Grade 12 Environmental Studies - Part 6 Human population dynamics Flashcards
Why has population growth **increased exponentially (more and more rapidly) **over the last 1000 years? Estimated 10 million people 10 000 years ago to now?
People died from starvation and disease
High infant mortality rates very high
THUS INCREASE because:
1. Reduced environmental resistance
1. increased **carrying capacity **of world’s food-producing regions
What is the current human population?
- Estimated just over 7.3 billion
- Increase of 216000 people each day 83 million people per year
- Virtually all the growth is in developing countries - youth population in the poorest of countries
China has largest population - 1.40 billion people (20% of world’s population)
**India **- 1.28 billion people = 17% of world’s population
What caused the alarming population growth?
-
Food production has increased substantially
* More cultivated land
* Improved methods of food production e.g. artificial fertilisers to increase yield of monoculture crops -
Methods of treating disease have improved greatly
* Thus more people reproduce.
Explain the two broad groups in which countries of the world can be divided in:
More developed countries (MDC’s)
* Slow population growth 0.1% per year
* High standards of living e.g. North America, Europe, Australia, Japan
Less developed countries(LDC’s)
* Rapid population growth 1.6% per year
* Lower standards of living e.g. Latin America, Africa, Asia
Discuss some of the future predictions for human population growth:
- Less exponential growth over the next 150 years - more logistic growth form
- Industrialised countries have moved to stable population growth that has begun to decline - due to late marriage, birth control, sexual abstinence
- LDC populations will continue to grow as improved medical treatments have enabled more women in reproductive years to live longer
What is the ecological footprint of MDC’s and LDC’s?
Growth placing extreme pressure on resources.
* LDC’s have higher growth rates, but environmental pressures are mainly because of MDC’s
* MDC’s responsible for more total polution and consumption than LDC’s
* MDC’s - 22% of the world’s population - BUT PRODUCE 90% of hazardous waste.
Do Learning Activity 19 on page 30
What is a population pyramid?
- Also called a age-sex pyramid.
- Bar graph that shows the composition, by age and sex, of a nation’s population at the time of census.
- Convenient way to show, in visual form, how a national population is made up.
Name the three major age/sex groups in a population:
- pre-productive
- reproductive
- post-productive
What determines the age structure of a population?
**What proportion of a population falls into categories **of pre-productive, reproductive and post-productive and the age groups of each.
Define age structure:
The **relative numbers of individuals **of each age in a population.
How is the population graph constructed?
Two back-to-back barr graphs - with population numbers plotted on horizontal axis and age on vertical axis.
What does the top and bottom of the population pyramid show?
Older population - bottom the younger
What does the left and right of the populatin pyramid show?
Left = number of males
Right = number of females
In 5 year age groups
Study the pyramid structures on page 31 and make sure that you can identify and discuss each type. Make sure you can interpret these pyramids.
- Rapidly growing population
- Stable population
- Declining population
What is the purpose of population graphs?
Great deal of info can be read from it e.g.
* how rapidly or slowly population is growing
* show if a country is more developed or less developed
* show how many people of each age range live in a country
* show the history of the nation’s growth
* be useful in determining the number of economic dependents being supported (those under 15 and over 65) Note: 0 - 15, 15 - 65, 65+
What factors can cause the make-up of a population change?
- HIV/ AIDS causing deaths of many sexually active young men
- Wars
- high proprtions of young immigrants being rapidly absorbed or losses due to emigration
- reduced birthrates - economic crises
Look at discussion on page 32 on SA’s population growth. 190% in 54 years. What impact did HIV have on SA Population?
- Despite rate of population growth in SA (17.4 million in 1960 to 54 million in 2014) the rate of population growth is dropping, mainly due to HIV Aids
- Estimated overall HIV prevalence rate = 10.2% of the total of SA Population.
- Estimated 5.51 million people living with HIV Aids
- Adults 15 - 49 = 16.8% is HIV Positive
The FUTURE OF SA POPULATION? Study the pyramids on page 32, Learning Activity 20!
Define ecological footprint and give some examples :
- MEcological footprint = measure of human demand on the earth’s ecosystem.
- Represents the amount of **biologically productive land and sea **area necessary to supply resources to human pop that they consume
- AND to assimilate the waste generated.
Footprint accounts for all demands on the biosphere, including:
1. Carbon emissions from fossil fuel
1. Demand on food sources
1. Quantity of living resources required to make the goods we consume
1. the amount of land we take out of production when we pave it over to build cities and roads
i
What is the total world ecological footprint?
2.7 global hectares per person
Problem: World average biocapacity is 2.1 global hectares = deficit of 0.6 global hectares per person
Changes continually.
Define biocapacity:
The amount of productive land and water available to produce the resources we use to absorb the waste we produce.
What do we call a country with an ecological deficit?
- An ecological debtor country.
- No defecit = ecological creditor country
What can be learned from ecological footprints?
- Many MCD’s are running ecological deficits - with footprints larger than their biological capacity.
- MDC’s have the largest ecological footprints.
- LCD’s may use very little of the world’s resources but their urban population is increasing rapidly as is standard of living = consuming more and more resources
- If ecological footprints continue to increase = natural resources needed to maintain human life will be greatly reduced
- Unless we solve them = plantet earth may be permanently damages
- 85% of world pop is living in a country with a biocapacity deficit
Can you calculate your own Ecological Footprint?
Go to Earth Day Network
www.earthday.org
Discuss the human need for land versus conservation:
Human population increases = expectations of living standards rise
Natural resources put under pressure
**Towns and cities **= generate and accumulate wealth and are centres of education, economic opportunity, employment and culture = they take over agricultural land and use large quantities of water, energy, foodstuffs, raw material and generate enormous waste and pollution.
Agriculture, forestry and mining = alter natural environment causing environmental degradation
Developing countires suffer = Exploitation of natural resources - food now v natural resources later
Balance - economic development and environmental degradation
