EM AS Unit 1 -- Population Notes

HUMAN POPULATION

Environmental Management AS

? Houston, we have a problem!
? 1800 – Population was 1 billion people
? Today we have about 7.2 billion and counting
? Every 5 days the global population increases by a million people.

? 7 Billion People and Rising
Click for the World Pop. Counter

The human population has grown rapidly because of the expansion of agriculture and industrial production and lower death rates from improvements in hygiene and medicine.
? I. Major Causes of Population Explosion
? Industrial Revolution beginning in the 1800’s
? Increased food production & distribution (better machines for planting, harvesting and transportation)
? Pesticides
? Fertilizers
? Machines
? Better sanitation and health (cleaner water and soap)
? Louis Pasteur – Germ Theory of Disease
? Throwing away trash
? Using flushable toilets
? Washing hands
? Mass production of SOAP
? Pasteurization & Sterilization
? Medicine and Medical Facilities (vaccines / antibiotics)
? Antibiotics – treat bacterial infections
? In early times molds were used to treat wounds
? 1877 – Louis Pasteur said one type of bacteria could kill another
? In 1928 Alexander Fleming discovered Penicillin
? Vaccines – reduce severity of viral infections.
? 1^st inoculation, surprisingly, was in 1000 AD in China
? II. Earth’s Carrying Capacity
? Carrying Capacity - maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment remain unchanged
? Population size is controlled by limiting factors.
? Limiting Factors - limits the growth or development of an organism, population, or process
? Biotic Factors -- any living component that affects another organism, including animals that consume the organism in question, and the living food that the organism consumes
? Abiotic Factors - non-living chemical and physical parts of the environment that affect ecosystems.
? Thomas Malthus – Human population will eventually exceed the food supply.
? III. Human Population Growth
? DEMOGRAPHY– study of human population and trends
? Demographer – one who studies human population and trends
? 3 Major Factors for Demography
? Birth Rates
? Crude Birth Rate (CBR) – births per 1000 people per year
? Death Rates
? Crude Death Rate (CDR) – deaths per 1000 people per year
? Migration
? Immigration - movement into a country
? Emigration – movement out of a country
? Equations to determine Human Population Growth Rates
? World Population Growth Rate (WPGR) in %
? WPGR = (Crude Birth Rate – Crude Death Rate) / 10
? National Population Growth Rate (NPGR) in %
? NPGR =[ (CBR + Immigration) – (CDR + Emigration)] / 10
? Current Numbers – Let’s Try It
? World CBR and CDR
? 2014 World Crude Birth Rate = 19.4/1000
? 2014 World Crude Death Rate = 8.3/1000
? World Population Growth Rate = ____________ %
? US CBR, CDR, Immigration and Emigration
? 2013 US CBR = 13.4/1000
? 2013 US CDR = 8.1/1000
? It is very hard to determine numbers in the United States to the high number of illegal immigrants coming into the country (11 – 20 million since 2000) and number of people emigrating is too expensive to determine
? Doubling Time – Amount time it takes for a population to double. (Rule of 70)
? Equation for Determining the Doubling Time in Years of a Population
? Doubling Time = 70 / Growth Rate
? Determine the Doubling Time for World Population from answer above for WPGR
? World Population Doubling Time = ____________ years
? The Graph below shows “Projected Human Population”
? IV. Fertility
? Total Fertility Rate (TFR) – average number of children that would be born to a woman over her lifetime
? Replacement Level Fertility – number of births required to offset the average number of deaths
? Today, there is a worldwide average of 5 births/second and 2 deaths/second.
? V. Life Expectancy
? Based often on access to health care.
? Predictor of resource consumption
? U.S. – total average = 78, men = 75, women = 81
? VI. Infant and Child Mortality Rates
? Infant Mortality – deaths of children under age 1 per 1000
? Child Mortality – deaths of children under age 5 per 1000
? World – 46
? U.S. – 6.6
? VII. Age Structure Diagrams
? Visual representation of age structure with a country. Three types.
? Population Pyramids
? Rapid Expansion
? India, Nigeria and Saudi Arabia
? Slow Expansion
? USA, Canada and Australia
? Declining Population
? Germany, Sweden and Bulgaria
? VIII. Theory of Demographic Transition
? Countries experience a population shift as they move from a subsistence economy to industrialization and increased affluence. (Better tech; More Money)
? Birth Rate
? Death Rate
? Population Size
? Phase 1: Slow growth
? Preindustrial- high birth/death rates
? Subsistence Economy
? Phase 2: Rapid Growth
? Industrialization begins
? Death rates drop
? China, India, many African countries
? Phase 3: Stable growth
? Birth Rates drop
? United States, Canada, Australia
? Phase 4: Declining growth
? Population declines
? Japan, United Kingdom, Germany
? IX. Family Planning
? As education and income increase: fertility decreases.
? Better Education
? More women in the work force
? Less women staying home
? Parents waiting longer to have kids
? Better contraceptives
? X. Population Size and Consumption
? The most critical factor to determine human’s impact on Earth is population size.
? Impact is not equal
? XI. Economic Development
? Developed countries have a bigger impact on our planet.
? Ecological Footprint – affluence is often the top predictor.
? How much “nature” your lifestyle requires
? U.S. - 9.0 ha
? World – 2.7 ha
? XII. IPAT Equation
? Impact = Population x Affluence x Technology
? Population – similar economic standards higher pop. is worse.
? Affluence - more affluence, higher impact
? Technology – positive or destructive, depending on what it is
? XIII. Local, Global, Urban Impacts
? Local Impact – biggest effect in developing countries
? Overuse of land
? Exploitation of “woody” resources
? Ex. Brazil – 2000-05 loss of 3 mil. Hectares of forest
? Urban Impacts – Half of world population live in a urban area
? More than 386 people per sq. km. = Urban Area
? Mumbai, India 60,000 people/sq. mile.
? Produce waste, pollution, carbon dioxide, etc.
? XIV. The Impact of Affluence
? Gross Domestic Product (GDP) is used to measure a nation’s wealth.
? Consumer spending
? Investments
? Govt. spending
? Exports – Imports
? The shift to sound environmental practice takes time.
? XV. Population and Community Ecology
? Population Ecology – studying factors that determine why populations increase and decrease.
? Population Size
? Population Density
? Population Distribution
? Sex Ratio
? Age Structure
? Population Size
? Density-Dependent
? Food
? Water
? Minerals
? Space
? Density –Independent
? Hurricanes
? Tornadoes
? Fires
? Volcanoes
? XVI. Growth Models
? The Exponential Growth Model
? No limitations.
? Produces a J-Shaped Curve
? The Logistic Growth Model
? Used to predict population sizes
? Focuses on density-dependent factors
? Produces a S-Shaped Curve
? XVII. Population Oscillations
? Some populations experience recurring cycles of overshoots and die-offs that lead to a pattern of oscillations around the carrying capacity
? Population Oscillations
? Reason why Oscillations occur?
? Competition for same resources
? Predator vs. Prey
? Diseases vs. Population Density
? VIII. Reproductive Strategies
? K – Selected Species
? Larger organisms
? Few offspring
? Prenatal care low
? Density – dependent
? r – Selected Species
? Smaller organisms
? Reproduce quickly
? Quick growth rate
? Density - Independent