12th Zoology

Human population and explosion


Environment literally means the surroundings of an object.
Environmental science or ecology can be defined as the study of organisms
in relation to their surrounding. Ecology is one of the most popular areas in
biology. Mankind is greatly interested in ecology in view of the problems of
over population, environmental pollution, human survival, pest control and
conservation of natural resources. The solution to all these problems involve
ecological principles. Hence knowledge of environmental science is necessary
for the survival of human race.

Human population and explosion – Issues

The world population was probably only a few million people before
the invention of agriculture and the domestication of animals. The following
table shows the alarming rate at which population has increased.
World population growth
Date – Population
5000 B.C. – 50 million
800 B.C – 100 million
200 B.C. – 200 million
A.D. 1200 – 400 million
A.D. 1700 – 800 million
A.D. 1900 – 1600 million
A.D. 1965 – 3200 million
A.D. 1990 – 5300 million
A.D. 2000 – 6100 million

It has been calculated that the human population is growing at a rate
of 90 million per year. At this rate the population would reach 12.5 billion
by the year 2050. If the population keeps growing at this rate, after a few
decades it will perhaps be too large for to be supported by the limited
resources available on the earth. The rapid growth will affect living
standards, resource use and the environment all over the world.

Demography (Human population and explosion)

Thomas Malthus studied the nature of population growth. He claimed
that population was increasing faster than food production and feared global
starvation. He proposed that, Population grows geometrically (1, 2, 4, 8)
rather than arithmetically (1, 2, 3, 4). The field of collecting, compiling and
presenting information about population is called demography, and the people
engaged in this work are named as demographers.

Malthus and population growth (Human population and explosion)

In 1798, the English economist Thomas Malthus realized that while the
human population was embarked on an exponential growth the
agricultural production remain limited. He forecasted that massive
famines would occur in the early 1800’s. Malthus foresaw a world, headed
toward calamity if something was not done to control the population
increase. Contrary to his predictions, technological innovations have
enabled enough agricultural production to the rapidly growing human

Population Dynamics (Human population and explosion)

A Population is a group of interbreeding organisms in a specific
region. It is analysed in terms of its variability, density and stability along with
environmental and other processes and circumstances that affect these
characteristics. Thus the nature of a given population is determined based
on birth and death rates, the distribution of ages and sexes, behavioral
patterns, food supplies, other environmental features and migration. Fertility
and birth rates, mortality and death rates helps us to assess the population
growth rates. A dynamic population possess a stable life span and life

Uneven distribution of population (Human population and explosion)

Declining mortality and not the rising fertility is the primary cause for
population growth during the past three hundred years. Population growth
and its variation among nations is not uniform. Some regions of the world are
over populated while others are literally uninhabited. The distribution of
population is influenced by a number of physical and economic factors. The
ecumen areas of the world with a congenial climate and fertile soils are
highly favourable for human occupancy. Areas of harsh climate – too hot,
too cold, too humid or too dry, rugged relief and low in resources are the
non-ecumen areas. These are the areas where the natural environment is
not conducive for human occupancy.

Related Topics in Zoology:

Bio Zoology All Important Topics

  1. Human population and explosion

  2. Population Explosion

  3. Growing Population and Environmental impacts

  4. Global warming – Green house effect

  5. Ozone layer depletion

  6. Prevention and Effect of Ozone depletions

  7. Waste management – Classification

  8. Management of hazardous wastes

  9. Management of non hazardous wastes

  10. Waste water treatment and management

  11. Biodiversity

  12. Conservation of Biodiversity

  13. Characteristics of a Bioreserve

  14. Energy crisis and its environmental impact

  15. Steps to be taken to resolve energy crisis

  16. Environmental impacts of Power Sources

  17. Poverty and environment

  18. Fresh water crisis and management

Unit 6. APPLIED BIOLOGY Topic List Zoology

  1. Livestock and Management

  2. Important cattle breeds and their characteristics

  3. Milch breeds (or) Dairy breeds

  4. Dual purpose breeds & Draught breeds

  5. Exotic breeds of cattle

  6. Common diseases and control in Cattle – Contagious diseases

  7. Non-contagious diseases – Cattle

  8. Techniques adopted in cattle breeding

  9. Poultry Breeds

  10. Farming methods

  11. Poultry byproducts

  12. Fish Pond

  13. Edible Fishes Of Tamilnadu

  14. Medical Lab Techniques – Stethoscope

  15. Sphygmomanometer

  16. Haemocytometer

  17. Urine Sugar analysis

  18. ECG Electrocardiogram

  19. Computed Tomography CT

  20. Endoscopy (Laproscopy) techniques , Artificial Pacemaker

  21. Autoanalyser

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