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