AP Environmental Science Practice Quiz: Human Impacts on Ecosystems

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 15 questions to check your progress.

Question 1 of 15

According to the provided text, oceanic dead zones are primarily characterized by which of the following conditions?

A)Abnormally high water temperaturesB)Low levels of dissolved oxygenC)High concentrations of heavy metalsD)An overabundance of coral species

All Questions (15)

According to the provided text, oceanic dead zones are primarily characterized by which of the following conditions?

A) Abnormally high water temperatures

B) Low levels of dissolved oxygen

C) High concentrations of heavy metals

D) An overabundance of coral species

Correct Answer: B

The text explicitly states that 'Oceanic dead zones are areas of low oxygen caused by increased nutrient pollution.'

Increased sediment in waterways from sources like construction or agriculture can negatively impact aquatic ecosystems primarily by...

A) Increasing the water's salinity

B) Converting elemental mercury into methylmercury

C) Reducing light infiltration for aquatic producers

D) Providing a food source for invasive species

Correct Answer: C

The content specifies that 'Increased sediment in waterways can reduce light infiltration (affecting producers) and disrupt habitats.' This directly impacts photosynthesis.

What is the role of bacteria in the process of mercury pollution in aquatic environments?

A) They break down mercury into a non-toxic substance.

B) They are the primary organisms that suffer from mercury poisoning.

C) They convert elemental mercury into a more toxic form.

D) They filter mercury out of the water, cleaning the ecosystem.

Correct Answer: C

The text states that when elemental mercury enters aquatic environments, 'bacteria convert it to highly toxic methylmercury.'

A fish species has an optimal temperature range of 15-20°C. Due to thermal pollution, the water temperature is consistently 25°C. Based on the concept of range of tolerance, what is the most likely outcome for this fish population?

A) The fish will experience rapid population growth due to a faster metabolism.

B) The fish will show signs of physiological stress and have reduced reproduction.

C) The fish will quickly adapt and evolve a new optimal temperature range.

D) The fish will be unaffected as the change is only 5°C above the optimum.

Correct Answer: B

The content explains that outside the optimum range of tolerance for a pollutant (or stressor like temperature), organisms 'may experience physiological stress, limited growth, reduced reproduction, and death.'

Which of the following describes a direct impact of oil spills on marine wildlife, as mentioned in the text?

A) The oil increases nutrient levels, leading to dead zones.

B) The oil coats the feathers of birds, reducing their ability to fly and stay warm.

C) The oil changes the pH of the water, dissolving the shells of mollusks.

D) The oil is mistaken for food and consumed by primary producers.

Correct Answer: B

The text explicitly states that 'oil coats wildlife feathers/fur,' which impairs their physical functions like insulation and buoyancy.

According to the provided information, which of the following is a significant human-caused threat to coral reefs?

A) Decreasing ocean salinity

B) Introduction of invasive kelp

C) Sediment runoff from coastal development

D) An increase in the population of reef sharks

Correct Answer: C

The text lists three factors causing damage to coral reefs: 'increasing ocean temperature, sediment runoff, and destructive fishing practices.' Sediment runoff is one of these listed factors.

How can heavy metals from industrial processes pose a threat to human health?

A) By causing oceanic dead zones

B) By contaminating groundwater that is used for drinking

C) By coating the fur of mammals

D) By reducing light infiltration in rivers

Correct Answer: B

The content states that 'Heavy metals used for industry can reach the groundwater, impacting the drinking water supply.'

After an oil spill, which group of organisms is at risk due to the sinking of oil components?

A) Phytoplankton living in the surface waters

B) Seabirds that dive for fish

C) Bottom-dwelling organisms like crabs and worms

D) Terrestrial plants on nearby coastlines

Correct Answer: C

The text specifies that after an oil spill, some 'components sink, killing bottom-dwelling organisms.'

The primary chemical pollutants in an oil spill that cause harm to organisms are known as...

A) Nutrients

B) Heavy metals

C) Methylmercury

D) Hydrocarbons

Correct Answer: D

The provided text directly states that 'Oil spills in marine waters cause organisms to die from hydrocarbons.'

A coastal development project involves clearing a large area of forest, leading to significant soil erosion. Which two impacts on the adjacent marine ecosystem are most likely to occur based on the provided text?

A) Increased heavy metal contamination and the formation of a dead zone

B) An oil spill and the conversion of mercury to methylmercury

C) Reduced light infiltration from sediment and damage to coral reefs

D) Destructive fishing practices and an increase in ocean temperature

Correct Answer: C

Soil erosion leads to sediment runoff. The text links increased sediment to reduced light infiltration and also lists sediment runoff as a cause of damage to coral reefs. This question requires synthesizing two separate points from the text.

Which of the following best describes the cause-and-effect relationship that creates an oceanic dead zone?

A) Increased sediment → Reduced light → Low oxygen

B) Increased nutrient pollution → Algal bloom and decomposition → Low oxygen

C) Increased ocean temperature → Coral bleaching → Low oxygen

D) Oil spill → Hydrocarbon release → Low oxygen

Correct Answer: B

The text directly links dead zones to nutrient pollution. While not detailing the full process, increased nutrient pollution is the stated cause for the effect of low oxygen.

If a pollutant is introduced into an aquatic environment, an organism is most likely to experience limited growth and physiological stress when the concentration of the pollutant is...

A) within its optimum range of tolerance.

B) completely absent from the environment.

C) at a level just outside its optimum range of tolerance.

D) at the lowest detectable level.

Correct Answer: C

The text states that 'Outside the optimum range, they may experience physiological stress, limited growth, reduced reproduction, and death.' This implies that these negative effects begin to occur just beyond the ideal conditions.

The transformation of elemental mercury into the more dangerous methylmercury is a biological process carried out by...

A) Aquatic plants

B) Sunlight

C) Fish

D) Bacteria

Correct Answer: D

The source material specifies that 'bacteria convert it to highly toxic methylmercury,' identifying the specific type of organism responsible for this transformation.

Which of the following lists three distinct stressors on aquatic ecosystems that are mentioned in the provided text?

A) Acid rain, plastic pollution, and overfishing

B) Heavy metals, increased sediment, and oil spills

C) Invasive species, noise pollution, and habitat fragmentation

D) Ozone depletion, global warming, and agricultural pesticides

Correct Answer: B

The provided text explicitly mentions the impacts of heavy metals, increased sediment in waterways, and oil spills. The other options list valid environmental stressors, but they are not included in the source content.

Destructive fishing practices, increasing ocean temperatures, and sediment runoff are all cited as major causes for the decline of which ecosystem?

A) Mangrove forests

B) Oceanic dead zones

C) Coral reefs

D) Freshwater wetlands

Correct Answer: C

The text directly states that 'Coral reefs have been suffering damage due to factors including increasing ocean temperature, sediment runoff, and destructive fishing practices.'