Enviro 2
Local Populations (US) what are determinants of population size?
births, deaths, immigration, emmigration
Population
Group of individuals of SAME SPECIES living in same geographic area at same time
What percent of US population growth is a cause of immigration? Is there a formal population policy? DOES US HAVE HIGEST RATE OF POP INCREASE OF ALL HIGHLY DEVELOPED COUNTRIES?
50%, no formal population policy!, YES! US has highest rate of population increase of all highly developed countries
What are environmental limits to prevent indefinite reproduction?
unfavorable food, water, shelter, predation…
what is K?
Carrying capacity–maximum # of individuals an environment can support, =leveling off of exponential growth, S SHAPED CURVE OF LOGISTIC POPULATION GROWTH
Density Independent
Doesn’t matter if population is high or not. Severe winter/fire will kill individuals
Density Dependent
population at really high density, predation, competition for resources, disease INCREASE!
Snowshoe Hare and Lynx what happens when snowshoe hares increase?
# of lynx increase as well because there is more food, therefore more predation is possible. (Population cycle)
Growth Rate of Species depends on (four factors)
F.A.N.N. fraction of lifespan it can reproduce, age reproduction begins, number of reproductive periods, number of offspring
r-selected species
small size, early maturity, LARGE BROODS, little parental care, LONG TERM SURVIVAL IS LOW (mosquitos and dandelions)
k-selected species
small broods, long lifespan, large body size, LATE REPRODUCTION, LOW reproductive rate. (humans and redwood trees!)
2000 years ago how many humans? 1000 years ago how many humans? How many humans in 1800? In 1999? for 2050?
300 million…310 million…1 BILLION…6 billion…9 BILLION
What country was most “fertile” in 2006? Least fertile?
Nigeria…China
What are the four demographic stages?
pre-industrial, transitional, industrial, post-industrial
Pre Industrial (what happens to birth/death/population size?)
birth and death rates fluctuate between 30 and 40 (per 1000), size of population is LOW
Transitional
birthrate stabalizes and at the end starts to decline, death rate declines A LOT, size of population climbs
Industrial
population reaches its peak, birth rate declines, death rate stabilizes at low number
Post Industrial
death rate is still lowest, but population size fluctuates and then declines because women are choosing to not have children
Population growth momentum
BECAUSE OF AGE STRUCTURE, if you have low fertility rates, population will grow because of potential reproductive people about to mature
Rapid population growth… slow population growth… declining population growth
Nigeria, United States, Germany
Can democracy and human dignity survive overpopulation?
NO !!!!!
What causes a decrease in carrying capacity?
Overuse of land
How do we solve the food problem?
control population growth, promote economic development of developing countries, provide access to food and land to people without them
What are the three major influences on total fertility rate?
cultural traditions, social and economic status of women, family planning
Women with more education…
Marry later, HAVE FEWER CHILDREN!
WHAT DID INDIA TRY TO DO IN 1976? IT FAILED AND WAS UNPOPULAR….what has gvt done in recent years?
COMPULSORY STERILIZATION… much more effective but still above replacement level…education
what did mexico do in 1974?
government carried out educational reform, family planning, health care. VERY VERY SUCCESSFUL!
Nigeria has what percent of people under age 15?
43% of population. Current National population policy: improve health care, population education
What is happening in Europe regarding proportion of elderly?
proportion elderly people in population is increasing due to low fertility rates. Decrease in population could cause decrease economic growth.
What are the 5 major biogeochemical cycles?
Carbon, Water, Nitrogen, Phosphorus, Sulfur
What happens in respiration, excretion, and decomposition(fungi and bacteria)?
convert carbon to CO2
Volcanic eruptions, cement production, burning of fossil fuels
release stored carbon as CO2
Does temperature affect how much carbon oceans can hold?
Yes! At lower temperatures oceans hold more carbon!
Why is methane so important?
30 times more efficient in trapping reradiating energy from the earth. BUT the lifetime of methane is only 12 years (can be broken down in atmosphere)
What is a Positive warming feedback?
BAD! process that amplifies change, melting permafrost, faster decomposition rates, warmer oceans hold less CO2
Melting has POSITIVE FEEDBACK. Describe it.
increased melting decreases ice, which decreases albedo which leads to further warming. OH CRAP
What are the two ways sea levels rise?
Thermal expansion (water expands as it warms) & Melting of land ice.
As water combines with carbon dioxide what happens?
H2O+CO2=H2CO3=carbonic acid–makes oceans more acidic.
What will happen to organism distribution as a result of global warming?
Organisms will move or become extinct !
What are fragile regions that will be affected by global warming?
Eskimos, Island nations, low lying delta regions
TO AVOID THE WORST of climate change CO2 levels must be stabalized at what value?
550 ppm
What are the TWO ways of dealing with climate change?
Mitigation (limiting greenhouse gases) & Adaptation (focuses on learning to live with environmental and societal consequences)
How will humans adapt to global climate change?
move inland, construct dikes and levees, REDO ENTIRE NEW YORK CITY sewer line, adapt to shifting agricultural zones
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