Biodiversity

Biodiversity on earth and India:-

• Total species present on earth = 20-50 million
• Global species diversity on earth =7 million (Robert May)
• According to Robert May = 22% of 7 million  species are discovered
•  discover Plant & Animal species  = more than 1.5 million
• Indian global diversity = 8.1 [ cover 2.4% Land  ]

• In India :- 
• 1) 45,000 Plant & 90,000 animal species discovered.
• 2) lakh Plant & 3 lakh Animal species yet to be discovered 
• Mega diversity country in world =12

Biodiversity on earth 

1).Animal                       

2). Plants

1)Animals (>70%) :-  A). Invertebrates & B).vertebrates 

A). Invertebrates 

1). Insect (>70%) Max 

2). Beetles (3 LAKH) species

3). Ants (20,000) species 

4). Other animal groups 

5). Mollusks

6). Crustacean

 B).vertebrates

1). Fishes (28,000) species 

2). Ave's

3).Reptiles

4).Amphibians

5).Mammals

2). Plants :-[orchids = 20,000 ] species 

1). Angiosperm (Max.)

2). Fungi

3). Algae

4). Mosses

5). Ferns & allies 

6). Lichens (mini.)

Note :- species  diversity of fungi is more than the combined total species  diversity of Fishes,Amphibians,Reptiles,Mammals.

**Prokaryotic  are  not estimated in global diversity because

* Are not suitable  for identifying microbial species.

* Many species are simply not culture under laboratory conditions.

* If we accept biochemical / molecular criteria  for delineating  species  for this groups then their diversity  alone might run into million .

Patterns of biodiversity

 Biodiversity in Amazonian rain forest

 

The largely tropical  Amazonian rain forest  in south america has greatest biodiversity on earth.

1). Invertebrates =1,25,000

2). Plants = > 40,000

3). Fishes = 3,000

4). Birds =1,300

5). Amphibians =427 

6). Mammals = 427

7). Reptiles = 378

Ques:- What is so special about tropics that might account for their greater biological diversity 

Ans:- 

A). SPECIFICATION ( new species formation ) = generally function of time 

B) . Relatively  remain undisturbed ,static, constant ,uniform environment for million of year

C).Due to this constancy nature, it provide /favor long evolutionary time essential for species diversification (or) speciation 

D) Tropical environment is less seasonal, more constant and predictable. so it promote 

* Greater species diversity

* Niche specialisation 

* Higher productivity due to availability  of more solar energy 

* High resource availability

* Less competition 

* Low rate of extinction 

E). Maximum annual rainfall 

      in turn ,higher productivity  indirectly contribute to greater diversity .

     

While in Temprates :-  frequent glaciations, more seasonal variation , non-uniform, and unpredictable environment leads less species diversity and no speciation 

 SPECIES - AREA RELATIONSHIP

 According to A.V. Humboldt 

" Within a region species - richness  increases with increasing explored area but only up to a limit.

              Relation between species richness and area 

Z=  Generally ranges between ( 0.1 - 0.2 )

Value of Z doesn't depend on taxonomic group of species and area .

[ कहीं  का कुछ भी हो हमेशा Z- value same रहेगी ]

 Ex. चाहें  ब्रिटेन  का Plant 

       चाहें  कैलिफोर्निया  की Bird 

       चाहें  न्यूयार्क का Molluscan

              

Above ex. are   Z-value same for all 

  But if this relationship is studied among very large 

(ex. entire continents, tropical rain forests ) then -

       

                 Z- value = 0.6 - 1.20

Ex.    Herbivores ( Fruit eating ) Bird  and Mammals in tropical forest of different continents then 

                   Z- value = 1.15 

Ques:- What do steeper  slope meant in this context  

Ans:- Steeper slope = increases Z-value = increases species  richness =  increases species diversity

The importance of species diversity in Ecosystem 

Rich biodiversity is essential for ecosystem health as well as imperative for the survival of human race on earth.

1. Long term ecosystem experiment (DAVID TILMAN)
2. Rivet- popper hypothesis ( PAUL EHRLICH )  
3. Loss of biodiversity according to ( IUCN Rule )
4. Example of recent extinction
5. Hot spot  
6. Effect of loos of biodiversity 
7.  Causes of biodiversity losses  
8. Biodiversity conservation { WHY } 
9. Biodiversity conservation { HOW }  
10. Susceptibility to extinction  
11. Special point  Some importance 
12. National park of India 
13. Some important sanctuaries of India 
14. Biosphere reserves 

1.Long term ecosystem experiment (DAVID TILMAN ) 

CONCLUSION :- Plots with  

• More species show less year to year variation in total biomass .
• Increasing diversity contributed to higher productivity .

 A stable community 

• Should not  show too much variation in  productivity form year to year 
• Must be either resistant / resilient to occasional disturbances [ Natural or man-made  ]
• Must be resistant  to invasions by Aliens species .

* Communities  with more species tend to be stable than those with less species 

                 2. Rivet- popper hypothesis ( PAUL EHRLICH ) 

• AIRPLANE = ECOSYSTEM 
• RIVETS = SPECIES 
• WINGS = KEY - SPECIES [ The drive major ecosystem function ]

*  Assume that, in an  airplane ( ecosystem )  all passenger in it starts pooping of Rivet (species ) causing every species to become extinct . It may not affect flight safety (Proper function of ecosystem ) initially.

• But as more and more rivets (species ) are removed from the airplane ( Ecosystem ) become dangerously weak with time .
• Further more , loss of rivets on wings is obviously a more serious threat to flight safety  than loss of a few rivets on the seats or window inside plane .

                 3. Loss of biodiversity according to ( IUCN Rule )

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