Immigration
Populations moving into an area
Emigration
Populations leaving an area
Two factors causing an increase in population
Birth and immigration
Two factors, causing a decrease in population
Death and emigration
A stable population
B+I=D+E
Population growth
There is more birth and immigration than death and emigration
Population decline
There is more death and emigration than birth and immigration
Example of type 1 survivorship
Human
Example of type 2 survivorship
Rodents
Example of type 3 survivorship
Fish, insects, amphibians
Type 1
Shows decline in later stages of life
Type 2
Shows a steady decline throughout all life stages
Type 3
Shows decline in early stages of life
Type 2 and 3
Have less time to give offspring because their morality rate is low is early stages of life. This leads to a higher population of offspring
Most type 1 survivors take care of their offspring while ______ and ______ don’t
Type 2 and 3
Humans might now show type 1 survivorship when…
They don’t want to take care of their kids, might not have enough resources to sustain a human life, or when the death rate is very high
Lag phase
Phase of growth curve, when population is just beginning to colonize in an area.
Exponential growth curve
J- curve, population growth appears to contribute unchecked
Logistic growth curve
S-curve, keeps going up and down
Environmental resistance and pressure
Causes population growth to slow down
Carrying capacity
The steady population that an environment can sustain. Population size fluctuate around it. (Predators and weather conditions case this)
Causes of rapid growth in populations
Environmental resources, availability of partners, less diseases, less predators
Exponential growth
The phenomena of populations that double in size every generation
Environmental resistance
Causes growth rates to slow down until a stable and sustainable population size is reached. (Such as a shortage of environmental resources))