Human activities related to livelihood and welfare generate waste.
All wastes are pollutants and they create pollution in one way or other.
Fundamentally air, land and water pollution results mostly due to improper
disposal of wastes. (Waste management)
Pollution, Pollutants
Pollution is the human caused addition of any material or energy
(heat) in amounts that cause undesired alterations to water, air or soil. Any
material that causes the pollution is called a pollutant.
Classification of wastes
1. Bio – degradable waste
These are wastes capable of being removed or degraded by
biological or microbial action. Waste from agricultural products, animal wastes
and waste from food processing, leather, fibre, paper and wood etc. come
under this group. (Waste management)
2. Non bio-degradable waste
The substances which are normally not acted upon and decomposed
by microbes are non-bio degradable wastes. It includes mineral waste,
mining waste and industrial waste and non-degradable metallic and plastics
substances. (Waste management)
3. Mixture of biodegradable and non-biodegraded wastes
It includes municipal waste and industrial waste. Municipal waste
contains household garbage, piles of food scrapes, old newspaper, discarded
and throw away materials, glass, cans, old appliances, broken materials,
leather shoes, fibres, plastics and others. Construction waste materials,
packaging materials, sewage, hospital waste, junk and vehicles are varied
types of urban wastes. All these wastes are found in the form of semisolid,
solid, semiliquid, sludge and in fly ash form. (Waste management)
If the ozone is depleted more ultraviolet radiations (especially
ultraviolet B (UVB) will reach the earths surface.
Effect on plants:- will affect crop yield and forest productivity.
Effect on animals:- will cause damage to fish larvae and other small
animals
Effect on human health:- Results in non-melanoma skin cancer and
melanoma, acute erythem a (sun burn), ocular abnormalities, cataract, affect
immune responses.
The general effect of ozone depletion is summed up in the following chart (Effect of Ozone depletions)
Preventing ozone depletion:
1. CFC’s (Chloro Fluro Carbons) should be replaced by HCFC’s (Hydro
Chloro Fluro Carbons). (If over used could damage ozone), HFC’s (Hydro
Flouro Carbons), Hydrocarbons such as butane and propane. (but flammable
and poisonous), Ammonia (must be handled carefully), Water and
steam.
2. Production, use and emission of ozone – depleting chemicals should be
controlled.
3. Recycling of these chemicals should be increased.
4. Servicing of refrigerators and air-conditioners should be regulated.
5. Refrigirants should be recaptured and used.
6. Adopt protection measures from sun’s radiation. (Effect of Ozone depletions)
Monitoring Ozone depletion
In early eighties scientists reported a large hole in the ozone
layers over Antarctica, where ozone level dropped by 30 percent. CFC
was the prime suspect for causing ozone depletion.
· Subsequently a similar hole was discovered over the thickly
populated northern hemispheres(North Europe and USA).
· An international agreement made in 1987 at Montreal organized
by 34 countries (Montreal Protocol) called for reduction in the
usage of CFC up to 50% by the end of the century.
· In June 1992 Japanese scientists announced that the ozone
hole was 13 times wider in 1991, than it had been in 1981.
· In 1990, at London conference the developed countries agreed
to 100 percent ban of CFCs by 2000 A.D.
· In 1991-1992, Scientists working in European Arctic stratosphere
Ozone experiment in Sweden sent 39 balloons with payload up to
500 kg and 800 ozone probes. Their findings revealed that ozone layer
was reduced by 15-20 percent. Chlorine was also found in active form in
the atmosphere. (Effect of Ozone depletions)
Ozone is a form of oxygen (O3). In the stratosphere (ozonosphere), ozone blocks out the sun’s ultraviolet rays and is a lifesaver.
Ozone as a natural sun block (Ozone layer depletion)
The electromagnetic radiation emitted from the sun includes
ultraviolet radiation, which is potentially harmful to most living things since it can damage DNA.
The ozone layer screens out the sun’s harmful ultraviolet radiation. Even 1% reduction in the amount of ozone in the upper stratosphere causes a measurable increase in the ultraviolet radiation that reaches the earth surface.
