Biomes of the World

A biome is defined as a very large geographical area, which is identified by distinctive plant and animal groups, that have adapted to a particular environment. The geographical and the climatic conditions determine as to what kind of biome can exist in a particular condition. The world's biomes are classified into the following six categories.

The salt water concentration in freshwater biomes is usually less than 1%. There are three main types, namely, ponds / lakes, rivers / streams, and lastly wetlands. Water biomes like ponds and lakes can range from a few square feet to thousands of square miles, and are scattered throughout the Earth.

In streams and rivers, the flora and animals found living in the water, depend on the distance of the stream from its source.

At the source, the stream is cooler, clearer, and has high oxygen content, hence, freshwater fish such as trouts can be found here. At the mouth of the stream, the content of oxygen is less and the water becomes murky because of all the sediments that the stream picks up on the way. Hence, the diversity of flora decreases considerably and fish that require less oxygen are found in abundance.

The marine regions cover about three-fourths of the Earth's surface. They include oceans, coral reefs, and estuaries. The marine algae is one of the biggest contributors of oxygen in the world and it also absorbs massive amounts of carbon dioxide.

Further, evaporation of the sea water causes rainfall on the lands. The oceans are separated into four main regions, namely intertidal, abyssal, benthic, and pelagic. All the four zones have a great diversity of species and it is also said that the diversity contained in the ocean is far greater than on land.

Coral reefs are widely distributed in warm shallow water and the dominant organisms found are coral. Estuaries are defined as areas where the freshwater streams and rivers merge with the ocean. The mixing of water with very different concentrations of salt creates an environment for algae, seaweeds mangrove trees, worms, oysters, and waterfowl.

One fifth of the Earth's surface is covered by deserts, which receive less than 50 centimeters of rain per year. Deserts are inhabited by specialized vegetation and animals. The vegetation prominently includes cactus. Large mammals are not seen, because they are not capable of storing water or withstanding the high temperatures.

The only large mammal seen is the camel, which can store flight in its hump, and small kangaroo mice. Reptiles which require very little water and food are predominantly seen in the deserts. The four types of desert regions seen are hot and dry, semiarid, coastal, and cold.

One third of Earth's land area is covered by forests. Unfortunately the forests are dwindling today because of large-scale industrialization and deforestation. Forests are classified based on latitudes and the 3 major categories are tropical, temperate, and boreal forests. The forests are acknowledged for great diversity in trees and are spread all across the world.

The grassland biome is characterized by lands that are dominated by grasses. The two main divisions of the grasslands are the tropical grasslands (also known as Savanna) and the temperate grasslands. Savannas are grasslands that are scattered with a few trees.

It is found across Central Africa, Australia, India, and South America. Warm hot climate is important to maintain the savanna region, and the annual rainfall has to be less than 50 inches every year.

Drought periods are important, otherwise these regions would change into tropical forests. The temperate grasslands are characterized with grasses and dominant vegetation. Large shrubs and trees are absent and the rainfall is lesser when compared to the Savannas. They are mainly seen in Central Africa and parts of South Africa.

Tundra is the coldest of all the biomes, and is noted for frost molded landscapes, very low temperatures, and short growing seasons. Its characteristics include low biotic diversity, a simple vegetation structure, and limited drainage. It is separated into two regions.

The first region is known as the Arctic tundra that is located in the Northern hemisphere, encircling the North Pole and extending southwards towards the coniferous forests of taiga. The second tundra region is the Alpine tundra and is located on mountains all over the world, where trees cannot grow.