apes 0-4

AP ENVIRONMENTAL SCIENCE

UNIT 0

Five Causes of Environmental Problems

1.  Population Growth

2.  Unsustainable resource use

3.  Poverty

4. Excluding environmental costs from prices

5. Trying to manage nature without knowing enough about it

Formulas

• Natural Capital = The natural resources (noun) + natural services (verb)

• Doubling time in years = 70 / %growth

• % change: (after-before)/before x 100 & (new value - old value)/old value x 100

• GDP per capita = GDP / population

Principles of Sustainability

1.  Reliance on solar energy

2.  Biodiversity

3.  Population Control

4.  Nutrient recycling

8 Causes of Collapse in Ancient Civilizations

1.  Deforestation/habitat destruction

2. Soil problems (erosion, salinization, soil fertility)

3. Water management problems

4. Overhunting 

5. Overfishing 

6. Invasive species

7. Human population growth

8. Increased per capita impact of people

4 Causes of Collapse in Modern Civilizations

1. Human-caused climate change

2. Toxic chemical build-up in the environment

3. Energy shortages

4. Full human utilization of Earth’s photosynthetic capacity

The Pathway to Collapse

1. Food shortages

2. Starvation

3. Competition over resources

4. Political takeovers

5. War    

Factors that Contribute to Societal Collapse (5)

1.  Damages that people inadvertently inflict on their environment. 

2.  Climate Change

3.  Hostile Neighbors

4.  Friendly Neighbors

5.  Societal response to problems

1.  Political

2.  Economic

3.  Social

4.  Cultural

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Principles of Sustainability

• Reliance on solar energy

  • Solar capital - a perpetual resource

  • The sun warms the planet and supports photosynthesis used by plants to provide food for themselves and for us and most other animals. 

• Biodiversity

  • The variety of different organisms, the genes they contain, the ecosystems in which they exist, and the natural services they provide

• Population Control

  • Competition for limited resources among different species places a limit on how much their populations can grow.  

• Nutrient Recycling

  • Natural processes recycle chemicals that plants and animals need to stay alive and reproduce. 

COLLAPSE

8 Causes of Collapse in Ancient Civilizations

• Deforestation / habitat destruction

• Soil problems (erosion, salinization, soil fertility)

• Water management problems

• Overhunting 

• Overfishing 

• Invasive species

• Human population growth

• Increased per capita impact of people

4 Additional Causes of Collapse in Modern Civilizations

• Human caused climate change

• Toxic chemical build-up in the environment

• Energy shortages

• Full human utilization of Earth’s photosynthetic capacity

Pathway to collapse

• Population growth forces people to increase their agricultural production.  This involves the use of irrigation, terracing, double-cropping and expanding farming from                                                prime lands to marginal lands. 

• Unsustainable agricultural practices leads to serious consequences for society to obtain resources:

  • Food shortages

  • Starvation

  • Competition over resources

  • Political takeovers

  • War    

Societal collapse

• Damages that people inadvertently inflict on their environment

  • People

  • Environment

• Climate change

  • This may be human induced, or natural fluctuations in climate.  

• Hostile neighbors

  • If your neighbors are mightier than you, you can be exterminated. 

  • Often societies collapse by what appears a military conquest, but underlying the conquest was something environmental that weakened the society.

• Friendly neighbors

  • Most every society needs good trading partners. 

  • If your trading partner becomes weakened, you will suffer too. 

• Societal response to problems

  • Political 

  • Economic 

  • Social 

  • Cultural 

SUSTAINABILITY

Five Causes of Environmental Problems

1.  Population Growth

   1. The world’s population is growing exponentially

2.  Unsustainable resource use

   1. Affluenza is a term used to describe the unsustainable addiction to overconsumption and materialism

3.  Poverty

   1. the inability to meet one’s basic economic needs. 

   2. concentrated in the  Southern Hemisphere

4. Excluding environmental costs from prices

5. Trying to manage nature without knowing enough about it

Environmental Science Key Concepts

• Environmental Science: Studies interactions between humans and nature.

• Worldviews:

  • Biocentric: All species have equal value.

  • Ecocentric: Ecosystems and organisms hold equal importance.

  • Anthropocentric: Focus on human well-being.

• Environment: All conditions influencing life.

Sustainability and Resource Use

• Sustainability: Using resources without harming future generations.

• Conservation: Careful use of resources to prevent depletion.

• Preservation: Maintaining ecosystems for continued survival.

• Tragedy of the Commons: Overuse of shared resources leads to depletion; requires management solutions like catch-share systems.

Ecosystems and Feedback

• Ecosystem Services: Benefits like clean water, timber, and crops.

• Environmental Indicators: Metrics for ecosystem health (e.g., biodiversity, CO2).

• Feedback Loops:

  • Positive: Amplifies changes.

  • Negative: Restores balance.

Systems and Impacts

• Closed System: No exchange of matter or energy (rare in nature).

• Open System: Energy/matter cross boundaries.

• Ecological Footprint: Land/resources needed to support an individual's consumption.

Historical and Ethical Perspectives

• Key Movements:

  • Agricultural Revolution: Improved soil and crop output.

  • Industrial Revolution: Increased pollution and fossil fuel use.

• Environmental Ethics: Moral responsibility to nature.

• Environmental Justice: Equal involvement in environmental policy.

Notable Figures

• Gifford Pinchot: Advocated for sustainable forestry.

• Aldo Leopold: Promoted wilderness conservation.

• Thomas Malthus: Warned of overpopulation impacts.

Key Terms

• Biotic/Abiotic: Living vs. nonliving elements.

• Fossil Fuels: Finite energy sources from ancient biological material.

• Millennium Ecosystem Assessment: Evaluated human environmental impacts.

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Principles of Sustainability

• Reliance on Solar Energy: Solar energy is a perpetual resource, driving processes like photosynthesis that support life.

• Biodiversity: The variety of organisms, ecosystems, and natural services essential for ecosystem resilience.

• Population Control: Limited resources create competition, naturally regulating population sizes.

• Nutrient Recycling: Natural processes recycle essential chemicals for life and reproduction.

