Unit 2 Review

Ecological succession

• The process by which the structure of a biological community evolves.

There are two types of succession, primary and secondary.

Primary succession

• Occurs in essentially lifeless areas - regions in which the soil is incapable of sustaining life as a result of factors such as lava flows, newly formed sand dunes, or rocks left from a retreating glacier.

Secondary succession

• Occurs in areas where a community previously existed and has now been removed. It is typified by smaller-scale disturbances that do not eliminate all life and nutrients from the environment.

Pioneer species

• Species that are the first to colonize newly created environments or recently disturbed environments during the process of primary and secondary succession. These include lichens, mosses, and fungi.

Succession

• Ecological succession is a series of progressive changes in the species that make up a community over time.

Indicator species

• A species that provides information about the health and condition of an ecosystem. It is often used to assess the presence or absence of certain environmental conditions or changes.

Over many years, due at least in part to changes in the environment caused by the growth of grasses and other species, shrubs will emerge, followed by small pine, oak, and hickory trees. Eventually, barring further disturbances, the oak and hickory trees will become dominant and form a dense canopy, returning the community to its original state.

Unit 3 Review

K strategist

Examples: Humans, elephants, pandas

• Often large

• Long life spans

• Lots of parental care

• More vulnerable to extinction

• It tends to be a specialist

  → has a narrow range of tolerance, particular needs

• Logistic curve (S-shaped curve)

R strategist

Examples: Insects, fish

• High growth rate

• Often are small

• Produce many offspring

• Little to no parental care

• tend to be generalist

  → organisms that can exist in many different environments, and have a wide range of tolerance

• tend to populate quickly

• Exponential curved (J-shaped curve)

• Boom bust cycle

Age Structure Diagrams (Population Pyramid)

• Shows the distribution of ages in a population and predicts future populations

TFR (Total Fertility Rate)

• Varies among countries

• The average number of children a woman has

• Affected by age, when women have their first child

• Educational opportunity

Carrying Capacity

The maximum population an area can sustain (Kr)

Replacement Fertility

The total fertility rate needed to keep a population stable

• Global average - 2.1

• Higher in some countries

  → Infant mortality rate

Greying Populations

• fewer young workers to support the elderly population

• More healthcare costs

• Found more in declining populations

The Demographic Transition

Factors that made it shoot up after 1850

• Advancements in medicine

• The industrial revolutions

Human Population Dynamics

Global population - 8 BIllion

Fasted Growing Areas - Asian and Africa

Growth Rate - 1.1% (globally) per year

5 Most populous Areas

• China

• India

• United States

• Indonesia

• Pakistan

Factors that Affect Growth Rate

• Total fertility

• Life expectancy

• Age structure

• Migration

Unit 4 Review

Formation and Erosion

Parent material in soil refers to the underlying material from which soil forms. It can be rocks, minerals, organic matter, or sediments.

Formation Affected by:

• Parent material (Rock)

• Over time, deeper layers form

• Climate (Warm, wet climate is best)

• Topography (The shape of land) (Slope can affect)

• Organisms (Burrow animals)

Horizons

O Horizon

• Contains mostly organic things

• Usually the smallest layer

• Carbon to Carbon bonds (leaves)

A Horizon

• Surface soil (topsoil/humus)

• Most moist, usually dark brown in color

• Where most plant roots are located

E Horizon

• Leaching layer, removing minerals and nutrients

• It is typically lighter in color and has a higher concentration of sand and silt particles compared to the layers above and below it.

B Horizon

• Characterized by the accumulation of everything

• Collects minerals and nutrients. It looks and feels different from the A horizon. It helps with water, nutrients, and root movement in the soil.

C Horizon

• The C horizon in soil is the deepest layer of soil, also known as the parent material. It consists of partially weathered or unweathered rock and has little to no organic matter. Its main function is to provide a source of minerals for the upper soil layers.

R Horizon

• The R horizon in soil refers to the bedrock layer, which is the deepest layer of soil. It consists of unweathered parent material and is typically found beneath the other soil horizons.

