The word Biodiversity is formed from the Greek word Bios meaning life and diversity. Biodiversity is the variety of living organisms. The difference or variety seen in all organisms living in a particular environment at a particular time is called biodiversity. In 1986 scientist Walter G. Rosen first used the term Biodiversity. There are three types of biodiversity. Dr. Siddiq Publications
1. Genetics diversity: The genetic differences or variations seen in different plants or animals belonging to the same species are called genetic biodiversity or genetic diversity. It is also called intraspecific variation. Inbreeding occurs between members of these species. Species with greater genetic diversity also have greater adaptive capacity. If a gene is susceptible to a disease, it is passed down from generation to generation. Although humans are of the same species (Homo sapien), there are many differences in size, shape, skin color, hair color etc. due to genetic reasons. Genetic variation occurs due to allelic variation of genes in species. New alleles of genes can be created due to mutation. Siddique Publications
Importance of genetic diversity
(i) Greater variation occurs when a species has more genetic variation. As a result, it helps the organism to survive in the changing environment.
(ii) Genetic variation leads to variety of physical characteristics in organisms. So survival and adaptability in nature increases.Dr. Siddiq Publications
(iii) Genetic diversity reduces the re-emergence of heritable unwanted traits.
(iv) Organisms with low genetic diversity are always under threat.
(v) Genetic diversity helps in resistance to parasites, pests and diseases.
(vi) Genetic diversity protects species from extinction. Because it has survival properties. Dr. Siddiq Publications
2. Species diversity: The difference between two or more species of plants or animals is called species diversity. It is also called interspecific diversity. The main components of species diversity are two. (species richness) and species evenness. The role that species play in the ecosystem is called ecological niche. Areas where species diversity is high are considered biodiversity hotspots. Species diversity is higher in regions where nutrients and climate are favorable. For example, tropical regions.
Measurement of species diversity
Animal species diversity is measured by species diversity index. The most commonly used index to measure species diversity is Simpson’s Diversity Index. It is expressed by D = ∑(n/N)2. n is the number of a particular animal species, N is the sum of all animal species and D is the value of animal diversity. The value of D ranges from 0-1. The higher the value of D at a site, the greater the animal diversity. In 1990, scientist Norman Myer (1990) called the world’s biodiversity hot spot. Dr. Siddiq Publications
Importance of species diversity
(i) Species diversity drives energy capture and storage, biomass production and decomposition, and water and nutrient cycling in ecosystems.
(ii) Species diversity increases the productivity of ecosystems.
(iii) Species diversity prevents soil erosion and pest control.
(iv) Species diversity controls the amount of gaseous substances in the atmosphere.
3. Ecosystem diversity: The environmental or ecological differences or differences between different types of organisms are called ecological diversity or ecosystem diversity. Ecological diversity arises when the physical, biological and chemical components of the natural environment change. For example, desert biome, forest biome, grassland biome, tundra biome etc.
Importance of species diversity
(i) Ecological diversity leads to decomposition of waste materials and increases soil fertility.Dr. Siddiq Publications
(ii) Ecological diversity controls plant pollination and predators.
(iii) Ecological diversity regulates productivity and stress tolerance. Siddiq Publications
(iv) Ecological diversity provides essential raw materials for the ecosystem.