A branch of astronomy that deals with the identification of habitable regions in the universe, the search for extraterrestrial life and effects of outer space environments on living organisms. It is the study of the origin and distribution of life in the universe. Astrobiology makes use of physics, chemistry, astronomy, biology, molecular biology, ecology, planetary science, geography and geology to …

An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving, physical components of the environment with which the organisms interact, such as air, soil, water and sunlight. It is all the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological …

Air hunger is the urge to breathe, which is caused by the detection of high levels of carbon dioxide in the blood by sensors in the carotid sinus. It is one of the body’s homeostatic mechanisms to ensure proper oxygenation. Air hunger may be caused by insufficient pulmonary minute ventilation, a sustained breath-hold constriction of the alveoli of the lungs, …

A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass. The concept of a keystone species was first introduced by University of Washington professor, Robert T. Paine in 1969. Paine studied …

Sciophytes are shade-loving trees or plants. These plants have larger photosynthetic units than sun plants or heliophytes. Sciophytes are also known as photophobous plants and they reach their saturation level in only 20% sunlight. Shade-plants essentially follow strategies of optimum use of available energy and conservation of energy. Adaptation to achieve these strategic goals include thinner leaves with a relatively …

The German scientist Paul Ehrlich, considered the father of chemotherapy, originally coined the term magic bullet in the 19th century to refer to arsenic containing chemicals that showed the remarkable ability to cure syphilis — a sexually transmitted disease. He proposed the seminal idea that each disease must be treated with a chemical specific for that disease. His greatest contribution …

Wood is, in fact, the secondary xylem formed by cambium (layers of tissues) during secondary growth. As the tree grows old, the wood at the centre ceases to perform the function of conduction and is blocked with organic compounds like oil, resins, and tannins, and develops a dark colour. This dark coloured portion of the wood is called heartwood. The …

Every now and then we hear of countries of the world carrying out heated discussions about nuclear bombs. The topics range from who has the right to own a nuclear bomb and who does not, who should use it and who must not and so on. But what exactly happens when such a bomb actually explodes? And how are nuclear …

In the 19th century, geologists could tell whether one rock layer was older or younger than another by the fossils they contained. But they could not measure the absolute ages of rocks until after the discovery of radioactivity in the 1890s. Radioactive substances, which are occasionally found in rocks, give off high-energy rays and decay (break down) at a fixed …

Yes, we can have light without heat. The light from such reactions is called cool light. Many chemical reactions produce both light and heat. A burning candle is such a reaction. It is much less common for a chemical reaction to produce light without heat. Such chemical reactions are called chemiluminescent reactions, the most familiar of which occur in living …