Earth's Resources and Sustainability Assessment practice KEY

Section 1: Non-Renewable & Renewable Resources

1. What is sustainability?

Sustainability is the practice of meeting the needs of the present generation without compromising the ability of future generations to1 meet their own needs. It involves balancing environmental protection, social equity, and economic viability.

2. What are minerals? Are they considered renewable resources?

Minerals are naturally occurring, solid material we use. They are not considered renewable resources. They form over geological timescales, which are vastly longer than human timescales of consumption. Once extracted and used, they are effectively gone from their original form and location.They are not evenly distributed throughout the Earth’s crust. Gold and cobalt are examples.

3. In your own words, what is the difference between a renewable resource and a non-renewable resource?

A renewable resource is one that can be replenished naturally over a relatively short period of time, often within a human lifetime or a few decades. Examples include solar energy and wind. A non-renewable resource, on the other hand, exists in finite quantities and forms over extremely long geological periods. Once these resources are used up, they are not replaced on a human timescale. Examples include fossil fuels (coal, oil, natural gas) and minerals.

4. Describe the three types of mining we examined in class.

The three common types of mining are:

Open pit mining: Use of a large open pit to expose ore deposits at the surface. Commonly used for copper, gold, and iron ore. It scars the landscape but is pretty cheap.

Vertical Shaft mining (or subsurface mining): This method involves digging tunnels and shafts deep into the Earth to reach mineral deposits that are too far below the surface for surface mining. It's common for extracting coal, gold, and diamonds. Expensive and dangerous but limits destruction to surface land.

Mountain top removal: This technique is literally takes the top off of a mountain to access an ore. Very disruptive to surface habitats but it is quick and cheap. Commonly used in coal mining

5. What is mining reclamation? What is involved with it? Why is it important?

Mining reclamation is the process of restoring land that has been disturbed by mining activities to its original or a more environmentally beneficial state. It's a crucial part of responsible mining.

What's involved: It typically includes:

• Reshaping the land: Contouring the disturbed land to blend with the surrounding topography and prevent erosion.

• Replacing topsoil: Spreading saved topsoil over the reshaped land to provide a suitable medium for plant growth.

• Revegetation: Planting native grasses, shrubs, and trees to stabilize the soil, prevent erosion, and restore habitats.

• Water management: Treating acidic mine drainage and managing runoff to protect water quality.

• Monitoring: Ongoing assessment to ensure the restored ecosystem is thriving. Why it's important: Reclamation is vital to mitigate the environmental impacts of mining, such as habitat destruction, soil erosion, water pollution, and visual blight. It helps restore ecological functions, biodiversity, and the aesthetic value of the land.

6. Describe how a thermal power plant works.

A thermal power plant generates electricity by converting heat energy into electrical energy. Here's a general overview:

1. Fuel combustion: A fuel (like coal, natural gas, oil, or even biomass) is burned in a furnace to heat water.

2. Steam production: The intense heat turns the water into high-pressure steam.

3. Turbine rotation: The high-pressure steam is directed to spin a large turbine.

4. Generator activation: The spinning turbine is connected to a generator, which converts the mechanical energy of the turbine into electrical energy.

^7.     What is the role of water in a thermal power plant?

Water plays a critical role in a thermal power plant. It acts as the working fluid that is heated to produce steam. This steam then drives the turbines to generate electricity. After passing through the turbines, the steam is condensed back into liquid water using cooling water, allowing it to be reused in the system. Water is also often used for cooling purposes to dissipate excess heat.

8. How does wind power work?

Wind power harnesses the kinetic energy of wind to generate electricity. Here's how it works:

1. Wind turns blades: Wind causes the large blades of a wind turbine to rotate.

2. Rotor spins: The blades are connected to a rotor.

3. Generator activation: The spinning rotor turns a shaft, which is connected to a generator.

4. Electricity generation: The generator converts the mechanical energy of the spinning shaft into electrical energy.

9.  How does a hydroelectric dam generate electricity?

A hydroelectric dam generates electricity by converting the kinetic energy of moving water into electrical energy. Here's the process:

1. Water reservoir: A dam creates a reservoir of water upstream, raising the water level.

2. Controlled release: Gates in the dam are opened, allowing water to flow downwards through large pipes called penstocks.

3. Turbine rotation: The force of the flowing water spins large turbines.

4. Generator activation: The turbines are connected to generators, which convert the rotational energy into electricity.

10. What is used to power a nuclear power plant?

A nuclear power plant is powered by nuclear fission which is the splitting of an atom., Specifically the fission of radioactive isotopes, most commonly uranium. In a nuclear reactor, the nucleus of a uranium atom is split, releasing a tremendous amount of heat energy. This heat is then used to boil water, create steam, and drive turbines to generate electricity, similar to a thermal power plant.

