3.1 & 3.2
A panda eats only bamboo in dense forests, while a raccoon eats fruit, garbage, and insects. If forest clearing occurs, which species faces a higher extinction risk?
What is the panda?
Explanation: Pandas are specialist species with narrow niches, making them poorly adapted to environmental changes or food loss compared to adaptable generalists like raccoons.
Songbirds face a constant 20% mortality risk every year throughout their entire life. Which survivorship curve type fits this population?
What is Type II?
Explanation: Type II curves represent a constant mortality rate across all age groups throughout the organism’s lifespan
When reindeer on St. Paul Island rapidly expanded past their environment's resource limits, what ecological event occurred right before the population crashed?
What is population overshoot?
Explanation: Overshoot occurs when a population temporarily exceeds carrying capacity, causing habitat degradation that triggers a die-off.
A severe drought dries up a lake, killing fish regardless of how crowded the water was. Is this a density-dependent or density-independent factor?
What is density-independent?
Explanation: Physical events (droughts, fires, weather) impact mortality rates regardless of population density
Cane toads produce thousands of eggs per clutch, mature in months, and leave their young. Which population strategy explains their invasive success?
What is an r-selected strategy?
Explanation: r-Selected species have high biotic potential and fast reproduction rates, allowing them to rapidly colonize new habitats and outcompete native species
Coral spawners release millions of larvae, but fewer than 1% survive to adulthood. Which survivorship curve type do they display?
What is Type III?
Explanation: Type III curves show extremely high juvenile mortality followed by high survival rates for the few individuals that reach adulthood.
Field populations near carrying capacity (K) rarely stay completely flat. What pattern do they follow around K?
What is oscillation?
Explanation: Real-world populations continuously overshoot K, experience minor die-offs, and recover, oscillating around carrying capacity
Two bacterial cultures in a fixed dish initially double every hour before leveling off. Which growth curve model did they transition into?
What is logistic growth?
Explanation: Logistic growth starts exponentially when resources are abundant, then slows as resources become limiting near carrying capacity
An invasive pest invades a park. Why is the resident bear population (K-selected) more vulnerable to decline than the resident beetle population (r-selected)?
What is low biotic potential?
Explanation: K-selected species have long lifespans, late maturity, and few offspring, making population recovery extremely slow after an environmental disruption
Female cougars protect and feed their cubs for two full years. Does this parental investment result in a Type I, II, or III survivorship curve?
What is Type I?
Explanation: Extended parental care keeps early-life mortality low, leading to high survival rates until old age.
In a hare and lynx ecosystem, why does the lynx population peak lag behind the hare population peak?
What is lynx reproduction depends on prior hare abundance?
Explanation: Predator birth rates increase only after prey becomes abundant, creating a delayed population response.
A wolf pack of 14 experiences 3 births, 5 deaths, and 4 immigrations. What is the net change in total pack size?
What is +2?
Explanation: Net Change = (Births + Immigrations) - (Deaths + Emigrations) = (3 + 4) - (5 + 0) = +2.
An animal has a 2-year gestation period and cares for offspring for years. How will its population recovery speed compare to an insect population after a major spill?
What is much slower?
Explanation: Mammals with long gestation and extended parental care (K-selected) reproduce at a much slower rate than fast-reproducing insects (r-selected)
An epidemic selectively targets elderly individuals in a wild sheep herd. Which portion of their Type I survivorship curve drops sharply—early life or late life?
What is late life?
Explanation: Type I species natively experience high early survival, with steep mortality occurring primarily in late-life age classes
If deer overgraze and destroy seed sources during a mild winter, what happens to the forest's carrying capacity for deer the following year?
What is it decreases?
Explanation: Severe resource depletion degrades the habitat, permanently or temporarily lowering the ecosystem's carrying capacity.
When severe overcrowding causes severe food shortages, what happens to the population's birth rate?
What is it decreases?
Explanation: Malnutrition from density-dependent competition reduces physiological fecundity (reproductive output)
Lizard A lays 2 eggs a year and guards the nest; Lizard B lays 200 eggs in sand and leaves. Which lizard’s individual offspring have a higher survival chance?
What is Lizard A?
Explanation: Heavy parental care and investment significantly reduce early-life mortality for individual offspring.
Between an oak tree (r-selected) and an elephant (K-selected), which invests more energy per individual offspring?
What is the elephant?
Explanation: K-selected species invest massive energetic resources into raising few individual offspring, whereas r-selected species spread minimal energy across vast quantities of seeds or eggs.
When disease wiped out most wolves on Isle Royale, what immediately happened to the island's moose population?
What is rapidly increased?
Explanation: Removing a top predator releases the herbivore population from top-down regulation, allowing uncontrolled growth
Seabirds aggressively defend 1-meter nesting territories on a cliffside. Which spatial distribution pattern will their nests show—clumped, random, or uniform?
What is uniform?
Explanation: Uniform distribution results from direct territorial competition, where individuals maintain equal distance from competitors.