If there was no ozone at all, the amount of ultraviolet radiation reaching us would be catastrophically high. All living things would suffer radiation burns, unless they were underground,
or in the sea. (Ozone layer depletion)
In the stratosphere, small amount of ozone are constantly being made by the action of sunlight on oxygen. At the sametime, ozone is being broken down by natural processes.
The total amount of ozone usually stays constant
because its formation and destruction occur at about the same rate. But unfortunately human activity has recently changed that natural balance. (Ozone layer depletion)
Some manufactured substances such as chloroflurocarbons and hydrochloroflurocarbons can destroy stratosphere ozone much faster than it is formed.
Ozone hole: (Ozone layer depletion)
Ozone loss was first detected in the stratosphere over the Antarctic.
The part of the atmosphere where ozone is most depleted is referred as
“Ozone hole” but it is not a real hole just a vast region of the upper atmosphere where there is less ozone than elsewhere.
Ozone-poor air can spread out from the Polar regions and move above other areas. In addition, direct ozone depleted are is also slowly increasing. (Ozone layer depletion)
Reasons for the Antarctic Ozone hole: (Ozone layer depletion)
Scientific observations prove that the ozone hole formed over
Antarctic is due to compounds of chlorine and bromine formed in the atmosphere. Nearly all of the chlorine and half of the bromine in the stratosphere comes from human activities, the chlorofluocarbons released due to human activities transported up into the upper stratosphere.
The most common Ozone depleting substances (ODS) are
chloroflurocarbons (CFC) or freon gases, bromine compounds on halons, nitrogen oxides and methyl bromide. These compounds are liberally released from air-conditioners, freezers, foam insulations, aerosol products, industrial
solevents, fire extinguishers and pesticides. (Ozone layer depletion)
Global warming refers to an average increase in the earth’s
temperature, which in turn causes changes in climate. During the past 4.65
billion years of its history, earth has warmed many times. But at present it is
facing a rapid warming mainly due to human activities. The average
temperature of earth is about 590F (150C). During the last century this
average has risen by about 10F. By the year 2100, it is believed that the rise
would be between 2.5 and 10.40F. This will cause dramatic changes such as
rise in sea level, changes in rainfall patterns, wide range of impacts on plants,
wildlife and humans.
Green house gases and Green house effect
The trapping of energy from the sun by certain gases in the
atmosphere leading to the rise in earth’s temperature is known as Green
house effect. Hence these gases are known as green house gases. Some
gases such as water vapour, carbon dioxide, nitrous oxide and methane act
as the trap. These gases absorb and reflect infra-red waves radiated by earth.
By doing so, these gases conserve heat as the glass in a green house does.
Normally all life on earth depends on this green house effect. If it
does not exist, earth would be cooled, and ice would cover earth from pole
to pole. But if the greenhouse effect becomes strong it could make the earth
warmer than usual. Even a little extra warming may cause problems for
humans, plants and animals.
Types of Greenhouse Gases
In the environment, greenhouse gases occur (i) naturally or (ii) from
human activities.
The most abundant greenhouse gas is carbon dioxide. It reaches
the atmosphere due to volcanic eruptions, respiration of animals, burning
and decay of organic matter such as plants. Normally carbon-dioxide is
removed by the plants by photosynthesis. Carbon-dioxide is also absorbed
into ocean water. But humans by their activities increase the release of
carbon dioxide into the atmosphere . Such activities include burning of fossil
fuels, solid wastes, wood and wood products to drive vehicles, generate
electricity etc. At the same time due to deforestation, the number of trees
available to absorb carbon-dioxide through photosynthesis has been greatly
reduced.
Human activities have caused carbon-dioxide to be
released to the atmosphere at rates much faster than that at which earth’s
natural processes can recycle this gas. There were about 281 molecules of
carbon-dioxide per million molecules of air (i.e., parts per million or ppm) in
1750. Today atmospheric carbon-dioxide concentrations are 368 ppm, a
31% increase.
Methane traps 20 times more heat than carbon-dioxide. It is
emitted during the production and transport of coal, natural gas and oil. It is
also emitted from rotting organic waste in sand fills, by the cows as a by
product of digestion. Since 1750, the amount of methane in the atmosphere
has more than doubled.
