Factors influencing world distribution of plants and animals | Biogeography | Principle Of Geography

 

Biogeography

Principle Of Geography

Geography Complete Study Material

(Paper - I)

Factors influencing world distribution of plants and animals

(Biome = Plants + Animals)

            The word biome is a short form of biological home. There is no unanimity among the scientists as for as the definition as well as classification of biome is concerned. Biome may be defined as a large natural eco-system wherein we study the total assemblage of plant and animal communities. Here, all the biota have the minimum common characteristics and all the areas of biomes are characterized by more or less uniform environmental conditions. Though a biome includes both plant and animal communities but a biome is usually identified and named on the basis of its dominant vegetation, which normally constitutes the bulk of the biomass. These vegetations are most obvious and conspicuous visible component of the landscape. By biomass we mean the total weight of all living organisms – plants and animals, found in the biome.

Factors Affecting or Influencing Biomes 

There are various factors which affects the size, location, and character of a biome. Important factors are as follow: 

• (i) Length of day light and darkness. This is mainly responsible for duration of photosynthesis. 
• (ii) Mean temperature as well as difference in temperature. Differences (both diurnal and annual) to find out extreme conditions. 
• (iii) Length of growing season. 
• (iv) Precipitation which includes total amount, variations over time and intensity. 
• (v) Wind flow that include speed, direction, duration and frequency. 
• (vi) Soil types 
• (vii) Slope 
• (viii) Drainage 
• (ix) Other plant and animal species.

CLASSIFICATION AND DISTRIBUTION OF BIOME 

           There are two major bases of classifying biome. In this section we will discuss two classifications which are simple and widely used. The bases of these two classifications and its various types are discussed below:

(A) On the basis of climate with special emphasis on availability of moisture

         According to this basis biomes are determined by the degree to which moisture is available to plants in a scale hanging from abundant (forest biome) to almost scarce (desert biome). But within each biome, conditions of temperature are vastly different from low to high altitudes and low to high latitudes. Consequently there is a need to sub-divide each biome in to further sub-types. However, according to this classification, there are four major types of biomes:

• (i) Forest biome
• (ii) Savanna biome
• (iii) Grossland biome 
• (iv) Desert biome

(B) On the basis of climate and vegetation 

       This classification argues that there is a close relationship between the world distributional patterns of plants and animal species and the climatic types of the world. Thus, based on this relationship the world has been divided into different biome types. The vegetation is the most dominant component of the biomes. As the vegetation and climate have intimate relationship the world is divided into various types on the basis of climates. Further, these climate based biomes are divided into various sub-types on the basis of vegetation. there are three types of biomes:

• (i) The Evergreen Rainforest Biome 
• (ii) The Temperate Grassland Biome 
• (iii) The Arctic Tundra Biomes