Human Population

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Human Population
A study of the human population explosion and its
impact on the environment FDP Sponsored by
AICTE,Ministry of HRD, Government of India

• Dr.Deepak vyas
• SPSU,Udaipur

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World Population (1900-2050)
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What happen to the population?

• At this moment, the world population is 6.4
  billion.
• 2000 years ago, it was 0.25 billion only
• Within 50 years, the world population will rise
  to 9 billion
• 9 billion 9,000,000,000
• What happened to cause the population explosion?

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What happen to the population?

• There are ¼ million people added to the planet
  per day.
• For one single hour, 10,000 babies born
• Every 3 seconds, a new life come to the world.
• The term population explosion refer to the
  situation that the human population grows so fast
  that it exceeds the carrying capacity of the
  environment.

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Population Explosion

• The human population growth of the last century
  has been truly phenomenal.
• Around 1800, the population was 1 billion, it
  took about 130 years to double itself and reach 2
  billion.
• It required only 45 years after 1930 for the
  population to double from 2 billion to 4 billion.
• The world population passed 6 billion just before
  the end of the 20th century.

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Factors affecting the rate of population growth

• Food supply
• Available of natural resources
• Disease
• Medical care
• Warfare
• Natural disasters i.e. earthquake, drought and
  flood
• Quality of life i.e. living condition
• Job opportunities and economic development
• Birth control
• Migration

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The early man (before 8000 B.C.)

• They lived in small, wandering groups with a
  simple hunting and food gathering
• This population was stable because
• Shortage of food wild animals and plants might
  be scared at times, so many people would be
  starved to death.
• Disease the absence of sanitation, people
  hygiene and medical care were the major reasons
  of the people deaths.
• Poor quality of life the constant exposure to
  sun, wind, cold, hunger and other physical stress
  would lower the life span.
• Predation by other animals snake, tiger, etc.

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Why?
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Why?

• According to last slide, we can see that the
  growth rate (slope) increased significantly from
  1800AD.
• What happened in 1800AD?
• The Industrial Revolution
• During that period, the development of machine
  and science has brought the world into a new era.

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Since 1800 to present

• It is the age of industrialization
• Advances in agriculture and transportation, which
  lowered the prospects of crop failure and
  improved distribution system, reduced famines.
• Medical advances conquered a number of fatal
  disease, reduced infant mortality, and increased
  life span.
• Adequate supply of food The yield of food has
  been greatly increased by improved farming
  techniques, better storage and distribution
  facilities.
• Green revolution the improved technologies also
  reduce the chance of crop failure and famine.
• Well medical care improved sanitation and
  control of infectious diseases lower the
  mortality sharply, especially for children. Thus
  the death rate decreased.
• High standard of life Living standards rose,
  widespread famines and epidemics diminished in
  some regions.
• As Birth rates gt death rates. So population
  started to grow greatly

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• Effect of population explosion

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• Global warming
• More natural resources were needed to sustain the
  new industrial system and the needs of growing
  societies.
• More forests needed to be stripped for
  agriculture and fuel
• ?CO2 level increased
• ?Greenhouse Effect Global warming
• Deforestation
• Less land for food production ? ever less food
• Limited resources
• Food
• The overall production of food is still enough to
  feed the present population.
• However, there is a surplus of food in developed
  countries wile starvation and famine occurs in
  some developing countries.
• Large quantities of food are being wasted in
  developed countries.

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Developed VS Developing
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Limited Resources

• Unequal distribution of resources
• Capital
• Most people in developing countries are poor,
  their living standards are very low as resources
  are not equally distributed in the world.
• As capital is insufficient, education, health
  care and some basic infrastructures are not
  provided in developing countries.
• As technology level is not high, large number of
  hands needed to perform low-technology
  agricultural tasks, thus the fertility rate is
  always high in developing countries.

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Limited Resources

• As population continues to grow, consumption rate
  of resources also increases.
• Natural resources that support human population
  are being exhausted at a faster and faster rate.
• Utilization of natural resources results in
  production of waste products and pollutions.
• As more energy is needed, there is a rise in
  energy crisis. Fossil fuel might be used up
  within a century.

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Diseases

• As people live in poor living condition and lack
  education, epidemics such as AIDS, Ebola threaten
  human life.

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Reasons for Unbalanced Food Supply

• Generally, there are several factors causing the
  problem
• Change in the use of the agricultural area.
• Over-grazed pasture
• Deforestation
• Wastage of food
• Artificial Modification of the environment
• Frequent Warfare

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Change in the purpose of the agricultural area

• In recent decades, farmers in many developing
  countries grow cash crop (e.g. coffee, cotton,
  tea and tobacco) in order to increase their
  income. As a result, less land is available for
  growing food crops.

