Biodiversity and conservation

 Biodiversity is defined as the totality of genes, species and ecosystems of a given region,

It is the variety and variability of life form (all animals, plants and microbes on earth) and the ecological complexes in which they occur. 

The term was first coined by Walter G. Rosen(1985),however the term was popularized by the American socio-biologist Edward Wilson(1988)

 BIODIVERSITY AND CONSERVATION

·       Biodiversity: the term biodiversity refers to the totality of genes, species, and ecosystems of a region.

·       Types of biodiversity described by Edward Wilson:

o    Genetic diversity: A single species might show high diversity at the genetic level over its distributional range.

§   Medicinal plant Rauwolfia vomitoria of Himalayan range produces active chemical reserpine shows genetic variation.

§   India has more than 50000 different strain of rice.

§   1000 varieties of mango.

·       Species diversity: different species of a single animal like frog.

·       Ecological diversity: diversity in the ecosystem level like desert, rain forest, mangroves, coral reef, wetlands, estuaries etc.

How many species are there on Earth and How many in India?

·       According to IUCN (2004), 1.5 million of plants and animals are in our biosphere.

·       Robert May places global species diversity at about 7 millions.

·       More than 70 percent of all the species recorded are animals.

·       All plants constitute about 22 percent.

·       Among animals insects constitute 70 percent.

·       India has only 2.4 percent of the world’s land area; its share of global species diversity is impressive 8.1 percent.

·       India is considered one of the mega diversity countries of the world.

Pattern of Biodiversity:

Latitudinal gradients:

·       Species diversity decreases as we move away from the equator towards the pole.

·       Tropic (23.5^o N to 23.5^o S) harbors more species than temperate and pole

·       The largely tropical Amazonian rain forest in South America has the greatest biodiversity on earth:

·       40,000 species of plants.

·       3000 species of fishes.

·       1300 of birds.

·       427 amphibians

·       378 reptiles

·       More than 1, 25,000 invertebrates.

Why tropical rain forest has greater biodiversity:

·    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.

·       Tropical environments. Unlike temperate ones, are less seasonal, relatively more constant and predictable, promotes niche specialization and lead to greater species diversity.

·       There is more solar energy available in the tropics, which contribute to higher productivity.

Species area relationship:

·       ALEXANDER VON HUMBOLDT observed within a region species richness increased with increasing explored area but only up to a limit.

       The relation between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola.

·       On a logarithmic scale the relationship is a straight line describe by the equation 

    LogS = logC +Z log A    Where S= species richness, A = Area, Z = slope of the line (regression coefficient), C = Y- intercept.

·       It has been noted that regardless of the taxonomic group or region the slope of the regression line are amazingly

   similar. However, for a very large area like the entire continent the slope of  the  line  is steeper.

Importance of species diversity to the Ecosystem:

·       Community with more species generally tends to be more stable than those with less species.

·       A stable community should not show too much variation in productivity from year to year; it must be resistant or resilient to occasional disturbances (natural or man-made)

·       Stable community must be resistant to invasion by alien species.

 David Tillman’s long-term field experiment finds that:

·    Plots with more species showed less year to year variation in biomass

·    Increased diversity contributed to higher productivity.

The rivet popper hypothesis:

·    In an airplane (ecosystem) all parts are joined together by thousands of rivets (species).

·   If every passenger starts popping a rivet to take home (species extinct), it may not affect flight safety initially but as more and more rivets are removed the plane becomes dangerously weak.

·     Further more which rivet is removed may also be critical.

·     Loss of rivets on the wings (key species) is obviously a more serious threat to flight safety than loss of a few rivets on the seats or windows inside the plane.

Loss of Biodiversity:

The IUCN Red List (2004) documents the extinction of 784 species.

·       Recent extinction includes:

·     Dodo (Mauritius).

·     Quake (Africa)

·     Thylacine (Australia)

·     Stiller’s cow (Russia)

·     Three subspecies of tiger (Bali, Java, Caspian).

·       Since the origin and diversification of life on earth there were five episodes of mass extinction of species.

·       The sixth mass Extinctions in progress now.

How the’ sixth Extinction’ is different from the previous five extinctions.

