APES final study guide

What type of energy is nonrenewable?

Nuclear

Which energy source uses heat from the Earth?

Geothermal energy

What type of energy uses photovoltaic (PV) cells to generate electricity?

Solar energy

List one advantage and one disadvantage of solar energy:

Advantage: It is a renewable, clean resource that produces no greenhouse gases during operation.

Disadvantage: It has high initial installation costs and is intermittent (dependent on sunlight/weather).

Draw or label the 3 types of survivorship curves (A–C):

K-selected species = Type I (late loss)

Dandelions (r-selected) = Type III (early loss)

Lizards (constant mortality) = Type II (constant loss)

Define:

Tragedy of the Commons: The depletion or degradation of a shared, renewable resource by individuals acting in their own self-interest contrary to the common good.

Range of Tolerance: The limits of environmental conditions (e.g., temperature, pH) an organism can endure and survive.

Label the stream diagram:

BOD spike (occurs immediately after the discharge)

DO minimum (occurs slightly downstream from the BOD spike)

Point of pollution discharge (Most likely discharge location is directly above the BOD spike)

Match the irrigation method with its key trait:

Drip: Delivers water directly to plant roots through perforated pipes (most efficient, ~90% efficiency).

Furrow: Water flows in trenches alongside crops (least efficient, high evaporation/runoff).

Spray: Sprays water over crops like artificial rain (moderate efficiency).

What does eutrophication mean and how can it be caused by humans?

Eutrophication is an over-enrichment of water with nutrients (like nitrogen and phosphorus), causing explosive algae blooms. Humans cause it via agricultural runoff (fertilizers) and wastewater discharge.

What does increased urban runoff do to natural water flow?

It increases the volume and velocity of water, leading to flash flooding, soil erosion, and disrupted natural water pathways.

How can cities reduce runoff and promote infiltration?

By using permeable pavements, green roofs, rain gardens, and preserving urban wetlands.

Albedo effect & positive Arctic feedback loop

Albedo is the measure of how much light a surface reflects. Ice has high albedo (reflects sunlight). Melting Arctic ice exposes darker ocean water (low albedo), which absorbs more heat, melting even more ice in a positive feedback loop.

Main cause of modern extinction:

Habitat loss and fragmentation (largely due to human expansion, deforestation, and agriculture).

Endocrine disruptors and invasive species:

Endocrine disruptor: Chemicals that interfere with the hormone systems of animals, causing developmental, reproductive, and neurological issues.

Invasive species: Non-native organisms that spread widely in a new area, outcompeting native species for resources and disrupting the ecosystem.

Habitat fragmentation and loss:

Habitat loss: The complete destruction of a natural habitat area.

Habitat fragmentation: The splitting of large habitats into smaller, isolated patches, which reduces biodiversity and genetic flow.

Atmospheric layers & weather:

Troposphere: Closest to Earth; contains most of the weather and greenhouse gases. (This is the layer that has the most weather).

Stratosphere: Contains the protective ozone layer.

Mesosphere: Where meteors burn up.

Thermosphere: Auroras occur here; very hot.

Which layer has the most weather?

Troposphere

Earth’s tilt and seasons:

Seasons occur because Earth is tilted on its axis (23.5°) as it orbits the sun. If the tilt changed to 20°, seasons would become less extreme (warmer winters, cooler summers).

Doubling time:

DT = 70 / 0.49% = 143 years

Definitions:

Crude Birth Rate (CBR): The total number of live births per \(1,000\) population in a given year.

LD50: The lethal dose required to kill \(50\%\) of a test population.

CFCs and global action:

Chlorofluorocarbons (CFCs) are chemicals historically used in refrigerants and aerosols that deplete the ozone layer. The Montreal Protocol is the global treaty that successfully phased them out.

CAFO:

Concentrated Animal Feeding Operation.

IPM strategies:

Mechanical: Hand-picking pests, using physical barriers (netting), or tilling.

Biological: Introducing natural predators (e.g., ladybugs) or parasites to control pest populations.

Bycatch

The unintentional catching of non-target marine animals (like dolphins, turtles, or seabirds) during commercial fishing.

Addressing overfishing:

Establishing catch quotas (limits), creating marine protected areas (MPAs), and banning destructive fishing practices (like bottom trawling).

Macroinvertebrates as indicators:

They are sensitive to pollution, stay in one location (cannot easily escape), and have varying pollution tolerances, making them reliable indicators of long-term water health.

Most abundant gas:

Nitrogen ( approx. 78%)

Greenhouse gas sources

Carbon dioxide: Burning fossil fuels (coal, oil, gas) and deforestation.

Methane: Livestock (enteric fermentation), landfills, and natural gas extraction.

Nitrous oxide: Agricultural fertilizers, soil bacteria, and fossil fuel combustion.

Montreal Protocol

An international treaty designed to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances like CFCs.

Clean Air Act

Authorized the EPA to regulate and limit emissions of six major criteria pollutants (such as SO2, NOx, CO, PM, lead, and ozone), significantly reducing smog and acid rain.

Trophic cascade

A phenomenon where changing the top predator population indirectly affects the entire food web. In Yellowstone, the reintroduction of wolves reduced the elk population, which allowed willow and aspen trees to recover, benefiting beavers, birds, and fish.

Carrying capacity & elk

Maximum population size an environment can support indefinitely. After wolves were introduced, they kept the elk population in check, preventing them from overgrazing and allowing the elk population to stabilize at a sustainable carrying capacity.

Terrace farming

Creating stepped, flat terraces on hilly terrain to slow down water runoff. This prevents soil erosion and retains water for crops.

Negative impacts of CAFOs

Concentrated animal waste can pollute nearby waterways (causing eutrophication), emit greenhouse gases (methane), and contribute to antibiotic resistance due to mass medication of the livestock.

Positive vs. negative feedback loops

Positive feedback loop: Amplifies or increases a change (drives the system further away from its original state).

Negative feedback loop: Dampens or reverses a change (brings the system back to a stable state).

Positive Arctic feedback loop

Melting permafrost releases methane, which is a potent greenhouse gas. This causes more warming, which melts even more permafrost.

Primary vs. secondary succession

Primary succession: Starts from bare rock with no soil (e.g., after a volcanic eruption or retreating glacier).

Secondary succession: Starts with existing soil after a disturbance (e.g., a forest fire or cleared agricultural field)

Role of pioneer species

They break down bare rock into soil, creating the foundation necessary for larger, more complex plants to grow.

Lower LD50 value

Indicates that a smaller amount of the substance is required to be lethal, meaning the substance is highly toxic.

Reducing urban runoff effects

(1) Installing green roofs or rain gardens to absorb water. (2) Using permeable pavement to allow water to soak into the ground instead of running off.