Human Population Size

Running Head : HUMAN POPULATION

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Human population

Birth rate

Natural population size continues to increase due to the fact that birth rates are still higher than death rates , and child /infant mortality rate is reducing . Crude birth rate is the ratio of children born per a thousand persons per year . Child /infant mortality rate is the ratio of specified period of time

An increase in birth rate causes a corresponding increase in the population size while a decrease in birth rate causes a decrease

in population (University of Michigan , 2006

The natural population increase rate is the difference between birth rate and death rate . The world population continues to increase exponentially (University of Michigan , 2006 ) When considering demographic transition (which is the transition from high birth and death rate to low birth and death rate , both high birth and death rates causes a slow but steady population growth , declining death rates and high birth rates causes a faster and unstable population growth University of Michigan , 2006 )The world population birth rate is decreasing

Factors affecting birth rates are

Rates of abortion - many youths are resorting to abortion when they get unwanted pregnancies . This decreases birth rate

Age structure - many developed countries have a big ageing population meaning their birth rates are low . A big population of 15-24 years would mean more births hence high birth rate (John W . Kimball , 2006

In developing countries children are seen as a source of income and labor resulting to a big birth rate

A low infant mortality rate will cause a low birth rate because people will give birth to fewer children when they know the children are more likely to arrive at the maturity age , and vice versa

Governments and the world economy believe that a small family size would mean less unemployment rates , better and reliable health and education facilities , and uniform and increased wealth distribution to all . With such believes , family planning and control measures have emerged

Increased availability and affordable family control measures such as contraceptives and pills

Fertility rate

Fertility rate is the average number of children a woman can have during her child- bearing age (in her life time . It is a good measure of birth rate since it is not affected by the age structure in a population . A fertility rate of 2 .1 means that a pair of parents only replaces itself i .e . if they live until the life expectancy age and their children arrive the age of 15 years

A lower fertility rate (mostly experienced in developed countries ) are due to : tremendous wealth , low mortality rates , easily accessible and affordable birth control (such as contraceptives , the belief that high population will contribute to economic saturation or decrease , and people study until late years when they can give birth or they may not give birth at all due to academic or work issues (Kamla Raj , 2005

A high fertility rate (experienced in developing countries ) are due to belief that more children result...