APES - Big Ideas from Unit #4: Earth's Systems & Resources (excluding 4.6)

(4.1) Order of Earth's Structure from Core to Surface

Core ➡️ Mantle ➡️ Asthenosphere ➡️ Lithosphere ➡️ Crust

(4.1) Earth's Core

Solid mass of nickel, iron, and radioactve elements, releasing a lot of heat.

(4.1) Mantle

The mantle is mostly solid ultramafic rock that flows plastically over geologic time. The asthenosphere (upper mantle) is weak/ductile and can contain localized partial melt; magma is generated by partial melting of mantle or crust and moves through cracks but the mantle itself is not a global liquid layer.

(4.1) Asthenosphere

A semi-solid, flexible layer of mantle, beneath the lithosphere.

(4.1) Lithosphere

Thin, brittle rock layer on top of the mantle (tectonic plates).

(4.1) Crust

The very outer layer of the Lithosphere, Earth's surface.

(4.1) 3 types of Plate Boundaries

Divergent, Convergent, Transform (aka Strike-Slip)

(4.1) Divergent Plate Boundary

Plates move away from each other, DIVERGING. Often results in the formation of mid-oceanic ridges, seafloor spreading, or rift valleys (if on land). Convection cycles occur. Mostly commonly occur along mid-ocean ridges.

(4.1) Convection Cycles (Divergent)

Cycles of heating and cooling magma that rise up to the Lithosphere, cool, and expand/solidify, forming new Lithospheric crust, all repeat the process again. Subduction occurs at convergent margins (sinking ocean plate melts back into Magma, forcing Magma up, creating new coastal mountains and volcanoes on land).

(4.1) Results of Divergent Plate Boundaries

Seafloor spreading, Mid-ocean ridges, or rift valleys (if on land), and Earthquakes.

(4.1) Convergent Plate Boundary

Plates move towards each other, CONVERGING. Often results in the formation of volcanoes, island arcs, Earthquakes, and Mountains.

(4.1) Oceanic-Oceanic Convergent Plate Boundary

One plate will subduct beneath the other, resulting in the formation of an offshore trench, and/or mid-ocean volcanoes, and island arcs.

(4.1) Oceanic-Continental Convergent Plate Boundary

The oceanic plate will subduct beneath the continental plate (due to the oceanic plate having greater density than the continental plate), and it will melt back into magma, resulting in the formation of coastal mountains (ex., the Andes), volcanoes on land, trenches, and tsunamis.

(4.1) Continental-Continental Convergent Plate Boundary

The crust will thicken and be uplifted, resulting in the formation of mountains. (Ex. The Himalayas).

(4.1) Results of Convergent Plate Boundaries

Mountains, Volcanoes, Island Arcs, and Earthquakes.

(4.1) Subduction

When one tectonic plate slides beneath the other.

(4.1) Transform Plate Boundary

Plates are sliding against each other, creating a fault. This is also known as a "Strike-Slip Plate Boundary." It happens when the rough edges on each plate get stuck. As the plates keep slipping, pressure builds up, but the edges stay stuck. When the stress becomes too great, the fault suddenly releases, and the plates slip past each other, unleashing energy that shakes the lithosphere and triggers an earthquake.

(4.1) Formation of Earthquakes from Transform Plate Boundary

As the plates keep slipping, pressure builds up, but the edges stay stuck. When the stress becomes too great, the fault suddenly releases, and the plates slip past each other, unleashing energy that shakes the lithosphere and triggers an earthquake.

(4.1) Result of Transform Plate Boundary

Earthquakes.

(4.1) Ring of Fire

Pattern of volcanoes around the Pacific Tectonic Plate, caused by convergent zones, which result in volcanic activity.

(4.1) Transform Faults

Likely location of Earthquakes.

(4.1) Hotspots

Areas of especially hot magma rising up to the Lithosphere (ex. Hawaii)

(4.1) Application of Plate Boundary Maps

A map of plate boundaries, such as a map of the ring of fire, ca be used to predict the locations of volcanoes, earthquakes, and island arcs, by examining previous earthquake activity, frequency of volcanoes, and the locaton of transform faults.

(4.2-4) Soil

Mix of geologic (rock) and organic (living) components.

(4.2-4.3) Arrange the main particles of soil from largest to smallest.

