Vocabulary
The number of individuals per unit area.
What is population density?
These are the two types of limiting factors.
What are density-dependent and density-independent limiting factors?
Ecologists study populations by examining their geographic range, growth rate, density and distribution, and age structure.
What characteristics do ecologists study to learn about populations?
The scientific study of human populations.
What is demography?
Data describing the ages and gender of individuals in the population.
What is age structure?
The type of growth that, when graphed, has an "S" curve.
What is logistic growth?
Hurricanes, droughts, floods, and wildfires are examples of these.
What are environmental extremes?
If carrying capacity falls low enough populations can be wiped out, leading to species extinction.
What may cause a species to become extinct?
This event, happening in the 1800s, resulted in rapid population growth.
What is the Industrial Revolution?
The number of individuals of a species that an environment can support.
What is carrying capacity?
The first phase of logistic growth.
What is the population grows rapidly?
This limiting factor occurs when animals fight over limited resources.
What is competition?
Birthrate, death rate, and the rate at which individuals enter or leave a population all affect population growth.
What factors determine the rate at which a population is increasing or decreasing?
The year when human population stopped growing exponentially.
What is 1999?
Any factor that controls the growth of a population.
What is a limiting factor?
This is the phase of logistic growth where the growth slows down.
What is the second phase of logistic growth?
This occurs when a species fights amongst itself because the population grows too dense.
These factors include birthrate, death rate, and age structure.
What factors help explain the differences in human population growth in different countries?
These two stages of the demographic transition are the only stages where birth and death rates are the same.
What are Stage 1 and 5?
A country's dramatic change from high birth and death rates to low birth and death rates.
What is a demographic transition?
What is growth stops? (or phase 3 of logistic growth)
This is determined by limiting factors in an environment for a species.
In response to such factors, a population may crash.
What happens to a population in response to a density-independent limiting factor?
Technological advancements in these three fields led to lower death rates in the United States.
What are nutrition, sanitation, and medicine?