Ch13ecology

• 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

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

Which theory lead to decrease in the death rate?

• A) evolution

• B) Thomas Malthus' theory

• C) germ

• D) atomic

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

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

B) famine

C) germ theory

D) Black Plague

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

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

Line 1

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?

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.

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.

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

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

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