·       The current extinction rate is 100 to 1000 times faster.

·       All others are pre-human period, this one is anthropogenic.

Effect of biodiversity loss:

·       Decline in plant production.

·       Lowered resistance to environmental perturbations such as drought.

·       Increased variability in certain ecosystem processes such as plant productivity, water use, and pest and disease cycle.

Causes of biodiversity loss:

·       The present loss is all due to human activity (anthropogenic)

·       There are four major causes “The Evil Quartet” are as follows:

Habitat loss and fragmentation:

·       Most important cause driving animals and plants to extinct.

·       The tropical rain forest reduced to 6 % from 14 % of earth land surface.

·       The Amazonian rain forest is called as ‘lungs of the planet ‘is being cut cleared for cultivating soya beans.

·       Degradation of many habitat by pollution is also threatens the loss of diversity.

·       Large areas are broken into figments also the cause of diversity loss.

Over-exploitation:

·       When ‘need’ turns to ‘greed’ it leads to over-exploitation of natural resources.

·       Many species extinctions in the last 500 years (Stiller’s cow, passenger pigeons) were due to over- exploitation.

·       Many marine fish populations around the world are over harvested.

Alien species invasion:

·       The alien species became invasive and cause decline or extinction of indigenous species.

·       Nile perch introduced into Lake Victoria in east Africa led to extinction of 200 species of cichlid fish in the lake.

     ·       Parthenium, (carrot grass), Lantana, and water hyacinth (Eichornia) posed a thread to indigenous species.

     ·       African cat fish Clarias gariepinus for aquaculture purposed is posing a threat to indigenous catfishes in our rivers.

Co-extinction·: 

· When a species becomes extinct, the plant and animal species associated with it an obligatory way also become extinct.

·     When a species becomes extinct, the plant and animal species associated with it an obligatory way also become extinct.

 ·      Extinction of Host species leads to extinction of the parasite also.

·       Co-evolved plant-pollinator mutualism where extinction of one invariably lead to the extinction of the other.

BIODIVERSITY CONSERVATION:

Why should we conserve Biodiversity?

 Reason for conservation biodiversity is grouped into three categories.

 a. Narrowly utilitarian.

      b.  Broadly utilitarian

      c.  Ethical

      Narrowly utilitarian:

·       Human derive countless direct economic benefits from nature-

·       Food (cereals, pulses, fruits), firewood, fiber, construction material.

·       Industrial products (tannins, lubricants, dyes, resins, perfumes)

·       Products of medicinal importance.

·       Bioprospecting: exploring molecular genetic and species-level diversity for products of economic importance.

Broadly Utilitarian

·       Amazonian forest along produce 20% of oxygen during photosynthesis.

·       Pollinator layer: bees, bumblebees, birds and bat that pollinate the plant without which seed cannot be produced by plants.

·       Aesthetic pleasure we get from the biodiversity.

How do we conserve biodiversity? In situ conservation:

     ·       When we conserve and protect the whole ecosystem, its biodiversity at all level is protected – we save the entire forest to save the tiger. This approach is called in situ (on site) conservation.

     ·       Biodiversity hot spot: regions with very high levels of species richness and high degree of endemism.(species confined to that region and not found anywhere else)

·       Hot spot in biodiversity is also regions of accelerated habitat loss.

·       Out of 34 hot spot in the world, three hot spot located in India:

         a.  Western Ghats and Srilanka.

         b.  Indo-Burma.

         c.  Himalaya.

·       Other protected area under in situ conservations are:

         a.    18 biosphere reserve-The first Biosphere Reserve in India is the Nilgiri Biosphere Reserve .

         b.  103 national park-A national park is an area set aside by a national government to preserve the natural environment. A national park may be set aside for purposes of public recreation and enjoyment or because of its historical or scientific interest. 

          c.  543 wild life sanctuary-A wildlife sanctuary is an area where animal habitats and their surroundings are protected from any sort of disturbance. The capturing, killing and poaching of animals is strictly prohibited in these regions.

 ·       Sacred groves: tract of forest were set aside, and all the trees and wildlife within were venerated and given total protection.