Section 2: Population Dynamics

11. What is population ecology?

Population ecology is the study of how populations of organisms interact with their environment, focusing on factors that affect population size, density, distribution, age structure, and changes in these over time. It examines birth rates, death rates, immigration, emigration, and how these factors influence population growth and decline.

12. What is population density?

Population density is a measure of how many individuals of a particular species live within a given unit of area. It's typically expressed as individuals per square kilometer (km²), individuals per square mile (mi²), or individuals per cubic meter (m³).

13. A country has a population density of 11 people per km². The population of the country is 7,381,023 people. What is this country’s land area in km²?

To find the land area, you divide the total population by the population density:

Land Area = Population / Population Density

Land Area = 7,381,023 people / 11 people/km²

Land Area = 671,002.09 km² (approximately)

14. Laos has an area of 230,800 km² and a population density of 34 people per km². What is the population of Laos?

To find the population, you multiply the area by the population density:

Population = Area × Population Density

Population = 230,800 km² × 34 people/km²

Population = 7,847,200 people

15. A rectangular nature preserve has a length of 11 km. Its width is 5 km. Within the preserve live 82 lizards. What is the population density of lizards in this preserve?

First, calculate the area of the preserve:

Area = Length × Width = 11 km × 5 km = 55 km²

Then, calculate the population density:

Population Density = Number of Individuals / Area

Population Density = 82 lizards / 55 km²

Population Density = 1.49 lizards/km² (approximately)

16. What are immigration and emigration?

• Immigration refers to the movement of individuals into a population from another area. (Think "I" for "into")

• Emigration refers to the movement of individuals out of a population to another area. (Think "E" for "exit")

17. What is the difference between a density-dependent and density-independent limiting factor? Give one example of both.

• A density-dependent limiting factor is a factor whose impact on a population's growth rate is related to the population's density. As the population becomes denser, the effect of the factor becomes stronger.

  • Example: Competition for resources (food, water, space), predation, disease, 

A density-independent limiting factor is a factor whose impact on a population's growth rate is not related to the population's density. These factors affect populations regardless of their size.

• Example: Natural disasters (floods, wildfires, earthquakes), extreme weather events (droughts, blizzards), pollution, habitat destruction by human activities.

18. Compare and contrast logistic and exponential population growth.

• Exponential growth: Occurs when a population has unlimited resources, no predators, and no disease. The population grows at an accelerating rate, resulting in a J-shaped curve on a graph. It's often seen in new populations or when a population is recovering from a major decline. 

• Logistic growth: Describes more realistic population growth, where environmental resistance eventually limits growth. The population initially grows exponentially but then slows down as it approaches the carrying capacity of its environment. This results in an S-shaped (sigmoidal) curve on a graph.

• Comparison: Both start with a period of rapid growth.

• Contrast: Exponential growth continues indefinitely, while logistic growth eventually levels off due to limiting factors.

19. What does logistic growth theoretically stabilize at?

Logistic growth theoretically stabilizes at the carrying capacity (K) of the environment.

20. What is carrying capacity?

Carrying capacity (K) is the maximum population size of a particular species that a given environment can sustainably support indefinitely, given the available resources (food, water, shelter) and space, without degrading the environment.

21. What is an r-strategist? What is a K-strategist?

These are two contrasting reproductive strategies:

• An r-strategist (or Type III) focuses on producing a large number of offspring with little parental care. They typically have short lifespans, mature quickly, and are well-suited for unstable or unpredictable environments.

  • Examples: Insects, bacteria, weeds, many fish, frogs.

• A K-strategist (or Type I) focuses on producing a few, high-quality offspring with significant parental investment and care. They typically have long lifespans, mature slowly, and are well-suited for stable, predictable environments where competition for resources is high.

  • Examples: Humans, elephants, whales, penguins.

22. An organism lays 8,000 eggs. After 1 year, 82 individuals of the original clutch of eggs are alive. What survival strategy does this organism exhibit?

This organism exhibits an r-strategist (Type III) survival strategy. The large number of eggs laid and the very low survival rate indicate a strategy of producing many offspring with little investment in each, relying on sheer numbers for some to survive.

23. Pickerel eat sunfish. Draw or describe a model of their population graphs if the sunfish start with a high population. (Hint: predator/prey).

This is a classic predator-prey relationship, which often shows cyclical fluctuations.

Description:

• If sunfish (prey) start with a high population, the pickerel (predator) population will likely increase a short time later as there is abundant food.

• As the pickerel population increases, they will consume more sunfish, causing the sunfish population to decline.

• As the sunfish population declines, the pickerel will have less food, leading to a decline in the pickerel population (due to starvation or reduced reproduction).

• With fewer pickerel, the sunfish population will then start to recover and increase again, restarting the cycle. This creates a classic oscillating pattern where the predator's population graph lags slightly behind the prey's graph.

