A. Coevolutionary arms races between parasites and hosts.
B. Commensal relationships where one species is neutral.
C. Succession in climax communities.
D. The transition from a pioneer species to a keystone species.
8. Lichens are composed of a fungus and a photosynthetic partner (algae or cyanobacteria). If the fungus provides structure and mineral absorption while the algae provides carbohydrates, this partnership is best described as:
A. Symbiotic Mutualism
B. Ectoparasitism
C. Saprophytism
D. Allelopathy
9. In a specific ocean ecosystem, remora fish attach themselves to sharks. The remoras gain transportation and scraps of food, while the sharks are largely unaffected. This dynamic represents:
A. Mutualism
B. Commensalism
C. Niche Overlap
D. Competitive Exclusion
10. Which process is responsible for the largest annual flux of carbon from the atmosphere into the biosphere?
A. Ocean acidification and carbonate precipitation.
B. Terrestrial and marine photosynthesis.
C. The weathering of silicate rocks.
D. Anaerobic respiration in wetlands.
11. Anthropogenic activities have altered the carbon cycle primarily by:
A. Decreasing the rate of cellular respiration in plants.
B. Reintroducing sequestered carbon from long-term geological sinks into the atmosphere.
C. Increasing the residence time of carbon in the biomass of herbivores.
D. Reducing the total amount of carbon available on Earth.
12. How does deforestation contribute to global warming beyond the immediate loss of carbon sequestration?
A. By increasing the albedo effect of the land surface.
B. Through the release of methane during the decomposition of cleared organic matter.
C. By reducing evapotranspiration, which alters regional precipitation and temperature.
D. By increasing the rate of nitrogen fixation in the soil.
13. The "Biological Pump" refers to:
A. The movement of carbon from the surface ocean to the deep sea via organic matter fallout.
B. The circulatory system of large mammals in cold climates.
C. The extraction of carbon from limestone by lithotrophic bacteria.
D. The transition of carbon from methane to CO2 in the upper stratosphere.
14. Which of the following acts as a significant long-term carbon sink in Arctic ecosystems?
A. Seasonal ice melt
B. Permafrost soil
C. Lichen biomass
D. Migratory bird populations
15. The "Enemy Release Hypothesis" posits that invasive species succeed in new environments primarily because:
A. They have evolved to be inherently more aggressive than native species.
B. They lack the specialized predators and pathogens found in their native range.
C. They can utilize resources that native species cannot digest.
D. They undergo rapid horizontal gene transfer with native populations.
16. Invasive species often lead to a decrease in biodiversity through which mechanism?
A. Niche construction
B. Competitive exclusion
C. Adaptive radiation
D. Character displacement
17. Why are island ecosystems particularly vulnerable to invasive species?
A. Islands typically have higher genetic diversity, allowing for more hybridization.
B. Native island species often lack defensive adaptations due to evolutionary isolation.
C. Islands have unlimited resources that support rapid population booms.
D. Invasive species on islands face higher rates of mutation.
18. The introduction of the Brown Tree Snake to Guam resulted in the extinction of most native forest birds. This impact is classified as:
A. Trophic cascade
B. Bottom-up regulation
C. Keystone predation
D. Ecological homogenization
19. Biological control involves introducing a natural predator to manage an invasive population. What is the primary risk of this strategy?
A. The predator may become invasive and target non-target native species.
B. The predator will likely die out due to lack of genetic variation.
C. It increases the carbon footprint of the restoration project.
D. Biological control is illegal under international maritime law.
20. Which of the following best defines a "Keystone Species"?
A. The most abundant species in an ecosystem by biomass.
B. A species that has a disproportionately large effect on its environment relative to its abundance.
C. Any species located at the very bottom of a food web.
D. A species that is first to colonize a barren habitat.
B Mutualism
C Intraspecific competition
D Parasitism
PART III
8. Which process is primarily responsible for removing Carbon Dioxide (CO2) from the atmosphere?
A Cellular Respiration
B Photosynthesis
C Combustion
D Decomposition
9. How does the burning of fossil fuels impact the global carbon cycle?
A It increases the amount of carbon stored in underground rocks.
B It releases sequestered (stored) carbon into the atmosphere as CO2.
C It speeds up the rate of photosynthesis in all plants.
D It has no significant effect on the total amount of atmospheric carbon.
10. Which of the following acts as the largest "carbon sink" (storage area) on Earth?
A The Atmosphere
B The Oceans
C Animal Biomass
D Glaciers
11. Deforestation contributes to the greenhouse effect primarily because:
A Burning trees releases oxygen which traps heat.
B Fewer trees are available to absorb CO2 through photosynthesis.
C Trees naturally cool the atmosphere through respiration.
D Leaves reflect sunlight back into space.
PART IV
12. Which of the following is a primary reason why invasive species often experience "explosive" population growth in a new environment?
A They have a mutualistic relationship with all native species.
B They bring their own food sources with them from their native range.
C They lack natural predators and diseases in the new ecosystem.
D They are always at the top of the food chain (apex predators).
13. The introduction of the Zebra Mussel to the Great Lakes led to a decrease in native mussel populations. This is primarily due to:
A Competition for resources
B Commensalism
C Mutualistic signaling
D Parasitic infection
14. Why are island ecosystems more vulnerable to damage from invasive species than mainland ecosystems?
A Island species have evolved in isolation and often lack natural defenses.
B Islands have more space for invasive species to hide.
C The climate on islands is always more favorable for new species.
D Islands have higher biodiversity, which invites more competition.
15. Which of the following is an example of an "ecological service" that a healthy ecosystem provides to humans?
A Pollination of crops by bees.
B Purification of water by wetlands.
C Regulation of climate by forests.
D All of the above.
16. A "Keystone Species" is best defined as a species that:
A Has the largest total biomass in the ecosystem.
B Is always at the very bottom of the food pyramid.
C Has a disproportionately large effect on its ecosystem relative to its population size.
D Is the first species to colonize a new habitat after a fire.
17. How does biodiversity affect the stability of an ecosystem?
A Higher biodiversity makes an ecosystem more vulnerable to change.
B Higher biodiversity provides more pathways for energy flow, making the ecosystem more resilient.
C Biodiversity has no impact on the long-term survival of a community.
D Ecosystems are most stable when they consist of only one dominant species.
18. When an apex predator is removed from an ecosystem, the resulting collapse of multiple trophic levels is known as:
A Energy pyramid inversion
B Trophic cascade
C Primary succession
D Mutualistic breakdown
19. Which of the following is NOT a greenhouse gas?
A Carbon Dioxide (CO2)
B Methane (CH4)
C Nitrogen Gas (N2)
D Water Vapor (H2O)
20. Biological control involves introducing a natural predator to manage an invasive population. What is the biggest ecological risk of this method?
A The predator may also become invasive and harm non-target native species.
B The predator will die too quickly due to a lack of habitat.
C It will cause the native species to grow too large.
D It increases the amount of solar radiation reaching the ground.