Sand, Silt, Clay

(4.2) Humus

Main organic part of soil (broken down organic matter)

(4.2) Nutrients in Soil

Ammonium, Phosphates, and Nitrates

(4.2) Role of Soil in Ecosystems - Plants

Anchors roots, provide water, shelter, and growth nutrients (N, K, Mg)

(4.2) Role of Soil in Ecosystems - Water

Filters rainwater/water runoff naturally via pore spaces and plant spaces, effectively trapping pollutants, resulting in clean, filtered water entering groundwater/aquifers

THINK: Pollutants in Water ➡️ Soil Pores ➡️ Pollutants Filtered by Soil Pores ➡️ Clean Water ➡️ Aquifer/Groundwater Reserves

(4.2) Role of Soil in Ecosystems - Nutrient Recycling

Home to decomposers (who break down organic matter—think: leaves, dead animals, dead plants), returning nutrients to soil.

(4.2) Role of Soil in Ecosystems - Habitat

Soil provides habitat for living organisms (ex. earthworms, fungi, bacteria, moles, slugs)

(4.2) Weathering

Breakdown of rocks via physical or chemical means.

(4.2) Physical Weathering

Mechanical breakdown of rocks and minerals via tree roots, wind/rain

(4.2) Chemical Weathering

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

Ex. Acid Precipitation - Responsible for rapid degradation of old statues, gravestones, and other limestone and marble structures.

(4.2) Acid Precipitation

Precipitation high in sulfuric acid and nitric acid from reactions between water vapor and sulfur and nitrogen oxides in the atmosphere.

In the context of Chemical Weathering: Responsible for rapid degradation of old statues, gravestones, and other limestone and marble structures.

(4.2) Erosion

Movement of weathered, broken-down rock fragments (sediment, soil, rock, and other particles) from a landscape or ecosystem to other landscapes or ecosystems, where they are deposited onto different soil types (in comparison to their original location).

- Can be done by water—streams, glaciers, wind

- Can be done by human causes—poor land use practices (ex. deforestation, overgrazing, unmanaged construction activity, road building)

(4.2) Timeline for Soil Formation

Hundreds to thousands of years for soil to form soil results from physical/chemical weathering of rocks and gradual accumulation of organic matter from the ecosystem

(4.2) How can we determine specific characteristics of soil?

Can determine specific properties of soil knowing...

· Parent material type

· Amount of time been forming

· Associated biotic/abiotic components

(4.2) Soil Formation - From Below

Weathering of parent material produces smaller, and smaller fragments, making up the geological/inorganic aspect of the soil

- parent material

- sand, silt, clay

- minerals

(4.2) Parent Material

Rock material from which the inorganic components of soil are derived

(4.2) Soil Formation - From Above

Breakdown of organic matter affects humus and the amount of soil. Erosion also has a significant influenece, leading to the deposition of soil particles from other areas, adding to soil.

(4.2) Influencing Factors for Soil Properties

1) Parent Material

2) Climate

3) Topography

4) Organisms

5) Time

(4.2-4.3) Influencing Factor for Soil Properties - Parent Material

Determines soil pH level (acidic or alkaline) and nutrient context

Ex. Soil w/ Calcium Carbonate parent material will contain abundant supply of Calcium, high, alkaline pH, may support high agricultural productivity.

(4.2-4.3) Influencing Factor for Soil Properties - Climate

Higher temperatures have a direct correlation with the rate of decomposition of organic matter. The rate of decomposition of organic matter has a direct correlation with the rate of soil formation. More precipitation has a direct correlation with more weathering, eroision, and deposition.

THINK:

⬆️ Temperature = ⬆️ Rate of Decomposition of Organic Matter

⬆️ Rate of Decomposition of Organic Matter = ⬆️ Rate of Soil Formation

⬆️ Precipitation = ⬆️ Weathering, ⬆️ Erosion, ⬆️ Deposition

(4.2-4.3) Influencing Factor for Soil Properties - Topography

Steeper slopes result in more soil erosion, a direct correlation. Likewise, level ground results in more deposition of rocks, forming soil.

THINK:

⬆️ Steepness of Slope = ⬆️ Erosion

⬇️ Steepness of Slope = ⬆️ deposition

(4.2-4.3) Influencing Factor for Soil Properties - Time

Amount of time soil has developed for.

Older soils are more fertile since they have had more organic matter over time.

