Population structure lesson4
Published on: Mar 4, 2016
Transcripts - Population structure lesson4
The interpretation of age / sex pyramids
POPULATION STRUCTURE: is the number of males and females in different age groups. The common method to show the structure is by a population pyramid. This diagram is made up by putting two bar graphs (one for male, one for female) side by side. From this you can read off what percentage of a population is of a certain gender and age range.
Key things to know about population pyramids: Population is divided into 5 year age groups. Horizontal line represents the percentage of male & female group The age groups are divided into 3 groups: Young dependent (0-14 years old) Working Population (15-64 years old) Elderly Dependent (65+ years old) Population is divided into males and females. The percentage of each age /sex group is given.
What does the shape of thepopulation pyramids tell us? Information of birth and death rates Information of life expectancy People living in a particular country or place
Comparing LEDC & MEDC
Three general profiles of population pyramids: Rapid growth: indicated by a pyramid with large percentage of people in the younger ages Slow growth: reflected by a pyramid with a smaller proportion of the population of the younger ages. Zero population or decreasing populations: shown by roughly equal numbers of people in all age ranges, tapering off gradually at the older ages
The population pyramid forKenya: Typical of a country in the LEDCs experiencing rapid population growth Wide base -large numbers of dependent children aged 0-14 as a result of high fertility rates Top of the pyramid indicates smaller proportion of the population lives to old age.
Implication of this type of population structure(rapid growth): Limited resources will be stretched to meet the needs of the large number of dependent children for schooling, nutrition and health care. As this group reaches working age, a large number of jobs will be needed As this group reaches child bearing age, it is likely that fertility rates will be high leading to high rates of natural population increase
The population pyramid for the USA: Typical for MEDC experiencing slow rates of natural increase Narrow base reflects low birth rates Wider top of the pyramid is the result of people living longer The bulge in 30-40 age cohort is a result of the baby boom of the 1960s
The population pyramid forGermany: Is similar to that of USA It represents a zero- population growth (BR – DR = 0) People are distribute evenly throughout the cohorts
Implication of this type of population structure Ageing populationA smaller proportion of the working age and are faced with the task of generating enough wealth to provide high levels of support for the elderly population
Consequences of ageingpopulation Limited manpower for defense of a country Give pressure to government to provide more medical and health facility for ageing population Shortage of labour, most of elderly retire and not enough young people to replace them Need more housing facilities and transport to meet the need of ageing population
Advantages of ageing population Tourism sector is boosted by the elderly taking holidays during off-peak seasons Industriesthat tap into the pensioner market (e.g. wheel chairs) Some large properties have been converted to profitable residential homes
Dependency ratioDependency ratio = % of population aged 0-15 + % of population aged 65+ % 0f population of working age