Carrying Capacity
the maximum population size that can be supported in a given environment.
Density Dependent Factors
factors that impact a population based on its size and increase in effect as the population increases. e.g. Biotic: food availability, disease; Abiotic: shelter, water.
Density Independent Factors
factors that affect a population regardless of size. e.g. environmental changes like natural disaster.
Lincoln Index
used to measure populations by using capture-recapture.
Lincoln Index Formula
N=(Mxn)/m. Where N is the target population, M is the no. individuals tagged in the first sample, n is the no. of individuals caught in the second sampling, m is the no. tagged individuals caught in the second sampling.
Exponential Growth
occurs when environmental conditions are favorable for rapid reproduction. Birth rates exceed death rates and cause a population boom. It creates a J-shaped curve when graphed.
Logistic Growth
realistic description of the growth rate of a population as it will be affected by density dependent factors. As these ecosystems reach carrying capacity the growth becomes stable with birth rates equaling death. This creates an S-shaped curve when graphed.
Dynamic Carrying Capacity
it is considered to be dynamic as it changes based on the availability of resources. Factors influencing it may be biotic or abiotic. It is tied to the availability of the scarcest resource.
Biotic Factors that Influence Carrying Capacity
fluctuating populations of food species or competitor species. e.g. predator and prey.
Abiotic Factors that Influence Carrying Capacity
weather or climate changes, or major environmental shifts.
Reproductive Strategies
the various traits and behaviors that help a species ensure its offspring reach maturity and reproduce themselves
r-Strategists
r refers to the biotic potential which is the potential of a species to increase in number. These organisms are short lived, high rates of reproduction, fast maturing and have minimal parental care. e.g. bacteria, insects.
K-Strategists
K refers to carrying capacity and shows the number of organisms an environment can support in the long term. These organisms produce fewer offspring and have high parental care. They take longer to mature and have high gestation periods. e.g. mammals.
Immigration
movement of individuals into a population
Emigration
movement of individuals out of the population
Population Growth Rate Formula
(birth + immigration) - (death-emigration)
