Population Size
Ecology
The study of how organisms interact with other organisms and their environment.
Size
Distribution
Ecology studies can be used to determine what influences population size and distribution.
Wildlife
Ecology can also be used to determine the affect that human populations have on wild species.
Demographics
Demographics are statistics used to describe a population.
Density
Demographics can be utilized to determine population size or the total number of individuals in a population.
These statistics can be used to determine population distribution.
Demographics can be used to determine population density: the number of individuals per unit area or volume.
Population distribution is the location of individuals relative to one another.
Population Sampling
Plot Sampling
Mark-Recapture Sampling
Techniques used to estimate the population size.
Estimating the total population size by using a direct count in a portion of the area.
Estimating population size by capturing and marking animals with identifying tags.
Immigration
Emigration
The arrival of new people within a givein population is known as immigration and it alters the population distribution.
When a person moves out of a given popualation, known as emigration. The population distribution changes.
Population Growth
When the population size increases the same per given time interval, the trend for the population is known as the exponential growth.
Exponential Growth
Zero Population Growth
Number of births and deaths are equal, and therefore the population growth is zero.
Per Capita Birth Rate
Birth Rate
Death Rate
Head count of individuals born in a given time period.
Head count of the number of deaths in a given time period.
The population growth can be calculated by the per capita birth rate in which subtracts the death rate from the populations birth rate.
The population size may experience population growth over time in which the population in a given area increases.
Biotic Growth
The population growth under ideal conditions (food, shelter, and resources) is known as biotic growth.
Predation
Parasitism
Disease
Density limiting factor that causes the population growth rate to stop increasing because predators are killing them off.
Parasites that lead to death is another density limiting factor.
Disease is another density limiting factor that increases the death rate compared to the birth rate.