Population growth

Pink packet

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))