Causes of Collapse

Ancient Civilizations

1. Deforestation / habitat destruction

2. Soil problems (erosion, salinization, fertility loss)

3. Water management issues

4. Overhunting

5. Overfishing

6. Invasive species

7. Human population growth

8. Increased per capita impact

Modern Civilizations

1. Human-caused climate change

2. Toxic chemical accumulation

3. Energy shortages

4. Full utilization of Earth's photosynthetic capacity

Pathway to Collapse

• Population growth increases agricultural demands, leading to irrigation, terracing, double-cropping, and farming on marginal lands.

• Unsustainable agriculture causes resource scarcity, resulting in:

  • Food shortages

  • Starvation

  • Resource competition

  • Political instability

  • War

Factors in Societal Collapse

• Environmental Damage: Human-induced harm, including climate change.

• Hostile Neighbors: Vulnerability to military conquest, often rooted in environmental weakening.

• Friendly Neighbors: Collapse of trading partners weakens dependent societies.

• Societal Responses: Depend on political, economic, social, and cultural adaptations.

Five Causes of Environmental Problems

1. Population Growth: Exponential global population increase.

2. Unsustainable Resource Use: Overconsumption driven by materialism ("affluenza").

3. Poverty: Inability to meet basic needs, mainly in the Global South.

4. Ignoring Environmental Costs: Prices exclude environmental damage.

5. Poor Environmental Management: Acting without adequate ecological understanding.

UNIT 1 & 2

Ecosystem Basics

Energy Flow in Ecosystems

Unit 1 & 2

The global distribution of fish varies because of some combination of:

• Salinity (salt concentration)

• Depth 

• Turbidity (clarity of water)

• Nutrient availability

• Temperature 

Freshwater biomes have low salinity, they include:

• Streams and rivers

  • originate from underground springs

  • runoff from rain or melting snow.

  • Streams are narrow and carry small amounts of water

  • rivers are wider and carry larger amounts of water.

• Lakes and ponds

  • Contain various zones

  • Lakes have levels of primary productivity

• Freshwater wetland

  • among the most productive biomes on Earth.

Marine biomes have high salinity, they include:

• Salt marsh

  • contains nonwoody emergent vegetation

  • one of the most productive biomes in the world.

• Mangrove swamp

  • occurs along tropical and subtropical coasts

  • contains salt-tolerant trees with roots submerged in water

  • help protect the coastlines from erosion and storm damage

• Intertidal zone

  • narrow band of coastline between the levels of high and low tide

• Coral reef

  • Found in warm, shallow waters beyond the shoreline.

  • Earth's most diverse marine biome

    • Coral bleaching: A phenomenon in which algae inside corals die,                                 causing the corals to turn white.

• Open ocean

  • located away from the shoreline where sunlight can no longer reach the ocean bottom

  • Contains zones

Lakes and Ponds Zones

The littoral zone consists of shallow water with emerging, rooted plants.

The limnetic zone is the deeper water where plants do not emerge. 

The profundal zone is the deepest water, where oxygen can be limited because little sunlight penetrates to allow photosynthesis by producers.

The benthic zone consists of the sediments that lie beneath the profundal zone.

Lakes Productivity

Oligotrophic  Describes a lake with a low level of productivity.

Mesotrophic  Describes a lake with a moderate level of productivity.

Eutrophic Describes a lake with a high level of productivity.

Open Ocean Zones

Photic zone: The upper layer that receives enough sunlight for photosynthesis.

Aphotic zone: The deeper layer that lacks sufficient sunlight for photosynthesis.

Biodiversity

• Natural resources 

  • food, water, wood, energy

• Natural services 

  • air and water purification, soil fertility, waste disposal, pest control

• Aesthetic pleasure

Ecosystem services

• Provisioning - material or energy outputs from ecosystems 

  • food, water, and other resources

• Regulating - services acting as regulators

  • regulating air and soil quality, flood control

• Cultural - recreation, tourism, aesthetic appreciation

• Supporting - habitats for species, maintenance of genetic diversity 

Measures of Biodiversity

• Species richness

  • Number of species in an area

• Species evenness

  • Relative proportion of individuals within the different species in an area

Theory of Island Biogeography

• Species richness increases as…

  • size of the habitat increases. 

  • distance to the mainland decreases.

Gene Flow

Process by which individuals move from one population to another and thereby alter the genetic composition of both populations.

• Arrival of individuals from adjacent populations alters the frequency of alleles in the population.

• Gene flow can help bring in genetic variation to a population.

Genetic drift

A change in genetic composition of a population as a result of random mating.

• genetic drift is a nonadaptive, random process.

• Important role in altering the genetic composition of small populations.

Bottleneck Effect

Reduction in genetic diversity of a population caused by a reduction in its size.

• Reduced population numbers mean reduced genetic variation. 

• Low genetic variation in a population can cause an increased risk of disease and low fertility.  

• Resulting low diversity can lead to decline and extinction.

Founder effect

Change in genetic composition of a population as a result of descending from a small number of colonizing individuals.

Threats to Biodiversity: HIPPCO

• Habitat destruction

• Invasive species

• Pollution 

• Population growth

• Climate change

• Overexploitation (overhunting, overfishing, overconsumption)

BIOGEOCHEMICAL CYCLES

• Hydrologic Cycle

• Carbon cycle

• Nitrogen cycle

• Phosphorus cycle

• Sulfur cycle

Hydrologic Cycle

Water moves from the atmosphere to Earth’s surface and back to the atmosphere.

Effects 

• Withdrawing large amounts of freshwater.

• Clearing vegetation and eroding soil.

• Polluting surface and underground water.

Carbon Cycle

Producers take up carbon from the atmosphere via photosynthesis and pass it to consumers and decomposers. 

Respiration by organisms returns carbon to the atmosphere and water. 

Effects

• We alter the carbon cycle by adding excess CO2 to the atmosphere through:

  • Burning fossil fuels.

  • Clearing vegetation faster than it is replaced.

Nitrogen Cycle

Moves atmospheric nitrogen (N2)  into soils through several nitrogen fixation pathways.

Denitrifying bacteria release nitrogen gas back into the atmosphere.

Effects

• Human activities (i.e., fertilizers) fix more nitrogen than all natural sources combined.

• Adding nitrous oxide to the atmosphere through farming practices warms the atmosphere and depletes ozone.

