Evaluate Solutions for Ecosystem Impacts - Biology

What is eutrophication?

Nutrient enrichment causing algal blooms and oxygen depletion. Excess nutrients promote algae growth, which depletes oxygen when it decomposes.
What is carbon sequestration?

Long-term storage of carbon in biomass, soils, oceans, or geologic formations. Removes $CO_2$ from atmosphere and stores it to reduce climate change.
What is the main environmental drawback of relying heavily on landfills?

Methane production and leachate that can contaminate groundwater. Organic waste decomposes anaerobically, producing greenhouse gases and toxic leachate.
Which option best reduces $CO_2$ emissions: improving energy efficiency or increasing coal use?

Improving energy efficiency. Efficiency reduces energy demand while coal increases emissions.
Which forestry strategy best maintains biodiversity while allowing harvest?

Selective logging with sustainable yield management. Removes only some trees while maintaining forest structure and biodiversity.
Which choice best reduces habitat fragmentation from a new road: wildlife overpasses or more lanes?

Wildlife overpasses (or underpasses). Allows animals to cross roads safely, reconnecting fragmented habitats.
Which strategy best reduces runoff and flooding in urban areas?

Green infrastructure (permeable pavement, rain gardens, green roofs). Mimics natural water cycle by allowing infiltration instead of surface runoff.
What is the main conservation advantage of protecting an ecosystem "hotspot"?

High species endemism and high threat make protection highly efficient. Protects maximum biodiversity per conservation dollar by focusing on threatened areas.
What is the most direct ecological advantage of wetlands for water quality?

Filter pollutants and trap sediments and excess nutrients. Natural filtration system that improves water quality through biological processes.
Which agricultural practice most directly improves soil structure and reduces erosion?

No-till or reduced-till farming. Maintains soil structure and organic matter while reducing disturbance.
What is the main difference between point-source and nonpoint-source pollution?

Point: single identifiable source; nonpoint: diffuse sources. Point sources are easier to regulate and control than diffuse nonpoint sources.
Which solution best reduces bycatch in commercial fishing?

Selective gear (for example, turtle excluder devices). Allows target species to be caught while non-target species escape.
What is integrated pest management (IPM)?

Using monitoring and multiple controls to minimize pesticide use. Combines biological, cultural, and chemical methods to reduce pesticide dependence.
Which policy tool sets a maximum total emission and allows trading of permits?

Cap-and-trade. Creates market incentives to reduce emissions while maintaining economic flexibility.
What is biodiversity (in a way relevant to evaluating ecosystem solutions)?

Variety of genes, species, and ecosystems in an area. Includes genetic diversity within species, species diversity, and ecosystem diversity.
What is the primary ecological benefit of riparian buffer strips along streams?

Reduce runoff, erosion, and nutrient loading into waterways. Vegetation along streams filters pollutants and stabilizes banks against erosion.
Which policy tool directly puts a price per unit of greenhouse gas emissions?

Carbon tax. Directly charges polluters for emissions, incentivizing reduction through price.
Which waste strategy best matches the term "source reduction"?

Preventing waste generation before it occurs. Most effective approach by eliminating waste at the source rather than managing it later.
Which solution most directly prevents introduction of aquatic invasive species by ships?

Treat or exchange ballast water before discharge. Ballast water carries organisms between ports, spreading invasive species globally.
Which option is the best solution to reduce eutrophication from farms: more fertilizer or buffer strips?

Buffer strips. Buffer strips filter nutrients before they reach water bodies.
What is an invasive species (as used in evaluating ecosystem management)?

Non-native species that spreads and causes ecological or economic harm. Outcompetes native species and disrupts natural ecosystem balance and function.
Which option best reduces urban heat and runoff: planting trees or replacing parks with asphalt?

Planting trees. Trees provide shade, absorb water, and cool air; asphalt increases heat and runoff.
Which farming practice most directly reduces soil erosion on slopes?

Contour plowing. Following natural slope contours slows water flow and reduces soil loss.
What is biomagnification?

Increase in toxin concentration at higher trophic levels. Occurs because toxins accumulate in fatty tissues and concentrate up food chains.
Which energy strategy most directly reduces $CO_2$ emissions from electricity generation?

