Download Environmental Science – Biodiversity Ultimate Exam and more Exams Technology in PDF only on Docsity!
Ultimate Exam
Question 1. Which metric incorporates both species richness and the relative abundance of each species? A) Species‑area curve B) Shannon‑Wiener Index C) Simpson’s Dominance Index D) Margalef’s Index Answer: B Explanation: The Shannon‑Wiener Index (H′) accounts for the number of species (richness) and how evenly individuals are distributed among those species (evenness). Question 2. A population that has lost many alleles due to a severe reduction in size is experiencing which phenomenon? A) Gene flow B) Genetic drift C) Inbreeding depression D) Bottleneck effect Answer: D Explanation: A bottleneck reduces genetic variation because only a few individuals contribute to the next generation’s gene pool. Question 3. Which of the following best describes a biodiversity hotspot? A) Any area with more than 100 species of birds B) A region with high species richness and at least 1,500 endemic vascular plants, with > 70 % of original habitat lost C) A marine zone with coral reefs D) A protected national park covering > 10 000 km² Answer: B Explanation: Hotspots are defined by high endemism (≥1,500 endemic vascular plants) and severe habitat loss (> 70 %).
Ultimate Exam
Question 4. In the theory of island biogeography, which factor most directly increases the equilibrium number of species on an island? A) Larger island size B) Greater distance from the mainland C) Higher elevation D) Lower precipitation Answer: A Explanation: Larger islands support more individuals and habitats, reducing extinction rates and raising equilibrium species richness. Question 5. Which evolutionary mechanism introduces new genetic variation into a population? A) Natural selection B) Genetic drift C) Mutation D) Gene flow Answer: C Explanation: Mutations create novel alleles, providing raw material for evolution. Question 6. Sympatric speciation most commonly occurs as a result of: A) Geographic isolation B. Allopatric divergence C) Polyploidy or ecological niche differentiation within the same area D) Founder effect Answer: C Explanation: Sympatric speciation arises without physical barriers, often via polyploidy in plants or resource partitioning.
Ultimate Exam
A) Accumulation of pollutants in an organism’s tissues over its lifetime B) Increase in contaminant concentration at higher trophic levels C) Transfer of nutrients from soil to plants D) Dilution of toxins in large water bodies Answer: B Explanation: Biomagnification describes the progressive increase in contaminant concentration as one moves up the food chain. Question 11. Ocean acidification primarily reduces the availability of which ion, affecting calcifying organisms? A) Nitrate (NO₃⁻) B) Sulfate (SO₄²⁻) C) Calcium (Ca²⁺) D) Carbonate (CO₃²⁻) Answer: D Explanation: Increased CO₂ lowers seawater pH, shifting carbonate equilibrium and reducing carbonate ions needed for shells. Question 12. Which conservation approach focuses on protecting species in their natural habitats? A) Ex‑situ conservation B) In‑situ conservation C) Captive breeding D) Gene banking Answer: B Explanation: In‑situ conservation maintains species within their ecosystems, such as national parks or reserves. Question 13. The SLOSS debate concerns whether it is better to establish: A) Single large reserves or several small reserves
Ultimate Exam
B) Marine protected areas versus terrestrial reserves C) Strict protection versus sustainable use zones D) Community‑based versus government‑managed parks Answer: A Explanation: “SLOSS” stands for Single Large Or Several Small; the debate evaluates which configuration maximizes biodiversity preservation. Question 14. The IUCN Red List category “Critically Endangered” indicates a species is: A) Extinct in the wild B) Facing an extremely high risk of extinction in the immediate future C) Vulnerable to habitat loss but not yet declining D) Data deficient Answer: B Explanation: “Critically Endangered” is the highest risk category before “Extinct in the Wild” and “Extinct”. Question 15. Which of the following is a keystone species in many North American forest ecosystems? A) White‑tailed deer B) Gray wolf C) Eastern chipmunk D) Red‑eyed tree frog Answer: B Explanation: Gray wolves regulate ungulate populations, influencing vegetation and overall ecosystem structure. Question 16. A trophic cascade driven primarily by the removal of top predators is an example of: A) Bottom‑up control B) Top‑down control
Ultimate Exam
C) Clean Water Act D) National Environmental Policy Act (NEPA) Answer: A Explanation: The ESA obligates agencies to identify and protect critical habitat essential for the conservation of listed species. Question 20. CITES primarily regulates: A) Habitat destruction within protected areas B) International trade of endangered flora and fauna C) Domestic hunting quotas D) Pollution emissions from factories Answer: B Explanation: The Convention on International Trade in Endangered Species controls cross‑border commerce of threatened species. Question 21. Which index gives more weight to the most abundant species in a community? A) Shannon‑Wiener Index B) Simpson’s Diversity Index (1‑D) C) Pielou’s Evenness Index D) Berger‑Parker Dominance Index Answer: D Explanation: The Berger‑Parker index is the proportion of the most abundant species, emphasizing dominance. Question 22. An example of a cultural ecosystem service is: A) Soil nitrogen fixation B) Recreational hiking in a national park C) Pollination of crops
Ultimate Exam
