Plant Diversity & its scope.pptx

Educational

1. Welcome…

2. Introduction The term Biological diversity also abbreviated as biodiversity introduced by the Walter G Rosen in 1985. It is defined as the variety and variability among the living organisms and the ecological complexes in which they occurs. It includes the diversity of the living organisms and their ecosystem. Biodiversity is the sum of the genes, species, varieties, populations of the different ecosystems. Biodiversity also refers to organisms found within the living world i.e. the number, variety and variability of living organisms. Diversity within species is referred to as genetic diversity. Diversity between species is referred to as species diversity and diversity at habitat level is referred to as ecosystem or ecological diversity

3. The totality of genes, species and ecosystems in a region. Biodiversity can be studied at four different levels: Genes Species Ecosystems Landscapes

4. Genetic Diversity (Study at gene Level) The Genetic variation in the organisms is due to the recombination in the genetic material of the organisms during the sexual reproduction. Each organism has their own genetic makeup and characters. The genetic diversity refers to variation of genes within species this includes distinct population of the same species or genetic variation within population. The term Gene Pool is used to indicate the Genetic diversity of the different species. The Gene pools of the wild and cultivated plants are very important for the development of the new varieties through the Natural selection methods or the artificial hybridization methods. The genetic variability of the plants especially economically important plants is very important for the healthy breeding populations to develop and evolution of the new characters in the plants. If the Genetic variability is reduced amongst the plants it leads to the inbreeding and leads to the extinction of the species.

5. Genetic Diversity in maize

6. Species Diversity (Study of varieties of species in nature) Species diversity refers to biodiversity at the most basic level. Species is defined as the group of similar organisms which interbreeds with one another and produces the offspring. Species is the basic unit of the classification. It includes all the species on Earth. Species diversity includes diversity of the species of the plants, animals and microorganism. In plants it includes diversity of the Algae, bryophytes, Pteridophytes, Gymnosperms and Angiosperms. It is the number of different species that are represented in a given community.

7. Diversity I dices based on species Numerous indices and methods are available for measurement of diversity. Ecologists have estimated biodiversity by three measures: ( i ) Species richness : which is indicated by the total number of species in an area (Ashton, 1992) (ii) Species abundance: which is indicated by the total number of individuals of a species in an area (iii) Species evenness: which represents equitability of species as given by their relative abundance.

8. Plant Diversity at the Ecosystem Level (Ecosystem Diversity) - The term Ecosystem was proposed by A. G. Tansley in 1935, Ecosystem is the collection of the living or biotic components like plants, animals and microorganisms and the abiotic components like climatic, edaphic factors. The richness of the biosphere is due to the ecosystem diversity. The Natural Vegetation is consist of Terrestrial, Aquatic, and other Ecosystems. The Terrestrial Ecosystem is Forest, Grassland and Desert Ecosystem while Aquatic Ecosystem is Fresh water and Marine water Ecosystem. The Artificial Ecosystem is Cropland Ecosystem. Kinds of the Ecosystem: Ecosystem can be Natural or Atificial . Temporary or Permanent. Large or small.

9. 1.Natural Ecosystem (a) Terrestrial Ecosystem: Forest, Grasslands, Deserts etc. In forest ecosystem heterogonous vegetation is present with the diversity in the mosses, Lichen, Ferns, flowering plants with the different habits like Herbs, Shrubs, Trees, Climber etc. The Desert ecosystem is the Ecosystem with the less rainfall and high temperature during theday and cold nights. (b) Aquatic Ecosystem: These Ecosystems further differentiated into ( i ) Fresh Water Ecosystems: These Ecosystems may be Lotic (Running water such as River, streams, springs, and Lentic (Standing water such as Lake, Pond, Pool, Puddle, Swamp etc. (ii) Marine Water Ecosystem: These includes salt water bodies with deep bodies(Ocean) or shallow bodies (Sea or Estuary).

10. 2. Artificial Ecosystem- These Ecosystems are called as Manmade or Man Engineered Ecosystem. E.g. CroplandEcosystem . Ecosystem diversity addresses the combined characteristics of biotic properties (biodiversity) and abiotic properties (geodiversity). Ecological diversity can also take into account the variation in the complexity of a biological community, including the number of different niches, the number of trophic levels and other ecological processes. The wide variety in physical features and climate situations have resulted in a diversity of ecological habitats like forests, grasslands, wetlands, coastal, marine ecosystems and desert ecosystems, which harbour and sustain the immense biodiversity.

