Population Ecology

What are the four major population growth factors?

• births

• deaths

• immigration - individuals migrating into the population

• emigration - individuals migrating out of the population

How do you calculate change in population size?

(births + immigrants) - (deaths + emigrants)

What is exponential population growth curve?

• occurs under ideal conditions (unlimited resources and no migration)

• J curve

What is logistic population growth curve?

• limited resources and carrying capacity

How can you identify which exponential growth curve has a higher r-max value when given a graph?

the curve with a steeper slope (faster increase) has the higher r-max value

What are density-independent factors?

• affect population size regardless of the population’s density

• ex: natural disasters, extreme weather

What are density-dependent factors?

• biotic factors that slow population growth as density increases

• cause drop in birth rates and increase in death rates

• ex: competition, predation, disease

What is carrying capacity?

the maximum population size than an environment can sustain indefinitely given the available resources

How can one estimate the carrying capacity from a population size graph over time?

identifying the population size at which the growth rate slows and stabilizes over time

How can you use population age structure histograms to determine if a population is growing, stable, or decreasing?

• broad base = population is growing

• equal width = stable population

• narrow base = population is decreasing