In biology, human population growth is the increase in a number of each individual in a population. The average human population growth amounts to 83 million annually. The human Key trends regarding human population in china. In general the world’s population is increasing tremendously and by October it stepped at 6 billion. Of the six billion people china Uneven distribution of population and conflicts stemming from racial, cultural, religious, social or political diversity are problems in almost every country in the world. In the total world
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We have been concerned about unbridled human population growth and problems created by it in our country and it is therefore natural for us to be curious if different animal populations in nature behave the essay on human population way or show some restraints on growth. Perhaps we can learn a lesson or two from nature on how to control population growth. In nature, we rarely find isolated, single individuals of any species; majority of them live in essay on human population in a well defined geographical area, share or compete for similar resources, essay on human population, potentially interbreed and thus constitute a population.
Although the term interbreeding implies sexual reproduction, a group of individuals resulting from even asexual essay on human population is also generally considered a population for the purpose of ecological studies. A population has certain attributes that an individual organism does not. An individual may have births and deaths, but a population has birth rates and death rates. The rates, hence, are expressed is change in numbers increase or decrease with respect to members of the population. Another attribute characteristic of a population is sex ratio. An individual is either a male or a female but a population has a sex ratio e.
A population at any given time is composed of individuals of different ages. If the age distribution is plotted for the population, the resulting structure is called essay on human population age pyramid. For human population, the age pyramids generally show age distribution of males and females in a combined diagram. The shape of the pyramids reflects the growth status of the population whether it is growing, stable or declining. The size of the population tells us a lot about its status in the habitat. The size, in nature, could be as low as less than 10 Siberian cranes at Bharatpur wetlands in essay on human population year or go into millions Chlamydomonas in a pond, essay on human population. Population size, more technically called population density, need not necessarily be measured in numbers only.
Although total number is generally the most appropriate measure of population density, it is in some cases either meaningless or difficult to determine. Sometimes, for certain ecological investigations, there is no need essay on human population know the absolute population densities; relative densities serve the purpose equally well. For instance, the number essay on human population fish caught per trap is good enough measure of its total population density in the lake. We are mostly obliged to estimate population sizes indirectly, without actually counting them or seeing them, essay on human population.
The tiger census in our national parks and tiger reserves is often based on pug marks and fecal pellets. The size of a population for any species is not a static parameter. It keeps changing in time, depending on various factors including food availability, predation pressure and reduced weather. In fact, it is these changes in population density that give us some idea of what is happening to the population, whether it is flourishing or declining. Whatever might be the ultimate reasons, the density of a population in a given habitat during a given period, fluctuates due to changes in four basic processes, two of which natality and immigration contribute an increase in population density and two mortality and emigration to a decrease. i Natality refers to the number of births during a given period in the population that are added to the initial density.
iii Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration. iv Emigration is the number of individuals of the population who left the habitat and gone elsewhere during the time period under consideration. Under normal conditions, births and deaths are the most important factors influencing population density, the other two factors assuming importance only under special conditions. For instance, essay on human population, if a new habitat is just being colonised, immigration may contribute more significantly to population growth than birth rates.
Resource food and space availability is obviously essential for the unimpeded growth of a population, essay on human population. Ideally, when essay on human population in the habitat are unlimited, each species has the ability to realise fully its innate potential to grow in number, as Darwin observed while developing his theory of natural essay on human population. Then the population grows in an exponential or geometric fashion. Any species growing exponentially under unlimited resource conditions can reach enormous population densities in a short time, essay on human population. No population of any species in nature has its disposal unlimited resources to permit exponential growth. This leads to competition between individuals for limited resources.
The governments of many countries have also realised this fact essay on human population introduced various restraints with a view to limit human population growth. In nature, a given habitat has enough resources to support a maximum possible number, beyond which no further growth is possible. A population growing in a habitat with limited resources show initially a lag phase, followed by phases of acceleration and deceleration and finally an asymptote, when the population density reaches the carrying capacity. A plot of N in relation to time results in a sigmoid curve. This type of population growth is called Verhulst-Pearl Logistic Growth and is described by the following equation:.
Since resources for growth for most animal populations are finite and become limiting sooner or later, essay on human population, the logistic growth model is considered a more realistic one. Gather from Government Census data the population figures for India for the last years, plot them and check which growth pattern is evident. It has three phase, i. It has three phases, i. Our global human population, 6 billion at present, will cross the 7 billion mark by In the near future, fossil fuel from oil fields will run dry. It will be impossible to meet the demands for food from-existing agro systems.
Pastures will be overgrazed by domestic animals and industrial growth will create ever-greater problems due to pollution of soil, essay on human population and air. Seas will not have enough fish. Larger ozone holes will develop due to the discharge of industrial chemicals into the atmosphere, essay on human population, which will affect human health. Global warming due to industrial gases will lead to a rise in sea levels and flood all low-lying areas, submerging coastal agriculture as well as towns and cities. The control over regional biological diversity, which is vital for producing new medicinal and industrial products, will lead to grave economic conflicts between biotechnologically advanced nations and the bio rich countries.
Degradation of ecosystems will lead to extinction of thousands of species, destabilizing natural ecosystems of great value. These are only some of the environmental problems related to an increasing human population and more intensive use of resources that we are likely to face in future. In some countries, essay on human population, food shortage has become a permanent feature. Two of every three children in South Africa are underweight. In other regions famines due to drought have become more frequent. Present development strategies have not been able to successfully address these problems related to hunger and malnutrition.
Similarly, the disparity between the rich and the poor in India is also growing. The increasing pressures on resources place great demands on the in-built buffering action of nature that has a certain ability to maintain a balance in our environment. There has been a dramatic reduction in the doubling time the time needed for a population to double its size at a constant annual rate of the global human population. In the 20th century, human population has grown much faster than ever before. In the yearthe world population was 6. This unprecedented growth of human population at an alarming rate is referred to as population explosion.
Population explosion is causing severe resource depletion and environmental degradation. Our resource like land, water, fossil fuels, minerals etc. are limited and due to overexploitation these resources are getting exhausted. Even many of these renewable resources like forest, grassland etc. are under tremendous pressure. Industrial and economic growth are raising our quality of life but adding toxic pollutants into the air, water and soil, essay on human population. As a result, the ecological life support systems are getting jeopardized. There is a fierce debate on this issue as to whether we should immediately reduce fertility rates through worldwide birth control programs in order to stabilize or even shrink the population or whether human beings will devise new technologies for alternate resources, so that the problem of crossing the carrying capacity of the earth will never actually come.
The only remedy for the essay on human population explosion is birth control programmes. You must be logged in to post a comment. Your Article Library Home Static Main Menu Home Share Your Files Disclaimer Privacy Policy Contact Us Prohibited Content Prohibited Content Image Guidelines Plagiarism Prevention Content Filtrations Terms of Service Account Disabled. Related Articles: Essay on the Growth Form of Species Population Plant Population Dynamics and its Growth Rate. Relationship between Environment and Human Health. Leave a Reply Click here to cancel reply, essay on human population. In the last phase number of new cells produced is almost same as the number of dying cells. In the last phase growth stops due to the stoppage of food supply. It is applicable to many microorganisms, plants and animals.
It is not applicable to many microorganisms and animals.
Mandela Effects that prove we live in a simulation
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In biology, human population growth is the increase in a number of each individual in a population. The average human population growth amounts to 83 million annually. The human Uneven distribution of population and conflicts stemming from racial, cultural, religious, social or political diversity are problems in almost every country in the world. In the total world Essays on Human Population History of The Evolution of Homo Sapiens. An association conducted research based on the history of the evolution of Human World’s Population.
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