changes in environments

Introduction - A dynamic environment of matter and material surrounds man. Since his birth he has been exposed to these changing surroundings. His curiosity to understand his surroundings and the events occurring around him, has led him to systematically enquire and collect info..

>Any change in the expression of a gene follows an interaction between nucleus, cytoplasm and environment. Cancer is a differentiation related disease. In cancer, the cells continue to divide due to lack of the property of contact inhibition. Cancer is caused by activation of genes c..

Variations, the raw materials for evolutionary change, are controlled by genes. When there is an error in DNA copying during sexual reproduction it leads to variation. Variations occur due to microevolution, that is, evolution on a small scale-within a species or a single population. It ..

The concept of green house - though identified by man late - is certainly as old as global environment itself. That is, a part of radiation received by earth's surface is reflected back to environment and trapped due to certain gases. These gases are called green house gases. Im..

Nervous Control in Human Beings - Nervous System - The nervous system carries out the following functions: It perceives the changes around us through our senses It controls and coordinates all the activities of the muscles in response to the changes outside It also maintains the..

Organic materials synthesised by the producers are eaten and assimilated by the consumers. With the help of decomposers, all the organic materials in the bodies of the consumers are eventually broken down into inorganic materials. These are then rebuilt into organic compounds by the synthetic activ..

Conservation of Mechanical Energy - We can see many situations in which energy is transferred to or from objects and systems, similar to money being transferred between accounts. In each situation, we assume that the energy that was involved can be accounted for, that is, energy cannot appear or di..

-shaped) and J- shaped curves'. An association of a number of different species in a common environment that can survive in nature is called biotic community and the relationship between the species in a community has evolved through their interactions based on the requirement and mode of..

There are saprophytic organisms (mainly bacteria and fungi) that live on dead animals and plants. In terrestrial ecosystem, bacteria act on animal tissue and fungi on plants but there may be exceptions also. This group of organisms plays a vital role in releasing back the biotic components into th..

Oncogenes - Growth and division of normal cells are regulated by control mechanisms. One such control mechanism is contact inhibition. As a result of multiplication, the cells become crowded and come in contact with one another. This surface contact checks movement and division of cells. Therefore,..