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But this is not always the case. Have a look at the following:

b) Which country’s population pyramid differs the most from Germany’s?

Male Female Male
USA 95 100
Japan 94 100
Germany 91 100
China 100 106
India 100 107

Activity 3:

To represent the differences in particular populations in pyramids

[lo 3.2]

  • When births and deaths follow their natural course in any community, and if there is no marked increase or decrease in numbers due to migration, the population structure is reflected as a “normal” pyramid, as in Figure 1. By now you already know it.

Within these normal communities with their “normal” pyramids, it might happen that cultural, social and economic factors change the composition of the population regarding age groups and gender. In this event the shape of a pyramid representing a particular community will begin to deviate from the norm. If a few thousand Turks leave Turkey annually to go and work in the city of Munich, the population structure of the Turkish territory, as well as that of Munich, will also change in due course.

  1. The pyramid for communities with a high birth rate , high death rate and a short life expectancy , will still be shaped like a “normal” pyramid, but the top will be lower and the pyramid will show marked indentations on the sides.

b) The pyramids for communities and populations with a low birth rate , an equally low death rate and a long life expectancy (an affluent society enjoying a good quality of life and medical care), will have a relatively narrow basis (narrower than the one above), gradually sloping towards the top.

  1. Only primitive communities (those in an early stage of development) have a high birth rate as well as a high death rate (the birth rate being the highest). This results in a rather rapid growth in the population
  1. The populations of developed countries (e.g. most of the Western European states) have a low birth and death rate . In some instances the birth rate is even lower than the death rate, resulting in a negative population growth. The life expectancy is high. In this case we refer to an “old” population.

Please note: The percentages on the horizontal lines are not the same for the four pyramids.

4. Why do changes in population occur?

In the long history of the world, most changes that took place related to growth only. Human beings simply continued to increase all over the earth. But this no longer holds true for all parts of the world. In some European countries the population is in fact shrinking (decreasing, becoming smaller).

And if you were under the impression that only (very) rapid growth in certain countries or areas cause problems, you’ll have to think again, for a decrease in the population can be equally problematic! In these instances people only have to cope with a different set of problems.

But before we pay attention to the effects and challenges of change, we have to establish why these changes occur in the first place.

Although it has already been said that some countries experience a decrease in their population, the major changes are mainly due to population increase. On the whole, the world population is actually growing .

Questions & Answers

how does Neisseria cause meningitis
Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
when we takee the specimen which lumbar,spin,
Ziyad Reply
How bacteria create energy to survive?
Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
what is sporadic nd endemic, epidemic
Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
explain assimilatory nitrate reduction
Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
advantages of normal Flora to the host
Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
what is cell
faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
what are emergency diseases
Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Lubega
Heyy Lubega hussein where are u from?
_Adnan
en français
Adama
which site have a normal flora
ESTHER Reply
Many sites of the body have it Skin Nasal cavity Oral cavity Gastro intestinal tract
Safaa
skin
Asiina
skin,Oral,Nasal,GIt
Sadik
How can Commensal can Bacteria change into pathogen?
Sadik
How can Commensal Bacteria change into pathogen?
Sadik
all
Tesfaye
by fussion
Asiina
what are the advantages of normal Flora to the host
Micheal
what are the ways of control and prevention of nosocomial infection in the hospital
Micheal
what is inflammation
Shelly Reply
part of a tissue or an organ being wounded or bruised.
Wilfred
what term is used to name and classify microorganisms?
Micheal Reply
Binomial nomenclature
adeolu
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Source:  OpenStax, Geography grade 7. OpenStax CNX. Sep 09, 2009 Download for free at http://cnx.org/content/col11021/1.1
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