Nitrous Oxide traps 300 times more heat than carbon-dioxide.
burning fossil fuels and ploughing farm soils releases nitrous oxide. Since
1750 its level increased by 17%. Hydrocarbons formed from the manufacture
of foams, coolants such as chlorofluorocarbons used in refrigerators
are the other gases responsible for global warming.
In 2000, scientists discovered an alarming increase in the level of a
new gas called trifluoromethyl sulphur penta fluoride. Eventhough the
gas is rare, it traps more effectively than all other greenhouse gases. The
saddest part of it is that the industrial source of the gas is not yet
identified.
Effects of Global warming
1. Due to the warming of oceans, sea level will rise. Glacier ice will also melt,
causing further rise in sea level. As a result in the 21st century sea level will
rise from 9 to 88 cm. Such a rise will submerge many parts of countries.
2. Seasons will be longer in some areas.
3. The warmed world will be generally more humid and greater humidity will
increases the rainfall.
4. Storms are expected to be more frequent and intense.
5. Some regions of the world would become dry.
6. Wind blows will be harder and in different patterns. Hurricane would be
more severer.
7. Weather patterns would be less prediclable and more extreme.
8. Crops and forests may be affected by more insects and plant
diseases.
9. Animals and plants will find it difficult to adjust to the changed
environment. Animals will tend to migrate toward the poles and toward higher
elevations.
10. Some types of forests may disappear.
11. More people will get sick or die from heat stress.
12. Tropical diseases such as malaria, dengue fever, yellow fever and
encephalitis will spread to other parts of the world.
Efforts to control Global warming
Two major ways are there to control global warming: 1. to keep the
carbon-dioxide out of the atmosphere by storing the gas or its carbon
component somewhere else, a strategy called carbon sequestration.
2. to reduce the production of green house gases.
Carbon sequestration
The simple technique is to preserve trees and plants more. Trees,
take up carbon-dioxide, break it down in photosynthesis, and store carbon
in new wood. It need massive reforestation. Carbon-dioxide can also be
sequestrated directly into deep ocean water or into oil wells or some aquifer
form which it cannot escape.
Usage of alternate fuels such as nuclear energy, solar power, wind
power and hydrogen fuel cells which emit no greenhouse gases are being
considered.
Increasing numbers of people put increasing demands on the
environment, both through demands for resources and through production of wastes. Most of the human population survived through subsistence agriculture to meet their needs. After the modern medicines and industrial revolution, the death rate plummeted and population growth increased.
(Growing Population and Environmental impacts)
What are the impacts of rapid growth on a population that is largely engaged in subsistence agriculture? Five basic alternatives are being played out to various degrees,
people can subdivide farms among the children or intensify cultivation of existing land to increase production per unit area.
open up new land to farm.
move to cities and seek employment.
engage in illicit activities for income.
emigrate to other countries legally.
The rapid population growth especially affects women and children. Increasing the average wealth of a population affects the environment both positively and negatively. (Growing Population and Environmental impacts)
Fertility is the actual production of offspring.
Birthrate is the number of births in a year per thousand persons.
The total fertility rate is the number of children born to an
average woman in a population during her entire reproductive life. (Population Explosion)
The Zero Population Growth Rate (ZPG) is the number of births
by which people are just replacing themselves.
Mortality or death rates is the number of deaths per thousand
persons in any given year.
Growth rates
Death rate subtracted from birthrate gives the natural increase of a population. The total growth rate includes immigration and emigration, as well as births and deaths.
Life span and Life expectancy
Life span is the oldest age to which a species is known to survive.
Life expectancy is the average age that a newborn infant can expect to attain in any given society.
Population Explosion
The rapid and dramatic rise in world population has occurred over the last few hundred years. The world’s population increased from 1.65 billion in 1900 to 3.02 billion in 1960 and reached 6.1 billion in 2000. Thus the size of the population nearly quadrupled in the span of 100 years, a historically unprecedented rate of increase. This sudden increase in population is called as Population Explosion or Population Bomb or Population Trap.
Regions with majority of world population
The major regions of population concentration are the East Asian
Region, South Asian Region and West European Region.
