human population environment
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This document discusses human population and its relationship to the environment. It covers topics like population ecology, growth, density and carrying capacity. It also discusses factors governing human settlement like land, food, water and energy resources. It describes population pollution due to overpopulation exceeding environmental carrying capacity. Reasons for overpopulation include high birth rates, low death rates, migration and illiteracy. Effects of overpopulation include increased demand for resources and generation of waste. The document also discusses population growth rates, theories of Malthus and Marx, and methods of population control and forecasting.
human population environment
- 3. INTRODUCTION • Population : The word population has been derived from the Latin word “populatio” which means people. • The group of individual species which occupy a definite geographic area is defined as population. • Population Growth : The change in population per unit area at particular time is called population Growth.
- 4. Population density :Population density is defined as the number of individual or people per unit area in per unit volume of Environment. Carrying Capacity : Maximum population size indefinitely supported by available resources .
- 5. Human Settlement • The human settlement can be defined as communities who live in city, village or town with all social, material ,organizational, spiritual and cultural elements which exist and sustain for long time. • The human settlement needs natural resources, physical elements as well as services to sustain. • These components comprises of fresh clean air, water , food, shelter and services include like education, medical facilities.
- 6. Environmental factors governing human settlement • LAND : As population increased , people started taking over more and more land for human settlements. Land was used to develop infrastructures like roadways , public complexes and industries. • FOOD : With the increase in population , there was a demand for more and more food and so more land was started to be used for agricultural activities.
- 7. Development of advanced technologies in the field Of agriculture caused use of fertilizers and pesticides for increasing productivity which deteriorated the quality of environment and health of human beings. • Water Resources: High population and settlement of human beings in different places caused the problem of water scarcity due to unequal distribution of water resources and unplanned use of these resources for industrialization and urbanization.
- 8. • ENERGY RESOURCES : Conventional energy resources started depleting due to high demand of increased population for energy. • FOREST RESOURCES : Due to increased population , use of more land area for human settlement and industrialization also increased.
- 9. Population Pollution • Population pollution is the pollution caused due to overpopulation. • Overpopulation is the condition when the population (number of organism) exceeds the maximum carrying capacity of the environment.
- 10. Population Pollution • The maximum carrying capacity of environment is the capacity to support human beings with the availability of food , water , shelter, as well as protecting human beings against the extremities in environment. • Over population is not a function of size or density of the population. • Determined by calculating ratio of population to available sustainable resources.
- 12. Reasons for Overpopulation High Birth Rate : • The crude birth rate is the number of child’s birth per 1000 people per year. • If the birth rate is high , it implies more number of people will be for human settlement and will therefore cause overpopulation. • Birth rates are affected by a number of factors : – Social beliefs – Religious beliefs – Mortality rate – Literacy – Economic prosperity – Abortion rate
- 13. Low Death Rate: • Decline in mortality rate • The crude death rate is the number of deaths per 1000 people per year. • Low death rate is basically due to technological advancement in the field of medical science which reduced the mortality rate. • Other reason for this may be: Average age , Nutritional levels, Standard of diet and housing, Access to clean water, Hygiene level.
- 14. Migration : • People from towns and villages generally migrate to cities in search of jobs and better living standards which overpopulates the cities. • Similarly, people from developing countries try to migrate to developed countries making them overpopulated.
- 15. ILLITERACY : • People of lower and poor classes generally have larger families due to poor education facilities. • In India, particularly in villages , due to religious beliefs or due to eagerness to have a male child people tend to have big families.
- 16. Effects of Population Explosion • Population Explosion: When the population increases suddenly, it is termed as population explosion. • Population Crash : When the population of human beings decreases , it is called population crash. • It is different from Overpopulation, since this condition arises when economic development fails to maintain pace with the population growth.
- 17. Effects of Population Explosion 1. High Demand Of Basic Needs : Population explosion causes scarcity of food and increase in the prices of food items. • It also leads to the formation of slums in big cities. • Shortage in agricultural land and water may also cause starvation in some parts. • It creates problems like rush in transportation, education and medical Facilities.
- 18. 2. Reduction In Natural Resources : Population Explosion causes depletion in natural resources due to more consumption of these resources by the people. It leads to high consumption of fossil fuels , minerals and forest resources. More forest will be cut down to provide wood for housing and fuel. More water is required for drinking, irrigation and industrial purpose.
