population ecology Flashcards
(17 cards)
What is a population?
A group of individuals of one species that interact regularly
What is population density?
A measure of how many individuals may come into contact with each other in a given area
What is dispersion in population ecology?
The geographic arrangement of individuals within a population
What is a key factor that influences population growth?
The reproductive rate (fecundity) of individuals in the population.
What is exponential growth?
A model where populations grow rapidly under ideal, unlimited conditions unless limited by external factors.
What is logistic growth?
Population growth that is limited by carrying capacity, slowing as it nears the environment’s maximum sustainable size.
What is the equation for population growth rate (r)?
r= (births−deaths) / n
, where n is the initial population size.
What is carrying capacity?
The maximum number of organisms an environment can support sustainably.
What are limiting factors?
Resources or conditions necessary for survival (food, temperature, mates, space) that restrict population growth.
What are density-dependent factors?
Limitations that intensify as population size increases (e.g., disease, competition, resource depletion).
What are density-independent factors?
Limitations not affected by population size, often related to disasters or environmental changes (e.g., floods, fires).
What is meant by “quantity vs quality” in reproduction?
Organisms choose between producing many offspring (quantity) or investing more in fewer offspring (quality).
What is the r-selected vs K-selected reproduction theory?
r-strategists: Reproduce rapidly, focus on quantity, thrive in unstable environments.
K-strategists: Reproduce slowly, invest in care, and aim to sustain populations near carrying capacity.
What human advancements have reduced limiting factors?
Agriculture
Medicine
Sanitation (e.g., sewer systems)
Technology for comfort in extreme environments (heating, clothing, housing)
What is an ecological footprint?
A measure of the land and resources an individual uses to sustain their lifestyle.
Why has the global population growth rate declined in some areas? (5)
Increased education for women
Lower economic need for children
Urbanization
High cost of raising children
Access to birth control
What feedback loops are involved in population change?
Positive feedback loop: Education and lifestyle changes reduce birth rates
Negative feedback loop: Improved access to contraception slows population growth
