He vegetative growth Is the change in the size of a population caused by the interrelationship between birth and death rates. If the birth rate exceeds the mortality rate, then the population will increase. If the death rate exceeds the birth rate, then the population will decline.
Of the three factors (fertility, mortality, and international migration) that determine the size of a country's population, fertility or birth rate and mortality rate are the determinants of natural or vegetative growth.
The first stage of demographic change is when the birth rate and death rate fluctuate and are quite high. This is the period when the rate of vegetative growth of the population is usually low.
The second stage of the transition is when the death rate begins to decline, while the birth rate remains more or less constant. This is the period in which the population growth rate begins to increase and reaches the maximum.
In the third stage, the birth rate also begins to decline in response to the decline in the death rate. Finally, the fourth stage is when the birth rate and the death rate are fairly close and the birth rate is close to the replacement level and fluctuates.
It is here that the vegetative growth of the population stops or decreases. Countries at this stage often tend to balance the size of the population through the immigration of some international migrant population.
The demographic balance can often be achieved a long-term goal when the birth rate of a population is equal to the mortality rate, ie when the replacement level is met and the rate is stable.
Current world population
At present, the world population is 7 billion and is expected to reach 10 billion by 2080 and then is expected to stabilize vegetative growth. The population has been growing exponentially in the last two centuries, going from just 0.75 billion in 1750 to 7 billion today.
The population increase reached its peak in the 1960s, when the natural increase in the world population was 2.2%. Today, natural increase is falling, but is not expected to stabilize until 2100.
Population doubling time: Briefly, the doubling time of the population is the time it takes the population to double.
-2% growth rate - the doubling time of the population would be about 35 years.
-3% growth rate - the doubling time of the population would be approximately 24 years.
-4% growth rate - the doubling time of the population would be about 17 years.
Components of population change
- Life Expectancy - The average number of years a person in a specific country is expected to live.
- Birth rate - Number of people (alive) born per 1000 inhabitants per year (normally per km2).
- Mortality rate: the number of people who die per 1000 inhabitants per year.
- Annual Population Change: This is when the cumulative change in population size after natural change and migration has been taken into account.
- Calculation of population change: Population change = Birth rate ± Mortality rate ± Migration.
Factors that influence natural or vegetative growth
Health
A high level of health care in a country will help reduce child mortality by reducing the birth rate since people do not need to have so many children to ensure that some survive.
High standards of health care ensure that people have good access to modern medical treatment, which prolongs life expectancy and lowers the mortality rate.
In areas with healthy and balanced diets, the mortality rate will be reduced, but in countries with poor diets or food shortages, the mortality rate will increase due to malnutrition. Countries with high health care standards will have access to retroviral drugs, which gives them the potential to fight HIV.
Education
The emancipation of women reduces the birth rate, since women are able to obtain careers instead of staying at home and caring for children which makes them less likely to have children.
Compulsory education ensures that people are educated about hygiene, venereal diseases and contraception. Knowledge of basic hygiene will lower the mortality rate since people can maintain a better standard of hygiene (assuming the necessary items are available).
Education on contraception will help reduce the birth rate, as people will be aware of the benefits of using contraception, but again, this depends on the provision of contraceptives from governments or charities.
Very high levels of education provide an opportunity for advanced education, paving the way for the training of medical doctors and researchers who will potentially reduce the mortality rate thanks to new discoveries and the availability of better trained physicians.
Social security
If adequate social care is provided to the elderly and given proper medical care, the mortality rate is reduced as they are able to live longer. If potable water is available, the mortality rate is reduced, since water-borne diseases such as cholera are no longer prevalent.
With an improved hygiene standard, the mortality rate is reduced. The availability of the media facilitates the education of people and awareness of disease outbreaks, potentially reducing the mortality rate.
The availability of the media is also essential for educating people about hygiene, avoiding diseases, etc. If these people could not have formal education.
Cultural Factors
In some cultures and religions, people are more respected if they have many children, resulting in an increase in the birth rate. For example, in some cultures having many children is seen as a sign of manhood in men.
On the contrary, some cultures and religions discourage large families, although this is rare. This would have the effect of reducing the birth rate. Certain religions see birth control and abortion as bad in the eyes of their beliefs.
As a result, they discourage the use of these procedures resulting in an increase in the birth rate in countries where these religions are frequent. In some non-secular countries, the use of contraception and especially abortion is prohibited, resulting in a significantly higher birth and death rate as a result of the spread of sexually transmitted diseases.
Some religions and cultures relegate the role of women who prevent them from obtaining an education or a career and are encouraged or forced to have large families, resulting in an increase in the birth rate.
Political Factors: Some countries offer benefits to people who have many children to encourage people to give birth (eg France) as a result of aging populations. This has the desired effect of increasing the birth rate.
Alternatively, some countries offer rewards to couples who have fewer children in order to encourage people to have fewer children, resulting in a low birth rate. If taxes in a country are high, people may not have children because they can not afford it and this, the birth rate decreases.
In times of war, the birth rate will drop significantly and the death rate will often increase substantially. After a war, however, there is often a"baby boom"or birth boom that results in a massive increase in the birth rate in a country.
Environmental factors
Countries with frequent natural disasters often have a high mortality rate. In addition, there may be large numbers of people migrating out of the country for fear of their lives, resulting in an overall reduction in the population of those countries.
Climate can affect mortality rates, in warmer countries, the death rate may increase due to the spread of diseases that spread more easily in hot climates.
In cold countries, the mortality rate may also be high due to the effects of cold and lack of supplies. In countries with heavy industry, air and water pollution could be very high, increasing the mortality rate as a result of contaminated water supply.
References
- Jackson, A. (2011). World Population Growth. 8-1-2017, from Geography AS Notes Website: geographyas.info.
- World Health Organization. (2014). Natural population growth rate. 8-1-2017, from WHO Website: searo.who.int.
- Kimball, J. (2012). Human Population Growth. 8-1-2017, Kimball's Biology Pages Website: biology-pages.info.
- Espenshade, T. (1975). The stable decomposition of the rate of natural increase. 8-1-2017, from Science Direct Website: sciencedirect.com.
- Worldometers. (2017). Current World Population. 8-1-2017, from Dadax Website: worldometers.info.