Date post: | 16-Jul-2015 |
Category: |
Science |
Upload: | vaishali789 |
View: | 52 times |
Download: | 0 times |
BIODIVERSITY or BIOLOGICAL DIVERSITY is the variety of the earth’s species , the genes they contain , the ecosystem in which they live and the ecosystem processes such as energy flow and nutrient cycling that sustain all life .
Biodiversity exists on several levels:
Genetic diversity
Species diversity
Ecosystem diversity
Figure 15.2
A SPECIES is a group of organisms capable of interbreeding and produce fertile offspring.
SPECIES DIVERSITY is the number and abundance of species present in different communities. It mainly consists of two components:
Species richness and Species eveness
GENETIC DIVERSITY is the variety of genetic material within a species or a population.
The Genetic Makeup of a population through successive generations is due to :
Genetic Variability
Mutations - random changes in DNA
Natural selection
Adaptations
Differential reproduction
Genetic resistance
ECOSYSTEM DIVESITY is the variety of different types of ecosystems such as terrestrial and aquatic ecosystems found in an area or on the earth.
It can be describes for a specific geographical region or a political entity such as country or state.
A region may have several ecosytems or it can have only one ecosystem. For example: DESERTS AND OCEANS having low ecological diversity while MOUNTAIN AREA that has lakes, forests, grasslands would have high ecological diversity.
Have you all ever thought WHY THIS MUCH OF BIODIVERSITY IS ESSENTIAL?
WHY cant we all human beings live alone on this planet earth?
Why should we care about any other species?
How our fate is connected to “DIVERSITY” ?
The most important question “who cares for biodiversity” ?
Consumptive value:
Food/Drink
Fuel
Medicine
Better crop varieties
Industrial Material
Non-Consumptive Value:
Recreation
Education and Research Traditional value
Ecological services:
Balance of nature
Biological productivity
Regulation of climate
Degradation of waste
Cleaning of air and water
Cycling of nutrients
Control of potential pest and disease causing
species
Detoxification of soil and sediments
Stabilization of land against erosion
Carbon sequestration and global climate change
Maintenance of Soil fertility
•With only 2.4 % of the world’s area, India accounts for 7–8 % of the world’s recorded plant and animal species.• India’s ten biogeographic zones possess an exemplary diversity of ecological habitats like alpine forests, grasslands, wetlands, coastal and marine ecosystems, and desert ecosystems.•HENCE , we can conclude that INDIA HAS LARGE SPECIES AS WELL AS ECOSYSTEM DIVERSITY.
HOTSPOT-A region with high biodiversity with most of spices being Endemic.
India have three Biodiversity Hotspots- East Himalayan Region, Western Ghats and India-Burma Region.
Natural causes:
Narrow geographical area
Low population
Low breeding rate
Natural disasters
Anthropogenic causes:
Habitat modification
Overexploitation of selected species
Innovation by exotic species.
Pollution
Hunting
Global warming and climate change
Agriculture
Conserving Biodiversity in protected Habitats-
In situ conservation – WILDLIFE
SANCTUARIES, NATIONAL PARKS
Ex situ conservation – ZOO, BOTANICAL
GARDENS
Seed Bank, Gene Bank, Pollen Bank, DNA
Bank