Geography Notes - for Competitive Exams

Geography Notes - for Competitive Exams - Part - 1

The term Geography has evolved from Greek words 'geo' (the earth) and 'graphein' (to write).

Geography is the study of man, his environment and the interaction between the two.

Geology is the science that studies the origin, composition and the history of the earth.

The central theme of geographical study is a spatial approach or space relations and spatial organization of various processes, patterns and phenomena. It studies spatial distribution and organization of phenomena and provides and explanation for the same. Everything that occurs in space (area), thus, constitutes the subject matter of Geography.

The zone that can support life is called the biosphere.

Analysis and explanation of spatial patterns is the basic theme of geographical studies. The spatial dimension sets this discipline fro other sciences and social sciences.

Eratosthenes was the first person to use the word "geography" and invented the discipline of geography as we understand it. He invented a system of latitude and longitude.

The credit of defining the scope of geography and separating it from history goes to Immanuel Kant. Immanuel Kant defined geography as a chorological science and history as a chronological science.

Physical Geography and Human Geography are the most fundamental divisions of geography.

Geomorphology can be defined as the branch of physical geography that studies configuration of the earth surface. It can be defined as the study of landforms. It is also concerned with the materials constituting the earth's crust and the processes and forces in the interior of the earth. Geomorphology is closest to geology.

Biogeography is the study of relationships of organisms with their environment.

Kant proposed the theory of "Gaseous Hypothesis" for the origin of earth.

Laplace proposed the theory of "Nebular Hypothesis" for the origin of earth.

Jeans and Jeffreys proposed the theory of "Tidal Hypothesis".

The denser matter forms the central part of the earth and the surface rocks are made up of the lighter materials.

The rocks forming the surface layer of the earth which are richer in lighter minerals such as aluminium are call sial (silica and aluminium).

The denser rocks forming the inner layers of the earth are called sima (silica and magnesium) and nife (nickel and iron).

The solid crust of the earth came into existence about 4.6 billion years ago and it is taken as the beginning of the history of the earth.

The most popular method of estimating the age of rocks forming the crust is carbon dating.

The whole history of the earth is divided into three Eras – Palaeozoic, Mesozoic and Cenozoic.

The period before the Palaeozoic Era is called Pre-Cambrian time.

The Palaeozoic Era is sub-divided into six geologic periods (from oldest to youngest): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. It spans roughly from 542 to 251 million years ago

Bacteria originated about 3.5 billion years ago in the Cambrian period.

Corals originated during the Devonian period (app. 435 million years ago).