The East Asian Regions : The largest populated areas. It includes countries like China, Korea, Vietnam, Cambodia, Japan and Indonesia with one fourth of the total population of the world.
The South Asian Regions : The countries with second largest
population concentration. India, Bangladesh, Myanmar, Pakistan and Srilanka are the South Asian countries accounting for 20% of the global population. (Population Explosion)
The West European Region : has the third largest population
concentration. European countries, Mediterranean and Arabian
countries and British islands are the examples.
Reasons for the population Explosion
The main reason for slow and fluctuating population growth prior to early 1800’s was the prevalence of diseases such as small pox, diphtheria, measles and scarlet fever. In addition, epidemics of diseases such as typhoid fever, cholera and plague eliminated large number of adults. Famines also were not unusual. Biologically speaking, prior to 180s the population was
essentially in a dynamic balance with natural enemies and other aspects of environmental resistance. High reproductive rates were largely balanced by high mortality. (Population Explosion)
Since the 19th centuary
discoveries of vaccination provides protections to many of the infectious agents
discovery of antibiotics is a major breakthrough in the medical history,
improvements in agricultural techniques,
improvements in the nutrition and
better sanitation and personal hygiene
brought about spectacular reductions in mortality, especially among infants and children. The birth rate has remained high. So the human population entered into exponential growth, as they were freed from natural enemies and other environmental restraints. (Population 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.
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
expectancy.
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.
Protein are linear chains molecules made up of units called amino
acids. Approxoimately twenty different amino acids make up a protein chain.
They are called polypeptide chains as they often contain a few to several
hundred amino acids linked with each other by peptide bonds. Several
polypeptide chains form subunits for a large protein. For example the
haemoglobin consists of four subunits (Two alpha and two beta chains) each
harbouring haeme, an iron containing molecule. The peptide bond between
amino acids is fairly flexible. As a result, oligopeptide and polypeptide chains
fold to a convoluted shapes.
Every protein folds in a particular way to form a distinctive configuration for its specific function. The protein configuration is made primarily by the amino acids side chains. Some amino acid side chains are electrically charged (positive or negative). Others called polar molecules or neutral and strongly attract the electrons. A third group of amino acids are said to have non-polar or hydrophobic side chains.
Thus proteins fold up in such a way that non-polar-hydrophobic groups remain buried inside the molecule and the polar and charged groups remain outside.
The sequential and linear arrangement of amino acids in a
polypeptide represents its primary structure. The folding of protein chain to
form recognizable modules such as alpha helix and beta sheets
represents its secondary structure .
The three dimensional shape of a polypeptide is called its tertiary structure.Alpha helices and beta sheets provide further stability to protein structure.
The proteins synthesized inside a cell undergo the above mentioned
configurational changes to attain stable structures. Otherwise, they will be
digested or destroyed by the cellular proteolytic enzymes.
The proteins take up different profiles as structural and functional proteins such as enzymes and hormones etc.
In proteomics, the amino acid sequences are read by automated
sequenators and stored in computers as internationally available databases.
The information regarding three-dimensional structure of protein is stored in
another computerized database called Protein Data Bank. Only three
dimensional forms are used to define protein structure.
Protein Model (Protein structure)
In proteomics, to delineate information about a protein at atomic and
molecular levels, models are constructed. X-ray crystallography can give a
skeleton model of a protein from its results on its atomic details. With atomic
data, computers nowadays generate graphic images of the molecules on
high-resolution screen. Computer modeling of protein began as early as 1970.
The computer-generated models depict not only the properties of amino
acids in a protein but also help to understand the protein function. One of the
computer graphic models is the “Glowing coal” model.
Uses of Protein structure
1. Protein structure helps in understanding biomolecular arrangement in
tissue or cellular architecture.
2. Protein structures, protein models and computer aided graphic
models help to understand biological reactions mediated by enzymes
(proteins).
3. Graphic models provided by computers are valuable to predict which
fragments of a medically important protein can be used to design drugs and
vaccines.
4. Proteomics also helps in chemical industries to manufacture drugs, various
chemical compounds and enzymes.