• Contaminating groundwater from nitrate ions in inorganic fertilizers.

Phosphorus Cycle

There is no atmospheric component in the phosphorus cycle.

Effects

Large amounts of phosphate removed from earth to make fertilizer.

Reduction of phosphorus in tropical soils by clearing forests.

Addition of excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

Sulfur Cycle

Sulfur exists as rocks and as they get weathered, they release sulfate ions (SO42−) that producers take up and pass through the food web. 

Sulfur dioxide combines with water to form sulfuric acid (H2SO4) and is carried back to Earth when it rains or snows.

SUCCESSION

• Ecological succession

  • The predictable replacement of one group of species by another group of species over time.

• Primary succession 

  • occurs in areas devoid of soil. 

  • Early-arriving plants and algae colonize bare rock and begin to form soil, making the site more hospitable for other species to colonize later.

• Secondary succession

  • occurs where soil is present, but all plants have been removed

Species

• Pioneer species

  • Moves and colonize into unoccupied habitat and adapt to its particular conditions.

  • Eg: moss, fungi, bacteria

• Keystone species

  • Species whose activities have a significant role in determining community structure.

  • Eg: beavers, wolves, elephants

• Indicator species

  • A plant or animal that, by its presence, abundance, or scarcity, demonstrates that some character or quality of an ecosystem is present.

  • Species that serve as early warnings of damage to a community or an ecosystem.

  • Eg: frogs, starfish, trout

• Foundation Species

  • create and enhance habitats that can benefit other species in a community.

  • Eg: elephants pushing/breaking trees to create space

• Resistance 

  • Measure of how much a disturbance can affect flows of energy and matter in an ecosystem.

• Resilience

  • Rate at which an ecosystem returns to its original state after a disturbance.

• Restoration ecology

  • Study and implementation of restoring damaged ecosystems.

Ecological Tolerance: the range of environmental conditions that an organism can survive in before becoming stressed or dying

Niche

• Niche specialist

  • A species specialized to live in a specific habitat or feed on a small group of species.

• Niche generalist

  • A species that can live under a wide range of abiotic or biotic conditions.

Watershed

• Help us understand how disturbances affect ecosystem processes

• All land in a given landscape that drains into a particular stream, river, lake, or wetland.

Intermediate Disturbance Hypothesis

Ecosystems experiencing intermediate levels of disturbance are more diverse than those with high or low disturbance levels.

Productivity

• Primary Productivity

  • Rate at which solar energy (sunlight) is converted into organic compounds via photosynthesis over a unit of time.

• Gross primary productivity (GPP)

  • Total amount of solar energy that producers capture via photosynthesis over a given amount of time.

• Net primary productivity (NPP)

  • Energy captured by producers minus the energy producers respire (R).

NPP = GPP – R

Levels of organization

• Individual

  • One organism

• Population

  • Individuals that belong to the same species and live in a given area at a particular time

• Community

  • All populations of organisms within a given area

• Ecosystem

  • A particular location on Earth with interacting biotic and abiotic components.

• Biosphere

  • Our planet where life resides; combination of all ecosystems.

Levels of organization

• Individual

• Population

• Community

• Ecosystem

• Biosphere

Symbiotic Relationships

• Mutualism

  • interaction between two species that increases the chances of survival for reproduction for both species.

• Commensalism

  • relationship in which one species benefits and the other species is neither harmed nor helped.

• Competition 

  • struggle of individuals to obtain a shared limiting resource.

•  Predation

  • interaction in which one animal kills and consumes another animal.

• Parasitism

  • interaction in which one organism lives on or in another organism.   

Trophic Levels

• Producers

  • like plants and algae, make their own food using sunlight through photosynthesis.

• Primary consumers

  • such as herbivores, eat producers to gain energy.

• Secondary consumers

  • like carnivores or omnivores, eat primary consumers.

• Tertiary consumers

  • top predators that feed on secondary consumers.

• Decomposers

  • like fungi and bacteria, break down dead organisms, and recycle nutrients back into the ecosystem.

Terrestrial Biomes

1. Tundra

2. Boreal forest

3. Temperate rainforest

4. Temperate seasonal forest

5. Woodland/shrubland

6. Temperate grassland/cold desert

7. Tropical rainforest

8. Tropical seasonal forest/savanna

9. Subtropical desert

UNIT 3 POPULATIONS

Age-Structure Diagrams

• Visual representation of the number of individuals within specific age groups for a country

• Some are called population pyramids.

• Populations with a large proportion of its people in the pre-reproductive stage have a large potential for rapid population growth.

Age Trends

• Prereproductive  (ages 0 -14)

• Reproductive  (ages 15 - 44)

• Postreproductive  (ages 45 and older)

• The number of young, middle, and older age groups determines how fast populations grow or decline.

• The number younger than age 15 is the major factor determining a country’s population growth.

DEMOGRAPHIC TRANSITION

Theory of demographic transition

As a country moves from a subsistence economy to industrialization and increased affluence, it undergoes a predictable shift in population growth.  Generally, both birth and death rates decline.

• Phase 1: Pre-industrial

  • Because high CBR (crude birth rate) and high CDR (crude death rate) offset each other, population growth is slow.

• Phase 2: Industrializing 

  • Rapid population growth because CBR remains high but CDR declines due to better sanitation, clean drinking water, availability of food and health care.

• Phase 3: Industrialized

  • Stable population growth as the economy and education system improve and people have fewer children.

• Phase 4: Post-industrial

  • Declining population growth because high levels of affluence and economic development encourages women to delay having children.

Demographic trap

• When death rates rise in a developing nation

• Occurring in Africa as a result of the HIV/AIDS epidemic. 

• The nation becomes trapped in Stage 2, and often reverts back to Stage 1. 

Solutions

• Elevating the social and economic status of women

  • Fertility is strongly related to female education in many developing countries.

• Family control: Regulating the number of offspring through the use of birth control

• Reducing poverty

India’s Failed Family Planning Program

• Poor planning

• Bureaucratic inefficiency

• Low status of women

• Extreme poverty

• Lack of administrative financial support

• Disagreement over the best ways to slow population growth

China’s Family Planning Program

• One child policy

  • More food

  • Larger pensions

  • Free health care

  • Salary bonuses

  • Free school tuition 

• China’s TFR decreased from 5.7 to 1.6 children. 

