All flashcards
Flashcard 1: What does a repeating rise-and-fall pattern around K typically indicate?
Answer: Population oscillations due to delayed density dependence. Time lag between density effects and population response.
Flashcard 2: What does the "deceleration phase" refer to on a logistic growth graph?
Answer: Growth slows as limiting factors intensify. Competition and resource scarcity reduce growth rate.
Flashcard 3: What is the term for a population graph that rises rapidly without leveling off (J-shaped curve)?
Answer: Exponential growth. Unlimited resources allow continuous acceleration of growth.
Flashcard 4: Identify the growth rate at a point where the population graph is perfectly flat.
Answer: Zero growth rate. No change means births exactly equal deaths.
Flashcard 5: Which curve type (J-shaped or S-shaped) is most consistent with limiting factors and K?
Answer: S-shaped (logistic) curve. Environmental resistance creates a carrying capacity.
Flashcard 6: On a logistic curve, is growth faster at N=2K or at N=0.9K?
Answer: Faster at N=2K. Growth peaks at half carrying capacity in logistic model.
Flashcard 7: What does the "exponential phase" refer to on a logistic growth graph?
Answer: Rapid increase when resources are abundant. Resources are plentiful, enabling maximum growth rate.
Flashcard 8: What does the term "lag phase" refer to on a logistic growth graph?
Answer: Initial slow growth as the population becomes established. Population establishes before entering rapid growth phase.
Flashcard 9: What is the formula for population change including migration?
Answer: DeltaN=(B+I)−(D+E). Accounts for births, deaths, immigration, and emigration.
Flashcard 10: What is the formula for per capita growth rate in a closed population?
Answer: r=b−d. Birth rate minus death rate gives net per capita growth.
Flashcard 11: What does a downward slope on a population size vs. time graph indicate?
Answer: Population decline (negative growth rate). Deaths exceed births, causing population to shrink.
Flashcard 12: What does a horizontal (flat) segment on a population size vs. time graph indicate?
Answer: Zero net growth; population size is constant. Births equal deaths, so population remains unchanged.
Flashcard 13: What does the steepness (slope) of a population size vs. time graph represent?
Answer: Population growth rate. Steeper slopes indicate faster population increase per unit time.
Flashcard 14: What does carrying capacity (K) represent on a logistic population growth graph?
Answer: Maximum sustainable population size in that environment. The horizontal asymptote where growth stops due to resource limits.
Flashcard 15: What is the key visual difference between exponential and linear growth on a graph?
Answer: Exponential curves upward; linear is a straight line. Exponential curves; linear maintains constant slope.
Flashcard 16: What is the term for a population graph that rises then levels off near a maximum (S-shaped curve)?
Answer: Logistic growth. Limited resources cause growth to slow and stabilize.
Flashcard 17: What is the term for a population graph that rises rapidly without leveling off (J-shaped curve)?
Answer: Exponential growth. Unlimited resources allow continuous acceleration of growth.
Flashcard 18: What is the term for growth rate expressed per individual (often labeled r)?
Answer: Per capita growth rate (intrinsic rate of increase). Growth expressed as rate per individual in population.
Flashcard 19: What does it suggest if a population remains far below K yet does not increase?
Answer: A limiting factor other than space/food is constraining growth. Hidden limiting factor prevents approach to K.
Flashcard 20: What does a population graph that approaches K asymptotically indicate about regulation?
Answer: Strong density-dependent regulation near K. Negative feedback prevents overshoot of carrying capacity.
Flashcard 21: Identify the growth type if the population doubles at regular time intervals on the graph.
Answer: Exponential growth. Fixed doubling time characterizes exponential growth patterns.
Flashcard 22: Identify the growth type if the population increases rapidly then stabilizes near a plateau.
Answer: Logistic growth. S-shaped curve with plateau indicates logistic growth.
Flashcard 23: Identify the sign of growth rate if the graph is decreasing with time.
Answer: Negative growth rate. Decreasing population indicates deaths exceed births.
Flashcard 24: Identify the sign of growth rate if the graph is increasing with time.
Answer: Positive growth rate. Increasing population indicates births exceed deaths.
Flashcard 25: Which option best estimates K on a logistic graph: the initial value or the long-term plateau?
Answer: The long-term plateau. Plateau represents equilibrium at carrying capacity.
Flashcard 26: If N is close to K, what should happen to the slope of a logistic growth curve?
Answer: It should approach 0 (growth slows to near zero). Near K, density effects minimize further growth.
Flashcard 27: If a population graph becomes flatter over time while still rising, what is happening to growth rate?
Answer: Growth rate is decreasing. Growth continues but slows as density effects increase.
Flashcard 28: If a population graph becomes steeper over time, what is happening to growth rate?
Answer: Growth rate is increasing. Steeper curves indicate accelerating population growth.
Flashcard 29: If N is much smaller than K, what should happen to the slope of a logistic growth curve?
Answer: It should be steep (rapid growth). Far from K, resources allow rapid growth.
Flashcard 30: If r=0 in a population model, what should the population graph look like over time?
Answer: A horizontal line (constant population size). Zero net growth produces flat population curve.