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
Nucleus - Largest component of the cell. Nucleus is double membrane bound dense protoplasmic body that controls cellular metabolism, enclose all the genetic information,

Q. Define High Density Lipoproteins ? High density lipoproteins (HDL) are the smallest of the lipoprotein species and transport approximately 20 to 30 per cent of plasma choles

Explain Osmotic Pressure Osmosis, as you may already know, refers to the flow of solvent into a solution, or from a more dilute solution to a more concentrated solution, when t

Principles Governing Cleavage a) The nucleus and mitotic achromatic figure tend to occupy the centre of active cytoplasmic density of the dividing cells, e.g., in isolecithal

What is the difference among white and red blood cells? What are leukocytes? Red blood cells are erythrocytes and white blood cells are the leukocytes. Leukocytes are cells

Measles: The causative organism for measles is paramyxovirus. Disease spreading takes place through the nasal discharge and saliva of persons affected with measles by dro

Respiratory Quotient Table also shows the ratio of the volume of carbon dioxide evolved to that of the amount of oxygen consumed during oxidation. This is the respiratory' quo

Explain the Modern Trends in Animal Taxonomy? Earlier you learnt how taxonomy is interrelated to other biological fields. You also learnt how information is used from other f

Explain the Body Tube of Microscope? Above the stage and attached to the arm is the body tube, to which eye piece(s) or ocular lens and revolving nosepiece is attached. Microsc

A plant grown from one of Mendel's yellow peas is selfed. Five progeny peas are obtained from this self and they are all yellow. If the original selfed plant had been homozygous, w