Negative Effects of the One-Child Policy

• Millions had to endure strict enforcement

  • forced sterilization and forced abortion.

• Births of additional children were undocumented

  • leading to many problems later on for those children 

• Sons were generally preferred over daughters

•  China’s birth and fertility rates remained low, leaving the population aging too rapidly and a shrinking workforce.

HUMAN POPULATION

Population boom

Expansion of agriculture

Industrial production 

Lower death rates from improvements in hygiene, sanitation, and medicine

Factors that drive population growth

• Population size

• Birth and death rates

• Fertility 

• Life expectancy

• Migration 

• Doubling time

  • The number of years it takes a population to double.

• Crude birth rate (CBR)

  •  Births per 1000

• Crude death rate (CDR)

  • Deaths per 1000

• TFR (total fertility rate)

  • estimate of the average number of children that each woman will bear throughout her childbearing years.

• Replacement level fertility

  • the total fertility rate required to offset the average number of deaths in a population to maintain the current population size.

    • Developed countries = 2.1

    • Developing countries = 2.5

• Immigration

  • the movement of people into a country or region, from another country or region.

• Emigration

  • the movement of people out of a country or region

IMPACTS OF POPULATION

Increase in population:

• More hunger

• More poverty

• More disease

• More depletion of resources

• More habitat destruction

• Less living space

Hunger

hunger: an aching desire for food

starvation: suffering or death from being deprived of nourishment

famine: widespread starvation

Poverty Cycle

Poverty → Undernutrition & malnutrition → Decreased energy → Decreased resistance to disease → Reduced ability to learn and work → Results in more poverty

Disease

• Diseases spread more rapidly among dense populations

• availability of clean water and sanitation

• Poor sanitation can lead to cholera, dysentery, hepatitis, etc.

Resources

• Freshwater

• Energy

  • for electricity, heating, and transportation

• Minerals

  • Greater demands on mineral resources for manufactured goods. 

Living Space

• The movement of people from rural areas to the cities is called urbanization.

• Emigration out of the city into the suburbs is urban sprawl. 

Habitat Destruction

• More land cleared for agriculture/grazing destroying forest and grassland habitats. 

• Water resources drained to provide drinkable water.

• Mining destroys other habitats.

POPULATION DYNAMICS

• Population size (N)

  • Total number of individuals within an area at a given time.       

  • N = births + immigration - deaths - emigration

• Carrying capacity

  • maximum population of a given species that a particular habitat can sustain indefinitely without being degraded.

• Population density

  • The number of individuals per unit area at a given time.

  • Population density = population size ÷ area

• Sex ratio

  • The ratio of males to females in a population.

Population Size Factors

• Density-dependent factor

  • A factor that influences an individual’s probability of survival and reproduction in a manner that depends on the size of the population.

• Density-independent factor

  • A factor that has the same effect on an individual’s probability of survival and the amount of reproduction at any population size.

Population Distribution

How individuals are distributed with respect to one another

• Clumped 

  • Better protection from predators

  • Temporary groups for feeding and caring for their young

  • Most common

• Uniform 

  • Trees in plantation

    • Adequate sharing of light and water

• Random 

  • Dispersed with no pattern

  • Trees in a natural forest grow where seeds are scattered through wind and birds

    • Least common

POPULATION GROWTH

Opposing Forces

• Biotic potential

  • Amount the population would grow if there were unlimited resources in its environment 

• Environmental resistance 

  • Limiting factors that act together to limit the growth of a population 

Population Growth Curves

1. Exponential

2. Logistic

Exponential Growth Model

• Intrinsic growth rate (r)

  • Maximum potential for growth of a population under ideal conditions with unlimited resources.

• Population is not limited by resources

• Creates a J-shaped growth curve

• Growth is independent of  population density

Logistic Growth Model

• Carrying capacity (K) = How many individuals the environment can sustain.

• As population grows, resources become scarce. 

• Creates an S-shaped curve

• Growth is dependent on population density

• Overshoot

  • When population becomes larger than the environment’s carrying capacity.

• Die-off 

  • Rapid decline in a population due to death.

Predator/Prey Cycle

 A predator and its prey populations fluctuate with each other.

Boom/Bust Cycle

If there’s a boom in the population beyond the carrying capacity, it’s followed by a bust.

Reproductive Strategies

• R-strategists

  • Species with high intrinsic growth rate- often leads to population overshoots and die-offs.

  • Large number of small offspring with little parental care

• K-strategists

  • Species with low intrinsic growth rate causing the population to increase slowly until it reaches carrying capacity.

  • Few, large offspring with invested parental care 

Survivorship Curves

A survivorship curve is a graph that represents the distinct patterns of species survival as a function of age.

• Type I Survivorship Curve

  • High survival early in life, with most deaths occurring in old age (eg. humans)

• Type II Survivorship Curve

  • Constant death rate throughout life (eg. birds)

• Type III Survivorship Curve

  • High mortality early in life, but survivors live long (eg. trees)

UNIT 4

ATMOSPHERE

The Atmosphere

• A fluid ocean of air that surrounds and protects the earth.

• 99% of the total mass of the atmosphere is within 20 miles of earth’s surface.

• It has a weight of 14 psi

• The earliest atmosphere of the lighter elements hydrogen and helium likely escaped out into space.

• Today’s oxygen-rich atmosphere that sustains life was first produced by bacteria 

• Nitrogen (78%) and oxygen (21%) make up 99% of the atmosphere.

• Aerosols are tiny droplets of liquids.

Layers of Atmosphere

• Troposphere

  • The layer closest to the surface of Earth, extending up to 10 miles

  • Made up mostly of oxygen and nitrogen

  • Where all the weather occurs

  • The temperature decreases as altitude increases 

• Stratosphere

  • Stable, very dry, no weather

  • extending 10–31 miles above the surface of Earth.

  • Ozone in the stratosphere absorbs some of the sun’s high-energy UV radiation protecting life from the harmful rays. 

• Mesosphere

  • The atmosphere’s coldest layer extends about 31-50 miles above earth’s surface. 

