Population dynamics: growth, distribution, and change

Population Dynamics

The world we live in is marked by constant change and this affects all features of every day life. Among the most relevant changes that affect the contemporaneous society, one could easily point out the larger number of possibilities and therefore the increasing demands and consumerism levels. To better explain, the business community has changed its focus from producing and then selling, to prospecting the market in order to only produce those items that will sell without much effort. In other words, as they are given more options and as the manufacturers are there to serve their needs, the populations increase their demands and consume more than ever. All these then reflect upon the environment, which suffers from excessive extractions. And the environment is a constant and necessity of our lives. In this particular context, the need to analyze the population dynamics from an environmentalist perspective arises.

Population Dynamics

The dynamics of population refer to the numbers and characteristics of certain groups of all mankind, animals and plants that need to function together as a whole and sustain each other. The population dynamics have been studied for years from numerous standpoints, including political, economic, mathematical and even medical. A new door opens when the matter becomes analyzed from a biological angle. "Population is the number of individuals of a particular species in an area. Animal and plant populations depend on many things for survival. Limiting factors like the vailability of food, water and shelter can impact an organism's population. In nature, populations of animals and plants are linked together like a puzzle. The pieces of the plant and animal puzzle depend on each other to form a complete picture. If something is wrong with any of the pieces, it affects the whole puzzle" (New Hampshire Public Television, 2008)

The population dynamics for the contemporaneous global community can be summarized as follows:

total of 6,677,563,921 people are currently inhabiting the earth

27% are aged between 0 and 14; 65% are aged between 15 and 64; 8% are older than 65 the median age is of 27.4 years for men and 28.7 for women in 2008, the population registered a growth of 1.159% birth rates: 19.97 / 1,000 population death rates: 8.32 / 1,000 population life expectancy at birth: 66,12 years - 64.18 years for male and 68.2 for female total fertility rate: 2.58 children born per woman literacy: 82% - 87% for male and 77% for female (Central Intelligence Agency, 2008)

Along the recent decades, several environmental changes have been felt and they begin to more and more impact the population dynamics. A first such change is given by the increasing global warming, which is likely to generate an increased temperature. "All model stimulations show a warming in the future [...] the frequency of winters classified as cold will decrease, whereas hot summers will become much more frequent" (Richter, Sondgerath, Suhnling and Braune). As a result of these changes, the populations are expected to live in an accelerated rhythm, meaning a more compact and generally shorter life, materialized in a quicker replacement of generations. "Egg deposition and larval development and mortality rates are accelerated, hence population densities are lower at elevated temperatures" (Richter, Sondgerath, Suhnling and Braune)

Aside from the foreseen increase in the global temperature, the biological implications of the changes in population dynamics can also refer to the fecundity of the populations. In this particular instance, minimal variations have been observed between groups. For instance, women's fecundity, as revealed by a study conducted on ethnic groups across the globe, has an average of 31 years, between 15 and 46; the results were similar within the United States. The study then concluded that there are no modifications due to climacteric conditions (women's fecundity is similar at the North Pole and in the tropical regions). In other words, variations do no occur between groups, but rather inside the groups and are given by differentiated access to vital resources, such as food, water, shelter or even vitamins. The studies revealed similar results in the case of men fecundity, with the specification that the procreation time is longer than for women (Thomlinson, 1976).

In the same line of thoughts, population dynamics can also be analyzed from the angle of infertility. In this particular instance, the number of infertile couples has increased along the years, but the matter continues to remain rather controversial. For instance, there are certain groups which forward religious explanations for infertility and take it as a given by God. "And Sarah said unto Abraham: Behold now, the Lord hath restrained me from bearing" (Genesis 16:2, quoted by Thomlinson). But a more scientific approach has been forwarded and it aimed to find solutions. For instance, in the case of couples where the man is sterile, the woman could choose to be artificially inseminated; or in the cases when the woman is sterile, the man could inseminate a surrogate mother. But these alternatives are sometimes frowned upon and seen as equal to adultery (Thomlinson, 1976).

The population dynamics and their environmental effects can also be analyzed from three different angles: size, distribution and composition.

Despite the increasing infertility, the population size continues to increase, directly impacting the surrounding environment. "Population size is inherently linked to the environment as a result of individual resource needs as well as individual contributions to pollution. As a result, population growth yields heightened demands on air, water, and land environments, because they provide necessary resources and act as sinks for environmental pollutants" (Hunter, 2000). As a consequence, efforts have been made to reduce the population size and they basically refer to a reduction in the natality rate. But for a successful impact upon the environment and the natural resources to be felt, additional efforts must be made. These basically refer to a reeducation of the population in regard to their behaviors relative to the nature and could materialize in educational programs as to how to increase the efficiency while reducing the water and energy consumption.

The distribution of population refers to the location of the groups and individuals across space and it has three primary environmental implications: "(1) the increased pressure placed on overextended resources in many less-developed nations as a result of relative increases in population densities, (2) the ecological strain put on coastal resources as a result of amenity-driven migration in the United States, and (3) the ecological effects of urbanization, including concentration of pollutants and land-use conversion" (Hunter, 2000). All these materialize in increased demands, increased consumption and damaging effects upon the natural environment through increased pollution and reduced resources.

Finally, from the standpoint of population composition - or the primary features of a group of individuals (such as age, gender or socio-economic background) - the findings are rather elusive. It has however been found that demands and consumerism, and consequently pollution and eliminated waste, tend to increase as the household income increases (Hunter, 2000).