Ch13ecology

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Transcript of Ch13ecology

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• Thomas More- Utopia Population is kept constantEqual food distributionCrops are controlled

• 1798- Thomas Malthus- popualtion growth is geometric; food supply is not- pop. Outgrows resources- leads to famine war, human suffering suggested late marriage, small families

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Increases in Growth Rate• Humans evolved~ 100,000 years ago- population controlled by starvation, predation disease- old age 35; high infancy mortality rateGrowth rate started to increase ~ 10,000 years ago w/ increase in agriculture- agricultural revolution with a steady food supply farming communities devloped, higher standard of living; world pop- 5-10 million peopleGrowth continued with industrial revolution- last 300 years greater food supply, shorter work day, better living conditions and distribution of food through technologyHealth Care- w/ germ theory advances in health care has increased life expectancy and lowered infant mortality rates germ theory- microorganisms responsible for many diseases Vaccines, antibiotics and other medical advances prolong life

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Which theory lead to decrease in the death rate?

• A) evolution

• B) Thomas Malthus' theory

• C) germ

• D) atomic

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Which change occurred during the agricultural revolution?

A) mass production of goods

B) reduction of the work day

C) increased life expectancy

D) improved health care

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Which would not cause a decrease in the human population?A) war

B) famine

C) germ theory

D) Black Plague

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Declines in Growth Rates• In mid 14th c - major

decline in growth rate Bubonic plague-Black Death: 25% of

Europe& Asia pop died; 50% England- also otbreaks of chlorea, typhus, malaria, yellow fever,small pox

Famine: 1840’s Irish potato famine; 1876-79 China famine

War: not only directly reduces Pop. But also causes famine, Disease and env. Destruction21.5 million WWI; 35-60 million- WWII

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Many people believe until we get to zero population growthWe can’t really solve the rest of the world’s problem.

Measuring Growth Rate

Birth rate- (minus)Death rate ( rates are per 1,000 people)

Doubling time is how long it will take a current population to double, at the present growth rate. (Mexico City- 10 yrs.)

If you are studying a specific pop. You must also take into

Account emigration ( leaving) and immigration (entering).

0200400600800

1000120014001600

8000BC

1650 1850 1930 1975

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Demography It is important to know how many people There are, but also what type of peopleMake up the population.

the science of changing vital statistics in a human pop. is called demography i.e sex, age, education, race, economic status etc.

By studying these things we can plan for the future- compare the graphs on page 205. Which country is going to have to invest in increased infrastructure and social institutions, assuming the death rate does not increase?

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What affects the needs of a society

PopulationTechnology Standard of Living

Industrialized nations energy needshave risen at a far greater rate than theirpopulationUndeveloped nations are expected to increase their populations the most.

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13.3 Challenges of Overpopulation

• Greater demand on space• Greater demand on resources• Less land available for other organisms• Life is interconnected- a problem in

China can affect the rest of the world (pollution, volcanic eruption, overpop.)• Health- related to pop. size; > pop

>disease, hygiene famine, medical problems

• Increased effect of damage to env.

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Planet Earth- Into the Wilderness:Human Population and Strained Resources

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Controlling Population Size

This is not as easy as it sounds

• unethical?• children are source of pride, work, • religious/cultural opposition• what happens when you do?- fewer young people- more old people

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Is overpopulation so bad?

Some say- no Increased technology allows us to

solve food production, health concerns and env, issues

Some say- YesThe Earth has a finite carrying capacity and we cannot exceed it