  • Meteors burn up in this layer

• Thermosphere

  • Beginnings of outer space

  • UV radiation reacts with layer of ionized gases and air particles which become electrically charged, creating the “Northern Lights” or aurora borealis.

• Exosphere

  • The outermost layer that blends into outer space.

  • Only hydrogen, helium, and trace oxygen. 

SEASONS

• Latitude

  • The distance north or south of the equator. 

  • Latitude is divided into increments of:

    •  degrees, minutes, and seconds. 

• Longitude

  • The distance east or west of a fixed point.

  • The lines of longitude are called meridians.  

• Prime Merdian

  • imaginary line of longitude that divides the Earth into the Eastern and Western Hemispheres

  • runs north and south through Greenwich, England.

• Parallels 

• Circles north and south of the equator

• 0° is the equator. 90°N and 90°S are at the poles. 

Movement

• Rotation

  • Spinning on its axis every 24 hours

• Revolution

  • One trip around the sun

  • It takes 365.24 days for one complete revolution

Earth’s Angle

• Its axis is tilted 23.5 °

• Earth’s orbit is slightly elliptical so it’s not always the same distance from the sun.

• Warming is not across the planet because of it’s angle

• Some areas of Earth reflect more solar energy than others. 

• Earth’s tilt produces predictable seasons.

Tropical regions near the equator receive more solar energy than mid-latitude and polar regions, where the Sun’s rays strike Earth’s surface at an oblique angle.

Reflection

• Albedo

  • percentage of the incoming solar energy reflected

• Whiter objects (snow and ice) reflect more solar energy

• Darker objects (forests and asphalt) reflect little and absorb much solar energy

  • This is an example of positive feedback

Day’s

• Earth is closest to the sun at perihelion. (Jan. 3)

• Earth is farthest from the sun at aphelion.  (July 4)

• Summer solstice (June 21 or 22) – The day with the most daylight.

• Winter solstice (Dec. 21 or 22) – The day with the least daylight.

• Autumnal Equinox (September 22 or 23) –Equal day and night. 

• Vernal Equinox (March 21 or 22) –Equal day and night.

ENSO

Layers

• Thermocline

  • the transition layer between warmer mixed water at the surface and cooler deep water below

• Warm water, like warm air, expands and rises. 

Ocean Currents

• Affected by:

1. Temperature

2. Gravity

3. Prevailing Winds

4. Coriolis effect

5. Locations of continents

• Gyre

  • A large-scale pattern of water circulation that moves clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

• Oceanic circulation patterns

  • the result of differential heating, gravity, prevailing winds, the Coriolis effect, and the locations of continents.

ENSO

• El Niño–Southern Oscillation (ENSO)

  • A reversal of wind and water currents in the South Pacific Ocean.

  • Every 3-7 years, the interaction of the Earth's atmosphere and ocean causes surface currents in the tropical Pacific Ocean to reverse direction. 

• Upwelling

  • the upward movement of ocean water toward the surface of diverging currents.

  • Brings cool and nutrient-rich water from the bottom of the ocean to the surface

Disease

• Wetter conditions 

  • Increasing mosquito breeding grounds

  • Flooding creates sanitation problems

• Warmer water

• bacterial growth increases in warm water

• Warmer water increases insect breeding

• Higher temperatures

  • Insects get a longer window of reproductive time

  • Insects normally killed by cold temperatures continue to live

• Drier conditions

  • Causing streams to become stagnant

  • Stagnant water increases mosquitos

• Drought

  • Less fresh water

  • Pollution gets concentrated in shallow ponds increasing diseases like cholera.

PLATE TECTONICS

History

• Pangea

  • Alfred Wegener proposed a hypothesis called continental drift in 1912

  • Began breaking up 200 million years ago

• Mesosaurus

  • Extinct reptile found in South America and Western Africa

• Glossopteris

  • Ancient extinct plant

Earth’s layers+

• Core, Mantle, Crust

• Convection currents in the mantle produce the force which move the crust

  • Causes earthquakes and volcanoes

• Fault

  • fracture in rock caused by a movement of Earth’s crust.

• Seismic Activity

  • The frequency and intensity of earthquakes experienced over time.

• Fault Zone

  • A large expanse of rock where a fault has occurred.

Hot Spots

• As the Pacific Plate moves over a hot spot under a mantle plume, a series of volcanic eruptions formed the Hawaiian Islands.

Plate Boundaries

• Divergent plate boundaries, plates move apart. 

  • Molten rock rises and fills the space between the plates as the plates move apart

  • This causes mid-ocean ridges

    • Eg. Mid-Atlantic Ridge. 

• Transform fault boundaries, plates slide past each other.

  • Where two plates are grinding past each other. 

  • An earthquake occurs when stress overcomes a locked fault, releasing stored energy.

    • Eg. San Andreas fault in California

• Convergent plate boundaries, plates collide.

  • Continental crust vs. Continental crust

    • There is uplifting creating mountains like the Himalayas. 

  • Oceanic crust vs. Continental crust

    • a subduction zone on the ocean floor.

    • OC is denser than CC

  • Oceanic crust vs Oceanic crust

    • The subducted plate melts, the molten rock rises along the trench

    • forms a chain of volcanic islands called an island arc. 

      • (e.g. Aleutian Islands in Alaska)

ROCKS

The geologic cycle governing the constant formation, alteration, and destruction of rock material that results from tectonics, weathering, and erosion, among other processes.

Three types of rock are: 

• Igneous

  • Directly from molten magma 

  • Intrusive igneous rock: magma rises up and cools in a place underground.

  • Extrusive igneous rock: magma cools above the surface of Earth.

• Sedimentary

  • Compression of sediments

  • Hold fossil records

• Metamorphic

  • Exposure to high temperatures and pressures

  • subjected to high temperature and pressure.

Exposed Rock

• Weathering

  • Physical weathering: mechanical breakdown of rocks and minerals.

  • Chemical weathering: breakdown of rocks and minerals by chemical reactions the dissolving of chemical elements from rocks, or both.

• Erosion

  • physical removal of rock fragments from a landscape or ecosystem.

  • result of two processes:

    • Wind, water, and ice move materials downslope.

