progressions

Systematic work on identifying and naming the many species has been in progress for the last 250 -300 years. But the known and described number of species of all organisms on the earth is between 1.7 and 1.8 million which is just about 15% of the total number existing. New species are bei..

The lutenising hormone induces the mature graafian follicle to burst and eject its egg into the fallopian tube. This is called ovulation. It occurs after about 14 days. The egg at this time is in the secondary oocyte stage with the second meiotic division in progress. The luteinising horm..

Glass if cooled rapidly becomes brittle and fragile and if cooled very slowly becomes opaque because of devitrification. For this purpose, before making articles, glass is passed through a long tunnel like furnace that is very hot at one end and very cold at the other. When glass is passed through ..

Major progress in understanding magnetism came after the relationship between electricity and magnetism was established by Hans Christian Oersted in 1820. He found that an electric current moves a compass needle and this effect lasts as long as the current flows through the wire. It..

Ageing - Ageing can be defined as the progressive deterioration in the structure and function of the cells, tissues, organ and organ systems of the organism with advancing age. The field of developmental biology that deals with the process of ageing is known as gerontology . The scientist..

Ten Percent Law - Lindemann (1942) put forth ten percent law for the transfer of energy from one trophic level to the next. According to the law, during the transfer of organic food from one trophic level to the next, only about ten percent of the organic matter is stored as flesh. The remaining is..

This was proposed by Weismann who did not agree with Lamarck's theory of inheritance of acquired characters. To prove his point, he cut off the tails of many successive generations of mice. This resulted in forced disuse of the tail. According to the theory of use and disuse, the tails should have..

The Linnaean system of classification consists of a hierarchy of graded taxonomic (named) ranks that are called as taxa. Any given taxon (singular) may contain several lower taxa, which can be usually distinguished based on certain common characteristics. Such lower ranks may in turn be divid..

Man's quest for sources of energy is inexhaustible. Early man depended mainly on muscular energy and later began to use wind and flowing water as sources of energy. He learned the art of making and controlling fire. Fire became his source of light at night. He used fire for warmth and realize..

Man's quest for sources of energy is inexhaustible. Early man depended mainly on muscular energy and later began to use wind and flowing water as sources of energy. He learned the art of making and controlling fire. Fire became his source of light at night. He used fire for warmth and realize..