24. What are population pyramids? What can they show us?

Population pyramids (or age-sex pyramids) are graphical representations that show the distribution of various age groups and the sex ratio within a population. They typically divide the population into five-year age cohorts, with males on one side and females on the other.

What they can show us:

• Age structure: The proportion of young, working-age, and elderly individuals.

• Sex ratio: The number of males compared to females in each age group.

• Growth trends: Whether a population is rapidly growing (wide base), stable (more rectangular), or declining (narrow base).

• Historical events: "Bulges" or "dents" in the pyramid can reflect events like baby booms, wars, or epidemics.

• Dependency ratio: The proportion of dependents (too young or too old to work) to the working-age population.

• Life expectancy: The shape of the top of the pyramid can give clues about life expectancy.

25. A population pyramid for a region displays that the majority of the population is over the age of 45. Absent other factors, do you think this population is growing rapidly, shrinking, or growing modestly? Why?

If the majority of the population is over the age of 45, this population is likely shrinking.

Why: A population pyramid with a wider top (older age groups) and a narrower base (younger age groups) indicates a low birth rate and/or a high death rate among younger cohorts, leading to fewer individuals entering the reproductive ages and replacing the older generations. This structure suggests that the population is not producing enough new individuals to sustain its current size, leading to a decline.

Section 3: Succession & Biodiversity

26. What is primary succession? Describe its steps.

Primary succession is the ecological process of community development that occurs in an area that is initially completely devoid of life and soil. It's a very slow process because soil must first be formed.

Steps:

1. Pioneer Species Colonization: Lichens and mosses (pioneer species) colonize newly exposed rock (e.g., after a volcanic eruption or glacial retreat). They begin to break down the rock and, along with decaying organic matter, start to form primitive soil.

2. Early Successional Plants: As thin soil develops, hardy plants with shallow roots like grasses and small ferns can grow. Their decomposition further enriches the soil.

3. Mid-Successional Plants: Shrubs and small trees begin to establish themselves, shading out the earlier colonizers. The soil continues to deepen and become more fertile.

4. Climax Community Development: Over very long periods, larger, more complex trees and other plant species that are well-adapted to the local climate and soil conditions become dominant, forming a stable, mature ecosystem known as a climax community.

27. What are pioneer species? How would you describe them?

Pioneer species are the first species to colonize a barren or disturbed environment during primary succession.

Description: They are typically:

• Hardy and tolerant: Able to survive in harsh conditions with little or no soil, extreme temperatures, and limited nutrients.

• Fast-growing and reproductive: They often have high dispersal rates (e.g., wind-blown spores) and reproduce quickly to establish themselves.

• Facilitators: They play a crucial role in preparing the environment for subsequent species by breaking down rock, adding organic matter, and creating rudimentary soil.

• Examples: Lichens, mosses, some types of algae, and certain hardy grasses.

28. What type of event has to happen for primary succession to occur?

Primary succession occurs after events that create new land surfaces completely devoid of soil and existing life. Examples include:

• Volcanic eruptions that form new islands or lava flows.

• Retreating glaciers exposing bare rock.

29. What are lichens?

Lichens are fascinating composite organisms formed from a symbiotic relationship between a fungus and an alga (or cyanobacterium). The fungus provides structure and protection, while the alga performs photosynthesis, producing food for both. They are incredibly hardy and are often pioneer species in primary succession, as they can grow on bare rock and slowly break it down to form soil.

30. What is secondary succession? When does it happen?

Secondary succession is the ecological process of community development that occurs in an area where an existing community has been disturbed or removed, but the soil or substrate remains intact.

When it happens: It occurs after disturbances such as:

• Wildfires (that don't destroy all soil).

• Logging or deforestation.

• Abandoned agricultural fields.

• Floods or hurricanes (that leave soil).

• Any event that removes existing vegetation but leaves the soil foundation.

31. What is a climax community?

A climax community is the stable, mature, and self-sustaining ecological community that results from ecological succession. It represents the final stage of succession, where the species composition remains relatively stable over long periods, in equilibrium with the prevailing environmental conditions. The community is dominated by species that are well-adapted to the local climate and soil, and it has reached its maximum potential for biodiversity and biomass under those conditions.

32.

A woodland area was surveyed, and the following numbers of individuals were found from four different bird species.

What is the species richness of this area?

Four. There are four different species.

Species richness is the number of different species present in a given area.

Calculate the relative abundance of each species.

(Relative abundance = number of individuals of one species ÷ total number of individuals)

Based on the example table above:

Total number of individuals = 42 + 28 + 56 + 42 = 168

• Relative abundance of Chickadees: 42 / 168 = 0.25 (or 25%)

• Relative abundance of Blue Jays: 28 / 168 = 0.17 (or 17%)

• Relative abundance of Cardinals: 56 / 168 = 0.33 (or 33%)

• Relative abundance of Woodpecker: 42 / 168 = 0.25 (or 25%)