Effect of Pollution and its Control

Air Pollution Dry air has 78% N2, 21% O2, 0.03% CO2 and the rest other gases are about 1%. Air pollution is principally caused by man. Due to human activities, the amount of solid waste or concentration of gases other than O2 increase in the air and disturb the natural composition of air. This phenomenon is referred to as air pollution. Air pollution is one of the most dangerous and common kind of environmental pollution that is reported in most industrial towns and metropolitans. Motor vehicles are the major problems of the world...

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Shirish 11:37 PM   No comment

Mountains and Nepal

Mountain is a topographical feature that rises more than 300m above the surrounding. There is a difference between mountain and hill. Hill is a land surface lower than a mountain that rises prominently above the surrounding lands to elevations less than 300 m. This region is represented by Siwalik and Mahabharat range in Nepal. Mountain environment is of great importance in Nepal. Nepal is predominantly a mountainous country. The Himalaya extends over a length of approximately 2400 km from the Indus to the Brahmputra. The central sector of Himalaya about 800 km lies...

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Shirish 11:21 PM   No comment

Frog (Rana tigrina)

Frog is an amphibian, living both on land and in water. The amphibians are the first group among the chordates that live outside water. But the amphibian is still chained to water, in water it is born, to water it must periodically return for respiration. They are cold-blooded vertebrates having two pairs of limbs- tetrapods. They have smooth and moist skin. Rana tigrina is studied in detail because of its easy availability and its structural details have very common features to other animals. Classification: Phylum: Chordata Subphylum: Gnathostomata Superclass: Tetrapoda Class: Amphibia Order:...

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Shirish 5:08 AM   4 comments

Plasmodium ( The Malarial Parasite)

Plasmodium is the best known protozoan parasite of man, which causes malaria. malaria is one of the widespread tropical diseases among human being. About one-third of the entire population of many hot countries suffer from it every year. It is a serious economic and social problem as it causes deaths and affects majority of population. It is responsible for persistent sickness, loss of working ability and slowing down of mental and physical development among children. In 1943, Russel estimated that there were three hundred million cases of malaria in the world. In 1957...

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Shirish 10:27 PM   No comment

Functional Aspects of Ecosystem

The functional aspects of ecosystem include the flow of energy and the cycling of nutrients. Inorganic compounds are synthesized into organic structure by the green plants through photosynthesis and solar energy is utilized in this process. Energy enters the ecosystem, when the producers build organic compounds during photosynthesis. The green plants (producers) fix solar energy and with the help of inorganic substances such as carbon dioxide and water taken from soil and aerial environment they build up complex organic matter. The organic matters are carbohydrate, fat, protein, etc. From green plants these organic...

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Shirish 1:44 AM   1 comment

Factors of Ecosystem [Part 2]

Topographic Factors (Physiographic Factors): Topographic factors include height, direction and the steepness of slope.1) Height or Altitude: Higher altitude (mountains, hills, etc.) is characterised by low temperature, high velocity of wind, lower atmospheric pressure, high humidity and rainfall. The temperature decreases with the increase of height and the lower temperature favour the formation of clouds and rain. Thus, the mountains and hills are favourable for plant growth and causes different types of forest due to above climatic variations. However, at very high hills and mountains the water vapours directly condense into snow and...

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Shirish 11:47 PM   No comment

Factors of Ecosystem [Part 1]

Every living organism is surrounded by materials and forces which constitutes its environment and from which it must derive its needs. Any external force, substance or condition which surrounds and affects the life of an organism in any way is referred to as environmental factor or ecological factor. These factors are living as well as non-living. The living factor is called the biotic factor and non-living is called the abiotic factor. Thus, the ecosystem is governed by two environmental factors (components) biotic factors and abiotic factors. These factors determine the quality and the...

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Shirish 3:11 AM   No comment

Reproductive System of Earthworm

Earthworms reproduce sexually. They cannot reproduce asexually. They are hermaphrodite (monoecious) i.e. both ovaries and testes are found in the same individual. They are protandrous, the male sex cells mature much earlier than the female cells, therefore, self-fertilization is not possible. The relative position of ovary and testes also makes self-fertilization impossible. Cross-fertilization is preceded by copulation and cocoon formation. Male Reproductive Organs: The male reproductive organ comprises testes, testis sacs, seminal vesicle, vasa deferentia, Prostate gland and accessory glands. Testes: The earthworm contains two pairs of testes, one pair in the 10th...

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Shirish 2:12 AM   2 comments