D) Water filtration by wetlands Answer: B Explanation: Cultural services include non‑material benefits such as recreation, spiritual value, and aesthetic enjoyment. Question 23. The “founder effect” is best described as: A) Random loss of alleles in a small isolated population B) Increased genetic variation due to mutation C) Reduced genetic diversity when a new population is established by a few individuals D) Gene flow from a large source population to a small one Answer: C Explanation: When few individuals colonize a new area, the resulting gene pool is a subset of the original, often reducing variability. Question 24. Which of the following processes is most directly responsible for the formation of new species through geographic isolation? A) Gene flow B) Allopatric speciation C) Sympatric speciation D) Horizontal gene transfer Answer: B Explanation: Allopatric speciation occurs when physical barriers split populations, leading to independent evolutionary trajectories. Question 25. Plate tectonics contributed to modern biodiversity patterns primarily by: A) Increasing atmospheric oxygen levels B) Creating new habitats and isolating populations through continental drift C. Accelerating mutation rates in marine organisms D. Reducing solar radiation reaching the Earth’s surface
Ultimate Exam
Answer: B Explanation: The loss of carbon‑sequestering forests amplifies CO₂ concentrations, leading to warming that can cause more forest die‑off—a positive feedback. Question 29. A species that occurs in a very restricted geographic area and is highly sensitive to environmental change is termed: A) Cosmopolitan species B. Endemic species C) Invasive species D) Keystone species Answer: B Explanation: Endemic species are confined to a limited region, making them vulnerable to habitat alteration. Question 30. Which of the following best describes “phenological shift” caused by climate change? A. A change in the genetic composition of a population over generations B. Altered timing of biological events such as flowering or migration C. Increased mutation rates due to higher UV radiation D. Expansion of species’ geographic ranges toward the poles Answer: B Explanation: Phenology is the timing of life‑cycle events; climate warming can cause earlier flowering, breeding, or migration. Question 31. The primary reason that small, isolated habitat patches support fewer species than larger ones is: A. Higher rates of immigration B. Lower edge effects C. Reduced carrying capacity and higher extinction probability D. Greater genetic variation within patches
Ultimate Exam
Answer: C Explanation: Small patches hold fewer individuals, making populations more vulnerable to stochastic extinction. Question 32. Which of the following is NOT a direct driver of the current sixth mass extinction? A. Habitat loss B. Overexploitation C. Natural climate cycles unrelated to human activity D. Invasive species Answer: C Explanation: While natural climate cycles occur, the accelerated loss of species is driven primarily by anthropogenic pressures. Question 33. The term “ecosystem resilience” refers to: A. The total number of species in an ecosystem B. The capacity of an ecosystem to absorb disturbances and retain its basic structure and function C. The amount of energy flowing through a trophic level D. The speed at which primary production occurs Answer: B Explanation: Resilience is the ability to withstand shocks (e.g., fire, drought) without shifting to an alternative state. Question 34. Which of the following is a primary method for ex‑situ conservation of plant genetic resources? A. Establishing wildlife corridors B. Seed banking in controlled storage facilities C. Reforestation of degraded lands D. Implementing community‑based forest management Answer: B
Ultimate Exam
Explanation: Edges create more light and varied microhabitats, favoring generalists and species that exploit disturbed conditions. Question 38. Which of the following is an example of an ecosystem service that supports “nutrient cycling”? A. Pollination of fruit trees B. Decomposition of leaf litter by microbes C. Recreational fishing D. Carbon sequestration in mangroves Answer: B Explanation: Decomposers break down organic matter, releasing nutrients back into the soil for plant uptake. Question 39. The primary purpose of “habitat corridors” in conservation planning is to: A. Increase the total protected area by merging small reserves B. Facilitate movement of organisms between isolated patches, reducing genetic isolation C. Create new habitats for invasive species to occupy D. Provide recreational trails for ecotourism Answer: B Explanation: Corridors link fragmented habitats, allowing dispersal, gene flow, and recolonization. Question 40. The “Red Queen hypothesis” in evolutionary biology suggests that: A. Species evolve primarily through random drift B. Organisms must constantly adapt to keep pace with co‑evolving species and environmental change C. Speciation occurs only after long periods of stasis D. Evolution stops once a species reaches an optimal fitness peak Answer: B Explanation: The Red Queen metaphor describes an arms race where continual adaptation is required for survival.
Ultimate Exam
Question 41. Which of the following best exemplifies a “mutualistic” interaction? A. A lion killing a zebra B. Mycorrhizal fungi supplying phosphorus to plant roots while receiving carbohydrates C. A parasitic wasp laying eggs inside a caterpillar D. A beetle feeding on dead wood Answer: B Explanation: Mutualism provides reciprocal benefits to both partners. Question 42. Which of the following is a direct effect of climate‑induced range shifts for a high‑altitude species? A. Increased genetic diversity due to mixing with lowland populations B. Potential loss of habitat as suitable climatic zones shrink upward C. Higher reproductive rates in the new range D. Reduced competition from other species Answer: B Explanation: As temperatures rise, alpine habitats move upward, often disappearing on mountaintops, threatening resident species. Question 43. The “Allee effect” describes a situation where: A. Population growth rate decreases at low densities because individuals have difficulty finding mates or cooperative partners B. High population density leads to increased disease transmission C. Genetic drift dominates in very large populations D. Mutation rates rise with population size Answer: A Explanation: The Allee effect emphasizes that very small populations may suffer reduced fitness and growth.
