CES Ecological Risk Assessment & Biodiversity 1 — Questions and Answers
Question 1: What is an ecological risk assessment?
- A process that evaluates the likelihood of adverse ecological effects from exposure to environmental stressors (Correct answer)
- A census of all animal species in a region
- A financial analysis of environmental cleanup costs
- A review of building permits for environmental compliance
Correct answer: A process that evaluates the likelihood of adverse ecological effects from exposure to environmental stressors
Ecological risk assessment evaluates the probability that adverse ecological effects (such as species decline or habitat loss) may occur as a result of exposure to environmental stressors including chemical contaminants.
Question 2: What is a biological indicator (bioindicator) species?
- An organism whose presence, abundance, or condition reflects environmental quality (Correct answer)
- Any species that is commercially harvested
- A species that has been genetically modified for research
- The most common species in any ecosystem
Correct answer: An organism whose presence, abundance, or condition reflects environmental quality
Bioindicator species are sensitive to environmental changes and their health, population, or behavior provides information about the condition of their ecosystem, such as macroinvertebrates indicating stream water quality.
Question 3: What is the Endangered Species Act (ESA) designed to protect?
- Species at risk of extinction and the ecosystems on which they depend (Correct answer)
- All animal species regardless of population status
- Only mammal species in national parks
- Agricultural crops from pest species
Correct answer: Species at risk of extinction and the ecosystems on which they depend
The ESA (1973) provides for the conservation of species listed as endangered or threatened, including the protection of critical habitat necessary for their survival and recovery.
Question 4: What is bioaccumulation in environmental science?
- The gradual accumulation of a substance in an organism over time because the organism absorbs it faster than it can eliminate it (Correct answer)
- The rapid reproduction of bacteria in contaminated water
- The natural decomposition of organic matter in soil
- The seasonal migration of species to new habitats
Correct answer: The gradual accumulation of a substance in an organism over time because the organism absorbs it faster than it can eliminate it
Bioaccumulation occurs when organisms absorb contaminants (like mercury or DDT) from water, food, or sediment faster than they can metabolize or excrete them, leading to increasing tissue concentrations over time.
Question 5: What is the difference between an endangered species and a threatened species under the ESA?
- An endangered species is in immediate danger of extinction; a threatened species is likely to become endangered in the foreseeable future (Correct answer)
- There is no legal difference between the two classifications
- Threatened species have larger populations than endangered species in all cases
- Endangered species are found only in the US while threatened species are found globally
Correct answer: An endangered species is in immediate danger of extinction; a threatened species is likely to become endangered in the foreseeable future
Under the ESA, 'endangered' means a species is in danger of extinction throughout all or a significant portion of its range, while 'threatened' means it is likely to become endangered within the foreseeable future.
Question 6: What is biomagnification and how does it differ from bioaccumulation?
- Biomagnification is the increasing concentration of a substance at each successive trophic level in a food chain, while bioaccumulation occurs within a single organism (Correct answer)
- They are the same process described by different terms
- Biomagnification only affects aquatic ecosystems
- Bioaccumulation occurs in food chains while biomagnification occurs in individual organisms
Correct answer: Biomagnification is the increasing concentration of a substance at each successive trophic level in a food chain, while bioaccumulation occurs within a single organism
Bioaccumulation occurs within an individual organism. Biomagnification describes how contaminant concentrations increase at each higher trophic level in a food chain, with top predators having the highest concentrations.
CES Ecological Risk Assessment & Biodiversity 1
What is an ecological risk assessment?