from past growth The “Packing Problem” approach Considers how many people might be packed onto Earth, not taking into sufficient account the need for lands and oceans to provide food, water, energy, construction materials, and scenic beauty and the need to maintain biological diversity

Human Death Rates and the Rise of Industrial Societies Acute or epidemic disease Appears rapidly in the population, Affects a comparatively large percentage of it, Declines then almost disappears, only to reappear later Chronic disease Is always present in a population Typically occurs in a relatively small but relatively constant presentation of the population Examples include heart disease, cancer, and stroke

Human Death Rates and the Rise of Industrial Societies Image © 2008 John Wiley and Sons Publishers Differences between Chronic & Acute (Epidemic) Illnesses

Longevity and its Effect on Population Growth Maximum lifetime: The genetically determined maximum possible age to which an individual of a species can live Life expectancy: The average number of years an individual can expect to live given the individual’s present age

Carrying Capacity The environment has a CARRYING CAPACITY for each population… Carrying capacity is the number of organisms that an environment can support. Once a population reaches its capacity, its growth stops.

Question What are some examples of things that can limit growth?

What can limit growth? Limiting factors limit growth Different sizes of populations will also have different factors affecting them. When growth has been limited its graph will look like this:

Growth Curves

Some factors fit into more than one category Limiting Factors Short-term factors Those that affect a population during the year in which they become limiting Intermediate-term factors Those whose effects are apparent after one year but before ten years Long-term factors Those whose effects are not apparent for ten years Some factors fit into more than one category

Density Dependent & Density Independent Factors 1. Density Dependant Factors are factors that have an increasing effect as the population increase, hence will affect larger populations. Examples: Disease, Competition, Parasites, Predators, Food These types of factors spread faster in larger populations. 2. Density Independent Factors effect any population, regardless of size. Population size does not matter. Examples: Volcanic eruption, Temperature, Storms, Floods, drought, chemical pesticides

How Can We Achieve Zero Population Growth? Delay the age of first childbearing by women Birth control Biological and Social Breast-feeding, which can delay resumption of ovulation Abstinence Induction of sterility with natural agents Contraceptive devices National Programs to Reduce Birth Rates Formal family planning programs to explain the problems arising from rapid population growth Describe the benefits to individuals of reduced population growth.

Thomas Malthus vs The Marquis de Condorcet Malthus: Population will outgrow food supplies (geometric growth vs arithmetic growth) Condorcet: Reasoned human action will reduce population, reduce waste, and maintain food supply http://cepa.newschool.edu/het/profiles/malthus.htm http://cepa.newschool.edu/het/profiles/condorcet.htm

Paul Ehrlich vs Julian Simon Ehrlich: Population is outgrowing earth’s sustainable capacity Simon: Population growth not problem, but contributes to economic development; Need for Individual Economic Freedom http://www3.interscience.wiley.com:8100/legacy/college/botkin/0471389145/ed/pa03.html

Population Problems Poverty Food Problems Standard of Living Environmental Consequences of Consumption Overcrowding

Population Growth: Solutions Override forced government programs to reduce population Collaboration voluntary programs and incentive based family planning programs Economic Development higher GNP per capita Social Development better education, health facilities, gender equity Family Planning Programs sterilization, promotion of contraceptive use