- 19. 3. Generation Of Huge Quantity Of Waste: • Population explosion results in generation of wastewater , industrial effluents and solid waste which poses the stresses over the facilities for disposal of wastewater. • Causes ecological imbalance
- 20. 4. OTHER EFFECTS : (a) Increase in migration rate and reduction in living standard of people. (b) Reduction in agriculture land. (c) Increase in unemployment (d) Deterioration in the quality of environment due to pollution in soil , air , water and air. (e) High crime rate (f) Energy crisis (g) Increases number of slums
- 21. Population Growth Rate • The population growth can be expressed by Population Growth Rate. • Population Growth Rate is the fractional rate at which the number of individuals in a population increases.
- 22. Exponential Growth Rate • In these , the rate of change of population is directly proportional to population at that time. • If after time ‘t’ population is Nt and r is the rate of population growth , then dNt/dt= rNt Nt=Noert • The above mentioned equation is used for calculating Exponential Growth Rate.
- 23. • Doubling Time : The time required for a population to double itself is called the doubling time. • In these, when Nt=2No , t=td, then the equation becomes td=0.693/r
- 24. Logistic Growth Rate • Rate of increase of population never remains constant but varies with time. • It is also called as S-shaped or Sigmoidal growth curve. • This curve is density-dependent. dN/dt=rN{1-N/K} where, N=Population size K=Carrying capacity r=Logistic growth Rate
- 25. • The factor (1-N/K) is called environmental resistance and it becomes negative when population exceeds carrying capacity and thus factor (1-N/K) is responsible for achieving logistic growth from exponential growth. • Logistic Growth is divided into three phases:
- 26. • Phase-I : In this phase, population size is much less than the carrying capacity and rate of growth is proportional to population size • Phase-II : In this phase, increase in population is rapid compared to phase-I and growth is steady . (dN/dt=Constant). • Phase-III : Here , population growth decreases as population approaches to carrying capacity i.e. dN/dt=0.
- 27. PREDICTING POPULATION GROWTH, Two modes of population growth.
- 28. • The Exponential curve also known as J-curve. It occurs when there is no limit no population size. • The logistic curve also known as S-curve. It shows the effect of limiting factor ( in these case the carrying capacity of environment.
- 30. Population Growth Theories • There are two important theories of population , which are related to the present trends of population growth. • MALTHUSIAN THEORY : • He born in 1766 -1834. • Wrote “ An essay in the first principle of population” first in published in 1798.
- 31. • Passion between sexes is necessary and will remain unchanged • Food is necessary for the existence of humankind
- 32. • Malthusian theory states that, human population increased with exponential rate while the ability to grow food increased arithmetically. • Population grows at a geometric rate i.e. 1, 2, 4, 8, 16, 32, etc. • Food production increases at an arithmetic rate i.e. 1, 2, 3, 4, etc.
- 33. The Core principles of Malthus • Food is necessary for human existence. • In these , Malthus suggests that the food is essential for the survival of man and that the size of population is determined by the availability of the food. • Human population tends to grow faster than the power in the earth to produce subsistence(food).
- 34. • A point will come when population overcome the food source resulting in crisis • Limiting the population in line with carrying capacity requires “ strong checks”. Preventive Checks and Positive Checks. • Positive check: disease outbreak • Preventive check: control of birth rate • In above mentioned point , Malthus concludes that the tendency of the population to indefinite increase may be controlled by the two types of checks.
- 35. • Preventive / Negative Checks : “This suggest to reduced or decreased birth rate” . preventive checks - postponement of marriage (lowering of fertility rate), increased cost of food etc. positive checks – These checks lead to an increase in the death rate. Famine(shortage of food), war, disease, would increase the death rate.
- 36. Limitations of Malthus Theory (A) Malthus did not consider migration of people. (B) Malthus failed to recognize the potential of human population to increase food supply. (C) He also did not consider man’s ability to use science and technology, advancement in the field of agriculture to increase food supply, family planning methods. (D) He has confused the instinctive desire for sexual relationship with the desire to have children
- 37. Malthus (cont.) Population grows geometrically…. Population exceeds carrying capacity… Population is kept in “check”– preventative and/or positive checks
- 38. Marxian Theory • Full Name: Karl Heinrich Marx • Birth: May 5th, 1818 • Death: March 14th, 1883. • Also called theory of surplus population • Karl Marx believed that depletion of natural resources, existence of poverty and pollution as well other social ills present in the society are indicated by the population growth.
- 39. • Therefore, population increase is an indicator rather than a cause of these problem. • According to him , there can be no universal law of population. • He believed that man’s tendency to pressing the means of subsistence(the means by which one maintains life) is due to the evils of capitalism which would disappear with the emergence of communism.