(4.2) Horizon

A horizontal layer in soil defined by distinctive physical features (ex. texture, color)

(4.2) Order of Horizons

O,

A,

E*,

B,

C

*E is not common.

(4.2) O Horizon (Organic)

Surface layer composed of organic matter (ex., leaves, needles, twigs, animal bodies, all in various stages of decomposition), serves as a moisture trapper for the soil (limits water from evaporating). Most common in forest soils, found in some grasslands.

(4.2) A Horizon (Topsoil)

Zone of mixed organic matter and minerals—layer of humus + minerals.

⬆️ (Most) Biological Activity = ⬆️ Nutrients

(4.2) E Horizon (Eluviation--not common)

Zone of leaching/eluviation—water; always above B horizon

(4.2) B Horizon (Subsoil)

Zone of accumulation of mineral material with very little organic matter, minerals and nutrients (if nutrients are in the soil)

(4.2) C Horzion (Weathered Rock)

Least weathered soil horizon, most similar to parent material

(4.2) How does soil filter groundwater?

The soil filters rainwater/water runoff naturally via its pore spaces and plant roots, in which pollutants are trapped, which results in clean water entering the groundwater and aquifers.

(4.2) Soil Degradation

Loss of some or all of a soil's ability to support plant growth

(4.2) Soil Degradation: Loss of Topsoil

Tilling (turning soil for agriculture) and loss of vegetation disturb soil, making it easy for erosion by wind and rain (dries out soil, removes nutrients, and soil organisms that recycle nutrients).

(4.2) Soil Degradation: Compaction

Compression of Soil reduces moisture-holding ability, harder for air/water to get in. Dry soil erodes more easily, decreasing plant growth and root structure.

(4.2) Soil Degradation: Nutrient Depletion

Repeatedly growing crops on the same soil removes key nutrients over time, decreasing the ability to grow future crops.

(4.3) Pores

Empty spaces between particles. They allow air and water to enter the soil easily.

(4.3) Permeability of Soil

How quickly soil drains depends on the texture of the soil.. It is a rate.

Ex. Since sand is a larger particle and has bigger pores, water is able to drain quickly compared to clay, a smaller particle, having small pores.

(4.3) Porosity of Soil

The amount of pore space a soil has--what is the difficulty for air and water to enter? How hard is it? How easy is it?

(4.3) Relationship between Soil Permeability & Soil Porosity

Particle size controls everything:

• Sand (large particles): lower porosity, very high permeability, low water-holding (drains fast).

• Clay (tiny particles): high porosity, very low permeability, high water-holding (retains water).

• Loam: balanced mix → good infiltration + retention.

Rule: High porosity ≠ high permeability (clay proves this). Smaller pores hold water more tightly, so fine-textured soils retain more water.

(4.3) Water Holding Capacity

How well water is retained/held by soil, contributes to land productivity and soil fertility. Varies with soil types.

(4.3) Relationship between Porosity, Permeability, and Water Holding Capacity

Inverse relationship.

⬆️ Porosity = ⬇️ Water Holding Capacity

⬆️ Permeability = ⬇️ Water Holding Capacity

(4.3) Collective Impact on Soil Fertility--Permeability, Porosity, and Water Holding Capacity

A balance is needed between permeability and water holding capacity, with a certain level of porosity.

Ex. (1) Too Sandy ➡️ drains water too quickly for roots ➡️ plant dries out

Ex. (2) Soil ≥ 20% clay ➡️ plants become waterlogged, roots are deperived of oxygen (suffocation)

(4.3) Soil Fertility

Ability of soil to support plant growth. 2 critical factors: nutrients & water holding capacity

(4.3) Soil Fertility--Factors that INCREASE Soil Nutrients

⬆️ Organic Matter (releases nutrients)

⬆️ Humus (holds/releases nutrients)

⬆️ Decomposer activities (recycles nutrients)

⬆️ Clay (able to attract positive nutrients since negatively charged)

⬆️ Bases (Calcium Carbonate—Limestone)

(4.3) Soil Fertility--Factors that DECREASE Soil Nutrients

⬇️ Acids attract positively charged nutrients

⬇️ Excessive rain/irrigation leeches' nutrients

⬇️ Excessive farming of same crops depletes nutrients (plants use up nutrients)

⬇️ Topsoil erosion

(4.3) Soil Fertility--Factors that INCREASE Water Holding Capacity

⬆️ Aerated Soil

⬆️ Compost/Humus/Organic Matter

⬆️ Clay Content

⬆️ Root structure (notably natives)

(4.3) Soil Fertility--Factors that DECREASE Water Holding Capacity

In a nutshell, Soil Degradation.

