The troposphere is the lowest atmospheric layer. All human activity takes place here. Everyday weather phenomena, such as clouds and storms, mainly happen in the troposphere. Here temperature decreases with increasing elevation. The troposphere is thickest in the equatorial and tropical regions, where it stretches from sea level to about 16 km. It thins toward the … Read more

Theory of Isostasy

Different relief features of varying magnitudes e.g. mountains, plateaus plains, lakes, seas, and oceans, faults, and rift valleys, etc. standing on the earth’s surface are probably balanced by certain definite principle, otherwise, this would have not been maintained in their present form. Whenever this balance is disturbed, there start violent earth movement and tectonic events. … Read more

Plate Tectonics

The rigid lithospheric slabs are called plates. The study of the whole mechanism of evolution, nature and motions of plates, deformation within plates and interactions of plate margins with each other is collectively called as plate tectonics. Plate tectonic theory, a significant scientific advancement of the decade 1960’s is based on two major scientific concepts e.g. (1) the continental … Read more


A large mass of bedrock or regolith sliding downhill is known as a landslide. Large, disastrous landslides are possible wherever mountain slopes are steep. Landslides can also result when the base of a slope is made too steep by excavation or river erosion. Landslides range from rockslides of jumbled bedrock fragments to bedrock slumps in which most … Read more

Demographic Transition Theory

Demographic Transition Theory in its original form was propounded by Warren Thompson and Frank Wallace Notestein. The theory postulates of a special pattern of demographic transformation high fertility and high mortality to low fertility and low mortality, when society progresses from a dominantly rural, agrarian and illiterate society to a predominantly urban, industrial and literate society. These changes occur in stages which are collectively known … Read more


Concept of underpopulation is just the opposite of overpopulation. Underpopulation occurs when the population of an area is too small for full utilization of its resources. The condition of under-population may also appear when the resources of an area can support a larger than the existing population without lowering the standard of living or without creating any type … Read more

Sedimentary Rocks

Sedimentary rocks are made from layers, or strata, of mineral particles found in other rocks that have been weathered and from newly formed organic matter. Most inorganic minerals in sedimentary rocks are from igneous rocks. When rock minerals are weathered, their chemical composition is changed, weakening the solid rock. The rock breaks up into particles of … Read more

Population Pyramid

The age-sex structure of a population refers to the number of females and males in different age groups. A population pyramid is used to show the age-sex structure of the population. It’s shape reflects the characteristics of the population. The left side shows the percentage of males while the right side shows the percentage of women in each age group. 1. Expanding Population Pyramid: … Read more

Malthus Theory of Population

The British economist and demographer Thomas Robert Malthus undoubtedly was the first scholar two propound a population theory based on scientific and natural law. His book on the principles of population growth was published in 1798. Malthus traveled various West European countries and collected many important data in support of his population theory. Thus, the Malthus theory of Population was … Read more

Population Problems of Developed Countries

The developed countries of the world are highly industrialized and urbanized. These countries include West European countries (UK, France, Germany, Netherlands, Iceland, Ireland, Belgium, etc.) European Russia, USA, Canada, Japan, Australia, and New Zealand. In these countries per capita income is very high in comparison to developing countries and most of their people are dependent on … Read more