During the past few
decades research in the basic science of biology has yielded amazing knowledge.
Application of biological knowledge has changed our lives in many ways. Humans
are an integral part of the living world. Human beings have applied knowledge
of biological science for the welfare of mankind. We will discuss few examples
of historical and current endeavors.
Principles of Genetics
By using principles of
genetics, new better varieties of wheat, rice, corn, chicken, cow and sheep
have been developed poultry breeders have developed broilers for getting quick
and cheap white meat. Genes of disease resistance and other desirable characters
have been introduced into plants by using the techniques of genetic
engineering. Plants having foreign DNA incorporated into their cells are called
transgenic plants.
The plants can be
propagated by cloning, using special techniques called tissue culture
techniques etc. it is a technique in which a tissue is cultured to form a new
plant e.g. A phloem tissue of an ordinary commercial carrot was removed and
placed in a germ-free medium containing an adequate food supply, mineral salts,
and growth substances. The cell developed into a complete carrot plant, which
flowered and produced seeds.
Pesticides
The chemicals which are
used for killing the pests are called pesticides. Many fungi cause diseases in
plants which are controlled by using fungicides. Insect pests that cause a
great loss of plants and plant yield are controlled by using insecticides. Use
of pesticides is harmful to animal life including human beings. It is also an
environmental pollution. Insects and fungi may become resistant to the chemicals
used. Now some bacteria are being used as biopesticides, to control the
pollution caused by pesticides.
Hydroponics
Plants are grown with
their roots in dilute solutions of mineral salts instead of soil. This
technique has been named as solution or water culture techniques. This water
culture technique for growing plants with their root in a recirculating water
solution is hydroponics. By this process exact and controlled amount of
elements can be provided to plants. This method helps to determines inorganic
nutrients required for the growth and development of plants.
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| Vegetable grown by hydroponics method |
Food Preservation
Food is preserved by using
different techniques like drying, freezing, sterilization, chemicals and heat.
Killing of bacteria by heat is called pasteurization, developed by Louis
pasture. Milk and milk products are preserved by this method.
Disease Control
There is a great success
in the control of diseases. Three ways are generally taken to combat various
diseases.
1. Preventive
measures
2. Immunization
3. Drugs treatment
Preventive measures
Prevention is better than
cure. Malaria can be prevented by using
nets in doors and windows to ward off mosquitoes. By knowing the cause many
diseases can be prevented easily. For example AIDS (Acquired Immuno Deficiency
Syndrome) is caused by HIV (Human Immunodeficiency Virus). This disease spreads
through free sexual contacts, through blood transfusion, by using contaminated
syringes or surgical instruments. The best way of prevention from these
diseases is to avoid the point of contact.
Immunization
By immunization we are
able to save millions of lives. Peoples use to die or suffer from diseases like
tetanus, polio, hepatitis, whooping cough, measles; mumps etc. Immunization
involves the using of vaccines. By vaccination many diseases have been
controlled or even eradicated e.g. small pox. Polio has been effectively
controlled in Pakistan by massive campaign like observing polio days for
vaccination of children.
Drug treatment
a) Antibiotics
An antibiotic is a
substance that is produced by an organism and inhibits or retards the growth of
the microorganisms. Thousands of people used to die during war by infections.
By using of antibiotics precious lives have been saved. Penicillin,
streptomycin are the common examples of antibiotics.
b) Chemotherapy
With the increasing
knowledge of biological science treatment of fatal diseases like cancer is
possible. Chemotherapy is the treatment of infectious diseases or cancer by
means of chemical compounds. Likewise cancer is also treated by radiation e.g.
X-rays etc. The treatment by radiation is called radiotherapy. Repair of the
defective gene is performed by isolating the normal gene and inserting it into the
host through the bone marrow. This is called gene therapy.
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| immunization campaign |
Cloning
A clone is an individual
having identical genetic make-up like its parent. Cloning is possible with many
plants because asexual propagation by cutting and grafting is relatively easy,
and has been common practice. With this procedure and have orchard of uniform
plants. Cloning in frog, mice, cows have been successful. In 1997 a sheep named
Dolly has been cloned in Scotland which has been killed in early 2003 due to
her illness.
During the process of
cloning in animals the nucleus from a fertilized egg is removed. Then a nucleus
from a cell of fully developed individual (donor) is inserted to the
non-nucleated fertilized egg. The altered zygote is where it completes its
development. The animal formed is genetically identical to animal whose nucleus
was used. Thus by cloning multiple copies of a desired animal or genotype can
be made.
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| the cloned sheep-dolly with her lamb bonnie |
Biological Control and Integrated Disease
Management
In biological control
experiments, specialized predators are introduced into an environment in an
attempt to reduce population of certain pests or disease causing organisms. For
example to control the snake population in Islamabad mongoose have been
introduced. As a result the number of snakes has reduced in Islamabad. World
Health Organization (WHO) looks after the management, control and eradication
of diseases all over the world. Some diseases have been irradiated e.g.
smallpox. Many diseases are under control e.g. malaria. There is a ministry of
health in federal Government and in provincial Governments, which looks after disease
management in Pakistan e.g. vaccination against polio all over Pakistan.
Diseases are also treated and control through Government Hospitals,
dispensaries, private hospitals and clinics. Combating of disease by utilizing
all methods as and when required and ensuring a participation of community in
the program is called integrated disease management. This requires an awareness
of the community about the severity of the problems, its causes and remedies.
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