What are the Major Biomes of the World?
Meaning of Biome-
Biomes are the geographically defined area on the earth with similar climatic conditions and ecological species.
The natural ecosystem comprises abiotic and biotic components known as the biosphere. Abiotic components include land, air, water, and soils whereas biotic components include plants, animals, and microorganisms. According to I.G. Simmons, “The most extensive ecosystem unit which is convenient to designate is called a biome”.
What are the Major Biomes of the World?
The biosphere is divided into several natural ecosystems based on life forms and world vegetation. Thus, based on the relationships between the distributional patterns of plants and animals and the world climates, major biomes of the world are- Tropical Evergreen Rainforest Biome, Savanna Biome, Mediterranean Biome, Temperate Grassland Biome, Tundra Biome, etc.
1. Tropical Evergreen Rainforest Biome-
It is also known as the equatorial type of climate. Various characteristics of equatorial climate are as follows:
Latitudinal Extent–
The equatorial region lies between 10 degrees North and 10 degrees South latitude. However, there is also seasonal shifting of the climatic zone due to seasonal shifting of pressure and wind belts.
Geographical Location-
It is found in various localities such as the Amazon basin in South America, Congo Basin in Africa, Guinea coast, and the Malaysian region mainly in Java, Sumatra, Malaysia, Singapore, Eastern Madagascar, etc.
Climatic Conditions-
In this region, the Earth’s surface receives medium insolation, almost vertical due to the presence of clouds above the equatorial surface throughout the year. The temperature of the equatorial region is high all over the year.
A thermally induced low-pressure belt develops around the equator. This region lies in the belt of calm and doldrums. The surface air is heated, it becomes light and moves upward thus forming convective currents. The convergence of trade winds from the subtropical high-pressure belts forms the Intertropical Convergence Zone (ITC) associated with cyclones. The tropical region contains high relative humidity and a higher precipitation rate.
Vegetation Community-
The tropical biome is also called the optimum biome due to the most significant biodiversity found in this region. The fauna of this region is classified by broad dense evergreen trees such as mahogany, rosewood, cinchona, sandalwood, bamboo, coconut, and a variety of flowers, etc.
Due to the substantial availability of rainfall, the soil stores moisture throughout the year. Alluvial, black, lava, etc. are the types of soil found in the equatorial region. Slash and Burn type of agriculture is prevalent there.
Animal Community-
The animals found in the tropical evergreen region are least mobile due to a regular and constant food supply. This region is the home of several animals and birds like monkeys, parrots, crows, tree snakes, crocodiles, lizards toucans, elephants, leopards, etc.
Rainforest is the home of tribal people. The houses of the Amazon Basin are known as Maloca.
2. Savanna Biome-
The word ‘Savanna’ has been used to indicate tropical wet and dry climate, categorized by the dominance of grasses. It is also known as the Sudan type of climate.
Latitudinal Extent-
The Savanna type biome is located between 10 to 20 degrees latitude on both sides of the equator.
Geographical Location-
Savana region includes Llanos of Colombia and Venezuela, northwestern South America, Campos of Brazil, Congo Basin, Tanzania, Uganda, etc.
Climatic Conditions-
Based on temperature, the Savanna region is classified into cold and warm dry seasons. This climate is located between equatorial low pressure and sub-tropical high-pressure belt. The coastal areas are affected by local winds, trade winds, and sea breezes.
Vegetation Community-
The structure of Savanna vegetation is divided into four types- (a) Woodland Savanna is dominated by trees, (b) Tree Savanna represents sparsely distributed trees, (c) Shrub Savanna is represented by treeless vegetation, (d) Grass Savanna is categorized by overdominance of dense grasses.
Animal Community-
A wide range of animal diversity is found in this region because of the development in different environmental conditions during various stages of evolution. For example, African Savanna accounts for the largest number of grazing vertebrate mammals whereas marsupials dominate the Australian Savanna. The South American Savanna includes deer, toucans, parrots, kingfishers, woodpeckers, etc.
3. Mediterranean Biome-
The Mediterranean type of climate is categorized by subtropical dry summer climates. It is called the Mediterranean type because most of the areas falling under this climate are situated around the Mediterranean sea.
Latitudinal Extent-
The latitudinal extent of the Mediterranean region lies between 30 degrees to 40 degrees latitude in both the hemisphere of the earth.
Geographical Location–
This region includes the European lands watering the Mediterranean sea, Central and Southern California of the USA, Central Chile of South America, North coastal lands of Africa such as Morocco, Algeria, and Tunisia and Asiatic lands including Western Turkey, Israel, etc.
Climatic Conditions-
On the basis of temperature variations, the Mediterranean climate is divided into two sub-types i.e. hot summer has inland location whereas climate of mild summer is located along the coastal margins of the continents. Because of moderate to scanty rainfall, the Mediterranean climate is known as a sub-humid climate. Orographic rainfall is common in coastal areas.
Sirocco local hot winds blow from Sahara northward picking red sands which are brought to Italy, Spain, Southern France, and Greece is known as blood rain. Some other local winds are Bora, Mistral, etc. affect the local weather conditions of the European Mediterranean lands.
Vegetation Community-
The structure of Mediterranean vegetation is such that it can tolerate the aridity of the summer season. The leaves have developed sclerophyllous characteristics. The xeromorphic structure such as succulent plants are found in dry conditions.
Animal Community-
The important animals include- grizzly bears, wolves, lizards, snakes, kites, hawks, antelope, etc.
4. Temperate Grassland Biome-
Temperate grasslands are located in the interiors of the continents. It is due to their interior locations they do not get sufficient rainfall and hence the grasslands are particularly treeless.
Climatic Conditions-
The temperate grasslands of the southern hemisphere are categorized by more moderate climate. The climate is categorized by a higher annual range of temperature. The precipitation is received in the form of snowfall.
Vegetation Community-
The perennial grasses are found in these regions. Famous temperate grasslands of the world are-
The temperate grasslands of Eurasia are known as Steppes extending from the shores of the Black Sea across the great Russian Plains to the foothills of the Altai mountains. It is known as Pustaz in Hungary. The temperate grasslands of North America are locally known as Prairies extending from the foothills of the Rockies, Pampas of Argentina and Uruguay of South America, Veld of South Africa, Downs of the darling basins of South Eastern Australia, and Canterbury grasslands of New Zealand.
Animal Community-
These regions are dominated by the species of grazing and migratory animals such as buffalo, antelopes, wild horses, etc. Predator animals include wolves, eagles, large hawks, etc. which depend on rodents for their food.
5. Tundra Biome-
The word Tundra is derived from a Finnish word that means Barren land. The Tundra biome includes parts of Alaska, the extreme northern part of Canada, Greenland, and northern Siberia, etc.
Climatic Conditions-
Tundra climate is divided into two subtypes- (a) Arctic Tundra climate and (b) Alpine Tundra climate. It is categorized by the absence of insolation and very low temperature throughout the year. The winters are long and bitterly cold while summers are very short but cool.
Vegetation Community-
The severe climate does not favor much vegetation growth hence most of the areas under tundra climate remain barren land. The ground is permanently frozen known as permafrost. Some evergreen flowering plants develop on the grounds during short cool summers.
Animal Community-
The animals of the Arctic Tundra biome are grouped into two categories- (a) resident animals and (b) migrant animals. Animals such as musk Ox, and the arctic fox who has thick fur on their body that protects them during severe winters.
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