The genome of an organism can be split up into different sized
molecules by a technique called electrophoresis. When DNA of an organism
is subjected to electrophoresis they migrate towards the positive electrode
because DNA is a negatively charged molecule. Smaller DNA fragments
move faster than longer ones. By comparing the distances that the DNA
fragments migrate, their number of bases could be distinguished. The
sequence of bases in the DNA fragments can be identified by chemical /
biochemical methods. Nowadays automated sequencing machines called
sequenators are developed to read hundreds of bases in the DNA. The
DNA sequence data are then stored in a computer accessible form. (Genome sequencing)
DNA library
A DNA library is a collection of DNA fragments, which contains all
the sequences of a single organism.
cDNA library (Complementary DNA)
In cDNA copies of messenger RNA are made by using reverse
transcriptase enzymes. The cDNA libraries are smaller than genomic
libraries and contain only DNA molecules for genes.
In the representation of either the nucleotides or the proteins, IUB/
IUPAC standards are followed. The accepted amino acid codes for proteins
are given below. (Genome sequencing)
To specialize in bioinformatics, knowledge of both biology and
information computer technology is required. A biologist needs to know
programming, optimization (code) and cluster analysis, as they are
bioinformatics methods. The biologists should also be familiar with key
algorithms (set of steps). The languages, which help in bioinformatics, are C,
C++, JAVA, FORTRAN, LINUX, UNIX etc. Besides knowledge of
ORACLE database and Sybase are essential. On the mathematical part
knowledge of calculus and statistical techniques are needed. Knowledge of
CGI (common gateway interface) scripts is also needed. With the above, a
bioinformaticist could collect, organize, search and analyze the biological
data viz., the nucleic acids and protein sequences. (Genome sequencing)
Uses of bio informatics
1. It helps to understand gene structure and protein synthesis.
2. It helps to know more about the diseases.
3. It helps to understand more about the fundamental biology and the thread
of life, – the DNA.
4.. It paves the way for the medical and bio engineering applications.
5. It helps to apply the biophysical and biotechnologicl principles to
biological studies. In turn, it will help to design new drugs and new chemical
compounds to be used in health and environmental management respectively.
‘Creating’ database means a coherent collection of data with
inherent meaning, used for future application. Database is a general
repository of voluminous information or records to be processed by a
programme.
Databases are broadly classified as generalized databases and
specialized databases. Structural organisation of DNA, protein, carbohydrates are included under generalized databases. Databases of
Expressed Sequence Tags (ESTs), Genome Survey Sequences (GSS), Single
Nucleotide Polymorphisms (SNPs) sequence Tagged sites (STSs). RNA
databases are included under specialized data bases.
Generalized databases contain sequence database and structure
databases.
a. Sequence databases are the sequence records of either nucleotides
or amino acids. The former is the nucleic acid databases and the latter are
the protein sequence databases.
b. Structure databases are the individual records of macromolecular
structures. The nucleic acid databases are again classified into primary
databases and secondary databases.
Primary databases contain the data in their original form taken as
such from the source eg., Genebank (NCBI/USA) Protein, SWISS-PROT
(Switzerland), Protein 3D structure etc.
Secondary databases also called as value added databases contain
annotated data and information eg., OMIN – Online Mendelian Inheritance
in Man. GDB – Genome Database – Human.
Nucleic acid sequence databases
European Molecular Biology Laboratory (EMBL) ; National
Centre for Biotechnology Information (NCBI) and DNA data bank of Japan
(DDBJ) are the three premier institutes considered as the authorities in the
nucleotide sequence databases. They can be reached at
www.ebi.ac.uk/embl (for EMBL)
www.ncbi.nlm.nih.gov/genbank (NCBI)
www.ddbj.nig.ac.jp (DDBJ)
Protein sequence databases
The protein sequence databases elucidate the high level
annotations such as the description of the protein functions ; their domain
structure (configuration), amino acid sequence, post-translational modifications, variants etc. SWISS-PROT groups at SIB (Swiss Institute of
Bioinformatics) and EBI (European Bioinformatics Institue) have
developed the protein sequence databases. SWISS-PROT is revealed at
http://www.expasy.ch/sprot-top.html.
