Unit 8: Human Population
8.1 Changes in population size
Growth
Exponential growth: the growth rate increases rapidly over time
Population: all the organisms of one species living in a defined area
Lag phase: the organism is adapting to a new
environment and the growth is slow
Log/ exponential phase: all requirements are in super
abundance and growth rate increases rapidly over
time
Stationary phase: Population is in equilibrium, has
reached the carrying capacity of the environment and
the growth rate has slowed to zero.
carrying capacity: maximum population size that the environment can support (food, water,
etc) without damage. Sometimes the population exceeds the carrying capacity. Humans
have constantly managed to exceed the natural carrying capacity, this is because of our use
of technology.
History of human populations
10 000 years ago → 5 million people
6000 years ago → start of growing crops and keeping animals (pop. started to
grow)
2000 years ago → 250 million people
200 years ago (1800s)→ 1 billion people
86 years ago (1930) → 2 billion people
41 years ago (1975) → 4 billion people
Today (2016) → 7 billion people
Birth rate and death rate
BR: amount of people born in a certain amount of time
DR: amount of people that die in a certain amount of time
BR - DR = rate of natural increase
(BR + immigration) - (DR + emigration) = true rate if natural increase
the RNI can be expressed in percentage: (BR - DR) × 100
Factors affecting BR and DR:
● in countries with a high death ate for the very young, birth rates are also high
● in agrarian (farming) economies of many less economically developed countries
(LEDC’s) more people are needed for manual labour, and so families tend to be
larger
● in more economically developed countries (MEDC’s) it is expensive to have children
and pensions are provided by the state
● many social and political factors result in low use of birth control in LEDC’s, whereas
in MEDC’s birth control is widely used, so both birth and death rates are lower.
Página 1 | 3
8.1 Changes in population size
Growth
Exponential growth: the growth rate increases rapidly over time
Population: all the organisms of one species living in a defined area
Lag phase: the organism is adapting to a new
environment and the growth is slow
Log/ exponential phase: all requirements are in super
abundance and growth rate increases rapidly over
time
Stationary phase: Population is in equilibrium, has
reached the carrying capacity of the environment and
the growth rate has slowed to zero.
carrying capacity: maximum population size that the environment can support (food, water,
etc) without damage. Sometimes the population exceeds the carrying capacity. Humans
have constantly managed to exceed the natural carrying capacity, this is because of our use
of technology.
History of human populations
10 000 years ago → 5 million people
6000 years ago → start of growing crops and keeping animals (pop. started to
grow)
2000 years ago → 250 million people
200 years ago (1800s)→ 1 billion people
86 years ago (1930) → 2 billion people
41 years ago (1975) → 4 billion people
Today (2016) → 7 billion people
Birth rate and death rate
BR: amount of people born in a certain amount of time
DR: amount of people that die in a certain amount of time
BR - DR = rate of natural increase
(BR + immigration) - (DR + emigration) = true rate if natural increase
the RNI can be expressed in percentage: (BR - DR) × 100
Factors affecting BR and DR:
● in countries with a high death ate for the very young, birth rates are also high
● in agrarian (farming) economies of many less economically developed countries
(LEDC’s) more people are needed for manual labour, and so families tend to be
larger
● in more economically developed countries (MEDC’s) it is expensive to have children
and pensions are provided by the state
● many social and political factors result in low use of birth control in LEDC’s, whereas
in MEDC’s birth control is widely used, so both birth and death rates are lower.
Página 1 | 3
