Population Study Note

TOPICS INCLUDE: • Population Growth • Demographic Data • Rule of 70 • Age-Structure Pyramids • Impact of Growth UNIT 3: POPULATION     # of individuals in a given area Uniform  equally spaced Clumped/Clustered  individuals associate in small groups Random  no particular pattern  Direct Count  count all  EX: Census  Quadrant  grid of sample squares  count fraction of population  estimate total population  EX: plants, trees (non-sessile)  Capture-Recapture  count & mark sample population in given area & then release  Repeat procedure several days  estimate mobile population  EX: beetles, butterflies, dolphin  Density-dependent not related to size of population  EX: food supply, temperature, weather, habitat destruction   Density-independent exert their effect as population size increases  EX: competition for resources, predation, disease, behavioral changes   R = intrinsic rate of growth (biotic potential)  K= carrying capacity (upper limit for population  Annual rate of population change (%)= [(birth rate – death rate)] /10 Example: The doubling time of a population growing at 2% each year is 70 divided by 2 or 35 years.        Total Fertility Rate (TFR) = average # of children born to woman during her lifetime Replacement-level Fertility = average # of children a couple must bear to replace themselves in the population (average is about 2.1 (some children die before reproductive age) Infant Mortality Rate (IMR) = # of babies out of every 1000 births who die before reaching 1st birthday Crude Birth Rate (CBR) = # births per 1000 people in population Crude Death Rate (CDR) = # deaths per 1000 people in population Immigration = migration of people INTO a population Emigration = migration of people OUT of a population  marriage age  high  in countries where women marry young (below 25) education  decrease  affluence  lower  in affluent areas child labor  higher    as level of education increase in countries where children are part of labor force opportunities for women  low when women have access to employment & education availability of birth control  reduced with widespread availability & use of birth control methods religious/cultural belief  high in countries where large families are deemed desirable  nutrition better nutrition & increased food production reduced deaths due to starvation  sanitation, water, hygiene improvements reduce IMR and lengthened life expectancy  medicine & public health improvements in medical technology health care delivery (antiobiotics, immunizations, insecticides) reduced deaths of diseases (smallpox, measles, influenza, etc) distribution of males & females in different age groups  Key factors:  # females in reproductive and pre-reproductive age groups affect future growth (TFR determine births  compare them to infer social changes within country  compare social condition among different countries  broad base = high population momentum; high IMR, poor health care, cultural preference large families, lack of opportunities for women  narrow base = low population momentum, aging population, slow growth, could lead to negative growth  birth rates and death rates are both high  modern medicine had not yet developed techniques to lengthen life substantially  standards of personal hygiene were comparatively low  both rates fluctuated depending on circumstances  no demographic transition has occurred  standards of hygiene and more modern medical techniques began to drive the death rate down leading to a significant upward trend in population size  birth rate remained high, as much of the economy was based on agriculture.  Mexico is currently between this and the following stage  Stage 2 and 3 are indicative of a partial or first demographic transition  urbanization decreases the economic incentives for large families  cost of supporting an urban family grew and parents were more actively discouraged from having large families  the birth rate started to drop, ultimately coming close to the death rate  increased population in Europe led to tremendous societal pressures that caused large scale migration (e.g., to the USA) and extensive global colonialization  characterized by a higher, but stable, population size  birth and death rates were both relatively low  standard of living became much higher than during the earlier periods  developed world remains in the fourth stage of its demographic transition  Example: Sweden countries having completed the second or a full demographic transition To determine a country’s development, these statistics are usually considered by the United Nations  1. 2. 3. 4. 5. GDP (Gross Domestic Product) Life Expectancy Literacy Rate Education Healthcare System  Usually refers to countries with low levels of ECONOMIC DEVELOPMENT  few factories  limited technology  limited transportation and communication systems  subsistence farming or herding  rural population  low per capita GNP  lower standard of living. Little industry, low standard of living, and low income -BUTHigh population  a modern industrial society with a welldeveloped economy  many factories  modern technology  efficient transportation  communication systems  commercial agriculture  urban population  high per capita GNP (gross national product)  higher standard of living  Family planning  education  on human sexuality, childcare, and contraception Social & economic incentives  subsidies or aid from government (tax relief, debt relief, lowcost housing, medical care)  Penalties for having more children than replacement level (fines, withdrawal of benefits)  Policies & laws  Pronatalist • (encourage births & large families) 1930’s France paid families government subsidies for raising children & paid maternal salary to women who had more than 2 children  Antinatalist (discourage births & encourage small families • China & Singapore raised legal age of marriage to shorten a woman’s period of fertility • 1980’s low-cost housing or subsidies were reduced when women had more than 2 children  no official population policy because rights lie among individual families not government  major factor contributing to growth is immigration (legal & illegal)  US policies tax laws: income tax deductions for families & child tax credits abortion laws: legal limits to abortion welfare laws: child benefits sex education: regulated @ local & state level; influenced by social & religious beliefs  India occupies 2.4% of the world's land area and supports over 17.5% of the world's population  1952 government initiated family planning, education, age of marriage and employment policies (not successful)  21st century economy is improving, may reduce population growth  1/6 of world population but only 7% of world’s farmable land  1960 policies family planning extensive health care education and employment social security marriage age  1/6 of world population but only 7% of world’s farmable land  1960 policies family planning extensive health care education and employment social security marriage age After WWII, reduced its rapid population by family planning policies (liberal abortion law, access to contraceptives, improving health care, improving pensions)  Japan approaching zero growth   aging & overall decline of workforce (automated industry)  aging population will require greater economic demand on governments health care & pension system while reducing tax base Hunger  Poverty  Disease  Depletion of resource (water, energy, minerals)  Living space (urbanization)  Habitat destruction 