Topic 3 – Human Population, Carrying Capacity, and

Resource Use

Topic 3.1- Population Dynamics

Current Human Population

• There are about 7 billion people living on Earth

• For about 200,000 years, there were between 1-15 million people on Earth

Milestones

• 1 Billion: 1804• 2 Billion: 1927• 3 Billion: 1960• 4 Billion: 1974• 5 Billion: 1987• 6 Billion: 1999• 7 Billion: 2012

Demographics• If you reduce the worlds population to a village of

100 people, how many would:• Be Male• Be White• Be Christian• Live in substandard housing• Be able to read• Be malnourished• Be without access to safe water• Have internet access• Have a college education• Have HIV• Be US citizens• Control 1/3 of the wealth

Predicted Growth

• Some predict a stabilization of human population, while others predict a continued increase

Calculating Rates

• Crude Birth Rate (CBR)• The number of live

births per 1000 people

• Equation:

Calculating Rates

• Crude Death Rate (CDR)• The number of deaths

per 1000 people

• Equation:

• Natural Increase Rate (NIR)• CBR-CDR

Calculating Rates

• Fertility• The average number of

births per women of child-bearing age

• Equation:

Calculating Rates

• Doubling Time• The amount of time it

takes for a population to double

• Equation:

Population Pyramids

Population Pyramids

Population Pyramids

Population Pyramids

Demographic Transition Model

Topic 3 – Human Population, Carrying

Capacity, and Resource Use

Topic 3.2- Resources – Natural Capital

Natural Capital

• Natural resources/natural assets

• Can become natural income• Goods or

services

Resources• Non-renewable• Cannot be

replenished at the same rate they are used

• Renewable• Can be replenished at

the rate they are used via human processes

• Replenishable• Non-living resources

that can be replenished via natural processes

Nature of a Resource

• The value of a resource changes with human technology/culture

Sustainability• Using resources at a

rate that allows natural regeneration

• Living within the means of nature

• Development that meets the needs of the present without compromising the ability of future generations to meet their own needs

Topic 3 – Human Population, Carrying Capacity, and

Resource Use

Topic 3.3 – Energy Resources

Making Energy

• Electricity is delivered to homes and businesses via alternating current (AC)

• AC power is generated when electromagnets are spun using a turbine

Energy Sources Worldwide

• 90% of the worlds energy comes from fossil fuels.

Fossil Fuels

Nuclear Power

Wind Power

Hydropower

Solar Power

Geothermal Power

Biofuels

Oil Palms

Future Solutions

• Hydrogen

• Nuclear Fusion

• Carbon Sequestration

Topic 3 – Human Population, Carrying Capacity, and

Resource Use

Topic 3.4 – Soil Systems

Soil

• Soil is eroded rock, nutrients, decaying organic matter, and water

Soil Formation• Soil is produced by:• Weathering of rock• Deposition of sediments by erosion• Decomposition of organic matter in dead organisms

• Soils generally have distinct horizons:

• A horizon• Humus (decaying organic

matter with mineral particles)

• E horizon• Not always present, pale

layer where minerals have been leached

• B horizon• Organic matter and mineral

deposits

• C horizon• Weathered rock/bedrock

Soil Horizons

• Soil type depends on the particle size• Sand = Biggest• Silt = Medium• Clay = Smallest

Soil Texture

Soil Texture

Soil Types

Potential to hold organic matter

Drainage Water holding capacity

Air Spaces

Plants and animals

Primary Productivity

Sandy Soil

Low Very Good

Low Large Few Low

Clay Soil Low Poor Very High

Small Few Very Low

Loam Soil

Medium Good Medium Medium

Many High

Nutrients

• Macronutrients• Nitrogen (needed for

chlorophyll)• Phosphorous (needed

for photosynthesis)• Potassium (needed

for fruiting and growth)

• Calcium• Magnesium• Sulfur

• Micronutrients• Boron• Copper• Chloride• Iron• Manganese• Zinc

nutrients

• Atmospheric Nitrogen has to be ‘fixed’ (usually by bacteria) for plants to use it.

Nitrogen cycle

• Water erosion• Wind erosion• Acidification• Groundwater use• Pollution• Desertification• Climate change• Overgrazing• Deforestation• Roads

Soil Degradation

Soil Degradation

Soil Degradation

• Mechanical/physical barriers

• Organic farming

• Afforestation

• Contour plowing

• Terracing

• Crop rotation

• Soil conditioners

Soil conservation