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Announcement
• LELLA reports due next week with Team Evaluations
• Quiz 3 December 2
Population
Objectives:
• Understand the difference between exponential and logistic population growth
• Understand how easy access to birth control influences population growth
• Calculate and Compare population growth rates.
World Population
World – 6.795 billion peopleUS Population – 307.9 million people
http://www.google.com/publicdata?ds=wb-wdi&met=sp_pop_totl&tdim=true&q=global+population
Population Density
Terms to know
• Growth Rate = birth rate + immigration rate – (death rate + emigration rate)
or
birth rate + immigration rate
– death rate – emigration rate• Doubling time
– The time it takes for a population to double if it is growing at a constant rate
– Doubling Time (years) = 70 / Growth Rate (%)
– Growth Rate (%) = 70 / Doubling Time (years)
Growth & Fertility Rates
• Total Fertility Rate = Average number of children born per female over her lifetime
• Replacement Fertility Rate = Total Fertility rate that maintains a stable population size For humans = 2.1
Factors that affect Population Growth
• Environmental Resistance
• Health – Medicine
• Resources – Food, Water
• Technology
• Birth Control– Issues in abortion, religious beliefs, education,
planned parenthood,China one child policy
Specific cases
• China – 1.3 billion 1.1 % growth rate– One Child Policy (lowered from 2.8% to 0.7%)– One-Two-Four Problem, infanticide, unequal sex
ratio, sex selective abortions, spoilt children
• India – 1.1 billion 2.2 % growth rate– No apparent growth control agenda
http://www.cnn.com/video/#/video/bestoftv/2009/09/21/ldt.population.enviroment.cnn?iref=videosearch
Types of growth
• Logistic Growth – Population that is not
increasing
– Carrying Capacity – maximum population size that a given environment can sustain
• Exponential Growth– Increasing by a fixed %
each year
– Example of Compound interest of $
Resource Consumption
• Thomas Malthus
– Predicted that population growth was exceeding food production and would be a limiting factor.
Carrying Capacity (K)
• The population that an area will support without undergoing environmental deterioration.
• The carrying capacity of an environment tends to limit population size.
• Food availability, reproductive behavior, and infectious diseases tend to keep animal populations in check.
Sustainability
• Definition “Meeting the needs of the present without
compromising the ability of future generations to meet their own needs.”
http://www.youtube.com/watch?v=gbqJ6FLfaJc&hd=1
Marine Fisheries
• Objectives:– To understand the impact of humans on a
global scale– To understand the concept of carrying capacity
and “tragedy of the commons”– Be familiarized, through the provided example,
of the real threat confronting global marine fisheries
Marine Fisheries
• Problems– Increase in technology– Increase in # of fishermen– Over fishing– Destruction of coral reefs
“Tragedy of the Commons” – Garrett Hardin
Sustainable Fisheries
• Solutions– Aquaculture or fish farming (1/3 of produce)
• Also has some environmental problems– Deforestation, food for fish stock, waste material
– Sustainable Fishing
Lab Experiment
• Scenario 1 – Sustainable Fishing
• Scenario 2 – Improved Technology
• Scenario 3 – Improved Technology with aggressive Fishing
Read Instructions Carefully
• Start with 20 brown and 10 white for the first season ONLY for each scenario. Every other season use the beans left from the previous season.
• To determine Fish available for next season– Medium Value fish 1st and 2nd season = fish left + (0.5 * fish left)– High Value fish 1st season =fish left; 2nd season only= fish left + (0.5 *
fish left)
• If no more fishes left to catch start recording negatives.• For graph plot # of fish available for next season (y axis) against
seasons (x axis) for medium and high value fish
Season
# of
fis
h
MH
10
20
0 1 2