(4.3) Chemical Properties of Soil: Cation Exchange Capacity (CEC)

Ability of a particular soil to absorb and release cations

(4.3) Chemical Properties of Soil: Impact of Acids & Bases (pH)

Soil acids ➡️ detrimental to plant nutrition (and growth)

Soil bases ➡️ promote plant growth

Base Saturation ➡️ Proportion of Soil bases to Soil Acids, expressed as a percentage.

(4.3) Soil Test: Texture

How to Test: Let soil settle in a jar of water, measure 3 layers that form (sand, silt, clay)

What we know from it: % of sand, silt, and clay—porosity and permeability of soil

(4.3) Soil Test: Permeability

How to test: Time for water to drain through column of soil

What we know from it: How easily water drains through soil. If too quickly (high), soil dries out. If too slow (low, roots don't get water or drown. Balance is optimal

(4.3) Soil Test: pH

How to test: pH strip for H+ ion concentration

What we know from it: Acidity or Alkaline soil is.

⬆️ Soil Acidity = ⬇️ Soil Nutrient Availability

(4.3) Soil Test: Color

How to test: Compare with a soil book color chart.

What we know from it: ⬆️ Darker Color = ⬆️ Humus;

⬆️ Humus = ⬆️ Nutrients & Moisture

(4.3) Nutrient Level

How to test: Measure ammonium, nitrate, or phosphate levels

What we know from it:

⬆️ Nutrient Levels = ⬆️ Plant Growth; Low level may indicate acidic soil, nutrient depletion.

(4.3) How to classify soil with the Soil Texture Triangle

1) Start at % sand on the bottom axis; draw the guide line.

2) From % clay (left axis), draw its guide line.

3) Where they meet, read the texture class (loam, sandy loam, clay loam, etc.).

Ex. 40% sand, 40% silt, 20% clay → loam.

(4.4) Relative Abundance of Each Gas in the Atmosphere

Nitrogen: ~78%,

Argon: ~0.93%,

Carbon Dioxide: ~0.04%,

Oxygen: ~21%,

Water Vapor: ~0-4%

(4.4) Relative Abundance of Nitrogen (N) in Earth's Atmosphere

Nitrogen: ~78%

Mostly in form of N₂, unusable to plants without being fixed by bacteria/other action.

(4.4) Relative Abundance of Argon (Ar) in Earth's Atmosphere

Argon: ~0.93%

Noble gas, nonreactive

(4.4) Relative Abundance of Carbon Dioxide (CO₂) in Earth's Atmosphere

Carbon Dioxide: ~0.04%

Most critical Greenhouse Gas—leading to Global Warming Traps heat on Earth, increasing the temperature of the atmosphere. Removed from the atmosphere via Photosynthesis.

(4.4) Relative Abundance of Oxygen (O) in Earth's Atmosphere

Oxygen: ~21%

Produced by photosynthesis, required for cellular respiration

(4.4) Relative Abundance of Water Vapor in Earth's Atmosphere

Water Vapor: ~0-4%

- Varies by region and environmental conditions

- Acts as a temporary Greenhouse Gas, but less drastic/concerning than Carbon Dioxide

- Quickly cycles through the atmosphere

(4.4) Order of Atmospheric Layers (from Earth to Space)

1) Troposphere

2) Stratosphere

3) Mesosphere

4) Thermosphere

5) Exosphere

(4.4) Atmospheric Layer: Troposphere

The first layer of the atmosphere, most dense due to pressure of the other atmospheric layers. Weather happens here. It is very cold since as temperature decreases with altitude since air expands as pressure drops

THINK: First, cold!

(4.4) Impact of Ozone in the Troposphere

Harmful.

Humans ➡️ acts as a respiratory irritant

Plants ➡️ damages plant stomata

Environment ➡️ forms smog

(4.4) Atmospheric Layer: Stratosphere

The second layer of the atmosphere, less dense compared to Troposphere, but incredibly warm, due to UV rays warming top layer of stratosphere as they are blocked by the Ozone Layer.

THINK: "S" for 2nd, warm!