Soil

Made out of

45% Soil particles, specifically sand, silt, and clay

25% Air

5% Organic matter

Causes of Erosion

Natural: Water, wind, and gravity can cause erosion

Anthropogenic: Human-caused erosion

• Deforestation

  • (through the roots as they hold soil in place)

• Agriculture

  • (Tilling, messing up the soil by disrupting soil structure)

• Pesticides and Fertilizer

  • (Changes the chemistry of the soil)

• Overgrazing

  • (Short grass = short roots)

Composition and Properties

What is it?

A renewable resource that can be replenished but can also be depleted (this is a cycle)

Porosity

The space between particles

• Sand has a high porosity

• Silt has a medium porosity

• Clay has a low porosity

Permeability

Porosity affects permeability
Permeability is the ability for water to move through different materials

• Clay has a low permeability

• Silt has a medium permeability

• Sand has a high permeability

This is because each of these materials is compacted in different intensities

Water Holding Capacity

Permeability affects water-holding capacity

How well soil can hold water

• Clay has a high water-holding capacity

• Silt has a medium holding capacity

• Sand has a medium holding capacity

The water-holding capacity of different materials varies based on their physical and chemical properties, such as porosity, surface area, and chemical composition. Materials with high porosity and larger surface area, like soil, can hold more water compared to materials with low porosity and smaller surface area, such as rocks or metals.

Chemical Properties

Plants need nutrients to grow

These nutrients are found in soil

• Nitrogen (N)

• Phosphorus (P)

• Potassium (K)

• pH

These factors can affect the growth of plants. Adjusting these elements to what fits best will lead to better plant growth.

Biological Properties

Organisms put nutrients in the soil due to decomposition

Soil Texture Triangle

Unit 5 Review

Sustainable Forestry

Timber Market Value - Economic value.

• Lumber - which is when timber is shaped can be used for paper, houses, and energy

Ecological Value

• Trees provide habitat, which helps moderate the local climate

• Prevents soil erosion

• Helps with soil formation

• Helps reduce runoff

• Helps store carbon

What is sustainability?
Sustainable forestry is using sustainable methods to log trees

• Reusing wood

Clearcutting - Cutting down trees all at the same time which leads to even-aged stands

Even-aged - These grow all at the same size

Uneven-aged stems: Trees grow at different sizes

The Green Revolution

Industrial agriculture - Mechanization and standardization applied to food reproduction

GMOs

Genetically Modified Organisms

Irrigation

Waterlogging - Roots that cannot get enough oxygen due to water

Salinization - Too much salt left behind through evaporation or saltwater intrusion which is toxic for plant growth

Ogallala Aquifer - A water table aquifer surrounded by sand, silt, clay, and gravel. Located beneath the great plains as one of the world’s largest aquifers.

Pest Control

Pesticides are substances used to control or eliminate pests, such as insects, weeds, and fungi, to protect crops and prevent plant damage.

Pros: Increases crop yield s while decreasing damage from pests

Cons: Human health risk, bioaccumulation, biomagnification, and can kill non-target organisms

Biocontrol

Biocontrol refers to using living organisms or their products to control pests or diseases in agriculture and forestry, reducing the reliance on chemical pesticides.

Pros: No chemicals
Cons: Species can become invasive

IPM

The goal of IPM is to use a variety of methods to control the number of pests (not trying to fully eradicate) and minimize the environmental impact

Sustainable Soil

Uses

• Organic fertilizer needs to be gathered (synthetic)

• Nutrient levels unknown

• Harder to use, synthetic is easier

Meat Production

Free Range

• Can overgraze which causes desertification

• Waste can be spread over large areas

• Benefit: Animals have access to the outdoors

CAFOs

• Concentrated animal feeding operations

• Increased antibiotic use

• ethical concerns

• waste issues

• Benefit: Effective method of producing meat because it is cost-efficient

Why eat less meat?

Leads to a decrease in greenhouse gases (methane), a decrease in land and water use, and a decrease in antibiotic use.

Aquaculture

• Cost-effective

• Less fuel used

Cons:

• Genetically modified fish can mate with native fish

• Waste issues

Over Fishing

How can we turn this around?

• Catch limit

• Treaties - CITES

• Laws - Endangered species act

So many fish are being taken away, what will be the consequences?

