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POPULATION PYRAMIDS - Contenido educativo
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Russia, with the largest territory in the world,
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has roughly the same total population as Nigeria,
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a country one-sixteenth its size.
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But this similarity won't last long.
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One of the populations is rapidly growing,
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while the other is slowly declining.
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What can this tell us about the two countries?
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Population statistics are some of the most important data
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social scientists and policy experts have to work with.
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But understanding a country's situation
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and making accurate predictions
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requires knowing not just the total size of the population,
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but its internal characteristics, such as age and gender distribution.
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So how can we keep track of all that data
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in a way that makes it easy to comprehend?
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Complex data is more easily interpreted through visualization,
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and one of the ways that demographers represent
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the internal distribution of a population is the population pyramid.
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Here, the data is divided by gender,
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with females on one side and males on the other.
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The population numbers are shown for each five-year age interval,
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starting from 0 to 4 and continuing up to 100 and up.
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These intervals are grouped together into pre-reproductive, 0 to 14,
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reproductive, 15 to 44,
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and post-reproductive years, 45 and up.
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Such a population pyramid can be a powerful predictor
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of future population trends.
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For example, Rwanda's population pyramid shows it to be a fast-growing country,
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With most of the population being in the youngest age groups
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at the bottom of the pyramid,
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the number will grow rapidly in the coming years.
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As today's children reach their reproductive years
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and have children of their own,
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the total population is almost certain to double
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within the next few decades.
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For our second example, let's look at Canada,
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where most of the population is clustered around the middle of the graph.
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Because there are less people in the pre-reproductive age groups
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than there are in the reproductive ones,
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the population will grow more slowly
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as the number of people reaching their reproductive years decreases.
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Finally, let's look at Japan.
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Because the majority of its population is in its post-reproductive years,
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and the number of people is smaller at each younger interval,
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this means that at current rates of reproduction,
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the population will begin to decline
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as fewer and fewer people reach reproductive age.
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Comparing these three population pyramids side by side
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shows us three different stages in the demographic transition
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as a country moves from a pre-industrial society
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to one with an industrial or post-industrial economy.
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Countries that have only recently begun the process of industrialization
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typically see an increase in life expectancy
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and a fall in child mortality rates
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as a result of improvements in medicine, sanitation, and food supply,
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while birth rates remain constant, leading to a population boom.
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Developing countries that are farther along in the industrialization process
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begin to see a fall in birth rates
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due to factors such as increased education and opportunities for women
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outside of child-rearing and a move from rural to urban living
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that makes having large families less economically advantageous.
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Finally, countries in advanced stages of industrialization
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reach a point where both birth and death rates are low,
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and the population remains stable or even begins to decline.
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Now let's take a look at the projected population pyramids
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for the same three countries in 2050.
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What do these tell us about the expected changes in each country's population?
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And what kinds of factors can alter the shape of these future pyramids?
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A population pyramid can be useful not only as a predictor of a country's future,
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but as a record of its past.
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Russia's population pyramid still bears the scars of World War II,
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which explains both the fewer numbers of elderly men compared to elderly women
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and the relatively sudden population increase
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as soldiers returned from the war and normal life resumed.
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China's population pyramid reflects the establishment of the one-child policy
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35 years before,
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which prevented a population boom such as that of Rwanda,
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but also led to sex-selective abortions,
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resulting in more male children than female children.
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Finally, the pyramid for the United States shows the baby boom
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that followed World War II.
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As you can see, population pyramids tell us far more about a country
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than just a set of numbers
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by showing both where it's been and where it's headed within a single image.
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And in today's increasingly interconnected world,
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facing issues such as food shortages, ecological threats,
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and economic disparities,
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it is increasingly important for both scientists and policymakers
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to have a rich and complex understanding of populations
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and the factors affecting them.
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- Subido por:
- Alicia M.
- Licencia:
- Dominio público
- Visualizaciones:
- 137
- Fecha:
- 10 de abril de 2024 - 15:50
- Visibilidad:
- Público
- Centro:
- IES LA SENDA
- Duración:
- 05′ 01″
- Relación de aspecto:
- 1.78:1
- Resolución:
- 1920x1080 píxeles
- Tamaño:
- 133.26 MBytes