(4.4) Atmospheric Layer: Mesosphere

The third or "middle" layer of the atmosphere, it less dense compared to previous layers, but incredibly cold, being the coldest place on Earth as few molecules are able to absorb UV heat at this density.

THINK: Meso or "M" for Middle/3rd, COLD!!!

(4.4) Atmospheric Layer: Thermosphere

The hottest layer of the atmosphere, less dense compared to previous layers, but the hottest place on Earth due to high amounts of solar radiation.

THINK: Therm for HOTTEST TEMP/Heat, HOT!!!

(4.4) Atmospheric Layer: Exosphere

The outermost layer of the atmosphere, less dense compared to previous layers.

(4.4) Trends in Atmospheric Temperature Gradient

The temperature cycles between cold and hot as we go through the layers of the atmosphere. If you start on land and climb up a mountain, it gets colder as you go up.

(1) Troposphere - Cold

(2) Stratosphere - Hot

(3) Mesosphere - COLD

(4) Thermosphere - HOT

(5) Exosphere - HOT

(4.7) Insolation

Incoming amount of solar radiation (the energy from the sun's rays) reaching an area, measured in Watts/m2. It is the primary source of Earth's energy and is dependent on season and latitude.

AKA Incoming Solar Radiation

CED Definition (Paraphrased, from CollegeBoard): "Incoming solar radiation, also known as insolation, is the Earth's primary source of energy, and its amount depends on the season and latitude."

(4.7) Latitude

Distance from Equator, measured in degrees, increase in latitude as you move away

(4.7) Significance of the Equator in the context of how the Sun's energy affects Earth's surface

Higher insolation than higher latitudes Sunlight strikes Earth at a perpendicular angle due to the curvature of the Earth

(4.7) MAKE A CLAIM (ACCURATE) & JUSTIFY YOUR REASONING, responding to the following prompt: Does the intensity of isolation across the planet's surface occurs evenly. Why or why not?

Your claim must be of factual accuracy.

No, it does not occur evenly--resulting in uneven warming patterns. 3 primary causes cause this uneven warming pattern:

(a) Variation in the Angle at which the Sun's rays strike Earth, impacting the amount of atmosphere the incoming solar radiation passes through.

(b) Amount of Surface Area over which the Sun's rays are distributed.

(c) Albedo--some areas of Earth reflect more solar energy than others.

(4.7) Intensity of Insolation: Variation in the Angle at which the Sun's rays strike Earth

At the equator, sunlight hits the Earth at a direct angle, traveling a relatively short distance through the atmosphere to reach the surface in the tropics.

In mid-latitude and polar regions, the Sun strikes at a more slanted angle, traveling a longer distance through the atmosphere to reach the surface near the poles.

Keep in mind that solar energy is lost as it passes through the atmosphere, so more solar energy reaches the equator than the mid-latitude and polar regions.

THINK:

As the sun's rays hit Earth closer to a 90 angle, there will be more isolation due to there being less atmospheric distance to travel through, resulting in intensive concentration and distribution. As the sun's rays hit Earth at a greater angle than 90, there will be decreased insolation due to an increase in atmospheric distance, resulting in less intensive concentration and distribution.

(4.7) Intensity of Insolation: Variation in Surface Area amount over which Sun's rays are distributed

(a) Solar Energy is LOST as it passes through the Atmosphere, directly affecting insolation intensity.

(b) The Equator ➡️ Intensive Insolation due to perpendicular angle of insolation and less atmospheric distance to travel through

(b) Mid-Latitude/Polar Regions ➡️ Less intensive insolation (compared to Equator) due to oblique/obtuse angle of insolation and increased atmospheric distance to travel through.

(4.7) Intensity of Insolation: Albedo

The percentage of insolation (incoming sunlight) reflected from a surface, directly affecting temperature.

Albedo and Temperature have an INVERSE relationship.

⬆️ Albedo = ⬇️ Temperature

THINK:

(a) Surfaces with ⬆️ Albedo REFLECT MORE insolation/light and ABSORB LESS insolation/heat, DECREASING Temperature.

(b) The INVERSE is also true.

(4.7) Albedo: Urban Heat Island Phenomenon

Urban areas are hotter than the surrounding rural areas due to the low Albedo of blacktop/black surfaces, meaning they absorb a lot of the incoming solar radiation, causing them to release a lot of infrared radiation.