Extremes of heat and cold, Biology

Extremes of Heat and Cold

Deserts are regions of aridity with rainfall of less than 20 cm per year and the soil, though L, fertile, is too porous to retain any water. In summer there is great diurnal variation in temperature from 40°C during the day to below 15°C the same night. The light intensity reaches higher peak due to lack of cloud cover. The true deserts are Sahara in Africa and Great desert in Australia where the annual rainfall is less than 2 cm. Plants and animals which survive under such conditions have special features that allow them to withstand high temperature and lack of water.

The other extreme of temperature is seen in the arctic and alpine tundras. The word tundra means bare mountain tops in Finnish. Tundras are kozen most of the year round and are very similar to deserts as the rainfall here is also about 20 cm per year. But during the short summers, water is plentiful as the topmost layer of ice melts. The ground gets covered with short grass and patches of moss and lichens. Beneath the thawed layer of 3-5 cm, the soil called permafrost remains permanently frozen. Since the roots cannot penetrate deep in the soil trees do not grow here.

Posted Date: 12/10/2012 6:35:49 AM | Location : United States







Related Discussions:- Extremes of heat and cold, Assignment Help, Ask Question on Extremes of heat and cold, Get Answer, Expert's Help, Extremes of heat and cold Discussions

Write discussion on Extremes of heat and cold
Your posts are moderated
Related Questions
Define Colorimetric Method - 2, 4 Dinitrophenylhydrazine Method? We shall use this method in estimating vitamin C in a given sample in the laboratory. Here, let us look at the

Describe the filaments in the muscle fiber A healthy skeletal muscle fiber is isolated and has no external forces on it. It has normal intracellular levels of ATP and is bathed

Radiolarians - Protozoan Radiolarians are entirely marine planktonic species with spherical bodies and radiating pseudopodia known as axopods. The spherical body is divided in

DIFFERENC E BETWEEN SPERMATOGENESIS AND OOGENESIS - S.NO . SPERM A T OGENESIS OOGENESIS 1.   2.   3.

Define role of Vitamin K in controlling gene expression? Prithrombin, a protein required for blood clotting is assembled with a large number of glutamic acid residues. In the p

Determine about the diseases Sleep attacks These are brief, often irresistible, episodes of sleep, probably slow wave, NREM, naplike sleep that last about 15 minutes and can oc

Define about Anthropometric and Physiological? Various physiological and anthropometric measurements give us an indication of the present status of an individual based on which

In what ways can modern agriculture threaten the survival of species? Modern agriculture destroys the natural vegetation (e.g. woodland, hedgerows) on a site, which means a nat

Explain ISP The specification of the Association of American Feed Control Officials, Inc. (AAFCO) defines ISP as "Major proteinaceous fraction of soybeans prepared from dehulle

Define the Role of Public Nutritionist in Health Care Delivery? It is clearly evident from the foregoing discussion that nutrition is an important, though not the only, determi