BLArch Bachelor of Landscape Architecture Bachelor of Landscape Architecture Environmental Science Ecology 3 — Questions and Answers
Question 1: Which ecological principle explains why energy decreases by approximately 90% at each trophic level?
- Law of conservation of mass
- Second law of thermodynamics (Correct answer)
- Liebig's law of the minimum
- Competitive exclusion principle
Correct answer: Second law of thermodynamics
The second law of thermodynamics states that energy transfers are inefficient, with roughly 90% lost as heat at each trophic level.
Question 2: A landscape architect designing a bioswale is primarily targeting which ecosystem service?
- Carbon sequestration
- Stormwater filtration and runoff reduction (Correct answer)
- Pollinator habitat creation
- Microclimate regulation
Correct answer: Stormwater filtration and runoff reduction
Bioswales are vegetated channels designed to slow, filter, and infiltrate stormwater runoff, reducing peak flows and improving water quality.
Question 3: The term 'phenology' in ecology refers to the study of:
- Sound production by animals in ecosystems
- Seasonal timing of biological events (Correct answer)
- Soil formation and development processes
- Genetic variation within populations
Correct answer: Seasonal timing of biological events
Phenology studies the timing of cyclical biological events—such as flowering, migration, and leaf-out—and their relationship to climate and season.
Question 4: Which soil horizon contains the highest concentration of decomposed organic matter?
- A horizon
- B horizon
- C horizon
- O horizon (Correct answer)
Correct answer: O horizon
The O horizon (organic horizon) sits at the surface and consists primarily of decomposed and decomposing organic matter like leaf litter and humus.
Question 5: In restoration ecology, 'reference ecosystem' refers to:
- A textbook description of an ideal habitat type
- A historical or nearby undisturbed site used as a restoration target (Correct answer)
- A GIS database of native plant species
- A laboratory model of ecosystem processes
Correct answer: A historical or nearby undisturbed site used as a restoration target
A reference ecosystem is an existing or historically documented site that represents the desired end-state for ecological restoration efforts.
Question 6: Which type of mutualism involves a fungus and plant roots exchanging nutrients?
- Commensalism
- Mycorrhizal association (Correct answer)
- Lichen symbiosis
- Nitrogen fixation partnership
Correct answer: Mycorrhizal association
Mycorrhizal associations are mutualistic relationships where fungi colonize plant roots, improving water and nutrient uptake in exchange for carbohydrates.
Question 7: What does the term 'guild' mean in community ecology?
- A group of species sharing similar environmental tolerances
- A set of species that exploit the same resource in similar ways (Correct answer)
- A collection of species at the same trophic level
- A cluster of endemic species in a biome
Correct answer: A set of species that exploit the same resource in similar ways
A guild is a group of species that exploit the same class of environmental resources in a similar manner, regardless of taxonomic relationship.
BLArch Bachelor of Landscape Architecture Bachelor of Landscape Architecture Environmental Science Ecology 3
Which ecological principle explains why energy decreases by approximately 90% at each trophic level?