Replacing fossil fuels with low-carbon renewables (wind, solar, hydro). Renewables produce minimal greenhouse gases compared to fossil fuel combustion.
What is the main ecological purpose of a marine protected area (MPA)?

Limit extraction to allow populations and habitats to recover. Provides safe areas where species can reproduce without fishing pressure.
Which option best reduces soil loss: planting cover crops or leaving soil bare after harvest?

Planting cover crops. Cover crops protect soil from erosion between main crop seasons.
Which water-treatment approach most directly reduces nutrient pollution from sewage?

Tertiary treatment that removes nitrates and phosphates. Advanced treatment specifically targets nutrients that cause eutrophication.
Which metric best indicates improved water quality after reducing organic pollution?

Higher dissolved oxygen (DO). Higher oxygen levels indicate reduced organic pollution and healthier aquatic ecosystems.
Which land-use approach concentrates development to protect surrounding habitat?

Smart growth (compact, higher-density development). Reduces urban sprawl and preserves natural areas around developed zones.
Identify the best method to reduce nonpoint pollution: riparian buffers or taller smokestacks.

Riparian buffers. Buffers filter diffuse pollution while smokestacks don't address nonpoint sources.
What is sustainable yield in resource management?

Harvest rate that does not exceed natural replacement rate. Balances human use with natural regeneration to maintain long-term productivity.
What is the most direct ecological meaning of sustainability?

Meeting needs without reducing future ecosystem function and resources. Ensures resources remain available for future generations while protecting ecosystem health.
Which approach best reduces negative impacts of mining after extraction ends?

Land reclamation (recontouring, replacing soil, replanting natives). Restores disturbed land to productive use and prevents ongoing environmental damage.
What does the precautionary principle recommend when ecological risk is uncertain?

Avoid actions with potential severe harm even without full proof. Better to be safe than sorry when ecosystem damage could be irreversible.
Identify the better solution for overfishing: catch limits or increasing fishing fleet size.

Catch limits. Limits prevent depletion while fleet expansion worsens overfishing.
What is the main purpose of an environmental impact assessment (EIA)?

Predict and mitigate environmental harm before a project proceeds. Identifies potential problems early so they can be avoided or minimized.
What is habitat fragmentation?

Breaking habitat into smaller, isolated patches. Reduces habitat size and connectivity, limiting species movement and gene flow.
Which option best addresses biomagnifying toxins: banning persistent pollutants or adding more pesticides?

Banning persistent pollutants. Bans prevent accumulation while more pesticides worsen biomagnification.
Which solution best protects biodiversity long-term: creating connected reserves or isolated small parks?

Creating connected reserves. Connectivity allows gene flow and migration; isolation leads to local extinctions.
What is the main purpose of a wildlife corridor in fragmented habitats?

Increase gene flow and movement between habitat patches. Connects isolated habitats, allowing animals to migrate and breed between patches.
Which option best restores a degraded stream: replant native riparian vegetation or channelize the stream?

Replant native riparian vegetation. Native vegetation filters pollution and provides habitat; channeling increases erosion.
What is the core claim of the "tragedy of the commons" in resource use?

Shared resources are overused without regulation or cooperation. Individual users act in self-interest, depleting shared resources for everyone.
Which choice best reduces invasive spread: cleaning boats between lakes or releasing aquarium pets?

Cleaning boats between lakes. Cleaning removes organisms from boats; releasing pets introduces invasives.
What is the definition of an ecosystem service in environmental biology?

Benefits humans obtain from ecosystems (provisioning, regulating, cultural, supporting). These are the four main categories of benefits ecosystems provide to humans.
What is a keystone species?

Species with disproportionately large effects on community structure. Their removal causes major ecosystem changes due to their critical ecological role.
What is the primary benefit of reforestation for ecosystem impacts?

Restores habitat and increases carbon sequestration. Trees absorb $CO_2$ from atmosphere and provide wildlife habitat.
What is the primary goal of biological control for invasive species?

Use natural enemies to reduce invasive populations with minimal chemicals. Uses predators, parasites, or diseases specific to the invasive species.
What is the primary goal of restoration ecology?

Rebuild degraded ecosystems toward native structure and function. Returns damaged ecosystems to their original state and ecological processes.

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