    • Living organisms burrow under the soil.

SOIL

A renewable resource

Made out of:

1. Eroded rock

2.  Mineral nutrients

3.  Decaying organic matter

4.  Water

5.  Air

6.  Billions of living organisms (microscopic decomposers) 

Function:

• A medium for plant growth

• A habitat for living organisms

• Breaks down organic material 

• A filter for water

Processes

• Infiltration

  • downward movement of water through soil

• Leaching

  • as water infiltrates down, it dissolves various minerals and organic matter in upper layers and carries them to lower layers

Soil Formation Factors

• Parent material

  • underlying rock material from which the inorganic components of a soil are derived.

• Climate

• Topography

• Organisms

• Time

Soil Horizons (5)

• O Horizon

  • Surface litter

  • Humus: most fully decomposed organic matter in the lowest section of this horizon

• A Horizon

  • Topsoil

• E Horizon

  • Zone of leaching

• B Horizon

  • composed primarily of mineral material with very little organic matter.

• C Horizon

  • Parent material

  • Least weathered soil horizon

SOIL PROPERTIES

Properties of soil

• Physical: texture, porosity

• Chemical: pH, N, P, K

• Biological: bacteria, snails,  insects, earthworms

Physical Properties

• Soil Texture

  • Determined by % of sand, silt, clay

    • LOAM

    • 40% sand, 40% silt, 20% clay

• Soil Permeability

  • Determined by soil texture

Sand

• Drains easily and quickly

• Low water-holding capacity, therefore it must be watered more frequently. 

• Low nutrient-holding capacity, so it must be fertilized more often. 

• Highly susceptible to wind and water erosion

Silt

• Medium size particles

• Forms crust, which is often hard.

• Created when rock is eroded, or worn away, by water and ice

• Promotes water retention and air circulation

Clay

• High water-holding capacity

• High nutrient-holding capacity

  • Poor drainage

• Waterlogged soil results in the roots being deprived of oxygen and other nutrients

• Crusting and cracking are common

• Difficult to work because it is so sticky

—--------------

Biological Properties

• Reflects how well-suited a soil is to support life

  • Earthworms

  • Fungi and Bacteria

  • Microorganisms

—-----------

Nitrogen

• responsible for plant growth

• In Amino acids = make proteins

• Required for enzyme reactions

Phosphorus

• Major component of DNA & RNA

• Root development

• Crop maturity

• Seed production

Potassium

• Indirect role in plant growth (activates over 80 enzymes)

• Helps plants withstand extreme temps

• Helps plants fight drought and pests

• Increases water use efficiency

• Transforms sugars into starch

SOIL CONSERVATION

Techniques

• Terracing

  • making “steps” to slow soil erosion down a slope

• Contour Planting

  • plowing and planting crops in rows across the slope rather than up and down the slope

• Strip Cropping

  • planting alternating strips of a row crop and another crop (cover crop) that completely covers the soil.

• Alley Cropping

  • a crop is planted in an alley between trees and shrubs. 

• Conservation Tillage

  • involves special machines that drill seeds directly through crop residues into the undisturbed soil

• Crop Rotation

  • plant a nutrient-depleting crop one year and a nutrient-enriching crop the next year

Soil Nutrients

• Organic fertilizer: made from plant or animal wastes. 

• Green manure: growing plants that are plowed back into the soil.

• Compost: decayed organic matter

• Inorganic fertilizer

  • Adds no humus (organic matter)

  • Releases greenhouse gases

  • Runoff produces water pollution

• Salinization

  • when water evaporates and leaves behind its salts. 

  • Salt tolerant crops = cotton

• Desertification

  • when the productive potential of drylands falls by 10% or more

UNIT 5

MEAT & FISH

Meat

• Feedlots are used to fatten up cattle before slaughter.

• Concentrated Animal Feeding Operation (CAFO) 

  • Large indoor or outdoor structure designed for maximum output.

Less Meat Consumption

• Reduce CO₂, methane, and NO2 emissions

• Reduce the use of antibiotics and growth hormones

• Conserve water

• Improve topsoil

Fish

• Aquaculture  

  • Farming aquatic organisms such as fish, shellfish, and seaweeds.

  • Pros:

    • Provide for more people

  • Cons:

    • Concentrate waste

    • Escaped fish compete/breed with wild fish. 

    • Increase in disease transmission

• Fishery

  • Commercially harvestable population of fish within a particular ecological region.

• Fishery Collapse

  • Decline of a fish population by 90 percent or more.

• Bycatch

  • Unintentional catch of nontarget species while fishing.

WATER

Importance

1. Global health issue

2. Economic issue

3. Women & children issue

4. National & global security issue

5. Environmental issue

Freshwater

Only  0.024 % of the earth’s water supply is readily available as liquid freshwater.

• Surface water: lakes, rivers, streams, oceans

• Groundwater: Underground water (aquifers)

  • Aquifer = permeable layer of rock and sediment that contains groundwater.

Other Waters

• Water table

  • The uppermost level at which the water in a given area fully saturates rock or soil.

• Groundwater recharge

  • A process by which water percolates through the soil and goes to an aquifer.

• Spring

  • A natural source of water formed when water from an aquifer percolates up to the ground surface.

• Artesian well

  • A well created by drilling a hole into a confined aquifer.

• Cone of depression

  • An area lacking groundwater due to rapid withdrawal by a well.

• Saltwater intrusion

  • Infiltration of salt water in an area where groundwater pressure has been reduced from extensive drilling of wells.

AGRICULTURE

Green Revolution (1950-67)

• A shift in agricultural practices that included: 

  • Mechanization

  • Fertilization

  • Irrigation

  • Pesticides

  • Improved crop varieties

• All these increased food output

Crops+

• The big three: Wheat, Corn, Rice

• Monocropping

  • large plantings of a single species or variety

• Cash crops

  • cotton, coffee, sugarcane, bananas

• Fertilizers

  • Organic

    • Organic matter from plants/animals

  • Synthetic

    • Made with fossil fuels

    • Aka inorganic fertilizer

Chemicals

• Pesticide

  • A substance, either natural or synthetic, that kills or controls pests.

• Insecticide

  • A pesticide that targets species of insects that consume crops.