• Loss of biodiversity

Mining

• Surface mining

  • Strip, open pit, or mountaintop

• Substance mining tunnels under the ground

What do we mine for?

• Coal, gravel, sand, diamonds

• They are harvested as ore and then refined

Mining

→Refinement

→Transportation

→Use

→Desposal

Impacts

1. Soil erosion

   • Dust pollution

   • Fossil fuel use

   • Water pollution

   • Mercury can be used to separate gold from ore which leads to mercury pollution as well

   • Cyanide is often used

   • Acid mine drainage

   • Tailings can contain sulfur that can form sulfuric acid

Remediation

• Turn mine into a recreational area

• Replant vegetation to combat acid mine drainage

The Impacts of Urbanization

Heat and Island Effect

Average temperatures are several degrees warmer in cities than in suburbs and other areas

Solutions

• Paint rooftops a lighter color

• Plant rooftop vegetation

Reduce Impacts

• Mass transit

• Permeable surfaces (pavements and more parks)

• Walkable cities

Impact on Water Cycle

• More runoff and less infiltration in cities from impervious surfaces

• Change that into more permeable surfaces through rooftop gardens and permeable pavement

Formation and Erosion

Parent material in soil refers to the underlying material from which soil forms. It can be rocks, minerals, organic matter, or sediments.

Formation Affected by:

• Parent material (Rock)

• Over time, deeper layers form

• Climate (Warm, wet climate is best)

• Topography (The shape of land) (Slope can affect)

• Organisms (Burrow animals)

Horizons

O Horizon

• Contains mostly organic things

• Usually the smallest layer

• Carbon to Carbon bonds (leaves)

A Horizon

• Surface soil (topsoil/humus)

• Most moist, usually dark brown in color

• Where most plant roots are located

E Horizon

• Leaching layer, removing minerals and nutrients

• It is typically lighter in color and has a higher concentration of sand and silt particles compared to the layers above and below it.

B Horizon

• Characterized by the accumulation of everything

• Collects minerals and nutrients. It looks and feels different from the A horizon. It helps with water, nutrients, and root movement in the soil.

C Horizon

• The C horizon in soil is the deepest layer of soil, also known as the parent material. It consists of partially weathered or unweathered rock and has little to no organic matter. Its main function is to provide a source of minerals for the upper soil layers.

R Horizon

• The R horizon in soil refers to the bedrock layer, which is the deepest layer of soil. It consists of unweathered parent material and is typically found beneath the other soil horizons.

Soil

Made out of

45% Soil particles, specifically sand, silt, and clay

25% Air

5% Organic matter

Causes of Erosion

Natural: Water, wind, and gravity can cause erosion

Anthropogenic: Human-caused erosion

• Deforestation

  • (through the roots as they hold soil in place)

• Agriculture

  • (Tilling, messing up the soil by disrupting soil structure)

• Pesticides and Fertilizer

  • (Changes the chemistry of the soil)

• Overgrazing

  • (Short grass = short roots)

Porosity

The space between particles

• Sand has a high porosity

• Silt has a medium porosity

• Clay has a low porosity

Permeability

Porosity affects permeability
Permeability is the ability for water to move through different materials

• Clay has a low permeability

• Silt has a medium permeability

• Sand has a high permeability

This is because each of these materials is compacted in different intensities

Water Holding Capacity

Permeability affects water-holding capacity

How well soil can hold water

• Clay has a high water-holding capacity

• Silt has a medium holding capacity

• Sand has a medium holding capacity

The water-holding capacity of different materials varies based on their physical and chemical properties, such as porosity, surface area, and chemical composition. Materials with high porosity and larger surface area, like soil, can hold more water compared to materials with low porosity and smaller surface area, such as rocks or metals.

Chemical Properties

Plants need nutrients to grow

These nutrients are found in soil

• Nitrogen (N)

• Phosphorus (P)

• Potassium (K)

• pH

These factors can affect the growth of plants. Adjusting these elements to what fits best will lead to better plant growth.

Biological Properties

Organisms put nutrients in the soil due to decomposition

Soil Texture Triangle