Environment is sum total of all the biotic and abiotic factors that actually affect an individual organism at any point in its life-cyckle. Human environment may be categorized as follows: 1. Natural Environment: Usual environment 2. Man-made Environment: Own environment made of his habitations, agricultural lands, industries, etc. 3. Social Environment: Part of the environment [...]
Ecology means the study of living organisms in relation to their environment. The world has been derived from the Greek word Oikos. On the way of cultural evolution man has created an environment of his own. Industries are built, Green Revolution is geared and natural balance is disturbed, as a result he himself has become [...]
The chloroflurocarbons (CFCs) are a family of organic carbons containing carbon, hydrogen and either chlorine or fluorine, or both. CFCs have a number of commercial applications such as refrigerators, cleaning fluids, propellants etc. Scientists have found that CFCs in the stratosphere decompose by sunlight. One product of decomposition, atomic chlorine reacts with ozone (O3) to [...]
It is a data gathering project adminstered by the United Nations Environment programme is known as the Global Environment Monitoring System (GEMS). The system was inaugurated in 1975 and it monitors weather and climate changes, changes in soils, the health of plant and animal species and also the environmental impact of human activities.
It is a natural phenomenon that traps radiation within the earth’s atmosphere. Natural greenhouse gases include CO2, nitrous oxide, methane and ozone. The direct result of human activities increases concentrations of these gases in the atmosphere and leads to pollution of the lower atmosphere and contributes to global warning. These gases let in sunlight but [...]
The symptoms of Itai-itai disease were first observed in 1913 in Japan. But it was his 1968, Japanese Ministry of Health and Welfare officially declared that the disease was caused by cadmium poisoning. The disease started with symptoms similar to rheumatism, neuralglia, neuritis and then ostomalacia and osteoporosis result.
The town of Minamata of Japan’s Kyushu Island gavet its name to one of the most notorious incidence of environmental contamination with mercury or its deravatives. The people of the town were poisoned when they ate large quantities of methyl mercury contaminated fish. It caused brain damage and birth defects.
It is the common name for phenomenon created when toxic algal blooms turn sea water red killing marine life and making water unsuitable for human use. These are caused by several species of dinoflagellates and diatoms. Red tides are dangerous because the toxins released by large number of plaktons can paralyse fish.
Mixture of compounds having from one to ten chlorine atoms attached to a biphenyl ring structure. PCBs resist biological and heat degradation. Polychlorinated biphenyls (PCBs) are now banned due to adverse environmental effects and ubiquitious occurrence. They further bioaccumulate in organisms and can cause skin disorders, liver dysfunction, reproductive disorders and tumor formation.
The best known number of a class of photochemical oxidizing agents known as the peroxy acetyl nitrate (PAN). It is formed when ozone reacts with hydrocarbons. These are commonly found in photochemical smog. PAN attacks plants, causing spotting and discolouration of leaves, desctuction of flowers and death of plants. In human beings PAN causes red, [...]
Dr. Amlan Kumar Mitra, Biology Guide Since 2009
