Exam 1 (Geol 470)

Understand how the population is increasing and what factors contribute to this Trend

• improved living conditions such as sanitation, farming, overall safety, air, water

• reduced mortality→ increased birth rate

Know how to calculate exponential population growth and/or growth rates

N=Noe^kt

N=population

No=initial population

K= growth rate (in decimal form so divide by 100)

t= time elapsed (years)

Be able to describe the consequences of population growth as related to the Easter Island case study 

• Originally fertile, volcanic solid (high nutrients), abundant trees

• population increase

• over population diminishes resources, logging subject soil enhanced erosion, and lowering of agricultural productivity

Understand the concept of sustainability and be able to provide the two major tenets of sustainability. 

• development that ensures future generations will have equal access to the resources of Earth

• developments that are economically viable, do not harm the environment, and are socially just

What are the major renewable and non-renewable energy sources and understand how these two energy sources are distinguished 

Renewable resources: replenishing continuously

• solar

• wind

• geothermal

• water

• biomass

Non- renewable: limits/bounds in these resources

• coal

• oil

• natural gas

• nuclear energy

Understand the spatial distribution of common geological phenomena (i.e., volcanoes, earthquakes, deposition…) 

• Volcanoes: occur at convergent boundaries due to subduction zones, rift valleys, hot spots, & mid ocean ridges

• Earthquakes: 90% of them happen at plate boundaries, fault lines, continental collisions zones/ occur in brittle zones where temperature is lower

• Deposition: surface process, driven by gravity, wind, water & ice. Occurs in river deltas, estuaries, ocean trenches, continental margins, desert basins, & glacial valleys

What are the common soil horizons?

O-loose and partly decayed organic matter

A- mineral matter mixed with some humus (partially degraded organic matter)

E- light-colored mineral particles (zone of eluviation & leaching)

B- accumulation of clay transported from above

C- partially altered parent material

R- unweathered parent material

What are the different soil characteristics?

Texture: relative proportion of grain size

Structure: morphology of soil sediment aggregates

Grain size/ grain size distribution:

• coarse (gravel, sand)

• fine (silt, clay, organic material)

• sorting (well- sorted, poorly- sorted)

• grading (well- graded, uniformly- graded, gap graded)

Plasticity: How moisture dictates soil behavior; more water means less load capacity.

Strength/Cohesion: The ability of soil to stick together and resist deformation via attraction, surface tension, or cementation.

Sensitivity: How much strength a soil loses due to disturbances (coarse soils are less sensitive).

Compressibility: How much a soil's volume decreases under structural stress.

Permeability: How easily fluids move through soil (high in coarse, well-sorted soils).

Corrosion Potential: Chemical degradation caused by incompatibility with materials.

Scale: Mineral buildup from fluids, typically linked to piping issues.

Shrink-Swell Potential: Volumetric changes driven by clay hydration and dehydration cycles.

Ease of Excavation: The effort needed to move soil (ranging from common to blasting).

Erodibility: How easily erosive forces can remove the soil.

What are the different approaches to soil pollution mitigation?

Bioremediation: use of organisms to degrade pollutants

Natural attenuation: use of native organisms

bioaugmentation: introduction of non-native organisms

Biostimulation: addition of nutrients, oxygen, & water to promote microbial growth

how does vegetation can prevent soil loss?

• intercepting rainfall

• anchoring soil particles with roots

• slowing surface water runoff

how do you calculate soil loss using the Universal Soil Loss Equation?

A= 2.24 x R x K x LS x C x P

R- rainfall & runoff factor

K- soil erodibility factor

LS- slope length gradient factor

C- cropping practice/ management practice factor

P- support practice factor

Aridisols

desert soils, enriched in soluble material

Mollisols

semiarid or subhumid, organic rich A horizon (prairie soils)

Vertisols

wet & dry seasons, rich in expanding clays

Ultisols/ oxisols

tropical & subtropical, highly leached (flushing soil), insoluble components are left behind

• rich in iron & Al oxides

Entisols

young soils, no stable surface to develop low degree of chemical weathering, soil horizons developed (loose sand)

Inceptisols

Arctic→ tropic, quickly developed, soil horizons difficult to differentiate

Place the soil types on the map:

• entisols

• vertisols

• inceptisols

• aridisols

• mollisols

• oxisols/ ultisols

1. Mollisols

2. oxisols/ ultisols

3. aridisols

4. vertisols

5. entisols

6. inceptisols

Define invasive species and provide examples

Non- native organisms that harm environment

• lionfish: pet release → invasive to east coast

• Zudzu: used to prevent soil erosion but grows too fast→ invasive to SE USA

• Japanese beetle: imported accidentally in iris bulbs→ invasive to all N America

• Zebra Mussels: accidental introduction in ballast water of cargo ships→ invasive in great lakes

what characteristics lead to high or low biodiversity

Increase biodiversity

• presence of diverse habitat with many potential niches

• relatively constant environment (temp, precipitation, & elevation)

• highly productive zones/ areas- organic rich soil

• presence of harsh/ limited environments may have specialized species that increase diversity

Decrease biodiversity

• presence of pervasive extreme environments like hot springs

• extreme disturbance or repeated disturbances

• transformation of the land (deforestation, urbanization)

• environmental stress (pollution)

• introduction of aggressive exotic species

• species over exploitation

How do we define processes that ensure sustained proper function of an 

ecosystem? 

Ecosystem Processes (or Ecological Functions). These processes maintain ecosystem sustainability and ecological resilience. They are driven by four core pillars:

1. Energy Flow (Primary productivity & biomass)

2. Nutrient Cycling (Carbon, nitrogen, water cycles)

3. Regulatory Mechanisms (Homeostasis & biological regulation)

4. Structural Support (Soil formation & retention)

How do organisms cope with low-nutrient environments?

• Symbiotic Relationships: Partnering with microbes (e.g., mycorrhizal fungi for phosphorus, nitrogen-fixing bacteria in root nodules).

• Morphological Shifts: Developing a high root-to-shoot ratio or specialized cluster roots to expand the underground search area.

• Physiological Adaptations: Evolving carnivory (e.g., pitcher plants) to bypass soil limitations or practicing nutrient resorption (recycling elements from leaves before they drop).

• Metabolic Suppression: Entering dormancy or torpor to conserve energy when nutrients are scarce.