list of biogeographic stones and provinces: https://www.exambin.com/wp-content/up...
Concept of Biodiversity
• Biodiversity is the variety of plant and animal life in the world or in a particular habitat.
Measurement of Biodiversity
• Biodiversity is measured by two major components:
1. Species richness, and
2. Species evenness.
Species richness : it is the measure of number of species found in a community and can be further divided into :
• Alpha diversity
• Beta diversity
• Gamma diversity
Species evenness : It measures the proportion of species at a given site, e.g. low evenness indicates that a few species dominate the site.
Genetic diversity
• Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species.
Species diversity
• It is the ratio of one species population over total number of organisms across all species in the given biome. ‘Zero’ would be infinite diversity, and ‘one’ represents only one species present.
• Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type
• Species differ from one another, markedly in their genetic makeup, do not inter-breed in nature. Closely-related species however have in common much of their hereditary characteristics. For instance, about 98.4 per cent of the genes of humans and chimpanzees are the same.
• The largely tropical Amazonian rain forest in South America has the greatest biodiversity on earth- it is home to more than 40,000 species of plants, 3,000 of fishes, 1,300 of birds, 427 of mammals, 427 of amphibians, 378 of reptiles and of more than 1,25,000 invertebrates.
Why tropics have greater biological diversity?
• Speciation is generally a function of time, unlike temperate regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.
Bioprospecting: nations endowed with rich biodiversity explore molecular, genetic and species-level diversity to derive products of economic importance.
Keystone species and Foundation Species
Keystone species is a species whose addition to or loss from an ecosystem leads to major changes in occurrence of at least one other species.
All top predators such as (Tiger, Lion, Crocodile, Jaguar ) are considered as keystone species because it regulates all other animal population indirectly. Hence top predators are given much consideration in conservation.
• If keystone species is lost, it will result in the degradation of whole ecosystem.
• Foundation species is a dominant primary producer in an ecosystem both in terms of abundance and influence. Example: kelp in kelp forests and corals in coral reefs.
Flagship species
• A flagship species is a species chosen to represent an environmental cause, such as an ecosystem in need of conservation.
Ecological diversity
• Ecological diversity refers to the different types of habitats. A habitat is the cumulative factor of the climate, vegetation and geography of a region.
Biodiversity of India
• India is a recognized as one of the mega-diverse countries, rich in biodiversity and associated traditional knowledge.
• With just 2.4% of the land area, India accounts for nearly 7% of the recorded species even while supporting almost 18% of human population.
• In terms of species richness, India ranks seventh in mammals, ninth in birds and fifth in reptiles.
India Represents
• Two ‘Realms’
• Five Biomes
• Ten Bio-geographic Zones
• Twenty five Bio-geographic provinces
Realms
• Biogeographic realms are large spatial regions within which ecosystems share a broadly similar biota.
•
• the Himalayan region represented by Palearctic Realm and
• the rest of the sub-continent represented by Malayan Realm
• In world Eight terrestrial biogeographic realms are typically recognized. They are
• Nearctic Realm
• Palaearctic Realm
• Africotropical Realm
• Indomalayan Realm
• Ocenaia Realm
• Australian Realm
• Antarctic Realm
• Neotropical Realm
Biomes of India
• The term biome means the main groups of plants and animals living in areas of certain climate patterns.
The five biomes of India are:
• Tropical Humid Forests
• Tropical Dry or Deciduous Forests (including Monsoon Forests)
• Warm deserts and semi-deserts
• Coniferous forests and
• Alpine meadows.
Bio-geographic Zones
• Biogeography deals with the geographical distribution of plants and animals.
• Biogeographic zones were used as a basis for planning wildlife protected areas in India.
• There are 10 biogeographic zones which are distinguished clearly in India. They are as follows:
Bio-geographic provinces
• Bio-geographic Province is a eco systematic or biotic subdivision of realms.
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