2. Genetic diversity A single species show
high diversity at the genetic level.
-Rauwolfia vomitoria (medicinal plant) show
genetic variation in terms of potency andgenetic variation in terms of potency and
concentration of the active chemical
(reserpine) .
-India has more than 50,000 genetically
different strains of rice, and 1000 varieties of
mango.
3. Species diversity The diversity at the
species level.
Eg. Western Ghats have a greaterEg. Western Ghats have a greater
amphibian species diversity than the
Eastern Ghats.
Ecological diversity The diversity at
the level of ecosystem.
7. Patterns of biodiversity
1. Latitudinal gradients
- Species diversity decreases as we move away
from the equator towards the poles.
- Tropics have greater biological diversity- Tropics have greater biological diversity
- (i) Tropical regions have remained
relatively undisturbed for millions of years.
- (ii) Tropical environments are
relatively more constant & predictable.
- (iii) More solar energy available in the
tropics.
8. 2.Species-area relationships
Alexander von Humboldt observed that
within a region species richness increased
with increasing explored area , but onlywith increasing explored area , but only
upto a limit.
10. Log S = log C + Z log A
where:-
S = species richness
Z = slope of the line (regression coefficient)Z = slope of the line (regression coefficient)
C = Y- intercept
- The value of Z lies in the range of 0.1 to 0.2
For very large areas like entire continent
slope of the line is much steeper .(Z = 0.6 to
1.2 )
11. Loss of Biodiversity
IUCN Red list 2004 documents the extinction of 784
species (338 vertebrates , 359 invertebrates , 87
plants.) in the last 500 years.
Some recent extinctions –Some recent extinctions –
Dodo ( Mauritius )
Quagga ( Africa )
Thylacine ( Australia )
Stellar’s sea cow ( Russia )
3 sub species of tiger ( Bali , Javan , Caspian )
12. Causes of Biodiversity losses
Habitat loss & fragmentation
When large habitats are broken up into small fragments due to
human activities mammals & birds requiring large territories and
animals with migratory habits are badly effected.
Over exploitation
Alien species invasionAlien species invasion
-Nile perch introduced into Lake Victoria in east Africa leads
to extinction of more than 200 species of cichlid fish in the
lake.
- Invasive weed species like carrot grass ( Parthenium ), Lantana
& Water hyacinth (Eicchornia )
- Illegal introduction of the African Cat Fish ( Clarias gariepinus
) for aquaculture purposes is posing threat to the indigenous cat
fishes in our rivers.
13. Biodiversity Conservation
Why should we conserve Biodiversity ?
Narrowly utilitarian arguments
economic benefits from nature-food , firewood , fiber , ,
construction material, industrial products & medicinal
products.
Broadly utilitarian argumentsBroadly utilitarian arguments
Ecosystem services like 20% 0f total oxygen is produced from
Amazon forests through photosynthesis ,pollination etc.
Ethical argument
Every species has an intrinsic value & we have a moral duty to
care for their well being and pass on them in good order to
future generations.
14. How do we conserve
Biodiversity ?
In situ conservation ( on site )
Hot spots Biodiversity regions with very high level of species
richness & high degree of endemism.
- There are total 34 hot spots in the world.
- Western Ghats & Sri Lanka , Indo-Burma and Himalaya cover
our country.
- Western Ghats & Sri Lanka , Indo-Burma and Himalaya cover
our country.
- India has 14 biosphere reserves , 90 national parks and 448
wild life sanctuaries.
Sacred groves
Tracts of forests are kept aside and all the trees & wildlife are
given total protection.Eg. Khasi and Jaintia hills in Meghalaya ,
Aravalli hills in Rajasthan etc.
15. Ex situ conservation
-Zoological parks , Botanical gardens , Wild
life safari parks.
-Gametes of threatened species are preserved-Gametes of threatened species are preserved
by cryopreservation techniques.
- Eggs can be fertilised invitro.
- Plants are propagated by tissue culture
techniques.
- Seeds can be kept for longer periods in Seed
banks.