• Herbicide

  • A pesticide that targets plant species that compete with crops.

• The pesticide treadmill

  • pest populations evolve resistance to pesticides, which requires farmers to use higher doses or to develop new pesticides.

Unsustainable

• Tilling

• Slash-and-burn farming

• Overuse of fertilizers

Genetic engineering

• Greater yield

• Greater food quality

• Reductions in pesticide use

• Reduction of world hunger by increased food production

• Increased profits

Integrated Pest Management (IPM)

Cultivation practices: Each year crops are rotated to other locations

Biological methods: Natural predators and parasites are used

Chemical methods: Limited amounts of pesticides can be applied.

Pros

• Reduces pesticide use

• Reduces pest control costs

• Does not reduce crop yield or food quality

• Reduces fertilizer needs

• Reduces pollution

Cons

• Requires expert knowledge of the pest situation

• Takes more time to become effective

• The control measures in one area may not be effective in another area

• Initial costs may be higher, but long-term costs are lower

• Resisted by pesticide manufacturers

Solutions

• An additional sales tax is applied to pesticides

• An IPM demonstration farm is set up in each county

• Train USDA personnel in the use of IPM

Green Revolution (1950-67)

• Shift in Practices: Mechanization, fertilization, irrigation, pesticides, improved crop varieties → Increased food output.

Crops

• Big Three: Wheat, corn, rice.

• Monocropping: Single species planting.

• Cash Crops: Cotton, coffee, sugarcane, bananas.

Fertilizers

• Organic: Plant/animal matter.

• Synthetic: Fossil fuel-based (inorganic).

Chemicals

• Pesticides: Kill/control pests.

• Insecticides: Target insects.

• Herbicides: Target weeds.

• Pesticide Treadmill: Resistance → higher doses/new pesticides.

Unsustainable Practices

• Tilling, slash-and-burn farming, overuse of fertilizers.

Genetic Engineering

• Higher yields, better quality, less pesticide use, reduces hunger, higher profits.

Integrated Pest Management (IPM)

• Cultivation: Rotate crops yearly.

• Biological: Use natural predators/parasites.

• Chemical: Minimal pesticide use.

IPM Pros

• Less pesticide use/costs.

• Maintains yield/quality.

• Reduces fertilizer needs/pollution.

IPM Cons

• Needs expertise.

• Slow effectiveness.

• Location-dependent.

• Higher initial costs.

Solutions

• Pesticide sales tax.

• IPM demo farms.

• Train USDA personnel

IRRIGATION & CONSERVATION

Methods

• The largest human use of freshwater is for irrigation (70%).

• Irrigation techniques include:

• Drip irrigation

  • uses perforated hoses to release small amounts of water to roots

  • This system is the most efficient

  • Expensive, not used often

• Flood irrigation

  • involves flooding an agricultural field with water

  •  can lead to waterlogging of the soil.

• Furrow irrigation

  • Involves cutting furrows (trenches) between crop rows and filling them with water.

  • This system is inexpensive

• Spray irrigation

  • pumping groundwater into spray nozzles across an agricultural field

  • more efficient than flood and furrow irrigation

  • LEPA (Low Energy Precision Application) sprinklers spray water directly onto crop.

Water Conservation

• Tiered water-pricing systems

  • A water allocation system that charges rates that increase with the amount of water consumed.

• Xeriscaping

  • Landscaping that removes water-intensive vegetation from lawns and replaces it with more water-efficient native landscaping.

• Hydroponic agriculture

  • The cultivation of plants in greenhouse conditions by immersing roots in a nutrient-rich solution.

  • Requires little or no pesticide use. 

  • Uses up to 95% less water than traditional irrigation. 

  • Crops can be grown year-round.

• Graywater: Wastewater from baths, showers, bathrooms, and washing machines.

Saltwater → Freshwater

• Desalination  The process of removing the salt from ocean water. 

• Distillation: A process of desalination in which water is boiled and the resulting steam is captured and condensed to yield pure water.

• Reverse osmosis: A process of desalination in which water is    forced through a thin semi-permeable membrane at high pressure.

Irrigation Methods

• Drip Irrigation: Most efficient; perforated hoses deliver water to roots; expensive.

• Flood Irrigation: Floods fields; can cause soil waterlogging.

• Furrow Irrigation: Trenches between crops filled with water; inexpensive.

• Spray Irrigation: Groundwater sprayed via nozzles; more efficient than flood/furrow.

• LEPA Sprinklers: Low-energy sprinklers spray water directly onto crops.

Water Conservation

• Tiered Pricing: Higher rates for higher water use.

• Xeriscaping: Replacing water-intensive lawns with native, drought-resistant plants.

• Hydroponics: Plants grown in nutrient solutions; uses 95% less water, no pesticides, year-round growth.

• Graywater: Reused water from baths, sinks, and washing machines.

Desalination

• Distillation: Boiling water and condensing steam into freshwater.

• Reverse Osmosis: Forcing water through semi-permeable membranes to remove salt.

LAND USE

Harvest Practices

Clear-cutting: Removing all or almost all of the trees within an area.

Selective cutting: Removal of single trees or a relatively small number of trees from the larger forest.

Ecologically Sustainable Forestry: Removing trees from forests in ways that do not unduly affect the viability of other noncommercial tree species.  The goal is to maintain both plants and animals in as close to a natural state as possible.

Fire

Fires are a natural process for recycling nutrients

Prescribed Burn:  fire deliberately set under controlled conditions to reduce the accumulation of dead biomass on a forest floor. Prescribed burns help reduce the risk of uncontrolled natural fires. 

Rangeland

Dry open grasslands used for grazing cattle.

Grazing too many animals can quickly denude a region of vegetation. 

Loss of vegetation can lead to land exposed to wind and water erosion.  

We especially should manage riparian zones (the edges of streams and rivers).

Protected Lands

National WIldlife Refuge: A federal public land managed for the primary purpose of protecting wildlife.

National Wilderness Area: An area set aside with the intent of preserving a large tract of intact ecosystem or landscape.

National Parks: Managed for scientific, educational, and recreational use. Human overuse can harm the environmental features that attract visitors.

Urbanization

Suburb  An area surrounding a metropolitan center, with a comparatively low population density.

