Population change around time by the action of factors such as birth and death rate and migration.
The basic rate for measuring the fluctuations in population are the following:
Crude Birth Rate (CBR)
The number of births per 1000 individuals in a population per year.
| Number of births x 1000 |
| population size |
Crude Death Rate (CDR)
The number of deaths per 1000 individuals in a population per year.
| Number of deaths x 1000 |
| population size |
Natural Increase Rate
NIR = (CBR - CDR) / 10
Doesn’t consider immigration and emigration.
Doubling time
The time in years it takes a population to double its size.
Doubling time = 70 / NIR
Total Fertility Rate (TFR)
It is the average number of children that each woman has over her life time. It shows the potential of population change.
- A TFR > 2.0 results in a population increase
- A TFR < 2.0 results in a population decrease
- A TFR = 2.0 results in a stable population
In developing countries, the fertility rate is usually higher than in MEDC’s
Humans impact on the environment is not just given out by its growth, but also by resource use and pollution. It’s impact is affecter by:
- It’s affected by the amount of wealth
- Resource desire
- Resource need
Individuals in a population, specially in a human population, interact with the environment in different ways. We cannot generalize for all the organisms within a population.
Wait for a detailed list of identification of resource use and waste profiles in a further post.
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