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Transcript of Population Pyramids
What is a population pyramid?
A vertical Y-axis on the graph, which represents age.
A population pyramid consists of:
A population pyramid is a graphic representation that displays the number of people in different groups, organized by age and sex, in the population of an area, region, country, or even the world.
It is also known as an age pyramid, or an age picture diagram.
How do you read a population pyramid, and what can be learned from them?
Who uses population pyramids, and for what reasons?
Who uses population pyramids:
What are the different types of population pyramids?
A population pyramid that shows an unchanging pattern of fertility and mortality.
Age groups are relatively equal in size.
Appears more so as a column than a pyramid, the exception being the top where it naturally shrinks due to the highest cohorts being older.
From the bottom to the top of the pyramid, the age goes from youngest to oldest.
The length of the horizontal bar for each cohort depicts the number of people within that age group within the population.
If the graph is in the relative shape of a pyramid, it means that the population is growing.
If the graph is in the relative shape of an upside down pyramid, it means that the population is shrinking.
How to read a population pyramid:
Population pyramids can help to determine the age and sex distribution of a population
They ascertain how regions have developed over the passage of time.
Population pyramids establish the rate at which a population in a given area will grow or decrease.
What can be learned:
Demographers use population pyramids to better their understanding of the composition of a given population.
Population pyramids allow demographers to see the trends of populations from the past, examine current population numbers and distribution, and also predict how populations could increase or decrease over time.
Why demographers use population pyramids:
A population pyramid that is usually associated with countries that have low fertility and mortality rates.
Similar to a stable pyramid, but it is less in the shape of a column, and further spread out.
The more rectangular the pyramid, the slower the growth of the population, meaning that older generations are being replaced by newer generations at approximately the same rate.
Two bar graphs that are placed back-to-back.
A horizontal X-axis on the graph, which represents population.
One half of the graph is dedicated to males, while the other half represents females.
It is sectioned into five-year age groups known as cohorts.
Demographers use population pyramids.
They are scientists who study the developments of populations as well as their fundamental statistics.
They use population pyramids to aid in their studies.
A population pyramid that is very wide at the base, and grows progressively shorter as they near the top. It shows a fast-growing population. The wider the base, the faster the population growth.
Depicts that there are more in the younger age groups than the older age groups, which means that more of the population will come of age to have their own children.
A top-heavy or upside down pyramid.
The bars in the higher cohorts are longer than those in the younger age groups, resulting in a narrow base that widens the higher up the pyramid.
More people in the older age groups than the younger groups mean that fewer people will have children and contribute to the future population.
Examples of Population Pyramids:
Over the span of 80 years, from 1931-2011, it can be seen that Canada's population grows exponentially, from 10, 376, 785 people, to 29, 732, 945 people.
The one thing to note though, in the graph for 1971, is that the youngest cohorts start to lessen in numbers. This continues into 2011, where there are fewer younger age groups, and they are producing less children.
The highest cohorts (the oldest groups) naturally decrease.
Over time, Canada's population growth, although large, gradually slows down.
Because of the slower growth and boxier shape of the pyramid in 2011, it could be said that it is a stationary pyramid.
Canada from 1931-2011: