Biodiversity

• Biodiversity is a modern term which simply means “ the variety of life on earth” .The term biodiversity was coined by Livejoy (1980) which refers to the variety and variability of species in a given habitat. It encompasses organismal diversity (species diversity), genetic diversity, and ecosystem diversity.
• Species diversity depends on species richness, species composition and their relative abundance in a particular habitat.
• Relative abundance of species refers to the measure of the relative number of individuals represented in different species in a given community or habitat
• species richness refers to the number of species in an area, taxa or community.
• Species diversity is also referred as organismal diversity which is actually the variation of the physical traits or phenotypic characters of the organism that differs anatomically,

  physiologically or behaviourally.
• Genetic diversity is the sum of the total genetic information contained in the genes of individuals of plants, animals and microorganisms.
• Mutation ares sudden and spontaneous changes in the cell and in particular mutation is an alteration of the DNA sequence within a gene or in a chromosome of an organism that produces new traits not found in the parental type.
• The term biodiversity was coined by Walter G. Rosen in 1985 when he published his book “Biodiversity” .
• Gene flow (gene migration) is the transfer of alleles of genes from one population to another.
• The natural selection is the process by which the environment limits the size of the population forcing individuals to compete for resources.
• genetic drift refers to changes in gene frequency of gene variants or alleles due to sampling error from generation to generations.
• ecosystem diversity represents the variety of ecosystems present in the

  ecosystem diversity represents the variety of ecosystems present in the biosphere, which deals with habitat and functional diversity. It also refers to the variety of ecosystems present in a biosphere.fers to the variety of ecosystems present in a biosphere.
• Throughout most of the history, species have disappeared at a low rate, called background extinction.