ESTUDYR
PCB 4674 MOST TESTED QUESTIONS AND ANSWERS
GRADED A+ WITH RATIONALES
The Hudson’s Bay Company fur–trade records are important to ecologists because they:
A. Contain DNA from historic animals
B. Track snowfall and climate data
C. C. Allow long-term tracking of population cycles of snowshoe hares ✔
Rationale: Fur returns provide multi-decade indices of hare abundance useful for population
cycle studies.
What is a primary cause of hare–lynx population cycles?
A. Lynx migration to other continents
B. Viral pandemics only
C. C. Food limitation at high hare densities combined with predation reducing hare survival ✔
Rationale: Resource depletion and predator-driven mortality interact to produce cyclical
dynamics.
Predation is best defined as:
A. A mutualistic interaction between species
B. When plants consume animals
C. C. A trophic interaction where an individual (predator) benefits by consuming another
individual (prey) ✔
Rationale: Predation yields direct fitness benefits to the predator via consumption.
Parasitoids differ from typical parasites because parasitoids:
A. Never harm the host
B. Live only outside hosts
C. C. Lay eggs in hosts; larvae develop inside and eventually kill the host ✔
Rationale: Parasitoids are lethal to their hosts, combining parasitism and predation.
Predators tend to focus their foraging in areas that:
A. Have the fewest competitors
B. Contain no prey at all
C. C. Yield abundant or profitable prey ✔
Rationale: Optimal foraging dictates predators concentrate effort where prey payoff is highest.
A “generalist predator” is one that:
A. Eats only a single prey species
,ESTUDYR
B. Has no diet and fasts constantly
C. C. Consumes a broad variety of prey items depending on availability ✔
Rationale: Generalists have flexible diets and switch prey with availability.
A “specialist predator” is characterized by:
A. Preferring specific prey even when alternatives are abundant
B. Eating only nonliving matter
C. C. Showing strong preference or adaptation to particular prey types ✔
Rationale: Specialists are adapted to capture/handle certain prey and may ignore others.
“Search image” by predators means:
A. Predators develop superior camouflage
B. Prey become more conspicuous intentionally
C. C. Predators improve detection of a specific prey through experience, leading to focused
hunting ✔
Rationale: Learned recognition increases capture efficiency for a prey type.
Herbivores are often specialists because:
A. All plants are identical in chemistry
B. Plants never evolve defenses
C. C. Plant chemical/structural defenses and digestive constraints favor specialization ✔
Rationale: Specific detoxification and feeding tools favor narrow diets.
Which ordering lists nitrogen content from greatest to least?
A. Xylem sap > phloem sap > animals
B. Seeds > animals > angiosperm leaves
C. C. Animals > seeds > angiosperm leaves > gymnosperm leaves > phloem sap > xylem sap ✔
Rationale: Animal tissue is nitrogen-rich; sap and woody tissues are relatively low in N.
Herbivory typically reduces plant:
A. Ability to photosynthesize perpetually only
B. Preferential herbivore species richness
C. C. Growth, survival, and reproduction (e.g., seed predation lowers reproductive success) ✔
Rationale: Tissue loss translates to reduced fitness components.
“Dispersal limitation” means a species:
A. Is prevented by predators from surviving anywhere
B. Can reach every suitable habitat instantly
, ESTUDYR
C. C. Cannot reach suitable habitats because of limited dispersal capacity ✔
Rationale: Even suitable patches remain uncolonized if dispersal is insufficient.
Predators forage by either active searching or by sit-and-wait strategies; an example of sit-
and-wait is:
A. Wolves traveling long distances
B. Birds that chase flying insects continuously
C. C. Carnivorous plants or ambush spiders that wait for prey to come within striking distance
✔
Rationale: Ambush predators conserve energy and strike passing prey.
For every prey defense, predators often evolve:
A. No response ever
B. Perfect tolerance with no tradeoffs
C. C. Counter-offensive adaptations (coevolutionary arms race) ✔
Rationale: Reciprocal selection drives evolved offenses and defenses.
Poisonous prey and predators demonstrate that:
A. Only predators can be toxic
B. Toxicity has no ecological cost
C. C. Some predators use venom to subdue prey and some prey evolve toxins; predators may
also evolve resistance ✔
Rationale: Chemical warfare can occur on both sides with evolutionary consequences.
Aposematic coloration functions to:
A. Hide prey from predators
B. Make prey easier to capture
C. C. Warn predators that the organism is toxic or unpalatable (bright signals) ✔
Rationale: Conspicuous signals reduce attack rates via predator learning.
Crypsis is a defense where prey:
A. Imitate toxic species
B. Warn predators loudly
C. C. Camouflage to blend into background and avoid detection ✔
Rationale: Crypsis lowers encounter/detection probabilities.