Exburb  An area similar to a suburb, but unconnected to any central city or densely populated area.

Urban Sprawl  Urbanized areas that spread into rural areas, removing clear boundaries between the two.

Urban blight  The degradation of built and social environments of a city that accompanies and accelerates migration to the suburbs. Positive feedback loop

Sources of Urban Sprawl

• Automobiles and highway construction

• Land costs

• Governmental policies

• Urban Blight

Solutions

Smart Growth  A set of principles for community planning that focuses on strategies to encourage the development of sustainable, healthy communities.

Smart Growth Principles

1. Create mixed land uses.

2. Create a range of housing opportunities and choices.

3. Create walkable neighborhoods.

4. Encourage community and stakeholder collaboration in development decisions.

5. Take advantage of compact building design.

6. Foster distinctive, attractive communities with a strong sense of place.

7. Preserve open space, farmland, natural beauty and critical environmental areas.

8. Provide a variety of transportation choices.

9. Strengthen and direct development toward existing communities

10. Make development decisions predictable, fair and cost-effective

Harvest Practices

• Clear-Cutting: Removes nearly all trees in an area.

• Selective Cutting: Removes specific trees, minimizing impact.

• Ecologically Sustainable Forestry: Maintains biodiversity and natural habitats.

Fire Management

• Natural Fires: Recycle nutrients.

• Prescribed Burn: Controlled fire to reduce biomass and prevent uncontrolled fires.

Rangelands

• Use: Grasslands for grazing cattle.

• Risks: Overgrazing causes erosion and vegetation loss, especially near riparian zones.

Protected Lands

• National Wildlife Refuge: Protects wildlife.

• National Wilderness Area: Preserves ecosystems.

• National Parks: Balances recreation, education, and conservation.

Urbanization

• Suburb: Low-density areas near cities.

• Exurb: Similar to suburbs but not city-connected.

• Urban Sprawl: Expansion into rural areas, erasing boundaries.

• Urban Blight: City degradation due to suburban migration.

Causes of Urban Sprawl

• Automobiles, highways, land costs, urban blight, and policies.

Solutions

• Smart Growth: Sustainable, healthy community planning.

Smart Growth Principles

1. Mixed land uses.

2. Diverse housing options.

3. Walkable neighborhoods.

4. Community collaboration.

5. Compact design.

6. Attractive, distinctive communities.

7. Preserve open spaces.

8. Transportation variety.

9. Focus on existing communities.

10. Predictable, fair development.

MINING

Ore  A concentrated accumulation of minerals from which economically valuable materials can be extracted.

Metal  An element with properties that allow it to conduct electricity and heat energy, and to perform other important functions.

Reserve  In resource management, the known quantity of a resource   that can be economically recovered. Where metals are

Smelting Heating the ore to release the mineral; produces air pollutants (especially SO2 which results in acid wastes). Chemical extraction is also done, but it results in many toxic wastes (like cyanide-laden water). 

Depletion - the time it takes to use up a certain proportion (usually 80%) of the reserves of a mineral at a given rate. 

Types of Mining

Surface mining for shallow deposits

1. Strip mining 

   1. Removal of large portions of soil and rock to expose ore

   2. Mine tailings  Unwanted waste material created during mining including mineral and other residues that are left behind after the desired metal or ore is removed. 

2. Open-pit mining

   1. Creates a large visible pit   or hole in the ground.

   2. Toxic water can accumulate at the bottom.

3. Mountaintop removal

   1. A mining technique in which the entire top of a mountain is removed with explosives.

   2. Resulting waste rock and dirt are dumped into the valleys and streams below.

4. Placer mining

   1. The process of looking for minerals, metals, and precious stones in river sediments.

Subsurface mining for deep deposits (e.g., coal)

1. Mining techniques used when the desired resource is more than 100 m (328 feet) below the surface of Earth.

2. Coal, diamonds, and gold are some of the materials extracted by subsurface mining.

Effects of Mining

• Enormous amounts of energy

• Land disturbance

• Toxic wastes

• Soil erosion

• Subsidence (cave in)

• Air and water pollution

Solutions

1. Industrial Ecosystem

   1. the wastes of one company are the raw materials of another company. 

2. Waste less

3. Reuse existing supplies

4. Recycle

5. Find a substitute 

6. Do without it

Key Terms

• Ore: Concentrated minerals for economic extraction.

• Metal: Conductive elements used in industry.

• Reserve: Known recoverable resources.

• Smelting: Heating ore to extract minerals; produces air and toxic waste pollutants.

• Depletion: The time it takes to use up a certain proportion (usually 80%)

Types of Mining

• Surface Mining: For shallow deposits.

  • Strip Mining: Removes soil/rock layers to expose ore; leaves waste (tailings).

  • Open-Pit Mining: Creates large pits; toxic water accumulates.

  • Mountaintop Removal: Explosives remove mountain tops; waste fills valleys/streams.

  • Placer Mining: Extracts minerals from river sediments.

• Subsurface Mining: For deep deposits (e.g., coal, diamonds); >100 m below surface.

TYPES OF MINING

Surface Mining: For shallow deposits near the Earth’s surface.

• Strip Mining: Removes large sections of soil and rock to expose ore; leaves behind mine tailings (unwanted waste materials).

• Open-Pit Mining: Creates a large, visible pit or hole in the ground; toxic water often accumulates at the pit’s bottom.

• Mountaintop Removal: Entire mountain tops are removed with explosives; waste rock and debris are dumped into nearby valleys and streams, causing environmental damage.

• Placer Mining: Extracts metals and precious stones from river sediments using water to separate heavier materials like gold and diamonds.

Subsurface Mining: For deposits more than 100 meters (328 feet) below the surface.

• Techniques: Involves creating tunnels or shafts to reach deep resources.

• Materials Extracted: Commonly used for coal, diamonds, and gold.

• Challenges: Risk of mine collapses, subsidence, and significant energy use.

Effects of Mining

• High energy use, land disturbance, soil erosion, toxic wastes, air/water pollution, and subsidence.

Solutions

• Industrial Ecosystem: The wastes of one company are the raw materials of another company. .

• Conservation: Waste less, reuse, recycle, find substitutes, or do without.