Ex-situ conservation:

    threatened animals and plants are taken out from their natural habitat and placed in special setting where they can be protected and given special care.

·      Zoological Park.

·       Botanical garden

·       Wildlife safari.

·       Conservation of gamete by cryopreservation.

·       Genetic strains are preserved in seed bank. Convention on Biodiversity:

·       “The earth Summit” held in Rio de Jeneiro in 1992 called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilization of its benefits.

World Summit on Sustainable development held in 2002 in Johannesburg, South Africa, 190 countries pledged their commitment to achieve by 2010 a significant reduction in the current rate of biodiversity loss at global, regional and local level.

 

Light- Slide presentation

 this is slide presentation on Chapter-Light.

Forest- Our LIfeline

·      Forest is a natural habitat for different kinds of plants and animals. They provide food and shelter for animals.

    ·      Forest serve as green lungs and water purifying systems in nature.

    ·      Forest floor and trees were covered with creepers and climbers.

        Creeping plants or creepers are generally considered to be small, viny plants that grow close to the ground 

     Climbers are those plants which develop special organs of attachment by which they climb over some objects for the support of their body as their stems are not self-supporting and weak. likes Amarbel,Grapes, ornaments plant and pumpkin etc

    ·      The branchy part of a tree above the stem is known as Crown of the tree.

    ·      The branches of tall trees look like a roof over the other plants in the forest. This is called Canopy.

·      Trees had crowns of different types and sizes. These had created different horizontal layers in the forest. These are known as understorey.

·      Tall trees constitute the top layer followed by shrubs and tall grasses. Herbs formed the lowest layer.

     ·      All animals depend directly or indirectly on plants for food.

    ·      Organisms which feed on plants often get eaten by other organisms and so on. Such as-

       Grass🠆 Insect 🠆 Frog🠆S     🠆Snakes 🠆 Eagle 

·      Several food chains are found in the forest. All the food chains are linked together. Every part of the forest is dependent on the other parts.

·         A food chain refers to the order of events in an ecosystem, where one living organism eats another organism, and later that organism is consumed by another larger organism. The flow of nutrients and energy from one organism to another at different trophic levels forms a food chain.

     ·      The food chain consists of four major parts, namely:

a).Producers: The producers in a food chain include all green plants. 

b). herbivores are known as primary consumers and 

c). carnivores are secondary consumers.

Consumers: Consumers are all organisms that are dependent on plants or other organisms for food. 

d). Decomposers: Decomposers are organisms that get energy from dead or waste organic material. This is the last stage in a food chain.

 Decomposers complete a life cycle, as they provide nutrients to soil or oceans, that can be utilized by autotrophs or producers. Thus, starting a whole new food chain.

·      Several organisms and micro-organisms are present in the soil .They feed upon the dead plant and animal tissues and convert them into a dark coloured substance called as Humus.

·   The micro-organisms which convert the dead plants and animals into humus are known as Decomposers.

·    Nothing goes waste in a forest. Even the dead bodies are converted into humus which enriches the soil with nutrients, which are again absorbed by the living plants.

·      Forest are called green lungs because plants release oxygen through the process of photosynthesis .

Importances of Plants-

·      They also maintain the balance of oxygen and carbon -dioxide in the atmosphere.

·      Forest is a dynamic living entity ,full of life and vitality. It harbours variety of plants, providing greater opportunities for food and habitat for herbivores. Larger number of herbivores means increased availability of food for carnivores.

·   Forest acts as natural absorber of rainwater. It helps to maintain the water table throughout the year.

     ·      Forest reduces noise pollution.

     ·      Forests helps in bringing good rainfall.

     ·      They prevent soil erosion.

     ·      They are a source of medicinal plants, timber and many useful products.

     ·      In the absence of forest amount of carbon dioxide in the air will increase resulting in increase of earth’s temperature, soil will not hold water , which will cause floods, Animals will not get food and shelter.

      ·      Deforestation will endanger our life and environment.

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Forest- Our Life line-slide presentation

This is slide presentation on  CHAPTER – 17 Forest- Our Lifeline For Class -7

  

                                          food web

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Wind, Storms and Cyclones -Slide presentation