Population Growth and Regulation Flashcards
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Read the first 7 Population Growth and Regulation flashcards as text
In a logistic growth model, population growth rate (dN/dt) is maximized when:
Answer: N = K/2
The logistic curve has maximum growth rate at exactly half the carrying capacity (K/2), where the product N(K-N) is greatest.
What is population momentum in the context of human demography?
Answer: Continued growth after fertility drops to replacement level due to youthful age structure
Population momentum occurs because even when fertility falls to 2.1 (replacement level), large young cohorts still move through reproductive years, driving further growth.
Contest competition differs from scramble competition in that:
Answer: A dominant subset wins full resource access while others get none
In contest competition, winners secure enough resources to survive and reproduce while losers are excluded entirely, stabilizing population near K.
Which life-history trait is expected in an organism occupying an unpredictable, frequently disturbed environment?
Answer: Early reproduction, many small offspring, short lifespan (r-selected)
r-selected traits evolve in variable, disturbed habitats where rapid population growth before the next disturbance is advantageous.
The Rescue Effect in metapopulation dynamics refers to:
Answer: Immigration reducing local extinction probability in declining subpopulations
The Rescue Effect occurs when immigrants from source populations supplement a declining sink population, reducing its extinction risk.
A population ecologist finds that the 95% confidence interval for population growth rate r includes zero. The best conclusion is:
Answer: The population is not significantly growing or declining based on current data
When the confidence interval for r includes zero, we cannot statistically distinguish the population's trajectory from stable (r=0) growth.
Which process is responsible for the cohort effect in population age structure analysis?
Answer: A specific birth-year group experiences unique conditions that affect its lifelong survival
A cohort effect occurs when individuals born in the same year share an environmental experience (e.g., drought year) that permanently affects their survival or reproduction.