- 40. • As a result unemployment spreads , wages decline and poverty increase. • He came to the conclusion that main cause of surplus of population was nothing but the wrong politics of the capitalists. • Marx stated that poverty and unemployment is not only due to increased population but due to capitalist system which failed to provide the job.
- 41. Control of population growth 1. Education 2. Living standard and employment 3. Government benefits and incentives 4. Publicity 41
- 42. Control of population growth • 1.Education • Improvement of literacy rate in villages and lower and middle class of people, particularly in women can control the population growth. • 2.Living standard and employment Employment will improve the living standard of people so there will be improvement in education and awareness of family planning which could control the population growth. 42
- 43. 3.Government benefits and incentives • Implementation of government policies to give special incentives to people having only two children and benefits to such children in education later on ,may play an important role in control of population growth. 43
- 44. 4.Publicity • Publicity by giving advertisements and incentives, stating importance ,need and significance of birth control and family planning may also control growth. 44
- 45. Population Forecasting Method • The data regarding present and past population of any city is always available from the records of municipal corporations but to design a new water supply scheme or waste water treatment plant, the current and future population must be forecasted. • Following are some methods of population forecasting:
- 46. Methods of population forecasting • Arithmetical increase method • Geometrical increase methods • Incremental increase method • Graphical extension methods • Logistic curve methods. Other: • Zoning Method • Decrease rate of growth method • Ratio and correlation method
- 47. • Arithmetical Increase Method :Principle of this method is that the rate of change of population with time is constant as show below. • dp/dt = constant • For past three to four decades , data for future population is calculated by the following formula:
- 48. Pn= P + n I Pn=population forecasted N=Decades P=Present population I=Average Increment of a decade
- 49. Geometrical increase methods • Principle of this method is that the percentage growth rate of population with time is constant. • For the past three or four decades , data for future population is calculated by the formula given below. Pn = Po{ 1+r/100}n
- 50. • Po= Initial population • Pn= Population forecasted for n decades. • r= % growth rate of population NOTE= This method is used only for those cities having high population growth.
- 51. DEMOGRAPHIC PROJECTION • Demographic projections are used to represent the increase in population, shift has been from high birth rates and high death rates to low birth rates and death rates. • Demographic transition (DT) refers to the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system.When the birth rates and death rates are equal then zero population growth rates are observed which is called as “Demographic Transition”
- 53. • There are four stages of demographic stages: • Phase-I: Due to lack of awareness, poor medical facilities, low education levels and natural disasters, high birth rates and high death rates are there. • Phase-II : In developing countries , due to advancement in technologies and improvement in medical facilities and Education system, death rates dropped rapidly compared to corresponding birth rates. This caused high increase in population in countries.
- 54. • Phase-III: In this, due to urbanization and industrialization, reduction in natural resources, women’s education and family planning scheme, high reduction in birth rates was observed which tried to level off the population growth. • Phase-IV : In this phase , both birth rates and death rates are low. High living standards and more jobs by women lead to reduction in fluctuating birth rates and death rates are also low because of high technologies and excellent medical facilities.
- 55. • Phase V: In developed countries like UK where population are now reducing well below their replacement level and population growth may tend to negative or zero. • This theory cannot predict correct future population as it does not consider factors like population migration.
- 57. Population Structure • Infant Mortality Rate: Measure of mortality rate which is deaths of infants per 1000 births, in a given year. • Natural increase of population: difference between crude birth rate and crude death rate • Sex ratio: number of females per 1000 males • Total fertility rate is average number of children that would be born to a women during her life time • Age structure: Pre-productive 0-14 Reproductive 15-44 Post productive >45
- 58. Urbanization • Growth in the proportion of a population living in urban area is called urbanization. • In developing and less developed countries, urbanization results due to demographic and economic pressure. • People migrate to bigger urban centers to seek jobs and other social services.
- 59. Environmental and Socio-economic problems due to Urbanization • Demand for dwelling place: as the population increases more and more land is required. • Overcrowding: as people migrate to urban areas for employment opportunity, education and medical facility leads to the overcrowding of urban areas. • Increase crime: increase unemployment and poverty leads to increase in growth rate of crime.
- 60. • Exploitation of ground and surface resources: demand for different resources like water, electricity, fossil fuel etc. will increase with population increase. • Increase of air pollution • Generation of solid and liquid wastes • Pressure on habitants of wild and domesticated animals
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