11. Measurement of the diversity- The measure of the biodiversity of the species also known as species richness. Whittaker (1972) describes three terms to measure biodiversity over spatial scales: The various ways by which we can measure the biodiversity are: 1. Alpha Diversity: Diversity within the particular area or Ecosystem and expressed by the number of species (Species richness) in that ecosystem. Combination of species richness and evenness is used to represent the diversity within community or habitat. 2. Beta Diversity: It is a comparison of diversity between Ecosystems usually measured as amount of species change between the Ecosystems. Species frequently change when habitat or community changes. The intercommunity or differentiation in diversity expressing the rate of species turn over per unit change in habitat can be assessed by the variety of indices. 3. Gamma Diversity: Measure of the overall biodiversity for the different ecosystems within the region. It study the diversity of the habitats over the total geographical area.

12. Major Ecosystem types of the World (1) Tropical Moist Forests: These are found between the Tropic of Cancer and the Tropic of Capricorn. In the Asian continent, they are found on the southern slopes of the Eastern Himalayas, in south-west India (Western Ghats), Sri Lanka, Malaysia, Indonesia, Philippines, Thailand and New Guinea. Tropical moist forests cover only 6 to 7% of the Earth's surface. (ii) Temperate Forests: Temperate forests occur mainly in the Northern Hemisphere. Temperate forests are dominated by deciduous hardwood trees and to a lesser extent by evergreen broad leaf hardwood trees and conifers. (iii) Arid and Semiarid Ecosystems: The biological diversity in these ecosystems is rather poor and is influenced by water availability. These ecosystems comprise drought evading, enduring and resisting taxa.

13. (iv) Boreal Forests: These are circumpolar biomes in North America and Eurasia. Boreal forests are generally poor in terms of species richness, but the functional diversity of component species is very high. (v) Arctic and Alpine ecosystems :These are cold-dominated ecosystems lacking trees. They occupy about 8% of the terrestrial surface of the Earth with 5% in the arctic region and 3% in the alpine. These ecosystems support only about 4% of the Earth's flora, with 1500 species in the arctic zone and 10,000 in the alpine regions. (vi) Grasslands : Grasslands often form natural vegetation on the land surface of the Earth. The grassland ecosystem is dominated by grass and grass like species, although in some areas shrubby and Herbaceous elements. (vii) Agroecosystems: Agroecosystems are those in which man has deliberately selected specific crop plants to replace the natural vegetation. Therefore, it is an artificial ecosystem. Agroecosystems include shifting cultivation, home and kitchen gardens, pastures, mixed farming, multiple cropping horticulture, alley farming, cereal and pulse cropping, orchards and plantations Agroecosystems also have weeds, escapes, parasitic microbes/pests and soil organisms.

14. (vii) Wetland Ecosystems : Wetlands are areas of marsh, swamp, peat land or water, whether natural or artificial, permanent or temporary. Freshwater Wetlands : Aselmann and Crutzen (1989) recognized the following categories of freshwater wetlands. Bogs : These can be defined as peat producing wetlands of moist climatic regions. Organic matter accumulates over long periods without decomposing due to lack of or slow activity of microbes. Fens : These are wetlands producing peat; fens are influenced by soil nutrients flowing through the system. Fens are more prolific than bogs in terms of supporting vegetation. Swamps : These are forested wetlands on waterlogged or inundated soils. However, there is no accumulation of peat here. Tree representatives are dominant in swamps. The very characteristic swamps of India occur in the Western Ghats with species of Myristica are predominant. Marshes : These are usually herbaceous 'swamps' or 'mires'. Grasses, sedges, reeds and foxtails usually dominate the vegetation. Marshes may be seasonal orpermanent . Flood-plains : These are wetlands periodically flooded with water occurring alongside rivers or lakes. They vary considerably in vegetation. Lakes : Lakes are open water bodies varying in depth from a few centimeters toseveral meters. Marine Ecosystems : Biodiversity of the marine environment is very poorly known. Marine ecosystem occupies 71% of earth's surface.

15. Scope of the plant diversity- 1. Plant diversity is the backbone for agriculture, aquaculture, animal husbandry forestry and a host of other applied branches of biology. Hence it stands at the very foundation of development. 2. To sustain ever growing population high yielding grains and pulses are need to be developed. Fresh water supplies are depleting day by day and also the soil quality is deteriorating throughout the world. Hence, new varieties of useful plants and new breeds of domesticated animals have to be evolved for increased yield/productivity desired lifetime, disease resistance etc. 3. Globalization has resulted to developmental activities and these are at the cost of pronounced deforestation. 4. Biodiversity is fast becoming the fundamental requirement on which the new industrial developments and innovations are going to be based. 5. Biodiversity will become the only purposeful scientific tool with which one can bridge the social and cultural world. 6. It offers new sources of food, medicine, fodder, fuel etc. 7. Biodiversity is the pillar of human development.

16. Thank you…!