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Over-grazed pasture

• The pastures are over-grazed in some area. The
  vegetation is eaten away at a faster rate than it
  grows. The fertile topsoil is then stripped off.
  Resulting in the transformation of pastures into
  deserts.

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Deforestation

• As thousands of trees have been cut down, the
  soil can no longer retain water, resulting in
  the soil erosion

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Wastage of food

• There are large quantities of food being wasted
  in developed countries due to the wasteful eating
  habits of the people.

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Artificial Modification of the environment

• The artificial modification of the environment
  has increased the chances of having natural
  disasters like droughts, flood and pests around
  the world. This would slow down the rate of food
  production.

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Frequent warfare

• Frequent warfare in many countries would lead to
  the reallocation of human resources and would
  bring damages to the agricultural area. These
  would seriously disturb the production processes
  of food

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Solution to the problem

• 1. Reduction of energy loss and food loss
• We should take in a larger proportion of
  food derived from the producers (e.g. plants and
  algae) and first consumer (e.g. herbivores) as
  eating low on the food chain is an effective way
  of reducing energy loss during the trophic
  transfer.
• Besides, the crops should be handled, shipped
  and stored properly after the harvest because the
  effective storage and transport systems can avoid
  the spoilage of food by insects or other
  pathogens.

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Solution to the problem

• 2. Increasing food production from crops
• The crop yields can be greatly improved by
  several methods (e.g. increase the protein
  content in crops by using fertilizers, crop
  rotation with leguminous plants, use of
  pesticides, application of plant growth
  regulators, GM technology and vegetative
  propagation methods.)

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Solution to the problem

• 3. Increasing food production from livestock
• The productivity and yield of livestock can be
  improved by selective breeding, the use of growth
  hormones and associated reproductive technology,
  and the use of antibiotics, drugs and
  immunization to control diseases and parasites.
  Moreover, the use of alternative food sources for
  livestock can reduce their consumption of human
  food proteins

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Solution to the problem

• 4. Development of technology in marine and
  freshwater cultures
• Many aquatic organisms are important sources of
  food proteins. The yield of the marine and
  freshwater organisms can be improved by
  controlling their ecological requirements, as
  well as controlling the diseases, parasites,
  predators and competitors in confined culture
  area.

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Solution to the problem

• 5. Development of technology to culture single
  cell proteins
• Single cell proteins are produced from cells of
  some organisms. The cellular products contain a
  lot of essential nutrients for the animals and
  human. If the appropriate conditions for growth
  of these organisms are identified. The process of
  producing the single cell proteins can be in a
  large scale.

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The need and strategies for human population
control

• If the growth of human population is allowed to
  continue without restriction, the population
  density might exceed the carrying capacity of the
  Earth.
• It will result in the exhaustion of natural
  resource, causing a large number of people die or
  suffer until the population reduce to a certain
  level.
• Thats why the countries around the world have to
  decide the strategies for controlling the human
  population.

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The need and strategies for human population
control

• Controlling the birth rate through intensive
  family planning and increasing access to
  contraceptive methods is an effective way to
  control the rapid population growth.
• Nowadays, a variety of contraceptive methods are
  widely adopted, which include rhythmic
  method,diaphragm, intra-uterine device,
  contraceptive pills, vasectomy and ligature of
  oviduct.

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The need and strategies for human population
control

• The status of women in the society can affect
  fertility levels to a certain extent. In
  developing countries, women should be provided
  with better education, health and other services.
  These widen their opportunities and reduce their
  dependence on giving birth to children for a
  status in the family.
• Moreover, the population control programmes in
  some countries may restrict the total number of
  children in a family. (e.g. the one child per
  family police in mainland China)
• Late marriage is also helpful in reducing the
  birth rate.

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Reference

• http//www.overpopulation.org/
• http//www.overpopulation.net/
• http//www.unfpa.org/swp/swpmain.htm
• http//www.census.gov/ipc/www/world.html
• http//epswww.unm.edu/facstaff/zsharp/103/lecture
  20192C20human20population.htm
• http//www.prb.org/Content/NavigationMenu/PRB/Educ
  ators/Human_Population/Human_Population__Fundament
  als_of_Growth_and_Change.htm
• http//www.globalchange.umich.edu/globalchange2/cu
  rrent/lectures/human_pop/human_pop.html
• Advanced Biology Principles Application
  (International students edition)
• Advanced-level Biology for Hong Kong Book 2