Ultimate Exam
Question 47. The “species‑area relationship” is mathematically expressed as S = cA^z. In this equation, what does the exponent “z” represent? A. The total number of species on Earth B. The rate at which species richness increases with area C. The amount of carbon stored per unit area D. The average lifespan of species in the area Answer: B Explanation: The exponent z (typically 0.15–0.35) quantifies how steeply species number rises as area expands. Question 48. Which of the following is an example of a “bioindicator” species? A. Apex predator that controls herbivore populations B. Amphibians that are sensitive to water quality changes C. A fast‑growing invasive grass D. A deep‑sea fish with low reproductive rates Answer: B Explanation: Amphibians have permeable skin and complex life cycles, making them responsive to environmental contaminants. Question 49. In the context of the “tragedy of the commons,” which management strategy is most likely to prevent overexploitation of a shared fishery? A. Open access with no regulation B. Assigning individual transferable quotas (ITQs) C. Encouraging increased fishing effort to maximize short‑term yield D. Leaving the resource unmonitored Answer: B Explanation: ITQs allocate specific catch rights, aligning incentives for sustainable harvest. Question 50. Which of the following best illustrates “bottom‑up control” in an ecosystem?
Ultimate Exam
A. Wolves reducing elk numbers, allowing willow regeneration B. Nutrient enrichment leading to increased primary production, which then supports higher trophic levels C. Invasive species outcompeting natives at the top of the food chain D. Predator removal causing mesopredator release Answer: B Explanation: Bottom‑up control originates from resource availability (e.g., nutrients) influencing the whole food web. Question 51. The primary driver of “marine acidification” is: A. Increased riverine runoff of nitrates B. Absorption of atmospheric CO₂ by seawater C. Higher solar radiation heating surface waters D. Decreased salinity due to melting ice Answer: B Explanation: CO₂ dissolves in seawater, forming carbonic acid and lowering pH. Question 52. Which of the following is a direct consequence of “overfishing” on marine ecosystems? A. Increase in average fish size B. Trophic downgrading, leading to algal overgrowth due to loss of top predators C. Higher biodiversity of reef fish D. Reduced oceanic carbon uptake Answer: B Explanation: Removing large predators can cause cascading effects, such as sea‑urchin proliferation and kelp decline. Question 53. An example of “genetic rescue” is:
Ultimate Exam
B. A reduction in the overall geographic area occupied by a species, often at the edges of its range C. Shift of phenological events earlier in the year D. Increased genetic variation within populations Answer: B Explanation: As suitable habitats shrink, species may lose peripheral populations, leading to a smaller overall range. Question 57. Which of the following is a primary reason that “large carnivores” are often used as umbrella species in conservation planning? A. They have low public appeal B. Protecting their large territories also safeguards many other species and habitats within those areas C. They are easy to breed in captivity D. They have short generation times Answer: B Explanation: Umbrella species have extensive habitat needs; conserving them confers protection to co‑occurring organisms. Question 58. The “precautionary principle” in environmental policy suggests that: A. Actions should be taken only after conclusive scientific proof of harm B. Lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation C. Economic development always outweighs biodiversity concerns D. Conservation funding should be allocated after cost‑benefit analysis Answer: B Explanation: The principle advocates proactive protection when there is plausible risk, even if data are incomplete. Question 59. Which of the following best explains why islands typically have fewer species than mainland areas of comparable size?
Ultimate Exam
A. Higher rates of mutation on islands B. Limited immigration and higher extinction rates due to isolation C. Greater habitat heterogeneity on islands D. More intense competition among island species Answer: B Explanation: Isolation reduces colonization, and small populations are more vulnerable to stochastic extinction. Question 60. The “Carbon‑Nitrogen (C:N) ratio” in soil is an indicator of: A. Soil temperature B. The balance between carbon and nitrogen availability, influencing decomposition rates C. Soil pH only D. Water holding capacity Answer: B Explanation: A high C:N ratio slows microbial decomposition, affecting nutrient cycling. Question 61. Which of the following is an example of a “keystone indicator” species? A. A common grass that dominates a prairie B. A rare amphibian whose decline signals broader ecosystem health problems C. A commercially important fish species D. A ubiquitous insect that feeds on decaying matter Answer: B Explanation: Indicator species reflect environmental conditions; a keystone indicator has outsized importance for detecting ecosystem change. Question 62. The “Lotka‑Volterra” equations are used to model: A. Photosynthetic efficiency in plants B. Predator‑prey dynamics and competition between species