Batesian mimicry is when:
A. A toxic species mimics a non-toxic species
B. Two mutualistic species coevolve
PCB 4674 MOST TESTED QUESTIONS AND ANSWERS
GRADED A+ WITH RATIONALES
The Hudson’s Bay Company fur–trade records are important to ecologists because they:
A. Contain DNA from historic animals
B. Track snowfall and climate data
C. C. Allow long-term tracking of population cycles of snowshoe hares ✔
Rationale: Fur returns provide multi-decade indices of hare abundance useful for population
cycle studies.
What is a primary cause of hare–lynx population cycles?
A. Lynx migration to other continents
B. Viral pandemics only
C. C. Food limitation at high hare densities combined with predation reducing hare survival ✔
Rationale: Resource depletion and predator-driven mortality interact to produce cyclical
dynamics.
Predation is best defined as:
A. A mutualistic interaction between species
B. When plants consume animals
C. C. A trophic interaction where an individual (predator) benefits by consuming another
individual (prey) ✔
Rationale: Predation yields direct fitness benefits to the predator via consumption.
Parasitoids differ from typical parasites because parasitoids:
A. Never harm the host
B. Live only outside hosts
C. C. Lay eggs in hosts; larvae develop inside and eventually kill the host ✔
Rationale: Parasitoids are lethal to their hosts, combining parasitism and predation.
Predators tend to focus their foraging in areas that:
A. Have the fewest competitors
B. Contain no prey at all
C. C. Yield abundant or profitable prey ✔
Rationale: Optimal foraging dictates predators concentrate effort where prey payoff is highest.
A “generalist predator” is one that:
A. Eats only a single prey species
,ESTUDYR
B. Has no diet and fasts constantly
C. C. Consumes a broad variety of prey items depending on availability ✔
Rationale: Generalists have flexible diets and switch prey with availability.
A “specialist predator” is characterized by:
A. Preferring specific prey even when alternatives are abundant
B. Eating only nonliving matter
C. C. Showing strong preference or adaptation to particular prey types ✔
Rationale: Specialists are adapted to capture/handle certain prey and may ignore others.
“Search image” by predators means:
A. Predators develop superior camouflage
B. Prey become more conspicuous intentionally
C. C. Predators improve detection of a specific prey through experience, leading to focused
hunting ✔
Rationale: Learned recognition increases capture efficiency for a prey type.
Herbivores are often specialists because:
A. All plants are identical in chemistry
B. Plants never evolve defenses
C. C. Plant chemical/structural defenses and digestive constraints favor specialization ✔
Rationale: Specific detoxification and feeding tools favor narrow diets.
Which ordering lists nitrogen content from greatest to least?
A. Xylem sap > phloem sap > animals
B. Seeds > animals > angiosperm leaves
C. C. Animals > seeds > angiosperm leaves > gymnosperm leaves > phloem sap > xylem sap ✔
Rationale: Animal tissue is nitrogen-rich; sap and woody tissues are relatively low in N.
Herbivory typically reduces plant:
A. Ability to photosynthesize perpetually only
B. Preferential herbivore species richness
C. C. Growth, survival, and reproduction (e.g., seed predation lowers reproductive success) ✔
Rationale: Tissue loss translates to reduced fitness components.
“Dispersal limitation” means a species:
A. Is prevented by predators from surviving anywhere
B. Can reach every suitable habitat instantly
, ESTUDYR
C. C. Cannot reach suitable habitats because of limited dispersal capacity ✔
Rationale: Even suitable patches remain uncolonized if dispersal is insufficient.
Predators forage by either active searching or by sit-and-wait strategies; an example of sit-
and-wait is:
A. Wolves traveling long distances
B. Birds that chase flying insects continuously
C. C. Carnivorous plants or ambush spiders that wait for prey to come within striking distance
✔
Rationale: Ambush predators conserve energy and strike passing prey.
For every prey defense, predators often evolve:
A. No response ever
B. Perfect tolerance with no tradeoffs
C. C. Counter-offensive adaptations (coevolutionary arms race) ✔
Rationale: Reciprocal selection drives evolved offenses and defenses.
Poisonous prey and predators demonstrate that:
A. Only predators can be toxic
B. Toxicity has no ecological cost
C. C. Some predators use venom to subdue prey and some prey evolve toxins; predators may
also evolve resistance ✔
Rationale: Chemical warfare can occur on both sides with evolutionary consequences.
Aposematic coloration functions to:
A. Hide prey from predators
B. Make prey easier to capture
C. C. Warn predators that the organism is toxic or unpalatable (bright signals) ✔
Rationale: Conspicuous signals reduce attack rates via predator learning.
Crypsis is a defense where prey:
A. Imitate toxic species
B. Warn predators loudly
C. C. Camouflage to blend into background and avoid detection ✔
Rationale: Crypsis lowers encounter/detection probabilities.
Batesian mimicry is when:
A. A toxic species mimics a non-toxic species
B. Two mutualistic species coevolve
